A masterpiece of fighter design, the Saab Draken was a sleek flying dagger designed for the defence of Sweden. Long before theMiG-29 made it world famous, the Draken was capable of the alarming Cobra Manoeuvre, in which the aircraft snaps its nose beyond a vertical attitude (without losing or gaining altitude). In this dynamic deceleration the entire aircraft acts like a giant airbrake forcing any pursuing fighter to instantly become the pursued. Bosse Engberg flew the majestic Saab Draken for the Swedish Air Force in the 1980s. Here he gives us the low-down on the sleekest of all European Cold War fighter aircraft.
Describe the Draken in three words
What was the best thing about the Draken?
The feeling of being one with the aircraft once you closed the canopy
…and the worst?
None (as I can remember)
What is the biggest myth about the aircraft?
I’d say it was the ‘Superstall’ – which was reality and not a myth. It could be used for the ”Cobra manoeuvre” during dogfights.
What was your first flight like?
We started off in the twin seat version (SAAB 35C). The first two flights were demo flights, seated in the backseat. Coming from the SK60 (SAAB 105) everything happened twice as fast but after a few flights you got used to the experience and had time to start enjoying it.
What was your most memorable experience flying the Draken?
As Sweden was a neutral country, placed between Nato and the Warsaw Pact we always practiced on our own. However, being based closed to the Baltic Sea, there were often things going on. My first experience happened when we were out as a two-ship, practicing low level dogfight over water. My leader (and instructor) was called and asked if we could perform at identification of an unknown low level object. He acknowledged and we were lead by radar towards the target, flying at 30 meters and speed M0.9+. Having less than 100 hours on the type and experiencing your first “mission” increased my pulse significantly. All of a sudden the object appeared – for my leader. I was concentrated following him but was not prepared when he fully extended the speedbrake and went to idle. I passed him and when looking forward I saw an Ilyushin Il-18, painted in Aeroflot livery, over water at 50 metres! Of course I passed that one too, with full speedbrake, idle and now even higher pulse. I realised I had to get in position behind him again so I made a climbing left turn. Stupid enough I crossed his flightpath, meaning “follow me”, and so he did! For a short while until someone else took command and turned back to the easterly heading they had before my manoeuvre. I got back behind my leader, this time with more suitable speed, and we informed the radar operator about type and registration. Running low on fuel we left him and returned to base. The older guys had some good laughs on my behalf at the debriefing. It would have been a good catch though, bringing home an Il-18 in my early career.
What was the role of the Draken and in which unit did you fly?
We were 99% fighters but with the capability to load and launch rockets at special occasions.
How would you rate it in the following categories”
A. Instantaneous turn rates
Quick to react, easily pull 9G
B. Sustained turn Speed decreasing quite rapidly (with high G load) since the shape of the wings produced a lot of drag
C. Climb rate Good but have nothing to compare.
D. General agility
A somewhat small and manoeuvrable fighter, quick responses and easy to fly – but you had to be cautious in low speed.
E. High angle of attack performance Unstable as the double delta shape quickly could throw you in to superstall. If I remember right, we had an α of 12-15˚ in the landing.
F. Off-base operations Sweden had a strategy of using normal roads as supplementary landing strips in case the runway at the base had been destroyed. Landings were practiced now and then, the first times an awkward feeling with high pine-trees standing close to the strip.
G. As a fighter
As it was the only role it was assigned for and I’ve only fired rockets a few times it’s hard to tell. It drank quite a lot of fuel in low level flight so any longer missions were not possible. So as an attack aircraft it was only considered as a last option.
We had an IR-sensor on the F2 version.
In terms of combat effectiveness and survivability?
This is quite hard to tell since the Draken never has been in combat for real. I know occasions that has taken place “for fun” over the Baltic sea with other countries fighters and performed well.
Cockpit layout and comfort?
Old fashioned layout, only analogue instrumentation. The comfort was good, you somehow “put the aircraft on you as a jacket” when you climbed down. It was tight, especially if you had your drysuit on. Then you had to perform some checklist items with your elbow. The chair was leaning at a comfortable 35˚.
What should I have asked you?
Was it hard to land? It was, in the beginning. Coming from a trainer with nose-down during approach the high AoA was a new experience. Rising the nose immediately required more thrust. Also the fact that you had to look somewhat sideways “around” the instrument panel to see the runway was initially an awkward feeling.
Did the aircraft have a nickname?
Not really but we all had our names and feelings for the Draken.
Which weapons did you deploy and which was the most spectacular from the cockpit?
I only had the chance to fire one Sidewinder (AIM-9B) and one Falcon (AIM-26B) during practice. We also practiced the ADEN cannon once a year. No particular sensation when firing the robots (missiles) just a short “swoosh” when they were fired. Firing the cannon was a different feeling since it was noisy and you saw the tracers.
Did you fly DACT?
We did not.
Do you love the aircraft?
But of course! It was love at first sight when I was 10 or 11 years old. To have the chance to fulfil the dream becoming a fighter pilot was extraordinary. Now living close to Swedens largest Draken museum is perfect, visiting once in a while to relive the specific smell.
What was unusual about Swedish air force tactics and culture?
As mentioned earlier, we could fly from roads in case of war being re-fuelled and re-armed on a small apron in the forest.
Bosse Engberg/lieutenant/F16 Uppsala (based two years at Tullinge, south of Stockholm/5 years flying Draken (version F1 & F2), in all 7 years in the airforce (1981-1988).
Interview with RAF C-130 Hercules pilot David Thombs
After 57 years of outstanding service in both K- and J-form, Britain’s Royal Air Force has taken the unpopular decision to retire the beloved C-130 tactical transport. Former RAF C-130 pilot, David Thombs, reveals the good, the bad and the ugly truth of the C-130.
“Wherever you find a war about to start there are always two aviation constants: the KC-135s will start appearing in strange places – and the world’s Hercules will start moving.”
VOLUME 2 is now fully funded and may be pre-ordered here.
Describe the C-130 in three words: Ubiquitous, adaptable and loud.
What is the best thing about the C-130? Wherever you find a war about to start there are always two aviation constants: the KC-135s will start appearing in strange places – and the world’s Hercules will start moving. Usually this will happen with a bunch of bodged on modifications, loads that aren’t yet cleared for carriage and or a stick of paratroopers that are out of currency. Above all, despite outwardly appearance, inside the thing it’s as noisy as hell, all Mks, no exception. Our Ground Engineers had to pass a Hercules GE Sim ride as part of their selection. It involved getting in a hammock in a cupboard under the stairs and switching the hoover on alongside. If you could sleep for six hours, you were in.
In which air arm did you fly and which unit? When?
Royal Air Force between 1989 and 2004. LXX Sqn ’93 to 99. Handling Sqn 99 to 2002 then 24 Sqn 2002 to 2004.
How are C-130 pilots different to fighter pilots? We were always described as ‘Aggressively below average’ by our small jet colleagues. That said you had to be good at:
A. Flying a big aircraft. Sound obvious but handling a C130, double asymmetric in a cross wind requires good hand eye coordination. Dropping people and stores at 1.1 vs at FL250 whilst depressurised could focus your mind somewhat too.
B. Crew management. It’d a team effort. Some of the best Captains never touched the controls. When things get tough, let your mate in the right-hand seat keep things the right way up whilst you do the big picture stuff.
C. We didn’t argue the toss over who was the greatest at the end of every trip. No need, we knew it wasn’t us.
Low speed handling. You could do a wing over in a Scottish glen in the thing if the weather closed in. Super stable at 1.25vs (Tac VaT and usual drop speed) and superb acceleration away if you needed it.
Low-speed handling. Stalling was bad. Power on there would be no buffet just a huge increase in rate of descent, later models suffered bad wing drop leading to complicated stick pusher/shaker systems being used. Don’t whatever you do apply the rudder in the wrong direction when asymmetric. You can build up and aerodynamic spring type force that when corrected caused a USAF aircraft to go in backwards. Losing speed. Residual thrust, especially from the Rolls-Royce engines on the J was high. No airbrakes meant losing speed on approach was difficult which is very unusual for a big turboprop.
C-130 Mk1/3 assessment
A. Pitch and yaw were great but the ailerons were too small. Tac landing speeds had to be raised because of this. Issues behind a VC10 with roll control from tip vortices. Elevator and rudder were powerful enough to overstress the aircraft at most speeds. At low speed the rudder was the primary lateral control with the ailerons used solely to keep the wings level. Surprising good at turning but never roll and pull at the same time as it stresses the ‘armpits’. Doesn’t mean you can’t roll then pull to 2.5G though.
B. Take off run. At light weights it could be quite startling how quickly it could get to rotate. At higher weights and in hot weather and at altitude it suffered like everyone else. Good on grass, sand, ice and snow.
Hmmmm. If it needed to get airborne most things were doable without or fixable. Usually not entirely in compliance with the AMM. The GTC could be started with a broom and a match, the battery busbar could be connected to the main using the grounding lead and crocodile clips whilst in flight. The engines could be slipstream started or windmill started by charging down the runway. But they were old and things broke occasionally. Usually in Nellis.
‘A face only a mother could love’ according to a Lockheed advert in Flight Magazine. Hard to argue.
E. As a tactical transport
As a tactical transport it initially suffered from ‘bulking out’ issues as really weight of a load wasn’t an issue. Hence the stretched Mk3 that addressed this but caused tail clearance issues later down the line on strips. Station Keeping Equipment allowed formations of up to 20 aircraft (that’s all we had with it) to maintain formation integrity when IMC, even up to release. HAVEQUICK etc allowed us to talk to anyone. Defensive aids became more and more effective as the aircraft aged and peaked with the C130Js. NVGs were used for airfield assaults and even 15’ heavy drops. I once played golf with a chap who tested the pilot retrieval system in the USA. Possibly a step too far….but they were successfully employed catching rolls of film dropped by satellites.
F. As a para platform
All things considered; I think it was the best para platform out there. Yes, the C-17 is bigger and faster but only carries a couple more troops. No idea about the A400 only that it has initial slipstream issues. OC 1 PARA once told me that he preferred the Dakota as if I managed to crash one he would only lose a few men rather than 80 odd, but some people are just strange. You could drop people from upwards of 25,000’ down to 300’ if they were brave. HALO, HAHO and the Canadian Tube all used in anger around the world.
The Canadian Tube was a large wooden tube full of stores with a drag chute to slow it to human terminal velocity. It was chucked out the back followed by some enthusiasts that were either attached to it or steered it with fancy gloves. Usually went out in the 20,000’ bracket with an opening height of around 1000’ to avoid anyone hearing the crack of the parachutes. Sometimes as low as 400’ if needed. Through cloud and at night. Hypoxia always a worry amongst everything else. Brave people
Aid work Perfect platform, no requirement for a prepared operating base or a need for a runway near the area in distress, just chuck the stuff out the back. Interesting piece of work done by the Belgiums on aid dropping. In Kenya the RAF gleefully dropped grain etc from 50’ watching it bounce and explode its way down the DZ. The Belgiums slowed right down and dropped it from 1000’. The bags soon lost their free air forward throw and hit the ground largely vertically and amazingly remained intact, presumably much to the relief of the people trying to pick them up. Aid work can be messy, any aircraft that you can hose down both inside and out at the end of the day is a winner.
H. Cockpit comfort
Biggest and best seats in aviation. Plus two beds on the flight deck. Difficulty was, staying awake.
I. Pleasantness of long flights
As above. Comfy but slow and noisy. Toilets terrible if even fitted. Great view of the world. Food usually great from Lyneham or from hotels. Just sit back, close your eyes and imagine a party heading towards you at 0.42M.
J. Ease of refuelling
AAR was difficult. Behind the VC10 we lacked speed and the engines would often become temp limited forcing a ‘toboggan’ descent to give the C-130 some overtake. Roll behind the 10 was a bad thing because of the vortices from its wingtips requiring left and right to be carried out using your feet. The slow speed basket was even worse, the VC10 would put out slats, aileron upset would activate and the thing would try and shake poor old Albert to pieces. Lost two HF aerials doing that.
What is the biggest myth about the C-130? You can put the engines into reverse in flight. Best not to really.
Tell me something I don’t know about the C-130
They float very well. A Columbian C-130 ran out of fuel and ditched. It was subsequently towed toward harbour but never quite made it.
My most memorable flight
So this is a long story. Back in the day, the House of Commons Armed Forces Select Committee would spend a couple of days on a Jolly Boys outing around the MoD. Back in ’96 it was RAF Lyneham’s turn to provide the entertainment and, perhaps unwisely, the Station Commander asked the mighty LXX Sqn to do the honours. At this point it should be pointed out that whilst no one was actually hurt during the day we all needed a long sit-down afterwards.
The day started early. The MPs and associated minders (none below the rank of Air Cdre for heaven’s sake) were awaiting us at Lossiemouth after a day of fact finding and a night on the raz. We launched as a 3-ship from Lyneham using SKE to get us above the weather before settling down to a late breakfast during the transit up north. A gentleman’s arrival over the fast jet community ensued followed by a nice lunch in the Mess. All was good.
Post-lunch, the MPs boarded. I got Nicholas Soames amongst others. Off we set, down the Great Glen at 250’ to a chorus of disapproval and associated vomit as it was a little bumpy. Un-deterred we pulled out of low-level and went in search of a VC10 that we’d booked over the Irish Sea. Sure enough, it was there, heading the wrong way and not showing any signs of slowing down for us. The leader asked him to perform a couple of S turns to help us out. This is where things started to go awry. Whilst myself and number 3 cut the corners to catch the 10, the leader just followed his ground track which went we met, rather unbriefed at the same altitude in the same place. Much to everyone’s amusement. Recovering our dignity, we tanked from the 10 before gratefully seeing it push off back to Brize to leave us on our way.
Once again we failed to learn from our errors. Back into low level at Llandudno looking for the A5 pass had our guests again regretting their 4th Merlot earlier. Back up to medium level for a brief tour of Wales then on the way to Pendine Sands. Now I know that landing on a beach is all the rage now but it wasn’t then. People had concerns about the tides, markers and the unexpectedly large crowd that had gathered where Babs met its fate, hopefully not in expectation of similar excitement. Luckily nothing really went wrong and we soon had 3 C-130s taxiing around on the beach looking nervously at the tide and wondering whether we’d actually done enough research into sand based acceleration performance given the rate of deceleration we had experienced. Still we got airborne and I slung in a swift 60° AoB departure as I knew my Uncle Bernard was in the crowd.
Down the Bristol Channel we went and back to 250’ on the run in to the Salisbury Plain Training Area. We were full of two Medium Stressed Platforms each, around 30,000 lbs in weight. We kept things gentle as the loads were unrestrained and ran into Keevil DZ for a nice elegant drop. Subsequent recovery to Lyneham was reasonably uneventful although we appeared to have, once again, attracted a largish crowd of what we hoped were well-wishers.
That wasn’t really the case. Dear old 101 Sqn had raised a couple of issues (as had the chap in charge of DERA Pendine). My Uncle Bernard seemed happy but it turned out he was in somewhat of a minority. Determined to limit the damage the MPs and high paid help retired to the bar. Didn’t end well as it turned out. People had been drinking in there for a while.
Flying on NVGs was interesting as the early aircraft were not designed or modified effectively for it. Drop heights down to 15’ were common. High altitude parachuting, IMC formation flying and AAR (both giving and receiving) were day-to-day events. When combined with a requirement for every crew to be current at all times in worldwide route operations it was quite a thing to keep on top of it all.
Of its rivals which comes closest and which is the worst? C-17 can drop a load heavier than a C-130 max landing weight from a speed below the C130 stall speed. Truly excellent thing. The Transall was a horror show as was some of the stuff Antonov produced.
The Transall was just so slow. I only ever overtook three aircraft in an airway, a Mk3 C130 when I was in a Mk5, a Transall and a Dakota. Very strange flat flightdeck where only the pilots appear to be able to see out. The French scared me to pieces in one at low level leading an RAF C-130. As the weather closed in they slowed right down which was impressive as flat out the thing only managed 180kts then started circling. Our aircraft behind got a face full of Transall before pulling out into the cloud. Something to do with the lack of low level Air Traffic Control in France apparently.
The An-12 literally fell to pieces in my hands. We had agreed a slightly illegal co-pilot swop the night before in Ancona during the Sarajevo airlift which I started to regret when I was told to always wear a hat to avoid getting hydraulic fluid in my hair. Next was setting the millibar setting on the peculiar altimeter with a screwdriver as the knob was by now somewhere in amongst the control runs under the seat. Still, the chaps seemed unconcerned, the food was great and apparently there was absolutely no requirement to flare the thing, it kind of just gave up flying and belly flopped down. That said, it was better than the Transall, felt like it was made out of concrete.
Your opinions on the RAF’s C-130 retirement and the A400M? The German AF is still buying C-130s and we are selling ours, read into that what you will. There are a lot of customers for ours as well. Ask yourself why there are so few in museums or guarding gates. The A400 is expensive and has a long way to go. Let’s give it the benefit of the doubt for now.
What kit should have been added to the C-130? Airbrakes please. JATO rockets. That cruise missile dispenser built by Lockheed. Bigger ailerons and a decent toilet. Perfect otherwise.
Some crazy things that the C-130 did?
Have a quick look at NVG TALO, SKE, Khe Sanh and all that kind of stuff that only the C-130 ever really did. ULLA was pretty scary at night as were the night clubs in Gander and Goose along with the bar staff at the Akrotiri Arms.
Too loud, too fast and too thirsty for mainstream acceptance, Britain’s VC10 was the Keith Moon of jetliners. Both Moon and the VC10 thundered onto the world’s stage in 1964; one was the best jetliner of its time, the other was The Who’s wild-man, the most influential drummer of his generation. While Keith Moon was frequently ‘hijacked’ by substance abuse, the VC10 suffered a disproportionate number of actual hijackings and other acts of violent freakish misfortunate. In getting to the bottom of this incredible story, I enlisted the help of an aerodynamicist, an aeronautical engineer, a professor of flying noise, an oil-rig worker – as well as a leading comedian/historian/percussionist. Oh, and a former Sea Harrier pilot for good luck.
Talking about my s-s-second generation jetliner…let’s find out why the VC10 was the Keith Moon of jetliners.
10. The Who versus ‘The Wey’: A need for speed
The VC10 was born close to Weybridge in Surrey, England at Brooklands. This was the centre of British speed, both motor racing and aircraft production. Brooklands was where the Hurricane took its first flight, and was instrumental in the creation of the declinist poster-boy, the cancelled TSR.2 bomber. Keith Moon was a centre of speed in his own right in both his drumming and drug of choice, in an interview he described his favourite food as ‘French Blues’ a slang term for Dexamyl amphetamines. Moon was born in Wembley, one time home of the Aircraft Operating Company.
The VC10 was one of the fastest airliner this side of Concorde and the Tu-144. Its never exceed speed was a spritely Mach 0.94. There is a story of a medical emergency onboard a VC10 en route from South Africa being addressed with a FL430 flight at a hair-singeing Mach 0.95. This would have even given Elvis’ speedy Convair a run for it money.
While the American Boeing airliners were getting progressively slower by generation, British airliners were getting faster.
Whereas the 707, in the guise of the E-3, often wore a ‘high-hat’, it was something Keith (and the VC10) would avoid like the plague. We asked historian and drummer Al Murray his thoughts:“Moon eschewed conventional technique it’s fair to say, as best recorded in Mono so that it sounded like one great big drum kit. As studios became more complex he got harder to get down on record. He used no hi hat, (until really late in his career) which is really odd; his style is best described as “lead drummer”.
The VC10 was considered for every conceivable military role including airborne early warning, but not with a large dish on the top but a big ‘bollock’ at the front and one at the back. According to Chris Gibson, author of Nimrod’s Genesis: RAF Maritime Patrol Projects and Weapons Since 1945, “A rotodome for a VC10 is a stupid idea and never looked at. The single bollock was the original alternative to the Fore Aft Scanner System (FASS).”
Although much touted as offering a quiet passenger experience, outside the aircraft it was a very different story. According to aircraft noise expert Prof. Michael Carley “Noise from VC10, according to then head of powerplant at Rolls Royce, was about 115EPNBb. Supposedly The Who were measured at 126dB 32m from the speaker, so I’d say they were about the same. The VC10 was about as loud as The Who. A 737 is about as loud as what you hear using a lawnmower. Somehow, it seems like what we deserve (A VC10 is cooler than one of Ryanair’s 737). It’s like a souped up Lambretta versus e-bike.”
(the British aircraft are manufacturer’s estimates and likely to be generously under the real figure)
7. Peaky blinder
We’re going to go a bit hardcore technical in this entry so if you haven’t had your coffee yet, feel free to scroll to number 6.
Over to aerodynamicist Stephen McParlin, “The VC10 was a significant milestone towards the early Airbus wings (although a Weybridge, rather than Hatfield design, RAE and NPL were providing much of the technology underpinnings for the aerodynamics). It’s recognisably a sonic rooftop design* for cruise, and these are usually pretty robust, in terms of their buffet margins when shocks eventually form. I think there’s something more important though. The earlier jet transports had high lift systems as an afterthought. Long runways were very much an operational paradigm for the B707 and DC-8, particularly with earlier engines. The VC10 was designed around a better balance between field length and cruise performance. This is important, because a better high lift system enables a smaller wing, and higher wing loading at cruise, hence better cruise Lift/Drag… This eventually became important for the next generation economics, when the A300B4 took on the US wide body trijets, and demonstrated superior economics, doing the same job with only two engines.
The VC10 wing design was a development that benefited extensively from work done by Kuechemann and Weber at RAE, and by Pearcey and others, including Robin Lock, at NPL. It was a fully 3D design, intended to have a near-sonic rooftop pressure distribution at cruise Mach numbers, with slightly higher Mach numbers in the leading edge suction peak. The numerical methods used (essentially the Inverse Weber method) were limited to purely subsonic Mach numbers normal to the wing isobars, although the locally supersonic peaks were an empirical add-on. There’s a great RAeS historical paper by Steve Liddle, describing an earlier form of the technology as applied to V-bombers… and review papers from 1961 and 1964 by John Bagley and Robin Lock respectively, in PiAS, covering design methods for swept wings.”
The VC10 was a significant milestone towards the early Airbus wings (although a Weybridge, rather than Hatfield design, RAE and NPL were providing much of the technology underpinnings for the aerodynamics). It’s recognisably a sonic rooftop design for cruise, and these are usually pretty robust, in terms of their buffet margins when shocks eventually form. I think there’s something more important though. The earlier jet transports had high lift systems as an afterthought. Long runways were very much an operational paradigm for the B707 and DC-8, particularly with earlier engines. The VC10 was designed around a better balance between field length and cruise performance. This is important, because a better high lift system enables a smaller wing, and higher wing loading at cruise, hence better cruise L/D. This eventually became important for the next generation economics, when the A300B4 took on the US wide body trijets, and demonstrated superior economics, doing the same job with only two engines.
*What is a sonic rooftop design? Ok, this gets into transonic aerodynamics. The ‘rooftop’ is that part of the design pressure distribution on the wing upper surface, from just aft of the leading edge peak suction (hence ‘peaky’) to a location further aft, where the pressure has to recover to something reasonably close to stagnation pressure at the trailing edge. The local Mach number at the rooftop is important. If it exceeds unity, you eventually have to deal with supersonic effects, including shock waves, and their adverse impact on drag, buffet boundaries and control effectiveness. A sonic rooftop design is one where the local Mach number in the rooftop is *just* subsonic, hence no shocks. Until 1968, when Murman & Cole cracked the problem in an early CFD method, mixed subsonic/supersonic flows weren’t amenable to numerical analysis, hence this was a technological limit on design. Until then, Weber’s compressibility rule was one of the best for designing right up to the limits of subsonic flow. A key difference between the VC10 and A300B4 wing was the level of rooftop suction allowable… and the A310 took that further, with the availability from RAE of transonic CFD methods that could handle both weak shocks and boundary layer effects. This was stretched even further by the A320, which was very much a joint effort between Des Treadgold at RAE and Jack Wedderspoon at Weybridge, for which both organisations received Queen’s Awards for technology.
6. POWER and GRACE
Modern airline engines are too big to be put at the back, but this wasn’t the case in the VC10’s time. According to McParlin, “The rear-mounted Conways were touted as reducing cabin noise, but the Conways suffered from being an early turbofan, and having a lower bypass ratio than later engines. These days, having engines in close proximity is considered a potential hazard for common mode failures, with uncontained failure in one engine potentially causing failure in the adjacent engine. There are issues around rear-mounted engines requiring heavier structure in both wings and fuselage, a consequence of losing bending relief in the wings, and having to beef up the fuselage structure to cope with the aft mounting of both wing and engines. However, post-Comet U.K. aircraft structures were detail designed to avoid crack propagation to a paranoid degree. The BAC 111 is probably the classic example of a structure where no details were left to chance when it came to fatigue, or stress corrosion. How these compared with the traditional conservatism and legendary damage-tolerance of Boeing structures is open to debate. The Aloha 737 incident showed what Boeing structures were capable of surviving. Thankfully, we’ll never know if a BAC 111 would have developed those cracks in the first place.
Joe Wilding notes, “The rear engine layout also came from the rough-field requirement as it provided for shorter landing gear that could be made lighter while withstanding the heavier loads. -Of course the rear mounted engines have their own drawbacks due to uncontained rotor burst, and maintenance accessibility. But overall, it resulted in a high performance aircraft for both takeoff and cruise speed. This is hard to achieve on a high-speed aircraft. The VC10 has a thrust/weight ratio roughly 20% higher than the 707 and DC-8. which probably explains even more of the takeoff performance. The Conway turbofan engine helped with this as it has a 10% better thrust/weight ratio than the original JT3C engines on the 707 and DC-8. (Later models of each of these aircraft also used the Conway. Of course the rear mounted engines have their own drawbacks due to uncontained rotor burst, and maintenance accessibility. But overall, it resulted in a high performance aircraft for both takeoff and cruise speed. This is hard to achieve on a high-speed aircraft.” It is not known the thrust/weight ratio of Moon, but he was likely the highest of The Who.
The take-off distance was up to 15% shorter than the 707 or DC-8, despite the VC10’s smaller wing. Similarly, Moon’s power was not dumb and indiscriminate but applied with great intelligence, according to Al Murray, “There’s the great story about Elvin Jones setting himself up as a drum teacher when he was in town. Everyone in London goes for a lesson. Moon turns up, Jones says ‘Ok show we what you can do’ and Moon does his thing – and Jones sits in astonishment at the whirling dervish before him. He asks Moon how much he earns, and terminates the lesson on the grounds that there’s nothing he can teach him.”
It’s one thing living a chaotic life of vandalism and wild sex, but bringing the actual apocalypse is clearly another level of carnage. Wisely, there were never plans to arm Keith Moon with up to eight Skybolt nuclear missiles.
4. Johanna Weber
Like Keith Moon, a woman was vital for the creation of the VC10 – over to historian Dr Nina Baker, “Dr Johanna Weber, was one of the foremost aerodynamicists of her generation”. Talking about her g-g-generation.
Born in Düsseldorf, Weber recieved teacher training but was barred from actually becoming a teacher as she bravely refused to join the Nazi party. Rather oddly, this did not apparently bar her from work in armaments. She first did ballistics research for the Krupp company in Essen and later moved to Göttingen’s Aerodynamics Research Institute (Aerodynamische Versuchsanstalt Göttingen) in 1939. This started her career-long work with aerodynamicist Dietrich ‘carrot’ Küchemann in Germany and later in Britain. “
At the end of the War, the British Royal Aircraft Establishment (RAE) recruited Küchemann and Weber, probably on the recommendation of Hilda Lyon who wrote the report covering their work. Her initial work at RAE was in Frances Bradfield’s Low Speed Wind Tunnels division, on air intake cowlings for jet engines, on which she co-authored a series of papers. The work for which she is more remembered today was on wing design, showing that a thin delta wing could generate sufficient lift to for take-off and landing for supersonic planes. Her concepts were implemented in the Concorde, VC10 airliner and Airbus A300B designs. She retired from the RAE in 1975 at the grade of Senior Principal Scientific Officer.”
3. Trashing & helicopter raids & hijackings A Quick One, While He’s Away
Keith Moon loved to trash a hotel room, much in the same way Israeli commandos loved to trash Lebanese airliners. In a widely condemned action, Israeli commandos stormed Beirut International Airport (arriving in 3 Israeli Air Force Super Frelon helicopters) and blew up 14 airliners, including one VC10, on 28 December 1968. In a similarly unexpected helicopter landing, Keith Moon landed on other famous piss-head Oliver Reed’s property. Oliver Reed had better air defences than Beirut Airport (a 12-gauge shotgun) but fortunately failed to shoot down Moon’s chopper.
On 20 November 1969, Nigeria Airways Flight 825 crashed on landing at Lagos, Nigeria killing all 87 onboard. This was the worst day in the VC10’s career but far from the only incident. On 9 September 1970, BOAC G-ASGN was hijacked, and blown up three days later at Zarqa, Jordan, in the Dawson’s Field hijackings. In another horrific accident, East African Airways Flight 720 5X-UVA crashed on take-off from Addis Ababa, Ethiopia, killing 43. On 3 March 1974, BOAC G-ASGO was hijacked and landed at Schiphol in the Netherlands. The aircraft was set on fire and fucked beyond economic repair.
Considering only 54 VC10s were built you’d thinking statistically its curse would have ended there, but on 21 November 1974, British Airways Flight 870 from Dubai to Heathrow was hijacked in Dubai. It refuelled at Tripoli before flying on to Tunis. Utterly badass Captain Jim Futcher had returned to fly the aircraft knowing the hijackers were on board. The three hijackers demanded the release of Palestinian prisoners in Egypt and the Netherlands. One hostage was killed, before the hijackers surrendered to Tunisian authorities on 25 November.
Whereas to 1960s’ eyes, fun and charisma of led many to turn a blind eye to toxic behaviour, today a more nuanced view can see the damage these great thunderous masterpieces left in their wake. Moon’s abuse of his ex-partner, and the VC10’s of the environment don’t seem so charming now. Different times. A prime example of the guilt of enjoying these smoky days can be smelt in the somewhat creepy hatred that some reactionary commentators express for the young environmental activist Greta Thunberg. A generous assessment of the VC10 would note its stellar aerodynamics and pioneering turbofan were a big step forward towards more efficient airliners, likewise separating Moon’s fabulous art from his personal life is possible.
1. Tankenstein’s Monster
Moon visited his enabling pal Oliver Reed for Reed’s 40th birthday party. During the celebrations, Moon performed an improvised helicopter impression by leaping from the dining table and grabbing the rotating blades of an overhead fan. As he spun he spattered the guests with blood from his gashed hands. At this point, even Reed wondered if Moon may be drinking a little too much. Both Moon and the VC10 loved drinking – and sharing it. When we asked former Sea Harrier pilot Paul Tremelling his thoughts on tanking from the VC10, he described it “Easiest of the lot! The Herc and Transall were way too slow. The Tristar on the centreline had few useful references. Same with buddy tank off Super Hornet. The KC-10 was OK but similar to Tristar.”
When the RAF pressed ex-airline VC10s into service as air-to-air refuelling tankers they had made a very good decision, the aircraft proved extremely well suited to the task. Chris Gibson, in his top 12 tanker aircraft, noted “By the mid-1970s Britain’s defence posture had pretty much settled down after the long retreat from Empire to focus on northwest Europe and the eastern North Atlantic. The GIUK gap was seen as a crucial theatre (like Cats or The Mousetrap) and the interdiction of NATO convoys by Soviet forces was viewed as a major threat. With Buccaneers to take out the surface threats and the new Tornado ADV to tackle Soviet air assets, there was a need to increase the RAF’s tanker force from the twenty-odd Victors then in service. Luckily, British Airways was dispensing with its VC10 fleet and, if a few more were acquired from airlines in east Africa, a couple of squadrons could be put together. So, the Air Staff got their tankers and the MoD saved money. It was trebles all round in Whitehall.”
McParlin: “The biggest issue for outboard receivers is part-span vortex shedding in the wake <essentially this means messy air makes air-to-air refuelling even more difficult>. VC10s would have very clean near- and mid-distance wake roll-up <again meaning nice predictable air>. The jet efflux would also be clear of both the outboard receiver and large aircraft using the centreline HDU. Probably a more benign case than the A330 or Tristar. Least said about the KC-135 for probe-and-drogue receivers, the better.”
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If you want to fuck up a railway network faster than even privatisation, then you need a Thunderbolt. If you value your life over glamour, then forget all other fighter aircraft. If you wanted to survive the bloody skies of World War Two, you needed to be in the cockpit of the gargantuan Republic P-47 Thunderbolt.
As aerospace engineer Joe Wilding noted, “The top-10 Thunderbolt aces all survived the war. This is a statistic, not shared by any other aircraft in World War 2”. That alone should be enough to give it bragging rights as the king, but there are myriad other reasons to choose the ‘Jug’. More were built than any other American fighter, and it proved itself again and again in every conceivable fighter-bomber role. It was far tougher and longer-ranged than the Spitfire. It had more firepower than the Mustang and carried 65% more ammunition. Whereas most fighter aircraft wheezed and flailed around at higher altitudes, the P-47 could take on the best the enemy had at 30,000 feet with a decisive advantage.
If Streetfighter II is a useful cultural reference for you, the P-47 was a perfect all-rounder like Ryu. Other fighters, like the Spitfire were more specialised – with greater Achilles’ heels – much like Menat.
In terms of American writers, it was the thuggish shotgun-wielding Ernest Hemingway, as opposed to the elegant but rather more fragile Mustang (which was clearly analogous to Truman Capote). Both Hemingway and the P-47’s primogenitor, the Seversky SEV-3, were present in the Spanish Civil War.
As an aside, in Spain Hemingway drank with Frank Glasgow Tinker, the first pilot to shoot down a Bf 109 (Tinker was not in a SEV-3 for this fight though, but a Polikarpov I-16).
You might prefer Capote as a dinner party guest, but you’d want Hemingway in your corner in a bar brawl. From the Battle of the Bulge to every other rough fight, the Jug was there and winning.
Notably the P-47 was the mount for the remarkable 1oGAVCA, the First Fighter Squadron of the Brazilian Expeditionary Force. This was the elite unit of the XXII Tactical Air Command in Italy. Although it flew a mere 5% of the total of missions carried out by all squadrons under its control it achieved the following percentages of targets destroyed: 85% of ammunition depots, 36% of fuel depots, 28% of bridges (19% damaged), 15% of motor vehicles (13% damaged). Oh, and 10% of horse-drawn vehicles*.
(info source: Ibidem Maximiano, Bonalume, Ricardo N. & Bujeiro, 2011)
The standard Luftwaffe tactic of diving away from attacks from above was suicide against the king of the divers, the P-47. Ideally for an escort fighter, the P-47 was in its element at height. Thanks to its game-changing turbo supercharger, it was more than a match for German fighter aircraft above 30,000 feet. Other than climb and acceleration, it was far superior to the Bf 109G and Fw 190A in every metric at altitudes between 25,000 and 30,000 feet. The P-47’s manoeuvrability and roll rate were far less hampered at high speed and high altitude than other fighters. If you were high you stayed well away from the P-47.
From 1942-1945, the Eighth & Ninth Air Forces alone destroyed 6284 enemy aircraft (in the air and on the ground) with the P-47, a massive blow to Axis air power. The P-47 was categorically a war-changing weapon. Its biggest asset was its survivability, which meant the most important weapon the air force had, experienced pilots, were kept alive.
In the Close Air Support role, the P-47’s fought in co-ordination with light spotter aircraft and airman embedded with ground forces. The results were spectacular. Other fighters only paid lip-service to an air-to-ground weapons, the P-47s bristled with eight .50 cals, rockets and bombs.
The P-47N was the most potent Allied fighter of the War, and if further evidence of Republic’s supremacy is needed that Republic was at the cutting edge of piston-engined technology, then let us bring in Exhibit B, the astonishing XF-12 Rainbow. The Rainbow was the most sophisticated and capable piston-engined warplane ever built.
The P-47 was also the best exemplar of the US approach to engineering – and was there at the birth of US mass production dominance. As a machine, the P-51 was too small and too British to typify the American approach, the P-40 too primitive, and the P-38 too weird. Only the P-47 highlights the real American approach of creating things that are absurdly big, powerful and milking the hell out of one world-beating technology (in this case the turbosupercharger) – and then making thousands of them! This is the skyscraper, the Cadillac, or the .50 cal of aeronautical engineering. This is the US fighter aircraft of World War II.
For those of us more versed in modern fighters it is unavoidable to look for a modern day equivalent. The A-10, the final Republic aircraft, shares its sturdy construction but is fair too slow and vulnerable to fast fighters to be seriously deserving of the name Thunderbolt II. As a versatile single-engined aircraft built in huge numbers it would be tempting to compare it to the F-16, but that is a modern P-51. As a heavyweight all-rounder you could it see it as the F-15E of its time. But as a massive single-engined fighter-bomber, the F-35 Lightning II, may well become a more appropriate analogue. Time will tell. Like the F-35, it would be easy to knock the Thunderbolt for its unit cost, but this needs to be weighed against a combat aircraft’s chance of making it home; when this is factored in the P-47’s ‘greater’ cost doesn’t look so bad at all.
The Thunderbolt was there when it was needed and could do anything you asked it to do, and what more can you ask? And just listen to the thing dive…talk about fine Georgian whine.
Only one days to go and only on 82%! This is a real nail-biter
The Jug spilleth over: the manifold relatives of the P-47 Thunderbolt
If asked to name an American fighter of WWII chances are most people would say “why the hell are you asking me that?” but anyone with a passing interest in aviation would probably pick the P-51 Mustang, much to the chagrin of P-47 fans.
The Thunderbolt is very much the American Hawker Hurricane, a rugged, versatile and extremely important aircraft overlooked due to its sexier stablemate. Unlike the dowdy Hurricane’s relationship with the Spitfire however, the P-47 was arguably a better fighter than the Mustang, variations on the P-47 theme ended up proving faster and longer-ranged than their slender P-51 rival and it was always the more versatile design. The antecedents of the Thunderbolt had also been around since the dawn of the ‘modern’ stressed-skin monoplane age and the beginning of the Thunderbolt story starts in a very unexpected place, both conceptually and geographically, its development required two completely separate companies and it nearly joined the jet revolution. Join us as we take a look at the eclectic and somewhat confusing realm of the Thunderbolt Family:
The Thunderbolt came into being due to the work of two designers, Alexander Nikolaievich Prokofiev de Seversky and Aleksandre Kartvelishvili, known as Alexander Kartveli, both Georgian emigres, thus making the P-47 the most famous Georgian aircraft design in history. The dapper one-legged air-ace de Seversky (he shot down at least 7 aircraft during WWI making him the top ranking naval ace of Imperial Russia) had been selected in early 1918 as assistant naval attaché in the Russian Naval Aviation Mission to the United States and opted to stay in the US whilst Russia was torn apart by civil war. A talented engineer, Seversky became rich from the sale of the world’s first gyroscopically stabilised bombsight and set up the Seversky Aircraft Corporation in 1931 with Kartveli (possessed of two legs), who had spent time during the 1920s working for Bernard and Bleriot in France, as chief designer.
The first product of the new company was the Seversky SEV-3 of which around 35 were built. Despite being a three seat amphibian, this aircraft was the direct ancestor of the Thunderbolt. As may be seen, the SEV-3 possessed the elegant semi-elliptical wing that would find its way largely unchanged into the P-47 and it was an advanced, stressed-skin radial engine monoplane with a distinctly chunky aesthetic that would be carried over into all the fighter designs produced in the immediate future by Seversky and Republic.
The SEV-3 was a fascinating aircraft. In amphibian form, main wheels were housed in the floats but to allow the aircraft to alight on land, the floats had to tip nose down to allow clearance for the tailwheel. The aircraft was also produced as a dedicated landplane with large trouser fairings enclosing the conventional fixed landing gear. The amphibian was to prove the more popular version and on 15 September 1935, a Wright Cyclone-powered SEV-3 set a world record speed for piston engine amphibian aircraft of 230 mph (370.8 km/h) which stood for 49 years.
SEV-3 amphibians served in the Spanish Civil War with the Republican Air Force and with the Colombian Air Force but a planned landplane trainer designated the BT-8, of which 30 were ordered for the USAAC, proved appallingly underpowered and was quickly discarded in favour of the north American BT-9 (which would morph into the fantastically successful T-6 Texan).
During development of the SEV-3, the design was tinkered with slightly to produce a two seat fixed-undercarriage fighter called the SEV-2XP with a 735hp Wright R-1820 Cyclone engine replacing the 420hp Wright Whirlwind of the SEV-3. With all this extra horsepower, great things were expected of the new fighter but it was damaged en route to a fly-off against the new Curtiss XP-36. Kartveli took the opportunity to rebuild and rework the aircraft into a single seat fighter with retractable(ish) undercarriage called the SEV-1XP and the new rotund fighter flew for the first time in August 1935, slightly later than the Messerschmitt Bf 109 and slightly before the Hawker Hurricane, both of which were considerably superior to the new Seversky. Nonetheless, the XP-35 was judged superior to the XP-36 (prompting a frenzied and ultimately successful effort to improve the P-36 by Curtiss). 77 P-35s were ordered by the US to become America’s first all-metal cantilever monoplane fighter with retractable undercarriage and enclosed cockpit but the slow P-35 was obsolete by the time deliveries concIuded in 1938 – this placing it in the unenviable position of being at the vanguard of progress whilst simultaneously hopelessly outdated. Nonetheless the type managed to secure an export order from Sweden though not all were delivered due to the June 1940 arms embargo on all nations except the UK.
Curiously, the P-35 drummed up more contemporary interest as a civilian aircraft than a fighter. In 1937 Jackie Cochran flew a Seversky SEV-S1, a variant of the P-35 fighter, from New York, to Miami, Florida, in 4 hours, 12 minutes, 27.2 seconds thus breaking the record set by Howard Hughes in the H1 racer. Cochran also used the Seversky to set the women’s world speed record, managing too coax the aircraft over the magic 300mph mark and garnering her the Harmon International Aviatrix Trophy in 1938. The aircraft was also campaigned in the Bendix air race and was modified into the SEV-1XP ‘Executive’ as a fast business aircraft with a (cramped) cabin for a single passenger in the rear fuselage.
Meanwhile the military P-35s had been despatched to America’s Far Eastern colonial possession, the Philippines. Some of these were from the repossessed Swedish order, which arrived proudly wearing the three crowns marking of the Swedish Air Force. In the Philippines the P-35s unexpectedly found themselves facing the juggernaut of Japanese expansion and proved tragically wanting against modern Japanese fighters, a single air to air ‘kill’ may have been achieved by the P-35 but details are unclear, though one managed to sink a minesweeper. The sole survivor flew its last sortie on 3 May 1942. The P-47 would ultimately avenge this poor showing many times over but it would take a few more goes for Seversky and Kartveli to end up with the Thunderbolt.
Seversky 2PA/A8V1/AT-12 Guardsman
Hindsight is a glorious thing and all that but as if designing a fighter easy for the Japanese to shoot down wasn’t enough, Seversky compounded the issue by selling a very similar fighter to Japan, just to make sure they knew exactly what they were dealing with. This move would prove catastrophic for de Seversky, the Japanese sale made him something of a pariah to the US Army which ordered no further P-35s. Seversky was also rather better at spending money than making it and was estimated to have lost the company over half a million dollars during 1938. As a result, in April 1939, while de Seversky was on an international business trip, the board of directors of the company that he had founded and which bore his name voted him out of office as CEO. The name of the company was changed to Republic and Alexander Kartveli was appointed as vice president and technical director.
The Seversky 2PA, which de Seversky had flogged to the Japanese was a two seat development of the P-35 (itself of course a single seat development of a two seat fighter) intended as a long range bomber escort and dubbed a ‘convoy fighter’ by Seversky. Curiously, the addition of the second crew position under the extended canopy made the aircraft appear considerably sleeker, though admittedly it is difficult to think of any change being made to the P-35 that could possibly make it look less sleek. Japan received 20 of the 2PA-B3 model and issued them to the 12th Kokutai based near Nanking which used them operationally, albeit briefly, in the reconnaissance role during the second Sino-Japanese war. The development of superior indigenous fighters by the Japanese had rendered the A8V1, as it was designated by the Japanese, surplus to requirements and the aircraft had been withdrawn by the time America entered the Second World War, nonetheless the A8V was allocated the sniggerworthy reporting name ‘Dick’ in the expectation that it would be encountered in combat by Allied pilots.
Meanwhile the Japanese order had been noted by Sweden who then ordered 52 2PAs of their own which they designated B6. Only two were delivered before the US arms embargo was enacted, the balance of the Swedish order being taken on by the USAAF and named AT-12 Guardsman, ‘AT’ standing for ‘Advanced Trainer’ though it is unlikely any AT-12 was ever used as a training machine, most being allocated to squadron commanders as high speed courier aircraft. One AT-12 is kept in airworthy condition by the Planes of Fame museum in Chino, California. This is the only flyable Seversky aircraft in the world.
The XP-41 started life as the last of the P-35s off the production line, it was then modified by Kartveli to attain the best possible performance that could be wrung out of the basic design. Externally, the most obvious change was a switch from the cumbersome rearward-retracting undercarriage to a far neater inward retracting design that closed flush when retracted. This was combined with a revised canopy and flush riveting throughout (a first for an American aircraft) resulting in a much more aerodynamic airframe. The engine was switched for a Pratt & Whitney R-1830 Twin Wasp with a two-stage supercharger delivering around 350hp more power than the Twin Wasp fitted in the standard P-35.
These improvements were sufficient to propel the XP-41 up to a creditable maximum speed of 323mph. However, by March of 1939 when the aircraft was first flown this was not all that impressive. The final nail in the coffin came when Seversky’s own AP-4, which could be considered something of a lash-up by comparison, proved to have a better performance than the highly refined and beautifully made XP-41, Kartveli abandoning the design to concentrate on development of the AP-4 into the P-43 Lancer.
Seversky’s numbering system was a mess. The AP-4 was actually preceded by the AP-7, which was Seversky’s designation for the civil P-35s it produced. Seversky’s prototype production was a mess too. The AP-4 was developed concurrently with the generally similar XP-41. It was less aerodynamically advanced, consisting of little more than a stock P-35 with inward retracting undercarriage but critically it had been fitted with Alexander de Seversky’s latest wheeze: a turbosupercharger in the rear fuselage.
This was an unusual location for such a piece of equipment and necessitated extensive ducting to carry exhaust gases to the rear of the fighter and then return the compressed air to the engine. The payoff for all this added complexity was the transformation of the aircraft’s high-altitude performance, proving far superior to Seversky’s own XP-41 which suffered a rapid decline in performance (which wasn’t exactly stellar to begin with) over 15,000ft. At the Army’s Pursuit competition of 1939, the AP-4 proved to have the best performance of all the entrants, but the Curtiss P-40 was judged the winner, largely due to the massive industrial capacity of Curtiss, the Army figuring it was in serious need of a lot of fighters as quickly as possible – correctly, as events were to prove. The fact that the AP-4 caught fire in flight on 22 March 1939 and was destroyed after the pilot bailed out probably didn’t help either. The performance of the AP-4 could not be entirely overlooked however and Seversky received the consolation prize of an order of 13 test examples of a refined AP-4 to be designated the YP-43. By the time the order was placed however, Alexander de Seversky had lost his job and the Seversky Aircraft Corporation had become Republic Aviation.
Republic P-43 Lancer
Whilst definitely a better aircraft than the bulky P-35, the Lancer wasn’t that much better. It certainly looked the part far more effectively though and had a particularly impressive range capability that was to prove extremely useful, though not in its intended role.
The Lancer ditched the somewhat cumbersome canopy design that had remained largely unchanged from the P-35, replacing it with the distinctive narrow spine that extended right up to the hood and that would become a characteristic feature of the earlier ‘razorback’ Thunderbolts. The new aircraft also saw the carburettor air intake moved from the port wing root to a position under the engine resulting in the signature ovoid shape that would be carried over onto the Thunderbolt. The 13 YP-43 test aircraft impressed the Air Corps with their excellent high altitude performance and long range. Unfortunately, although pilot’s reported the aircraft to be generally pleasant to fly the maneouvrability of the Lancer was underwhelming. More serious however, given the reality of modern air to air combat, was the absence of any armour and the lack of self-sealing fuel tank, the wing itself being sealed to form a large fuel tank, a so-called ‘wet wing’ which conferred upon the P-43 its prodigious range. Nor could the wing be retrofitted with self-sealing fuel tanks either, being simply too thin to contain them.
By 1941 when the P-43 first flew it was clearly obsolescent and the Army was far more interested in Kartveli’s AP-10/P-47 design which appeared to offer considerably more development potential. Nonetheless 272 examples of the Lancer were built which made it the most produced Seversky/Republic design so far, although the orders were placed primarily with the primary intention of keeping Republic solvent until P-47 production could begin.
Despite the somewhat lacklustre reception given to the P-43 by the USAAF, the Chinese Air Force ordered over 100 examples of the Republic fighter. In operational service the wet wing gave trouble, the repeated stress of flight and landings caused leaks to appear around rivets and panel joints and the Lancer was prone to catching fire, especially if leaking fuel escaped onto the turbosupercharger. Several P-43s were lost to fire on routine ferry flights causing the deaths of several experienced pilots. On the other hand, the P-43 had a much superior altitude performance to any other Allied aircraft in China, potently demonstrated by ‘Flying Tigers’ pilot Robert Lee Scott Jr who filmed the summit of Mt Everest from a height of 44,000 feet. More relevantly to the war effort, this impressive altitude capability to intercept the Mitsubishi Ki-46 reconnaissance aircraft which was otherwise immune to interception. Gradually the leaky wing situation was improved and some armour added making the aircraft more combatworthy and the Lancer was used ever more as a reconnaissance machine, a role in which it proved extremely useful and serving into 1944 before being replaced by the F-5 Lightning.
Republic XP-44 Rocket
This one didn’t even exist but it came very close. The P-43 possessed obvious potential, especially when compared to the lumbering P-35, but wasn’t fully competitive with the world’s best and thus Kartveli schemed the P-44 ‘Rocket’. Essentially a re-engined P-43, the Rocket was to be powered by a 1400hp Pratt & Whitney R-2180 in a low-drag installation. Estimated top speed was 386mph, a useful increase over the P-43 but the armament was to remain the same quartet of 50 calibre machine-guns. The USAAC was keen and by September 1940 Republic possessed firm orders or letters of intent for more than 900 P-44s, a huge order by the standards of the day.
Nonetheless, the P-44 was destined never to be built. Reports of combat over Europe began to filter back to the US and Kartveli became aware that the AP-4 (and the AP-10 described below) was unlikely to prove a particularly effective fighter. More power, greater speed and better armament were obviously required and Kartveli undertook to rework the AP-4 into a larger, faster aircraft, no longer merely a warmed-over P-43 but an altogether more formidable machine.
Republic XP-47and XP-47A
At last! It’s the P-47 itself. Or is it? Not exactly, for the first design to be actually designated the P-47 was, bizarrely, a small, lightweight fighter designed around the Allison V-1710 V-12 inline engine – a distinct departure from the huge, radial engine powered heavyweight we know and love (or are barely aware of and totally indifferent towards).
Kartveli proposed the AP-10 during the latter months of 1939 and the Army was keen, ordering two prototypes: an XP-47 with six gun armament and the reduced weight XP-47A with just four guns. The contract also covered tooling for an initial production run of the new fighter. Unfortunately development ran into difficulties, Kartveli found it impossible to keep the weight down whilst allowing for the necessary armament and equipment and at the same time doubt was being cast on the wisdom of using the Allison V-1710. This engine was also fitted to the P-38, P-39, P-40 and in due course, the P-51, thus making all US Army fighters reliant on just one engine type, with all the concomitant risk to the fighter fleet if supply were to be interrupted. With renewed interest in a radial powered aircraft, Kartveli ditched the XP-47/XP-47A and reworked the P-44 design into the AP-4L, or XP-47B as it was known to the Army.
Republic P-47 Thunderbolt
And here it is at last, Alexander Kartveli’s masterpiece, the P-47 Thunderbolt. Carrying over the best traits of the P-43 Lancer, the Thunderbolt was considerably larger and more powerful, indeed it was the largest and heaviest single engine fighter of the entire war. It was also extremely expensive (in 1945 a P-47 cost $83,000 compared to the P-51 at just shy of $51,000). Despite this, it became the most produced American fighter aircraft in history with 15,636 rolling off the production line between late 1941 and December 1945. Entire volumes have been devoted to its development and service, the following is merely a brief introduction to the basic Thunderbolt variants.
The Thunderbolt prototype, the XP-47B flew for the first time in May 1941. Despite superficially resembling the P-43, it was some 65% heavier and fitted with a Pratt & Whitney R-2800 Double Wasp rated at 2000hp, as also utilised by both the Vought F4U Corsair and Grumman F6F Hellcat. The XP-47B was lost in August 1942 by which time the first production P-47Bs were coming off the line. Unlike the turbosupercharger installation in the P-43, which was almost an afterthought, Kartveli set about designing the ideal installation for this equipment in the new fighter. Accepting that it was best located in the rear fuselage (some 22ft (6.7m) away from the engine) a complicated system of ducting took exhaust gases back to the turbine whilst cooling air was directed to the intercooler and further ducts brought compressed air forward to the carburettor. Despite its complexity, it performed reliably in service and proved surprisingly resilient to battle damage.
171 P-47Bs were built, all of which were retained in the US for training. These were followed by 602 P-47Cs which differed from the B primarily by having an eight inch extension to the forward fuselage to shift the centre of gravity forward and improve flying characteristics. The earlier P-47Bs are easily distinguished by the angled radio mast on the spine. The P-47C was the first Thunderbolt variant to see combat, with the first mission flown on the 10 March 1943. The classic P-47D differed very little from the C model and the two are indistinguishable externally, minor changes were made to the turbosupercharger and a different model of R-2800 engine was fitted. Huge orders were now being placed for the P-47 and Republic could not supply demand, despite a second factory being built to produce it. As a result, orders were placed with Curtiss-Wright to build the Thunderbolt, Curtiss built aircraft being designated P-47G and were essentially identical to the D-model.
It was around this time that the ‘Jug’ nickname was coined for the Thunderbolt. Some sources allege that this is because the aircraft resembles a classic milk jug in profile. However the fact that it requires quite a leap of imagination to visualise suggests that it is possibly a load of rubbish. An alternative theory is that when the 4th Fighter Group (the only fighter group operational with the 8th Air Force in Britain when the P-47 arrived) switched from flying the spitfire to the P-47C, the rotund seven ton Thunderbolt contrasted so starkly with the elegant and comparatively tiny Spitfire V that it acquired the soubriquet of ‘juggernaut’, quickly shortened to ‘jug’. Although the truth will probably never be known, the latter explanation seems (to me at least) more likely.
Following the ‘D’, Republic built the XP-47E which was fitted with a pressurised cockpit and the XP-47F which featured a laminar-flow wing. Both were modified P-47Bs and neither would enter production. Meanwhile, the Thunderbolt was going from strength to strength in combat. The habit of 8th AF pilots of strafing targets of opportunity when returning from escort missions saw the ground attack potential of this purpose-designed high altitude fighter being seriously explored and ultimately resulted in the P-47 becoming the most important USAF fighter-bomber of the war. The P-47 proved highly amenable to this change of role by dint of its heavyweight lifting capability and remarkable ability to absorb battle damage.
Complaints about rearward visibility saw Republic experimentally fit the bubble canopy from a Hawker Typhoon to a P-47D with a cut down rear fuselage. Known as the XP-47K, (a second bubble canopy conversion being designated the XP-47L) the result was so successful that the bubble canopy was introduced on the production line forthwith. Oddly, for such a seemingly major change, neither the P-47K or P-47L designation was used for production aircraft and bubble canopy Thunderbolts remained plain old P-47Ds.
The final iteration of the ‘standard’ P-47 was the ‘hot rod’ P-47M, developed specifically to combat the V-1 flying bomb with uprated engine for maximum speed at low level, though teething troubles prevented the aircraft from entering service until after the V-1 attacks had ceased. 130 P-47Ms were built, externally identical to bubble canopy P-47Ds, these representing the penultimate Thunderbolt variant to achieve series production.
Although several airframes were field modified with a second seat, the only factory-produced two seaters were a pair of P-47Gs modified on the Curtiss-Wright production line as prototypes of a trainer variant with a pupil’s seat directly in front of the normal cockpit in place of the main fuselage fuel tank. Further production did not go ahead.
Deciding that the regular Thunderbolt wasn’t massive enough already, Republic thought shoving an untried inverted V-16 engine designed by Chrysler might be a good idea. As well they might, for the Chrysler XI-2220 was rated at a lusty 2500hp for take off, making it nearly four times as powerful as the P-35.
Despite its impressive output the XI-2220 possessed a commendably small frontal area and thus combined excellent streamlining with great power, promising excellent performance for the XP-47H. Republic took two P-47-D-15-RAs from the production line in August 1943 and set about modifying them for the new power unit. Unfortunately the modifications required were extensive and the first flight by an XP-47H only took place in July 1945. By then the USAAF was utterly fixated on jet power and the performance of the XP-47H was of largely academic interest. Expected to achieve a maximum speed in the region of 490mph, the top speed recorded in testing was 414mph, though more may well have been possible. Unfortunately, the test programme of the first aircraft was brought to an abrupt end in November after 27 flights totalling 18 hours flying time when the propeller shaft failed, resulting in a dead stick forced landing. The second XP-47H was flown briefly after the war but no further development occurred.
Despite the fact that it is obscure in the extreme today, the Superbolt recorded the fastest known speed in level flight of any propeller driven aircraft during WWII, achieving the colossal speed of 505mph (813km/h) on 4 August 1944. It was also decorated with a natty portrait of Superman brandishing a lightning bolt on the cowling, which probably didn’t make it go any faster but certainly ups its credentials as a cultural artefact.
In contrast to the XP-47H, the XP-47J was not a conversion but built from scratch, as such it incorporated a considerable amount of weight saving alterations to the structure. The aircraft was powered by the R-2800-57(C) which delivered 2800hp and was force cooled by an engine driven fan directly behind the propeller spinner. As a weight saving measure two of the machine guns were deleted leaving the XP-47J with six 50 calibre Brownings in the wings. The pilot also benefitted from an extra perspex panel behind the canopy hood which greatly improved the rearward view from the cockpit, though the unbuilt second prototype was intended to feature a bubble canopy.
The Superbolt flew for the first time on 26 November 1943 but didn’t fly again until March of the following year. At some point before August the aircraft was fitted with a General Electric CH-5 supercharger (not turbosupercharger) and became capable of the exceptional speeds that should have rendered it famous but ultimately didn’t.
So why didn’t the P-47 enter production? Mass production of the P-47J actually was seriously considered for a time but ultimately did not go ahead for several reasons. Most seriously, the XP-47J enjoyed only 30% commonality with the P-47D which was busy proving a highly successful fighter in Europe and the Pacific, a switch to the P-47J would have required a significant change to production tooling resulting in delays which could not be tolerated at this stage of the war – better to have a large amount of the extremely good P-47D now than wait several months for the slightly better P-47J. Furthermore, the lightened structure of the XP-47J resulted in a reduced fuel load and therefore a shorter range, at exactly the time when ever longer ranged fighters were desperately needed.
The final nail in the coffin for the P-47J though came from Republic themselves: applying the same engineering solutions to a new aircraft with the even more powerful new R-4360 Wasp Major promised even better performance than that achieved with the Superbolt. This aircraft would subsequently appear as the XP-72 and further development of the P-47J was abandoned.
The best of the various Thunderbolt variants and developments to actually enter service, the P-47N also saw the only major change to the basic structure of the P-47 to see series production, featuring a completely new wing.
Much P-47 development work had been performed in an attempt to extend the range of the aircraft and the P-47N, intended as a B-29 escort in the Pacific, took that work to its logical conclusion. With no more room available for fuel in the fuselage and no simple way to increase external tankage the only option for more fuel was to provide wing fuel tanks. With a greater fuel load then pushing up the weight, a strengthened wing with greater area was required and so a new wing was designed with a 22 inch greater span giving an increase of 22 square feet in area, with square cut wingtips fitted for increased roll rate. The maximum fuel load for the P-47N was an astounding 4792 litres (for comparison, the Spitfire Mk.I carried 386 litres). All this fuel pushed the loaded weight up to over nine tonnes and the P-47N was extremely sluggish at take-off until some of that fuel had been expended. Republic’s efforts certainly paid off though – the P-47N could outrange the famously long-legged P-51D and it was no slouch either, topping out at 460mph at 30,000ft, whilst the best the P-51D could manage was (an admittedly still impressive) 440mph at its best height. The big Thunderbolt also retained all the earlier P-47’s best traits such as its superlative damage resistance and exceptional build quality. As an all-round fighting machine, the P-47N has a pretty good claim to being the best Allied fighter of WWII to see production and actual operational service.
The first P-47Ns went into action during April 1945 in the vicinity of Okinawa and mostly flew bombing and strafing missions over Southern Japan until the end of hostilities. During the course of these operations, P-47N pilot Oscar F Perdomo became the last American ‘ace’ of WWII when he shot down five Japanese aircraft in a single mission a mere two days before the end of hostilities. With the end of the war production came to an abrupt end, contracts for 5934 P-47Ns were cancelled, the relatively modest total of 1806 P-47Ns was actually built.
Republic XP-72 Ultrabolt
Despite receiving an order for 100 production P-72s, the mighty Ultrabolt (or Super-Thunderbolt or Superbolt (again)) was destined never to be built in quantity, the USAAF decided the future lay with jet aircraft and changed the order to cover 100 P-84 Thunderjets instead. Given the performance of the early Thunderjet, they may have had cause to regret that decision as the P-72 was an absolutely sensational aircraft that bid fair to becoming the most formidable piston engine fighter ever built. Key to its spectacular potential was its engine, the Pratt & Whitney R-4360 Wasp Major, a ludicrous 28 cylinder four-row radial engine that delivered a whopping 3450hp as fitted to the XP-72 but which would ultimately exceed 4000hp in R-4360-51 VDT form intended for the B-36C. Today the Wasp Major enjoys a somewhat frenetic retirement as the power plant of choice for many of the highly modified Reno air racers. These aircraft are, tellingly, very, very fast indeed.
Schemed as a low-risk back up to Republic’s XP-69 (which would ultimately never be built) and seen as a more promising design than the XP-47J Superbolt, the USAAF was initially very keen on the XP-72 due to its obvious potential for chasing down V-1 flying bombs. Like its XP-47J predecessor, the close cowled engine was force-cooled by a fan and a supercharger was mounted in the rear fuselage, not a turbosupercharger, this being powered by a fluid coupling and shaft drive running back from the engine. Armament fitted to the prototypes was six 50 calibre Brownings, though this could be changed for the fearsome alternative armament of four 37-mm cannon.
Two prototypes were built, flying in February and June 1944 respectively. As completed the XP-72 was roughly the same size and weight as the P-47D but possessed about 50% greater power and was more aerodynamic, the resulting performance was fantastic, a 490mph top speed was recorded and developed versions of the R-4360 were expected to give production P-72s a speed of 540mph (an optimistic figure but indicates the uncharted realms of performance the P-72 was expected to be operating in).
Alas it was not to be. The war situation did not require the P-72 to enter production and the advent of promising new jet fighters suggested that its performance, spectacular though it was, would soon be outclassed by a whole new kind of aircraft. One airframe, without its engine, was given to a Long Island, New York chapter of the Air Scouts in August 1946 and its ultimate fate is a mystery. The other airframe was scrapped.
The ultimate Thunderbolt development never made it off the drawing board but it is an intriguing concept. In 1944, the Army suggested that Republic might look at a jet powered Thunderbolt derivative, the large size of the fuselage was obviously amenable to house potentially quite bulky power units and the airframe was a known quantity with good high speed flying characteristics. Furthermore, with P-47 production in full swing, a jet fighter in the form of the ‘Jetbolt’ (or Turbobolt) might be able to be produced quickly and relatively cheaply without the need to produce substantial amounts of new tooling, an obviously attractive prospect.
Initially the General Electric J31 engine, a centrifugal flow turbojet based on the British Whittle W.2B was considered but even the portly Thunderbolt’s fuselage was not sufficiently large to satisfactorily accomodate this large diameter engine. Further development centred on the Allison J35, America’s first axial flow turbojet, which was slimmer. Removing the R-2800 piston engine freed up space in the nose for the jet intake and the proposed armament of six or eight 50 calibre machine guns giving a more concentrated firepower than the wing mounted guns of the standard Thunderbolt. The jet engine was mounted below the cockpit floor, necessitating a slightly deepened fuselage with the jetpipe taking up the space previously filled by the large turbosupercharger and its extensive associated ducting, which were obviously no longer required.
Ultimately the Jetbolt would progress no further, the P-47 was reaching the aerodynamic limits of its design, even in piston engine form, and jet propulsion promised only a marginal improvement. Kartveli was working on his first purpose-designed jet aircraft by this time and this was clearly a more promising line of development. This would appear in 1946 as the F-84 Thunderjet and brought to an end around a decade of continuous direct line development that all stemmed from the SEV-3 amphibian of 1933 but even this wasn’t quite the end for the P-47 line.
In 1948, Republic proposed a mixed-power ground-attack version of the P-47 to be powered by an R-2800 piston engine in the nose and with a Westinghouse 24C jet engine replacing the turbosupercharger in the rear fuselage. The cockpit was to be placed further forward to provide the pilot with a better view over the nose. Oddly for an aircraft featuring a jet engine, a tailwheel undercarriage was intended to be used and the aircraft featured the wing of the P-47N.
Despite some pretty impressive performance estimates, the mixed-power solution for combat aircraft was gradually falling out of vogue in the United States, with pure jet aircraft being developed to fill virtually all combat roles and the Ryan FR-1 Fireball became the only fighter example of this arrangement to actually enter service (with the US Navy). The USAF were not sufficiently interested in the AP-47 to order a prototype and the final iteration of the basic P-47 design remained on the drawing board.
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The P-47 Thunderbolt was the most versatile fighter aircraft of the Second World War. It was not “best in class” in any category, however, it was very good in just about every category. Fast, long-legged and well armed, it was also the most survivable fighter of the entire war. In scale and concept, the P-47 was a design outlier, and was different from every other fighter of the war. Somehow, the unusual Thunderbolt came together in a magical way that resulted its outstanding operational record. Myth and misconception surround the aircraft, and much of this leads to an under-appreciation of what the aircraft actually accomplished. This article will dive into some of those misconceptions and look at the real capabilitiesof those ferocious flying juggernaut.
Before we get started, I will address the elephant* in the room: the P-47 is ugly. There, I said it. Many often state that if an aircraft l***s good, it will f*y good. No one ever talks about the corollary, that if an aircraft is ugly, it will not fly well. This is never mentioned because it is not true. And besides, beauty is in the eye of the beholder. There are plenty who love the P-47 due to its rugged, badass looks. It’s in a similar category to the Westland Wyvern and the A-10 Thunderbolt II (the P-47’s grandchild!). Unfortunately I think the (lack of) sex appeal of each of these aircraft has limited their popularity in a wider public (‘P-47 Thunderbolt’ will garner 8 million results of Google search results, compared to over 20 million for the P-51 Mustang).
But aircraft performance and effectiveness is not a popularity contest. The facts stand on their own. So Let’s dig in!
*Note that the heaviest elephant in the room is a metric ton lighter than the P-47.
The Size is the Prize: Big doesn’t mean sluggish
The P-47 is the largest single piston-engined fighter ever built. And it is indeed large and heavy! Its empty weight is similar to or greater than every other contemporary single-engine fighter’s maximum weight. It is over twice as heavy as the original Spitfire and Me 109 fighters. There is a common misconception that large size and weight correlates with low performance. The perception is that a larger aircraft will be slow, lumbering, unmanoeuvrable, and ineffective. I believe this idea comes from comparison to other large aircraft. And indeed, most larger aircraft (bombers and transports for instance) do fit this description. But that is not specifically due to their size; it is due to their design attributes.
There are two primary metrics that affect a fighter’s performance: wing loading and power to weight ratio. The first of these states how large the wing is relative to the weight of the aircraft, and is measured in pounds per square foot or kilograms per square meter. A larger wing can produce more lift and it determines how aggressively a fighter can turn at a given speed. In general, the lower the wing loading (i.e. the larger the wing), the more “manoeuvrable” a fighter will be. Wing loading is a compromise though. The larger the wing, the more drag it produces. So a really low wing loading limits the top speed of an aircraft. Both manoeuvrability and speed are the key performance qualities of a good fighter.
The second parameter, power-to-weight ratio, states the power of the engine relative to the weight of the aircraft, measured in horsepower per pound or kilowatts per kilogram. This parameter is directly related to the top speed of the aircraft, but also to the takeoff and climb performance. A high power to weight ratio results in an aircraft that will climb and cruise faster than a competitor with a lower ratio.
The bottom line is that size and weight of an aircraft do not determine the aircraft performance. It is quite possible to build a large and heavy high-performance fighter, as long as it has the right sized wing, and a big engine. Let’s look a little deeper at how the P-47 used each of these metrics to its advantage.
A Beast of a Fighter needs a Beast of an Engine
““It will be a Dinosaur, but will be a dinosaur with good proportions” – Alexander Kartveli, Chief Designer of the P-47
The P-47 had much smaller and humbler beginnings. The concept started in the late 1930s as two different evolutions of the successful, but dated, P-35 design. The company delivered a small number of P-43’s with a similar design and layout, but using a much smaller R-1830 engine. The next iteration, the P-44, was to use the liquid-cooled Allison V-1710, but was never built. In late 1939, after Germany started its rampage in Europe, the US Army Air Corp had a meeting to discuss the noncompetitive state of the current and coming US fighters. The conclusions that emerged from the meeting was that the Air Corp desperately needed a fighter with more speed, more armor, and more firepower. Alexander Katveli, the Chief Designer of Seversky Aircraft happened to be in attendance. On the train ride home, he sketched an up-scaled version of the P-43 with the goal of meeting this newly desired aircraft specification.
More armour and armament means more weight. To be a competitive fighter, the engine power would have to grow as well. Katvelli turned to the new R-2800 twin-row radial engine being developed by Pratt & Whitney as the only viable powerplant. This engine had over 50% more displacement than the Allison, and initially had 33% more horsepower. A second problem that plagued US fighters of the day was the lack of sufficient power and performance at higher altitudes. Most of the contemporary American engines used a single-stage, single-speed supercharger. This design leads to significant falloff in power at altitudes starting around 15,000 feet. The combat experience in Europe was showing that the air battles were often going to be fought much higher than this.
The R-2800 engine had a single-stage supercharger which was integral to the engine. The P-47 design added an exhaust-driven turbo-supercharger to create a second stage. A turbo-supercharger is effectively a variable speed device, being engine exhaust-driven and having a wastegate control system. This allows peak engine power throughout a wide range of altitudes. By comparison, the famous Rolls-Royce Merlin engine used a 2-speed, fixed-ratio supercharger which provided peak power at only two specific altitudes.
The downside of a turbo-supercharger is that the installation occupies a lot of space. Fortunately the P-47 was already being drawn as a large fighter, and Kartveli was able to squeeze the turbo and even larger intercooler into the belly of the aircraft. This packaging is the primary reason the aircraft looks more like a pregnant whale rather than a sleek fighter, thus contributing to the perception of it being a dog.
Later versions of the R-2800 engine increased the boost pressure of the supercharger system and, along with the use of water-methanol injection, could deliver over 2,800 HP.
Great, you got a big engine – but can you turn?
Manoeuvrability is a term that gets tossed around a lot. It’s a simple concept. But when applied to a fighter, it quickly becomes complex. There are at least four aspects that affect what we call “maneuverability.” First is the aircraft’s roll rate, or how fast the pilot can bank the wings when choosing to fly in a different direction. Several aircraft details determine this parameter including the wing span, the size and design of the ailerons, and the weight distribution of the aircraft. (Aircraft with twin-engines on the wings have reduced roll rate.) I think roll rate is somewhat overrated in assessing maneuverability. In most dogfights, a majority of the time is spent in sustained turns, not switching turn direction. But a pilot will always be happier with an aircraft that responds quicker to control inputs.
The most important manoeuvrability aspect is the turn rate. However, there are really two versions of this: instantaneous and sustained. Instantaneous turn rate is the maximum rate at which you can turn as soon as you roll to a given bank angle and pull back on the stick. The force to create this turn is created by wing lift, and in a fighter it can be a LOT of lift. The aircraft wing is what determines instantaneous turn rate. A large wing and/or a well-designed wing can produce a lot of lift, and therefore a high turn rate. Unfortunately this lift creates a lot of extra drag. As soon as you start this maximum performance turn, you start slowing down. This leads us to the second turn rate parameter: maximum sustained turn. As you slow down in a turn, the drag will decrease and eventually you will reach an equilibrium point where drag matches the thrust your engine can produce, and you can sit here turning until your fuel runs out. This turn rate is lower (usually much lower) than the instantaneous rate. But this is where many dogfights culminate – slower, sustained turning battles with the better aircraft and/or pilot out-turning the opponent and claiming victory.
A fourth manoeuvrability aspect is the difference between turn rate and turn radius. These are related, but not the same thing. The relation is affected by the speed of the aircraft. When flying slower, a given turn rate will result in a smaller turning radius. The relationship between these three (speed, rate, radius) complicates a dogfight. This can be used to an advantage if you can force your opponent into a speed range where your aircraft is superior in either rate or radius and you maneuver accordingly.
A final comment on manoeuvrability – it is greatly affected by altitude. Both the aircraft aerodynamics and the engine performance change with altitude. The balance of these determines the aircraft manoeuvrability. An ace aircraft at one altitude might be a complete dog at a different altitude.
Let’s get back to the P-47. How did it rate in the manoeuvrability category? The basic answer is “pretty good.” Many fighters could outturn it, especially at lower altitudes. But the margin was small – small enough that a better pilot in a P-47 could often outturn a lesser pilot in a Me109 or Fw190. (It takes a lot of skill to precisely fly a fighter at its maximum turn performance.) The P-47 wing loading was not as low as some of the higher-performance fighters and its instantaneous turning ability was a little less because of this. However, the big R-2800 engine really helped its sustained turn performance. This is particularly true at higher altitudes. The turbo-supercharger provided tremendous power at 25,000 feet and higher. This allowed the aircraft to be on par or better than any of its opponents in a sustained fight at these altitudes.
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A quick note on the P-47 wing. You will often hear this called the “famous Seversky wing.” The lineage of Seversky aircraft dating back to the early 1930s shared a common wing design in both planform and a proprietary airfoil. The planform is elliptical, which is a theoretical optimum for reducing drag due to lift–a critical factor for fighter turning performance. However, you can get an almost equal performance with other wing shapes that might have other benefits such as easier manufacturing or better stall characteristics. At first glance, the Seversky wing looks similar to the elliptical Spitfire wing. The primary difference is the chord layout in the planform view. The P-47 has a straight leading edge, which is much easier to manufacture. All of the elliptical curvature is pushed to the trailing edge control surfaces. These are easier to build with curved edges. (The aerodynamics performance is essentially the same.) The P-47 and Spitfire designers have both commented that the elliptical wing is not just about aerodynamic efficiency. It also provides a thickness distribution that is convenient for both installing large guns, and providing structural efficiency. For all of these reasons, the P-47 did indeed have a very good wing.
Range – What good is all of this if you can’t get to the battle?
The range of the P-47 is probably the most misunderstood part of its performance. You often hear about how Mustangs could exclusively escort bombers all the way to Berlin, and thus turned the tide of the war. The real story is much more complicated and steeped in Air Corps politics. The reality is that the P-47 could also escort to Berlin and further much earlier than many people think.
Aircraft range is a simple parameter affected primarily by two things. First is how efficient the aircraft can fly at given speed and altitude measured by how much fuel it needs per hour. Second is how much fuel it can carry. The P-47 does burn a lot of fuel with its large size and weight. However, this larger size also allows it to carry proportionately more fuel. Per the pilot’s manual, the P-47D with maximum internal fuel could fly 890 miles (compared to 1,120 for the Mustang). With two drop tanks, the Thunderbolt range increases to 1,360 miles, leaving plenty of margin for the 1,000 mile round trip from England to Berlin.
So why does everyone think the P-47 can’t reach Berlin? Much of this misconception comes from some range maps that were published at various times by the US Army Air Corp which show the Mustang having superior range. I highly recommend watching the “Greg’s Airplanes and Automobiles” YouTube episode on the range of the P-47. Piecing together a lot of historical data, he tells a compelling story about how this myth evolved. Early in the war, the US bomber doctrine was anchored on the idea of bomber self-defence. It was believed the combination of speed, altitude, and defensive firepower would ensure the bombers would get through to the target without the need for fighter protection. Because of this, the Air Corp leadership downplayed the need for long-range fighters in an effort to spend more funds on bomber development. This even went as far as showing no interest in the development of fighter drop tanks.
Reality prevailed once the bombing effort commenced in Europe and it was quickly learned that the bomber did indeed require fighter escort to minimize bomber losses. The Air Corp leadership was slow to learn or at least admit this lesson which likely explains the existence of these range maps with misleading information. Eventually all of this caught up, drop tanks were used, and long range escort mission were flown by both the P-51 and P-47.
The final P-47N version had a redesigned wing with internal fuel and larger drop tanks, enabling an escort range in excess of 1,000 miles. This version was developed to escort B-29s in the Pacific theater. Given this extended range, and the consistent performance at high altitudes, the aircraft was incredibly effective in this role.
But how fast can it go?
In level flight, the Thunderbolt top speed performance is much like the rest of its performance envelope. It was not the fastest aircraft at any altitude. But it was very fast and was quite competitive in top speed. This is particularly true at high altitudes, where its engine produces superior horsepower. At 30,000 feet, the P-47D was within 7 mph of catching a P-51D, and significantly faster than an FW190A-8 or Bf109G.
The final P-47N version was extremely fast, again, especially at high altitude. Its R-2800 engine could produce 2,800 horsepower with water-methanol injection and this resulted in a top speed of 470mph.
To fully appreciate the speed capabilities of the P-47, you have to talk about its ability to dive. We will dig into that next.
Dive Dive Dive!
Donald Balkeslee, the first Thunderbolt ace is quoted saying “It ought to be able to dive, because it certainly can’t climb.” We will begin this topic with a brief discussion of the physics of diving.
Just like manoeuvrability, the ability to dive is complex and affected by many parameters. At the beginning of a dive you have to manoeuvre the aircraft into a diving attitude, either by pushing the nose over, or rolling upside down and pulling the nose down. Once you are in a nose-down diving attitude, the aircraft will accelerate due to the relative balance of aircraft weight, drag, and thrust available. All of these affect the acceleration rate, and your ability to pull away from (or catch) an opponent who is also diving. Depending on the dive angle, at some point your aircraft will reach a speed limit, which requires you to reduce the dive angle to prevent exceeding the limit. At any given altitude, this limit might be set by the indicated airspeed or the Mach number (the speed relative to the speed of sound). The relationship between these two limits is complex, and it changes as your altitude changes. Finally, a dive is affected by the controllability of the aircraft as it reaches higher speed, and the ability for the pilot to maneuver out of the dive before impacting the ground.
The P-47 was excellent in every one of these dive aspects, which makes it one of the best diving aircraft of the period. With its throttle-body fuel injection, the engine did not suffer from negative-g fuel starvation like the early Merlin engines. So a pilot could freely push the nose over to initiate a dive without the fear of the engine cutting out. Once in the dive, the P-47 accelerated quickly due its engine power and reasonably low drag. Best of all, the Thunderbolt had one of the highest dive speed and Mach limits of any fighter of the era. So the aircraft could keep accelerating away from an opponent. Finally, the P-47 was highly controllable in a dive, with little concern about Mach effects reducing the control authority. Many fighters of the era had Mach limits set with margin to a flight condition from which you could not recover. Most models of the P-47 also had a dive brake, which allowed an even steeper dive angle, and more recovery margin at the end of the dive.
“The top-10 Thunderbolt Aces all survived the war. This is a statistic, not shared by any other aircraft in World War 2”
This dive ability was a real benefit for P-47 pilots and contributed to its high survivability rate. If a pilot was found in a condition where the aircraft performance was less than an opponents, diving away from the opponent was almost always an option. This would usually result in escaping the immediate threat.
Big Aircraft Can Pack a Punch
We have talked about how the size and weight of the P-47 didn’t really hurt its performance due to the well-chosen design parameters and a large engine. Now let’s talk about what that extra weight allows you to do. The short answer is you can carry a lot of armament!
The P-47 had eight Browning M2 50-calibre machine-guns, four in each wing, whereas most contemporary fighters had no more than six fifty cals. The Thunderbolt sometimes gets criticised for not having any larger-calibre cannon. The aircraft certainly could have carried them. However, for its intended mission of destroying enemy fighters, the 50-calibre round is quite effective, and the combined firing rate of its eight guns meant a much higher probability of getting hits than with a slower-firing cannon.
The aircraft could carry 3,400 rounds of ammunition which, for comparison, was 65% more than a P-51. This high quantity of ammunition resulted in an interesting evolutionary role for the aircraft as the war progressed. At the end of an escort mission, the pilots often found they had significant unused ammunition. A tactic was developed for the pilots to then drop to a lower altitude and strafe ground targets of opportunity on the flight home. With eight guns and good diving qualities, the aircraft proved highly effective in this role. As the Luftwaffe became less of a threat late in the war, P-47s were more often assigned to ground attack as a primary mission because of their effectiveness in this role.
In addition to the guns, the P-47 could carry a heavy load on its external hard points. Between two wing racks and a belly rack, the aircraft could carry up to 2,500 lbs of external weapons. Initially this mostly consisted of bombs. Later, the aircraft was equipped to carry ten “High Velocity Aircraft Rockets” or HVAR. These unguided rockets did not have pinpoint accuracy, but were quite effective against larger ground targets. Each had a 45-pound warhead which was equivalent to a 105-mm Howitzer artillery round.
The P-47 was the first aircraft to drop a Napalm munition in combat. The original version of this was fabricated in the Pacific theater using drop tanks. This of course went on to infamous use in later wars. The aircraft could also carry a chemical dispersal pod. This is rarely discussed for political reasons. But the capability was in place for use of such a weapon late in the Pacific war if it came to that.
Protect the aircraft, Protect the Pilot
One of the original goals for a future fighter, as defined by the Army Air Corp in that 1939 meeting, was an increase in armour and aircraft systems to improve the survivability of both the aircraft and the pilot. The P-47’s size and weight made this feasible.
The P-47 had thicker armour in more locations around the pilot than any other contemporary fighter. There were a lot of other features on the aircraft that offered protection and made the aircraft more survivable in a crash landing. With a smooth belly free of cooling features, the aircraft responded well in a gear-up landing with minimal tendency to overturn. Additionally the fuselage contained an internal belly skid structure that contributed to survivability in a crash. It also made the aircraft more repairable after the crash. The original razorback P-47 had a substantial roll-over structure behind the pilot. This was omitted in later versions with the bubble canopy due to a low occurrence of roll-over accidents and the added benefit of better pilot visibility.
An aircraft with an aircooled-engine is generally considered more survivable than a liquid-cooled counterpart. The cooling lines and radiators are particularly vulnerable in that the engine will likely quit soon after a single hit to one of these systems. By comparison, an engine can typically run much longer after a hit to air cooling ducts, or even the turbocharger (at reduced performance).
All of these resulted in a very survivable aircraft. The top-10 Thunderbolt Aces all survived the war. This is a statistic, not shared by any other aircraft in World War 2.
All of these factors contributed to the P-47 being a very effective fighter in the Second World War, against both air and ground targets. The overall aircraft destroyed and the kill ratio for the P-47 was impressive. By the end of the war, the Mustang had beat the Thunderbolt in both of these categories, by a healthy margin. However, these metrics alone don’t tell the complete story. You have to factor in both how and when the aircraft was used.
The Thunderbolt started flying significant combat missions in Europe in the Spring of 1943. This was around 9 months before the Mustang arrived. During this time, the Luftwaffe was at the peak of its experience and effectiveness. This provided a very challenging opponent for the Thunderbolt pilots. By the time the Mustang was flying in significant numbers, the establishment of Allied air superiority was setting in, and many of the more experienced Luftwaffe pilots were no longer in the fight. Additionally, the German aircraft had a more difficult time keeping up with the performance advances of the Allied aircraft due to a shortage of certain materials and high-octane fuel. Before the Allied invasion on D-Day, The P-47 had amassed over three times the combat flight hours of the P-51, and 50% more than the P-38.
A second factor is how the aircraft was used. Due to its superior firepower (and a reduced threat from the Luftwaffe) more P-47 sorties were ground attack missions in the later stages of the war. While these missions were highly effective and greatly appreciated by the ground forces, they don’t contribute to air-to-air statistics, which is how most people judge a fighter’s effectiveness. However, there is much more to the story than these simplified statistics.
Closing Thoughts and Legacy
The above facts and commentary make the case for the P-47 being one of the most well-balanced, versatile, and effective fighters of the Second World War. It excelled at every mission it was assigned, and proved to be a well-loved aircraft by both the pilots and the mechanics supporting the aircraft.
Between its size, and complexity of the turbo-supercharging system, the P-47 was an expensive aircraft to produce. It cost over 50% more to build than the P-51. Despite this, the P-47 was (and likely will remain) the highest-produced fighter in US history. It is a strong contender on the world-wide fighter production rankings as well, coming in at number 6.
`The P-47 left quite a legacy in years to come. Most aircraft companies (like musicians and authors) tend to attempt a repeat of a previous winning formula when embarking on an updated endeavour. This was certainly true of Republic Aviation. After the war the company switched over to the development of jet aircraft. The first-generation F-84 was only partially successful, but the company learned a lot about this new form of propulsion and how to properly design a fighter around a jet engine. The next aircraft, the F-105 was a very successful ground attack aircraft. Following the P-47 family heritage, it became the largest single-engine jet fighter ever produced, and had similar traits of heavy firepower and strong armour. The final success story with the same lineage was the A-10 Thunderbolt II, for much the same reason.`The P-47 left quite a legacy in years to come. Most aircraft companies (like musicians and authors) tend to attempt a repeat of a previous winning formula when embarking on an updated endeavor. This was certainly true of Republic Aviation. After the war the company switched over to the development of jet aircraft. The first-generation F-84 was only partially successful, but the company learned a lot about this new form of propulsion and how to properly design a fighter around a jet engine. The next aircraft, the F-105 was a very successful ground attack aircraft. Following the P-47 family heritage, it became the largest single-engine jet fighter ever produced, and had similar traits of heavy firepower and strong armor. The final success story with the same lineage was the A-10 Thunderbolt II, for much the same reason.
Joe Wilding was the co-founder of Boom Supersonic, an independent company attempting to build a supersonic transport aircraft. He is Chief Engineer at Cosmic Aerospace, Engineering Mentor and Coach.
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Despite being complex and expensive to operate, the P-47 was rugged, potent and reliable. After 1945 the Thunderbolt was eagerly snapped up by a swathe of nations, particularly in Central and South America. Nicaragua was a major user of the type and loaned a handful to the CIA-backed Guatemalan insurgent Air Force in 1954 who used the Thunderbolts in the early stages of a successful coup to oust the democratically elected government and install the military dictatorship of Carlos Castillo Armas. The final aerial combat for the mighty ‘Jug’ came in January 1955: during a border dispute, Gerald Delarm Amador (who has earlier flown in the same aircraft in the Guatemalan coup) shot down a Costa Rican Mustang in a Nicaraguan F-47N. This aircraft survives in the collection of the Commemorative Air Force in the US. Last user of the Thunderbolt though was Peru, the last operational Peruvian Thunderbolts were withdrawn in 1966.
Aeroplanes are wonderful and terrible. Though they have made the world smaller, they have also made it dirtier and more endangered. In this top (or bottom) 12 we will look at aircraft that are particularly filthy as solo artists – and ones that have proved so popular that their net effect is globally terrifying. Set watches for doomsday, and let’s meet 12 of the worst offenders that ever flew.
Agent Orange was just one of a diabolical gang of quaintly-named Rainbow Herbicides. Inspired by British use of toxic jungle-killing chemicals in the so-called ‘Malayan Emergency’*, US forces attempted to expose Viet Cong forces by removing the cover allowed by dense jungle, and to destroy crops to starve them out. Secretary of State Dean Rusk advised President John F. Kennedy that the British cop-out* had established a precedent of legality. A decade (61-71) of air deployed anti-crop and defoliation efforts left the ground poisoned and resulted in massive long-term health problems and terrible birth defects for the unlucky civilian population.
*One benefit of the British repeatedly to avoiding the term ‘war’ was that accusations of military chemical warfare could be denied, as this was a ‘policing’ action.
11. Messerschmitt Me 163/North American X-15 ‘Rockets to the crypt’
Horribly toxic rocket fuel and high altitude flight make these two speedsters particularly bad. The 163 flew more, but the X-15 flew higher and so increasing its environmental effect.
10. Avro Lancaster‘Av-death-row’
The worst aerial attack in European history in terms of structural damage was on Hamburg on 27 July 1943. 787 RAF aircraft – 353 of them Avro Lancasters* burnt 18,000 civilians to death in a firestorm that destroyed much of the city. Across World War II, Lancasters flew a total over 156,000 sorties and dropped over 608,000 tons of bombs.
9. Boeing B-17 Flying Fortress‘Memphis Smell’
In World War II, B-17s dropped a staggering 640,036 tons of bombs. The nearest rival to this, the B-24, dropped 452,508 tons of 464,500+ tons released by all other U.S aircraft types.
8. North American XB-70 Valkyrie ‘Viking Sky Burial’
Generally speaking the higher a jet aircraft flies the worse its environmental impact. Flying at an extraordinary 70,000–75,000 ft (21,000–23,000 m) the Valkyrie mach 3 bomber, with six General Electric YJ93 was an absolutely filthy beast. Airframe-for-airframe the six-engined Valkyrie was the least Green aircraft in history.
7. Lockheed SR-71 Blackbird‘Trisonic Plague’
Though three times less damaging to the environment than the XB-70, the SR-71 flew many more hours at extreme altitudes. It is not known (at least to us) whether its special JP-7 jet fuel was better or worse than standard fuel.
The Hush-Kit Book of Warplanes is a gorgeous heavily-illustrated – and often irreverent – coffee-table book covering the history of military aviation from 1914 – the present. Volume 2 is now crowd fund-raising through advanced pre-orders here.
6. Boeing B-29 Superfortress‘Carbon Sasquatch Footprint’
One dropped atomic bomb releases about 690m tonnes of CO2, and destroying cities with firebombs is also not so green. The B-29 competes with the B-52, B-17 and Lancaster as the most destructive aircraft in history and may edge ahead of both in terms of C02.
5. Boeing 747 ‘Jumbo Number 5’
With a cruising height of 35,105 feet, four engines and many long-haul routes, the 1,500 747s made have done an awful lot of damage. Considering there were single 747s with more than 136,569 flight hours alone, then the 747 has a huge grubby footprint.
Spending more time per airframe at supersonic speeds (at extremely high altitudes) than any aircraft in history, Concorde’s green credentials were pretty damn poor. It was also one of only two airliners (the other was the Tu-144) that used afterburners. Add to that its contributions to acoustic pollution and the most beautiful machine in human history starts to look very ugly. The Soviet Tu-144 was even dirtier but didn’t fly very much.
3. Boeing 737‘The price of success’
As with anything, there is evil in the large-scale, so the effect of the extremely popularity of the Boeing 737, which in itself is not the worst, is sobering. For total net effect, rather than dirtiness per airframe, the Boeing 737 has to be the worst. With 264 million flight hours under its petite belt. The A320 series (essentially a European 737) is also a prime offender due to its popularity.
2. Boeing B-52 Stratofortress ‘The Dirty Reaper’
Between 6 and 8 million tons of munitions were dropped or launched during the Vietnam War (this compares with 2,057,244 tons dropped by US bombers in World War II), around 1000Ibs for each Vietnamese citizen. The majority of this figure was by USAF, and much of the USAF total from its heaviest bomber, the B-52. The Vietnam air campaign featured the longest and largest aerial bombardment. The B-52 has probably killed more people than any other aircraft as well as taking part in part in more atomic weapons test than any other aircraft (its closest rivals for nuclear weapons test are likely the Tu-16 and Tu-95). Even when it is not bombing the B-52 is a dirty bastard, one flypast from the eight-engined dinosaur is akin emits “as much carbon dioxide as 130 average mid-size cars emit per year.”
Messerschmitt Bf 109 ‘Fritz Harm Man’
Blaming World War II on the ‘109 is not as ridiculous as it first sounds. The Blitzkrieg method of combined fighting required air superiority, and until the arrival of the Fw 190 in 1941, Germany had no first-class single-engined fighter other than the Bf 109. Neither the invasion of France, the trauma of ‘Fighter Day’ or the attempted invasion of the USSR could have been considered without the 109. World War II was a catastrophe for the environment and CO2 emissions and it could not have happened without the nasty little 109.
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The Hush-Kit Book of Warplanes is a gorgeous heavily-illustrated – and often irreverent – coffee-table book covering the history of military aviation from 1914 – the present. Volume 2 is now crowd fund-raising through advanced pre-orders here.