Broken boomerangs: Ten forward swept wing aircraft that never were


The F-16SFW responding to the 1980 ‘Queen Kong attack’.

Today, every aircraft that travels faster than 500 mph has a swept-back or delta wing. However, this isn’t the only solution to high-speed flight: the swept forward wing offers several advantages (for the same given wing area), among them a higher lift-to-drag ratio, better agility, higher range at subsonic speed, improved stability at high angles of attack, and a shorter take-off and landing distance. In the early to mid 1980s it seemed inevitable that forward swept wings (FSW) would catch on, but despite some mouthwatering artist’s impressions they never did. Despite advances in materials that made FSW designs viable, the advantages weren’t enough, and despite a few limited production oddbod aircraft, the concept never really spread. Here are ten FSW aircraft that never made it into production. 

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10. Rockwell Sabre Bat ‘Hyper Sabre’ (1980)


Neeeoowww! Rat-a-tat! Boom!

If the world was run by 7-year-old boys (admittedly we’re not far off this right now) the skies would be full of Sabre Bats duelling with MiGs. The name is perfect,  it looked perfect- but it was not to be. The Sabre Bat was Rockwell’s response to a DARPA brief for a FSW research aircraft, that led to the Grumman X-29. Though Rockwell’s entry offered 10 degrees greater forward wing sweep than the winning X-29, the Sabre Jet did not win the tender. However, Rockwell got quite caught up in the Sabre Bat project and proposed it as the basis for a super agile light fighter.

According to Boeing: “Mike Robinson, the Sabrebat (sic) program manager for Rockwell and now with Phantom Works business development, recalled that the Sabrebat FSW concept was based on the HiMAT (Highly Maneuverable Aircraft Technology) test flight experience (see Page 8 of the May 2007 Boeing Frontiers). “That program amassed a wealth of transonic/supersonic data on HiMAT’s graphite composite variable-camber wing.” Robinson continued, “The FSW demonstrator program proved to be very successful in that we developed a high-tech design team, tools and insights at a time when there were few new designs in work.”


The Sabre Bat mock-up.

Intriguingly, North American (Rockwell’s predecessor) had experimented with wind tunnel models of P-51 Mustangs with swept forward wings for greater manoeuvrability.

9. Junkers Ju 287 ‘Junk, gifted und bleak’ (1944)


With their thick reptilian skin, beady eyes, grasping claws and thin reedy voices it’s not hard to spot an affectionado of late-war German aircraft, and one of their favourite aeroplanes is the Junkers Ju 287.  The ‘287 was a testbed to explore the technologies required for a new jet bomber. The forward swept wings allowed space for a large single bomb-bay at the aircraft’s centre of gravity – and helped achieve a swifter take-off (early jet aircraft, especially the Me-262, were particularly vulnerable during take-off runs as they required a long distance to reach flight speeds). A version controlled by a piggy-backing fighter aircraft, and released as massive missile was considered but never used. Aeronautical engineer Brunolf Baade, who had worked on the  Ju 88, Ju 188, Ju 388 (and at North American before the War)- was a vital member of the Ju 287 design team.

8. OKB-1 140 ‘OKB cupid’ (1948)


Following a period of capture by US forces, Baade continued work on a variant of the Junkers Ju 287 jet bomber known as the OKB-1 EF 131 for the Soviet Union. The final prototype was adapted for use in the OKB-1 140 programme, an improved variant with changes that included Soviet engines and defensive guns. The OKB-1 150 used advanced materials, but progress was hampered by the official suspicion of German expatriates. This concept grew into a larger and more capable aircraft, but was cancelled in favour of far more ambitious bomber designs in 1952.

7. Sukhoi S-37 ‘Berkut’ ‘Gorbachev’s Cobra’/Yeltsin’s Toboggan’  (1997)


‘Flanker’s flanking.

The US spent the ’80s and ’90s in a stealth frenzy while the Soviet Union seemed more interested in fast climbing aircraft with extreme agility. As the Su-27 prepared for service entry in the early 1980s, the Soviet Union started considered its next generation of advanced tactical fighters.

Though the operational fighter that could have evolved from the Sukhoi S-37 ‘Berkut’ would have been stealthier than this technology testbed, it’s hard to imagine it being very stealthy, which raises the question of what advantages it would have offered over an advanced ‘Flanker’?  Today’s heavyweight future fighter, the Sukhoi PAK FA, does not feature forward swept wings. The degree to which it was a general testbed rather than the template for an actual fighter remains a hotly debated subject. It was certainly superbly sinister its black paint scheme.


Work done on the internal weapon’s bay of the S-37 may have aided the design of the PAK FA. Similarly, the S-37 large round LERX may have led to PAK FA’s unique adjustable leading edge vortex controllers (LEVCONs).

6. North American WS-110A Supersonic Bomber ‘Nemesis the supersonic warlock’ (1955)


In 1955, USAF issued General Operational Requirement No. 38 for a new bomber. The new aircraft should have the payload and intercontinental range of the B-52 combined with the Mach 2 top speed of the Convair B-58 Hustler. This was a time when anything could be improved by adding a fin, some Brylcream or a nuclear reactor so both conventional and atomic powered (or fuelled) aircraft would be considered. The (barely) conventional jet-powered version was assigned the designation Weapon System 110A. North American Aviation’s responded to this extremely demanding brief, clearly after their draughtsmen had got smashed on martinis, with the WS-110A.  The WS-110A featured huge wing tip fuel tanks that could be jettisoned when their fuel was expended, allowing a supersonic dash to the target. The tanks also consisted of the outer portions of the wing, which were swept forward. Properly insane, and possibly wonderful, the WS-110A never happened but it did pave the way for the doomed, and incredibly impressive Mach 3+ North American XB-70 Valkyrie.

Top 11 Cancelled French aircraft here

7. Grumman ‘Concept 9’ ‘Bananarama’ (1982)

After winning the DARPA contract, Grumman flew the X-29 in 1984. Prior to this, Grumman submitted four different concepts for the 1982 USAF Request For Information for an advanced tactical fighter (a project that Lockheed won that culminated in the F-22 Raptor). All featured twin vertical fins (the single finned aircraft illustrated is an earlier study) and vectored thrust. ‘Concept 9’ was a 51,414 lb fighter with a forward swept wing design based on the nascent X-29. It is likely that the real designs were stealthier than the artist’s impressions shown.

6. Rockwell D-645-1 ‘Rocky’s Revolver’ (1979)


The Rockwell D 645-1 was a 1979 concept for a low-cost subsonic missile carrier. Why are the engines located above the wings? I don’t know. Why has it got such an unusual configuration – again I don’t know. Seems kind of stealthy  (in terms of frontal cross-section) in a squashed pancake kind of way, but then there’s hugely visible open compressor faces and a massive vertical tail -so who knows? I’m going to have to dig out my ‘Warplanes of the future’ (1985), do some homework and then amend this entry. Cruise missiles were to be carried on a rotary launcher, effectively making the aircraft a giant flying revolver.

You’d think that a low-cost subsonic cruise missile carrier would just be a 737 derivative, but I suppose that wouldn’t interest Rockwell.

5. General Dynamics F-16 SFW (Swept Forward Wing) Windscreen Viper’ (1980)


You can do anything with an F-16: stick a delta wing on and you’ve got a long-range attack aircraft (F-16XL), change the landing gear you can make a decent naval fighter (V-1600) – so why not make a FSW demonstrator? In 1976, DARPA (Defense Advanced Research Projects Agency) awarded funds to General Dynamics, Rockwell and Grumman under the Forward-Swept Wing Program. The engineers at General Dynamics, of course, suggested fitting a FSW to their F-16. In 1981 DARPA decided to opt instead for the Grumman X-29 based on the F-5/F-20, a decision many said was due to the F-16s over -representation in upcoming DARPA test programmes. In the end the X-29A featured a load of F-16 components, including an adapted form of its fly-by-wire system.

Ten incredible cancelled military aircraft here

4. Convair XB-53/XA-44 ‘Convair the meerkat’ (1945)


This was an unusual forward-swept wing medium bomber design powered by three J35-GE turbojets, proposed in the 1940s. The wing, with its 30° forward-sweep and 8° dihedral was strongly influenced by wartime German research. Classified as a medium bomber, the XB-53 would have carried up to 12,000 pounds of bombs as well as 40 High Velocity Aerial Rockets (HVAR) mounted on underwing pylons.

3. British Aerospace P.1214  ‘Bond’s X-wing’ (1980)


You can’t put conventional afterburners on a Pegasus engine for several reasons – the hot and cold air is separated, the inlets do not slow the airflow sufficiently for serious supersonic flight, and the jetpipes would be too short- and it would also set fire to everything (it was tried from the 1960s and proved problematic) . This is a shame as a Harrier is desperate for thrust on take-off and could do with the ability to perform a decent high-speed dash. Though conventional afterburners are out of the question, you you could however use plenum chamber burning (PCB). This technology was developed for the Mach 2 Hawker Siddeley P.1154 (think the lovechild of a Harrier and a F-4, with the wingspan of a Messerschmitt Bf 109) – which never entered service.

PCB chucks additional fuel burnt into a turbofan’s cold bypass air only (instead of the combined cold and hot gas flows as in a conventional afterburner). This is great, but how do you incorporate this into swivelling nozzles without destroying the rear fuselage with heat and vibration? BAe thought it found the answer – get ride of the rear fuselage altogether, and mount the tail onto two booms. Worried that this already eccentric idea might seem too conventional, BAe decided to add an ‘X-wing’ configuration with swept forward wings (which were in vogue in the early 1980s). This did produce the coolest fighter concept of the 1980s, even in the -3 variant shown which had conventional tails.

The P.1214 would have been extremely agile (and probably short-ranged). As fashion changes, the P.1214 lost its swept forward wings and became the P.1216 which was intended to satisfy the USMC and RN’s desire for a supersonic jump-jet (a need eventually met by the F-35B). A full-sized wooden P.1216 was built to distract Thatcher from stealing children’s milk, predictably (as it was British) the whole project was scrapped.


The P.1216: think P-38 for the F-16 generation.

2. Northrop-Grumman ‘Switchblade’ ‘X-files jetski’ (1999)


This 1999 patent is most often viewed online through the skunk weed fug of a Black projects observer’s bedroom in Delaware. No other variable geometry- or swing wing- aircraft came close to having the huge arc of possible wingsweep angles of the ‘Switchblade’. Did the severe raked-back wing-sweep hint at a mach 3+ plus capability? Was the forward sweep for a short take-off, or extreme dogfight agility? Little is known for sure but it looks like stealth was a consideration. Note the unusual placing of the engines – to shield them from ground radars perhaps? The Switchblade remains to this day a mysterious concept.

One thing it did influence was the fictional F/A-37 from the 2005 borefest ‘Stealth’.

Boeing Model 449-3 ‘Antoine de Saint-Exupéry Pootly Pepperpot’ (1944)


The 1940s were for jet fighters what the 1960s were for Rock ‘n ‘Roll — it was a time for wild experimentation, the ingestion of copious quantities of LSD and it ended in Prog Rock. Shortly after World War II had ended, Boeing produced a series of designs for a swept-wing jet fighter under the Model 449 designation. Both swept-forward and -back wings were considered, but it is unlikely that contemporary materials would have been able to deal with the loads and aeroelastic twisting imposed on a FSW design.


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This picture again.


  1. spamtrap19990601

    Cruise missile carrier? My suggestion was to install four overhead trolley hoists in a C-5. The cruise missiles would be stored in two or three layers on the floor. To launch the missiles, a missiles would be picked up by a hoist, wheeled to the rear of the airplane. The missile would be started then pushed off the end of the ramp or dropped off the hoist.

  2. Andy1960

    I always wondered why Concorde never evolved in to a military aircraft. It has supercruise, decent payload and cruised at a pretty high altitude (for the day)

  3. tonyo262

    I’ll have you know my affections towards Helga ‘late-war’ Germaine were strictly platonic. Yes, she had a propensity for thin skin (in an exclusive 1973 interview, she blamed the diet of fliegerschokolade and cabbage), a voice that could be described as a raptor ice-skating on a blackboard and a vicious tongue when cornered, but let me tell you, she was all Deutscher Mädel under that impeccably tailored feldgrau twinset. But I, a lowly T-Stoff taster, could only worship her from afar and couldn’t compete for her affections when he head was turned by Brunolf and his Bauhaus inspired back to the future ideas.

    Its not widely appreciated today, but it was to placate Helga’s love of older men in spats that drove Bru’ to incorporate twin faired non-castoring nose wheels on the ‘zwei-acht-seben’ scream-liner. Helga’s influence didn’t stop with over endowed undercarriages and the cockpit aesthetic owed less to a see-through reimagining of a stahlhelm and more to the fact that she spent much of her teen years wearing a goldfish bowl (she mistakenly thought that the bowl would emphasise the ‘good’ eye after her french half-cousin Paris Saint taunted her about having a ‘beady’ eye at a eyebrow herding party hosted by Rudolf Hess).

    Helga never quite got over the trauma of the surgery to remove the bowl…

    Of course Brunolf tempted her more than once with the offer of chief test pilot, and even the promise of her own chalet at Peenemunde wasn’t enough to get her on board until ‘Bru’, frantic to beat his rival Wili to having a ‘hot chick’ to test his far out fantasy, agreed to her demands for a redesign of the ‘pit glazing. Junkers records state that it was ‘Ziggy’ Holzbau who carried out the first test flights. But this is only partly true and his penchant for smoking schnapps infused cheroots eventually got the better of him. Company rumours abound about his dalliances with Helga as the reason for his meteoric fall from grace, but the truth has it that he spat a well chewed stogie out the side window during a ground run and this was ingested into the port ‘004 causing it to ‘blow the onion out of its arse’. In the process it set fire to several of the schwarzmen who were valiantly trying to bend the conventional tail into a rakish forwards facing angle with mole grips.

    Disgraced, Ziggy spent much of 1948 hurling over-ripe turnips and right wing jokes at Russians from the back seat of a late model Stuka. Another urban legend (probably started by his friend and felt fetishist Joe Beuys) has it that he had the Stuka’s pilot seat and control column removed and operated the swede toting elderly dive bomber by a system of strings and mirrors…

    Meanwhile, Brunolf in a final act of desperation, agreed to add more yet spats to the ‘turd shaped aussie nightmare’ (Helga’s words, not mine…from the 1973 interview). Overjoyed at the prospect of finally getting to flight test a ‘shit hot’ aircraft, her bi-polar high was short lived as the Red wave poured into Pomerania putting paid to any further flights. Helga and the mendicant 287 desperately clung to the Weimar dream and after several months of hiding in barns by day and working sleazy clip joints at night, eventually fetched up on the Lancashire coast where they spent most of 1949 living off a diet of pickled whelks and giving piggy back joy rides to demobbed spats salesmen on Morecambe beach.

    A sad end to a promising career.

    Post script:
    Never one to be accused of being backwards in coming forwards, in my defence (thats with a ‘c’ for all your pre-pubescent colonial readers) the Junkers is ‘kinda half-sexy’ and should be your ‘nummer eins’ on the list. (I don’t get out much and am in the process of knitting a 1/12th scale 287 tea cozy in an effort to forget Helga).

    Do you think 4 ply will provide enough rigidity?

  4. John Usher

    Well, the propulsion engineers are looking again at ‘Propfans’ (Unducted fans, Ultra High Bypass turbofans – whatever) for future airliners (ear defenders, anyone?), so why not forward sweep, providing it can be ‘aeroelastically tailored’ to stop the wings ripping off at high speed manoeuvering (ready the Bang Seat…)! KBO…

  5. william chick

    My own personal opinion is the following it is a pity we didn’t go ahead with the British Aerospace P.1214 in a 1980s not only would it probably been a world beating aircraft, But we would not have ended up having to buy that piece of rubbish the F35 for the Royal Navy and the Royal Air Force, I am yet to be convinced that the F35 will be any good and the more I look at it the more I don’t think it will do its job.

  6. william chick

    One aircraft that you forgot to mention with its forward sweeping wings was the Heinkel He P.1076.

  7. Mike

    I have a problem with statements like this “The US spent the ’80s and ’90s in a stealth frenzy while the Soviet Union seemed more interested in fast climbing aircraft with extreme agility.”

    First off I’m not an American so this isn’t any nationalistic blindness. However why is there a common notion that the Americans went for Stealth while the Soviets went for performance. This is a crude misconception, the US spent $66 billion on the ATF (F-22) program to over match the Soviets in every conceivable way,

    The new fighter would be superior in every aspect to all known or projected Soviet aircraft, Observability, Maneuverability, Speed, Sensors, it would be head and shoulders above anything,

    In fact YF-23 and F-22 test pilot Paul Metz said in an interview that one factor that led to the YF-22 being selected was because the F-15 “mafia” in the airforce was very influential and they wanted the most maneuverable plane money can buy. The YF-23 was no slouch in that regard but the YF-22 was simply eye watering.

    To this day no in-service fighter produces more power and has a higher thrust to weight ratio and lower lift loading (weight divided by total lift produced not just by wings but also body, tail, vortex lifting surfaces etc) than the F-22.

    The US also had so many high maneuverability test aircraft, F-16 VISTA, F/A-18 HARV, F-15 Active, X-29, X-31, HiMAT just to name a few. How many high maneuverability test aircraft did the Russians/soviets employ.

    The US also pioneered so many maneuverability enhancing technologies. Fly-by wire, Relaxed static stability, body lifting surfaces, Vortex lifting surfaces, even the canted tail which allows the tail surfaces to catch the vortecies produced by the LERX/Chines and allows yaw control at extremely low airspeed negating the need for 3D Thrust vectoring has been used by the US since the 80s in the F/A-18A. Russians kept using straight tails until the PAK-FA which still in prototype stage.

    So the notion the the US did not prioritize maneuverability is just flat out wrong.They wanted to be the best at everything.

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  10. Andy

    Hello, sorry to comment on an old thread but I have an explanation for the design of the Rockwell D-645-1.

    The book you need is “Aircraft Design: A Conceptual Approach” by Daniel P. Raymer. To get all nerdy, there is a taper ratio for every sweep angle that will give near elliptical lift distribution on an untwisted wing. For an angle of -22 degrees the taper ratio is 1, so the root and tip chords will be the same and the wing should be easier to manufacture. He writes that analysis showed that this method produced a heavier wing and would actually cost more than a conventional design and so was not taken any further.

    The main benefit of this forward swept wing and foreplane combination is that the large cruise missile bays would be at the centre of gravity with the main wing box passing behind them. I think that the reason the engines are over the wing is mainly for ground clearance.

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