Michael Pryce goes deep into the strange untold stories behind the Harrier

From intuition machines to Mach 3 jump-jets, via illicit liaisons in Paris, the story of the Harrier is as bizarre and exciting as the machine itself. We spoke to Michael Pryce, author of Jump Jet: The Secret History of the Harrier, to find out more.

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HK: Short-ranged, killed tons of pilots, hard to use, slow, real dispersed combat operations never happened, and when a quick-to-deploy attack aircraft was needed for Afghanistan, the Tornado proved easier to deploy — was the Harrier a waste of time?

MP: Fight’s on! The Harrier helped win a war or two, did manage dispersed ops in them, and was ‘only’ (!) as dangerous as many conventional 1950s designs, its real peer group. It was much safer than any other jump jet that flew – the first Harrier-family fatality took almost a decade, while other prototypes took much less time to kill their pilots. It was “easy to fly”, but also “easy to crash” as one test pilot told me. Training and procedures mattered.

The Tornado got to Afghanistan eventually, after the Harrier, and there are various ‘swings and roundabouts’ comparisons online between what they both did there, but having worked alongside the Harrier team a bit in 2008-10, I was impressed by how fast they could get new kit developed and delivered to the front line. That was a real difference.

So the Harrier was French, and the Lightning was German… tell me more.

They were both British but took ideas and influence from others. We all share the same air, and no sector is more international than aviation, so that’s not surprising. What did surprise me was how the Lightning derived from a very single-minded German designer’s focus on highly swept wings for supersonic flight. Of course, WW2 German science influenced post-war British design, and in this case this ex-Focke-Wulf chap’s theories on leading-edge suction were what drove Britain’s leap into supersonic fighter design.

The Pegasus engine for the Harrier certainly started with Frenchman Michel Wibault, but it took a British engineer, Gordon Lewis, to bash it into a sensible shape, and Harrier designer Ralph Hooper helped. All of them were conducted by an American in Paris, Willis Chapman, who was the real-life model for Colonel Cathcart in Catch-22. At the start of the project, there was a lot of international influence, and some money.

The planes and their engines were designed and made in Britain for the most part, although the original Harrier has some bits from Northrop engineers working in what is now a SpaceX factory. Ideas flowed between nations and people. I found learning all that fascinating.

The fantastically sexy BAe P.1214-3…what was it, and what are your thoughts on it?

It was the first supersonic jump jet design I ever clapped eyes on, in Bill Sweetman’s Aircraft 2000 when I was a kid. Despite knowing there was supposed to be a new jump jet in the factory at Kingston, near where I grew up, I thought it must be total fantasy. FSW designs were all the rage in the 1980s, but none entered service.

Realistically, such wings need a canard to make them work, but for a vectored-thrust jump-jet a canard poses control problems at low speed (basically, the engine tries to push the nose up so the canard trims it back down, producing negative lift just when you want maximum lift). So, without a canard, the P.1214 was likely impractical. In addition, the kink in the wing leading edge would produce unswept isobars right where the twin booms join it. Swept wings work by sweeping back the isobars, the imaginary lines that connect equal air pressure over a wing, so straightening them out slows you down, especially at the thickest point on the wing.

Still, it looked cool enough for supposed spies to try and swipe a P.1214 model on display by BAe at a USAF trade show in America.

Thinking about Ralph Hooper’s P.1216: What was the single most difficult architectural problem in making the transition from a subsonic V/STOL aircraft to a genuinely supersonic jump-jet?

Ralph Hooper was clear that it was hot gas ingestion (HGI). With plenum chamber burning (PCB) engines you have a lot of hot gas near the engine air intake that can cause an engine surge and cut thrust. Despite lots of modelling and full-scale tests it was still a challenge, but one that was very unpredictable. Lots of people said it was impossible, and that the hot PCB exhaust would dig post holes in the ground etc., but what was surprising was that the engineers closest to the problem thought it could be solved, but only by detailed testing on a near-final design.

Airflow under hovering aircraft is still an immense challenge to predict – my day job involves trying to make this work for electric flying taxis, decades after Ralph Hooper’s team tried. The specifics really matter.

The P.1216 looks radically different from the Harrier. How much of that geometry was driven by supersonic flight, and how much by V/STOL?

The whole layout was driven by the need to keep the hot exhaust, with six times the energy of the Harrier engine if PCB was used, away from the rear fuselage. On the Harrier, the exhaust caused vibration that would crack its structure and shake equipment to failure, so upping the levels on a supersonic jump-jet made it all that much worse.