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Although the Messerschmitt Me 163 rocket-powered interceptor had a number of frequently-lethal features (its extremely-toxic, violently-reactive, enthusiastically-explosive hypergolic propellants; its few-minutes-brief endurance in powered flight, allowing enemy fighters to wait and then pounce on it as it glided home; its skid landing gear, which rendered it an immobile sitting duck upon landing until it could be towed to safety), its handling characteristics were not one of these; despite its unusual semitailless design (a vertical tail, but no separate horizontal tail), it was extremely docile at both low and high speeds (despite its excellent manoeuvrability, something more usually found in conjunction with very un-docile handling), being difficult to stall or spin even deliberately and showing no untoward changes in stability characteristics even at very high speed.

In contrast, other similarly-configured semitailless aircraft (DH 108, X-4, F7U) were uniformly beasts to fly, being prone to severe pitch oscillations at high speed, yaw and roll oscillations as well at slightly higher speeds, and generally poor handling characteristics overall.

What kept the Me 163 free of the handling difficulties that plagued all those other semitailless aircraft?

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Firstly, the Me 163 is classed as tailless, not semi-tailless. The fin does not count.

Secondly, its characteristics were not wholly benign but they were acceptable by the standards of the moment for a high-speed fighter. Its lateral stability was marginal and it could behave unpleasantly in the stall. When Junkers developed it further, they found it necessary to make the leading-edge slots automatically variable and to increase the area of the landing flaps. But on the whole, yes, it was better than most tailless types.

So, why was this particular plane adequate? You will have to bear with me. A long trail of aerodynamic refinement begins with JW Dunne's tailless swept monoplanes and biplanes of the pioneer era. His D.10 biplane became the first aircraft ever to be officially certified as stable. The finless monoplanes could at least be stalled, but simply pancaked down rather than dropping a wing. Around thirty Dunne machines were flown in the UK and US and none ever had a fatal accident, a staggering safety record for that era. Dunne's secrets were many and subtle, expounded to the Aeronautical Society of Great Britain in 1913.

In the 1920s an ex RAF Captain, GTR Hill, took up the unstallable challenge once more and refined Dunne's aerodynamics, developing among other things the mathematics of the constant centre of pressure via reflex camber. A German visitor whose name I forget took it back to Germany where it was further enhanced and there Alexander Lippisch discovered it. He had the luxury of ten years' single-minded research and experimentation on one prototype after another, from glider to propeller to rocket, until the Me 163 emerged. But neither Hill nor Lippisch could get rid of the fin.

Meanwhile the detailed technical work of Dunne received only voice plaudits from others, while that of Prandtl in the early 1930s went unnoticed. Reimar Horten trod the path for himself to arrive at the finless Horten/Gotha flying-wing fighter which also handled well but came too late for wartime production.

What Dunne intuited and tested in hundreds of models, Lippisch half-grasped and Horten rediscovered and calculated, never made it over to Northrop or General Aircraft or any of the others. When Dunne's trademark conical leading-edge droop was rediscovered and used on the Convair deltas to make them flyable at low speeds, the path to it lay through quite another labyrinth. Back in the UK, Dunne and de Havilland renewed their old friendship, for DH had been Dunne's successor at Farnborough and both had trod the corridors of the RAeS together. DH wrote to Dunne that during the development of the DH.108 he would tease his staff that Dunne had got it right all those years ago, so they better had too. But like Lippisch, even he had to keep the fin. And despite also being informed by both Lippisch and the Hortens, his DH 108 was described by one test pilot as "malignant".

The real questions must be; why did so many designers turn a blind eye to the tailoring of span loading and sideways flow to eliminate adverse yaw and the need for a tail fin? and how did they manage to introduce appalling stall characteristics when Dunne's original breakthrough was to tame the stall? The key lessons had been in print since 1913, for those who had eyes to see, and Horten at least had proved capable of finding them for himself. Simple ignorance, preoccupation with conventional design issues and "not invented here" are my best guess. Prandtl's and Horten's contributions are only now beginning to receive wider acknowledgement. The epilogue must go to General Aircraft, whose GAL.56 was described by the ubiquitous Winkle Brown as the most badly-behaved aircraft he had ever flown, before it went on to kill the most experienced tailless aircraft test pilot in the world and who had consequently flown many Lippisch creations, Robert Kronfeld.

For those who want provenance and more detail I fear that you will have to wait until I can get quite a backlog of stuff past our Covid-coma'ed publishing industry. Or you may tread the Science Museum Archive's Dunne Collection for yourself, all 30,000 documents and boxfuls of artefacts of it.

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    $\begingroup$ Was Otto Lippisch in any way related to Alexander Lippisch? Strange that both designed tailless aircraft at the same time … $\endgroup$ Aug 13 '20 at 15:27
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    $\begingroup$ @PeterKämpf Well spotted, now corrected. I made that same typo a few weeks back. I shall be embarrassed if it was here and you were the one who pulled me up then! $\endgroup$ Aug 13 '20 at 15:29
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    $\begingroup$ "Thirdly, the DH.108 was also a pleasure to fly, better in fact than the Me 163 (Eric "Winkle" Brown was among those blessed few who flew - and survived - both)" - Would this by any chance happen to be the same Eric "Winkle" Brown who described the DH 108 as "A killer [...] Vicious undamped longitudinal oscillation at speed in bumps." and the Me 163 as "the only one [of the five types of semitailless aircraft he flew] that had good flight characteristics"? $\endgroup$
    – Vikki
    Aug 29 '20 at 22:03
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    $\begingroup$ @Sean You are right. The "killer" epithet was largely because of the flutter at high Mach number, a problem not confined to tailless types. But on re-reading his accounts it was unpleasant in other ways, even "malignant". I will delete that bit of my answer. $\endgroup$ Aug 30 '20 at 7:28

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