All three DH 108s crashed killing all three pilots. Maybe that's why the British decided tailless aircraft might be something they could do without for the time being.
Cheers
Steve
The DeHaviland DH108 might be the source of the myth that tailless designs can't go supersonic or transonic. The fact that the Me 162 was the fastest aircraft of the war and suffered less Mach tuck than most other aircraft with conventional tails and perhaps even the Me 262 should dismiss that idea.
If fact tailless designs were of great interest to early transonic jet designers since the lack of a tail meant the effects of shock impingement of the wing on the tail was eliminated.
The crash of all three DH108 seems to have had nothing to do with their tailless design.
The DH108 had been designed as a test bed for proposed tailless versions of the comet airliner and used the
stubby flat nose of that companies Vampire jet, a Mach 0.75 aircraft. When the comet went for a conventional layout the DH108 was 'misused' for supersonic research. It's a case of adapting a design for a new purpose it had not been originally considered for, of forcing a square peg into a round hole.
As the aircraft approached the speed of sound the relatively blunt nose experienced a dramatic increase in pressure and pitched the nose up in what was described as a shock stall. Worse, aerodynamic forces were transmitted back from the elevons to the joystick and a severe type of vibration called PCO pilot couple oscillation set in. The whole sequence was so severe it seems to have Brocken DeHaviland's neck before the aircraft pitched up and broke its wing spars.
Eric Brown experienced the same problem but says that as he was shorter he didn't hit his head on the canopy AS DeHaviland likely did.
The solution was to fit a pointy nose from late model vampires and to use fully hydraulic irreversible controls rather than power boosted controls.
Despite the lack of supersonic wind tunnels in Britain compared to Germany and the capture of German data the evolution of the DH108 the genesis of the DH108 as a comet test bed seems to have lead to this somewhat predicable outcome. There was plenty of data from large calibre naval guns in Britain, the German V2 missile had been modelled on an artillery shell, the German Mauser M1898 rifle had had its bullet changed from round tipped to pointy and created the 'spitzer' bullet. The Miles M52 didn't have a blunt nose, nor did the Bell X1.
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There is only a little truth to the tailless claim. Wings have pressure distribution: much of the upper surface of a wing has a lower pressure than ambient and much of the lower a higher pressure. This generates a wings lift and also its lift distribution (ie pitching moment). As the wing approaches the speed of sound the behaviour of the air becomes non linear, compressible and so the centre of lift moves aft to the shock wave. The aircraft is now nose heavy an may not be able to pull out of a dive. P-38 and P-47's could end up in death dives. The improvised solution was to introduce dive recovery flaps under the leading edges to pitch the wing up.
Modern aircraft use wing sections which don't change their pitching moment much. The wings are thinner and the thickest portion of the wing is already at 50% rather than 20%. Electronics does the rest, simply automatically trimming out the change in pitch.
In theory a tailless design doesn't have as much tail moment arm but in practice if the right airfoil is used and there is sufficient sweep tailless designs work fine. The deltas such as the F101/106, Mirage, Fairey Delta etc work fine.
The
Vought Cutlass was a tailless supersonic design, Americas first supersonic, after burner equipped, missile carrying fighter was tailless. It had problems but they came from the under powered engines and systems.
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Some tailless deigns used an auto stable air foil, the Fauvel flying planks for instance. The Northrop designs did not, they used wing sweep, wing twist so that the wing tips were positioned to perform the function of a tail. Northrop also added slats to improve the pitching moment.
The Me 163 used an bit of both, wing sweep and an auto stable air foil as well as slots (similar to slats).
The Horton Ho 229 used an auto stable air foil on the bat like tail but not on the wings. All of the Horton designs handelled well except for one they made using a laminar flow air foil.
These reflexes and wing twists if severe enough can cause shock wave problems but if the sweep is enough they can be moderate.
