Further to Harry
Fraser-Mitchell's comments in News Letter No. 12, Ralph Denning expands
his argument...
Harry F-M has charged me with making a (non-aerodynamic!) 'canard' in
saying that Handley-Page got the idea for the crescent wing from Arado.
He further implied that Arado used the crescent wing to solve a
short-term problem of getting the centre of lift nearer to the C.G. I
still stick to my views; in particular that Arado's main aim was
aerodynamic. Arado's Chief Aerodynamicist, Rudiger Kosin, gave a full
explanation in a book by Wolfgang Wagner entitled 'Die Ersten
Strahlflugzeuge der Welt' (The World's First Jet Aircraft), as follows:
More On The
Origin Of The Crescent Wing
"When,
in 1942, Arado considered the application of the swept wing
effect, three wind-tunnel models with different constant sweep angles
were tested in the low speed tunnel of the DVL...At higher angles of
sweep the models showed massive flow detachment at the wing tips and,
in fact, increasingly so at increased sweep which, with even greater
growth, would have led to nose-up pitch, stall and nose dive.
Experiments fitting leading edge slats, similar to those used on the Me
109, led to nothing so they hit on the idea of sweeping the wing more
steeply on the inboard section than on the outboard section. Arado
patented this idea in 1942...Despite all this theoretical work the
flight behaviour of the wings with decreased outboard sweep was still
not assured. Therefore it was decided to undertake a practical
experiment with a large scale model." Kosin also states that "the wing
plan form evolved in this way was employed after the war by
Handley-Page on the Victor bomber, and permits attachment points on the
fuselage to be retained with the same centre of gravity and landing
gear...very important taking into consideration the pressure of
deadlines in 1944."
This may well be the model photographed in
the LFA A.1 tunnel shown in my lecture. I would also comment that RS
Stafford (Chief Designer, Handley-Page) was a member of the Farren
Mission to Germany that visited LFA Volkenrode in June 1945.
Harry
agrees that HP knew of the Arado work but says that none of it was used
by them. This seems to enter the field of semantics. My lecture was
concerned with conceptual design issues rather than detailed design. It
should also be remembered that all swept wing activity stems from
Busemann and the simple sketch in his paper to the 1935 Volta Congress.
Harry
also makes the point that HP optimised the exchange of sweep angle and
thickness:chord ratio which was not done by Arado. I would say that
with the engine thrust levels available in Germany from 1942 to 1945
the pursuit of the highest transonic Mach number was not the immediate
priority.
Finally, I must emphasise that I wholeheartedly agree
that Handley-Page optimised the crescent wing concept, as did Avro the
delta, but using the German work, discovered in 1945, as a starting
point.