Harry Fraser-Mitchell has more
to say and comments on the above piece...
I believe that (Kosin's comments re wing attachment points and the
undercarriage) supports the point I made which is that the sweeping
forward of the outer panels of the Arado wing was allied to CG
The AR234 wing tested in the wind tunnel had sweeps of approx. 32, 24
and 17 deg from the apex outwards and corresponding thickness:chord
ratios of 10.5, 10.5, 10 and 9 %. The Victor wing in its earliest form
had sweeps of 50, 40 and 30 deg and t:c ratios of 16, 12, 10 and 9 %
linked to this to keep the Mcrit constant across the span. I do not
think that the Arado wing had this linkage and I believe this
constitutes a major difference between the two layouts. Another
difference is that the Victor wing had an intake at the root whereas
the Arado had podded engines. The shape of the intersection at the
Victor fuselage was also helpful in maintaining isobar sweep right up
to the wing root.
More on Crescent Wing
us now consider what influence knowledge of the Arado work may have
had on the thinking of HP's Chief Aerodynamicist at the time, Godfrey
Lee. In a letter to Dietrich Kuchemann he wrote: "The real start of the
Victor design was a visit in the autumn of 1945 to...Gottingen and
Volkenrode by an MAP fact-finding team in which the Handley Page
representative was the writer. It was here that the concept of swept
wings as a means of enabling an aircraft with a reasonably thick wing
to fly at high subsonic speeds without drag rise first became clearly
understood." He goes on to say "...led to the need to have both high
sweep and moderately high aspect ratio...For us combining high sweep
and high aspect ratio gave rise to the tip stall problem. The so-called
'crescent wing' was evolved to deal with this difficulty."
note. For brevity I paraphrase Harry's letter here...Lee established
that the main reason for the problem was outward drift of the boundary
layer towards the tip, basically due to the action of a flow obliquely
entering a region where suction reduces to the rear which causes the
flow to try to turn in a direction parallel to the swept isobars. He
proposed three solutions but settled on: "reduce the outflow at the
tips by reducing the obliquity of the isobars for the outer part of the
wing, and this clearly suggests a progressive reduction in sweepback
from the centreline to tip."
Harry also says that that he has
May-June 1946 correspondence between Lee and Lachman, Head of HP
Research engaged in translating and analysing German reports. A letter
to Lee included a sketch of the Arado wing and a sketch of his own idea
of a 'crescent' planform.
Thus, says Harry, we can establish that the Arado work was known about;
but was the idea adopted from Arado's work?
believes not, from the sort of analysis in HP reports and
work in the low speed wind tunnel. In a letter to Lachman in June Lee
says of his wing; "It is rather like the Arado planform." Thus Harry
believes that Lee arrived at his conclusions for reducing wing outboard
sweep quite independently of Arado, and when their work was pointed out
by Lachmann he used it to support his contentions. To say that HP's
ideas of how to ameliorate the low speed behaviour of swept wings owed
anything to, and certainly not the "adoption" of, Kosin's ideas is,
Harry believes, far from the truth and gives less than justice to the
originator of the Victor wing helped, as he always maintained, by
others in the firm and in the UK research establishments.