whilst reading the other thread about the fan-lift delta uav I began to consider the point raised by Tim in his post today about the high speeds
damaging the blades of the lift fans. My thoughts were drawn towards the idea of those blades maybe changing their pitch until they form a smooth flat
surface during wing-borne flight both protecting them and improving the overall drag characteristics of the design I feel.
Imagine then how amazed I was after a bit more investigation to discover that this was not my idea at all, but something I had read many years earlier
in a long forgotten book on aviation and this question, raised by Tim, had merely dredged it back to the front of my mind as a possible solution.
The idea I rediscovered was for a passenger carrying aircraft resembling, in operation but not in appearance, the V-22 or the Rotodyne, in that it was
designed to take of vertically with a pair of outrigger rotors, much like the V-22 does, and then the vehicle flew like an aeroplane as the Rotodyne
was intended to do.
The adventurous and amazing part was the way this was to be achieved, as airspeed increased by means of pusher propellers, the pitch of the rotors
was gradually reduced so that when flat they formed perfectly circular wings! The journey would then be completed in this manner of flight before,
upon slowing down, the wings 'split' back into rotors and the aircraft landed vertically again.
This idea may well have some flaws in it of course (for example the stresses at the inboard end of the 'blades' compounded by the very broad tips
required to allow a perfect circle to be formed when flat etc) but the most truly amazing thing of all is that this design for a VTOL passenger
convertiplane dates from 1843!
Yes, that was an 8 not a 9 in that date. Ten years after this design, and exactly half a century before the Wrights famous achievement at Kitty Hawk,
the man who had designed it, George Cayley, achieved the first recorded manned flight in a heavier than air vehicle in history. It wasn't actually
Cayley who made the flight, he 'only' created the glider, it was his footman who made the flight but unfortunately his name is not recorded for
history and in any case, he resigned on the spot straight afterwards!
Sure the actual design of this convertiplane looks ridiculous to us now, but I ask you to look beyond the cosmetic appearance of the design and
consider just how advanced the idea, and how accurately conceived the features needed to achieve it, were. This is no harnessing of captured birds or
contraption with pedals and flapping wings, but a seriously advanced and well reasoned concept created at a time when such ideas ought to have been
This was no lucky shot either, Cayley is regarded as the father of aviation and he was the first man in history to conduct serious experiments into
aerodynamics, his 1804 glider, although a hand launched model, was the first ever to demonstrate controllability through a moveable tail, such as
every aeroplane in history has used.
The Wright brothers themselves were heavily influenced by his work and much of their own research confirmed Cayley's findings and theories to be
exactly right. The Wrights of course had the good fortune to be working in a time when the petrol engine could deliver the right power/weight ratio
for these theories to be put into practice where Cayley did not.
included finally below are two small images, one of a postage stamp showing the convertiplane idea from 1843 and the other is a first day cover to
commemorate the 150th anniversary of that first glider flight produced in 2003 and features a photo of the replica glider was built and flown to mark
for more information on this, well, 'genius' is the best word I suppose, follow this
before maybe running a google search of your own. Also, for maximum impact, I suggest you read the quote at the very beginning of the linked page
whilst at the same time thinking about the wing shape of the Global Hawk and F-22 and look at the picture of the bloke who said it, amazing!
[edit on 10-11-2006 by waynos]