A look at some real saucer and roundish aircraft
I recently picked up a book on weird aircraft at the bargain bin. The book could use some serious editing, but it did go over a variety of interesting designs that are not often mentioned in aviation books - often with good reason. Many of these I have also seen around the web, particularly since I'm fascinated with designs that didn't go anywhere. There was also a comment on one of my blogs about a real saucer that I decided to follow up on (the comment is on the wrong page somehow as it should really be part of the "Saucerfull" post, but anyway.) It is an interesting story, but nevertheless not that unique in aviation history, that is the idea of a flying disk. It is also an idea that predates the classic flying saucer story from 1947.The more I prepared this post, the bigger it got, so I'm going to break this into separate parts to make it easier to digest (particularly for me).
What is a round wing?
There is some variation into what may be considered a round wing. One could say that it is of a circular wing planform (looking from top down) or a flat ring like (circular) wing planform. Disk wings are also described as low aspect ratio wings, meaning that the width of the wing (the chord) is large when compared to the wing's length. The surprising benefit of this type of arrangement is that it provides a considerable amount of lift at low speeds and high angle of attack (the angle of the wings with respect to the airflow). As a result these aircraft could fly at very low speeds and were attractive designs in the era pre-dating helicopters.Another type of round shaped wing comes from annular wing design. In this case the wing is encircles the fuselage. It is sometimes flattened out and made boxier for a shape that resembles a stretched box kite. This general design is also referred to as a closed wing design.
A variation of round shaped flying machines is perhaps closer to what we would think of as a flying saucer. In a sense, these are wingless, because while the shape is generally considered to generate a certain amount of lift in flight, the main aspect of the shape is to house primary lifting devices that operate symmetrically. The more traditional lift devices make use of exhaust jets or ducted fans of some sort to redirect a mass of air directly downwards to counteract gravity. A more sophisticated method makes use of the Coanda effect to create an area of low pressure over the surface to lift the craft. More esoteric methods described are sometimes more whimsical than practical, such as electromagnetic levitation. One practical method that has been investigated is the usage of the shape as an energy receiver in the form of microwave or laser energy which can then be used or focused to superheat air at the base of the disc to generate thrust.
Flying Pans and Pancakes
DaVinci's Helicopter The prototypical flying saucer? |
The advent of actual flying machines did not initially discourage inventors from trying unique and imaginative variations on flying machines. This was due in part to the availability of the resources in lightweight materials and powerplants that finally made these plans viable. There was also a lack of specific knowledge of aerodynamics that might have been used to better analyze these aircraft. It has also been noted that the Wright brother's aggressive protection of their patents did encourage investors to find "different" ways of flying. Louis Bleriot and Gabriel Voisin for instance working in Europe had very sketchy information about the Wright's success (in fact many in Europe doubted they had really flown at all). They chose an annular design for their biplane creating a sturdy structure for their floatplane. In the end, the design did not work and after some modification both designers went their separate, but ultimately successful, ways.
The J.G.A. Kitchen, G. T. Richards, and Cedric Lee designed aircraft that used a circular wing planform. Initially Kitchen created a circular biplane which was refined with Richard's help. Disagreement between the designers resulted in subsequent work being developed by Richards with Lee. The Richard Lee Monoplane went through various versions (1,2,3) from 1912 up to 1914. The final version crashed with Lee at the controls, who managed to escape with minor injuries, but the aircraft was a total wreck.
Stephen Nemeth's, another "Umbrella Plane" built in 1934, mounted a circular wing above a standard fuselage looking like some of over-sized parasol and hence the name. It could take off and land in very short spaces due to that low aspect ratio wing. The circular wing was also only 15 feet in diameter making it easy to store in a hanger "not much larger than the ordinary garage" as the Modern Mechanics of June 1934 noted.
The Nemeth "Umbrella Plane" of 1934. If you can find newsreels of it, it flies surprisingly like a gyrocopter |
All these aircraft show remarkable STOL flight characteristics and unique flying characteristics such as maneuvering at slow speeds. In fact newsreels of the craft show them taking off with very little space and practically dropping straight down for landings with rolls of only a few feet. The claim that it could take off and land from your own backyard does not look far fetched.
World War II
The U.S. Navy has a strong interest in aircraft that could easily take off and land in short spaces. They considered a design proposed by Charles H. Zimmerman from Chance-Vought. Zimmerman reportedly visited the Arup Company and investigated using the combined effect of the disk-like wing with air blown at high speed from the propellers to enhance lift. Test models of the design were shown to rise practically vertically with good control. Moreover, the design could potentially have fighter-like performance. The prototype V-173 was flown several times and showed much promise. The fighter prototype was the Chance-Vought XF5U-1. It's development was protracted and not completed by the end of the war. After the war it was undergoing engine tests prior to flight tests when the program was canceled. It was a victim of the jet age, as most cutting edge propeller designs were at the end of World War II.When talking about World War II saucer aircraft, some mention must be made of Nazi projects. It is true that several strange and unusual aircraft designs were produced by German aircraft designers during the war. It is also true that even stranger, futuristic designs were still on the drawing boards (or actually just left there) at the war's end. They had developed rocket and jet technology to the limits of engineering capacities at the time and in many ways were considerably more advanced than what the Allies had developed by that time. Even so, the stories of highly advanced "flying saucer" designs based on advanced electromagnetic devices or supersonic turbines have to be taken with a relatively large sized grain of salt.
One of the few documented German "saucers" was fairly conventional and along the lines of Arup and Zimmerman. The Sack AS-6, had a truly circular planform. It was powered by a small engine and in that form would have been limited to simple utility work such as reconnaissance or field courier. Beyond research into that type of wing, nothing really came from that design.
Other designs appear to be nothing more than quick paper studies: the Focke-Wulf Rochen that would have hidden a lift fan inside it's teardrop shaped lifting body fuselage, and the Heinkel Wespe and Lerche II designs which were tail-sitters with annular wings. It is doubtful that there was any way these technologically advanced craft could go much beyond theoretical work at the time. After the war much of this information fell into Allied hands, and truth be told, many of these designs proved impractical even with the huge military research budgets of the Cold War. As far as anything else, I really don't want to delve into some of the crazier rumors out there.
Next time: More human flying saucers...
Links and Resources for Part I
There is of course many areas on the Internet to find out about flying saucers, real and imaginary. Unfortunately, due to their connection to alien technology, they can be pretty odd. In the case of the speculative human saucers, they can also be rather odd (particularly the Nazi ones, which seem to be in a mythological class by themselves). If one can overlook some of the personal points of some of these sites one can find out quite a bit on the real designs. The grain of salt comes when looking at designs that may have been nothing more than a sketch on a piece of paper by people with little aeronautical expertise that's been lost for decades.- Celtic Cowboy's Odd Wing Gallery - a collection of various images of odd aircraft including many round disk and annular/closed types. It is also fairly extensive with respect to the really early craft.
- Helicopter Designs at Aviastar.org - Contains various articles on helicopters, but for this subject the interesting one are the really early designs. You can browse the site to see other disk like shapes.
- Short article at Stanford on low aspect ratio wings and high angles of attack
- One of the few spots I found more detailed information about the Kitchen-Lee-Richards aircraft was located on this post and at the Russian site flyingmachines.org, the Kitchen biplane and the Lee-Richards monoplane.
3 comments:
Hello,
I enjoyed you article on circular wings. I too am interested in this shape wing.
https://www.facebook.com/SfFlugtag
http://www.instructables.com/id/2012-San-Francisco-Flugtag-Aircraft-Model/
Can you tell me what you have found to be the negatives of this design?
Thank you
The Sack plane didn't get off the ground, in a couple of variations. The modern Rowe UFO accomplished this with circular planform.
Zimmerman worked with NACA and in that capacity saw the Arup planes fly.
It's not clear why they thought the Arup planes had unusual high parasitic drag due to wing-tip wash around. They didn't exhibit this, so why did he and Vought & the Navy make the monstrosity of the silly flapping prop V-173, instead of the B-390, which was a copy of the Arups.
While biplanes might have accomplished STOL performance, few if any were as slow landing as the Arup, and none of them were as low-drag. With 900+bs and 37hp and 23kts landing speed, the S-2 could do 90+kts. It was also more robust and maintain-able than any of them or autogyros.
The Nemeth was reportedly also named for the steep descent as well as near-zero landing roll with any wind. It also had steep 40degree+ climb and it was faster than the Alliance Argo biplane which the fuselage came from.
At the same time, Farman built the 1020, on the fuselage of a Farman 402 monoplane, semi-circular trailing edge in the center of the wing back right before the tail; like the Nemeth and Arup/Hoffman planes it was stall-spin proof, super-STOL, and faster than the original. It attracted no interest and he went on to other things.
See also the 1918 Stout "Vampire" batwing monoplane. Completely clean unitary wing/body, first US monoplane and first all in wood veneer.
Rhomboidal (nearly square wing turned 45 degrees with pointed nose & tail and wing-tips) Pronounced aft edge elevator, wing-tip ailerons, and big fin & rudder.
It flew well, but pilots declared it unflyable because of utterly absent forward/downward visibility (Stout called the view atrocious).
Piana Canova made Rhomboidal aerobatic gliders and by some reports flew clean monoplane wing/body test planes. Again, going nowhere despite successful machines.
The Eshelman "flounder" flew well, making many flights, showing the same abilities and going 156kts on 130hp, super-STOL. At one point he was trying to attract attention to it as a naval fighter.
There are others. The Avrocar was the VTOL half of a supersonic fighter, the USAF "Weapons System 606a" It was finless, so they were counting on fine controls from the lift engine wich apparently were problematic. With fins and the depicted normal driving jets, it might work. Note that the lift engine doesn't need to go faster or higher, as long as they can get the nose up for taking off into "parachute lift".
At the same time in the USSR, Sukhanov was flying little circular-wing test gliders, the "Discoplan". First a parasol in '58 with with all-moving stabilator up on the fin, the second in '61 with sleek unitary wing/body & prominent fin, with elevons & rudder. Both are presently in museums. Video shows aerobatics and super-STOL handling.
Letayushchiy (flying) disk
Летающий диск (1964) 17:20
https://youtu.be/UQ1XiIMgLck
video
https://www.youtube.com/watch?v=at77GUZm9rY
See also the Rowe "UFO".
https://youtu.be/eFgr90LobAQ
And the youtubes on the Hatfield "Little Bird" follow-on to the Snyder/Hoffman Arup planes by a man who flew the Arups and promised Dr Snyder that he'd build another. By the 3rd iteration, he had a smooth, sleek little composite ultralight that matched the tales of the Arup performance.
And of course the '90s Wainfan "Facetmobile", needs its own article. Barnaby Wainfan is seen in a recent video of a talk to the EAA about very-low aspect-ratio planes (aspect ratio = span^2 / area). He addresses what seems to be conventional wisdom that they must always be very draggy: "I'm getting 100+kts on 40hp, with 340lbs useful load. I don't see the inefficiency". Facetmobile could stay aloft at <16 kts. (his pitot tube couldn't read any slower)
Post a Comment