Hi all I am currently trying to design a prone pilot flying wing in ultralight configuration but am not having any luck finding any plans or any aircraft like this at all has it been tried or is a flying wing to unstable for ultralights
Thanks HW that did help. I’m looking for something like the horten iii sailplane…about a 15- 20 ft wingspan but with two 100cc two stroke engines with pusher props. do you think I could use that wing design for a fairly slow flying aircraft or would I need a higher camber and or longer wingspan to lift the extra weight
Hi! I am reading Anderson Aircraft design book. He covers everything, but there are some details that are spared. Hopefully other books will come next to study the specific details. So far, I am working, as an exercise/divertimento, on the conceptual design of a very simple and affordable...
I'm going to flat recommend against head first prone configurations; they are dangerous for the pilot.
If you want a US part 103 ultralight, get into the reg and the calculations to get an idea about the wing area required to meet the stall speed.
Flying wings don’t like high cambered airfoils. You will need Horten like long wings. 30 ft range probably. The problem with prone is your neck will hate you very quickly. Easy to stare at the ground but hard to see where you are going.
Kasper wing, either Bekas or Cascade Ultralights, or Mitchel Wing B-10 could be converted to prone position.
There was a NACA WWII vintage investigation of prone pilot position that had good things to say but I did not save a copy and have found it difficult to find. The solution is to not lay the pilot too flat. Keep the back about 45 degrees to the vertical with bent legs and knees. It is a larger profile but much more comfortable. Some found it better than upright. Similar to the B-17 or B-29 bombing position or KC-135 refueling position I believe.
IMHO - Visibility and center wing flow separation are issues that needs to be worked with the swept flying wing. Additional improvements are desirable.
Check PMs if you would like to further refine the design and simplify construction.
The 3-B Wing (Bennett-Boyd-Boone), unsuccessful cantilever, foot-launch, flying wing, Northrop MX-334, glider version of the Northrop Flying Ram, more recently the ZEVA EVTOL are all prone pilot position aircraft. You will find the Horten's indeed employed a pilot position akin to kneeling over a footstool, they reported it to be very comfortable for soaring flights lasting many hours. Pilot over or under the wing spar is a difficult decision, many tradeoffs for each configuration, 15-20ft wingspan will result in high landing/flight speeds and will not be Part 103 compliant. My preference for an ultralight airplane, pilot under the wing, seated. Prove us wrong and build your dream, I would however recommend a building large scale R/C model to test your theories.
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The "problem" with prone positions is proper support and safe restraints.
the 2 most successful systems are probably the Horton, semi reclined which is much like a modern racing motorcycle in position. Head up for visibility and supported shins/feet to work controls. Then you have to consider the seat & shoulder straps, which have to support multiples of your mass in a deceleration direction.
The other is hang glider prone harnesses, which offer freedom of movement you don't need in a cockpit, but will hold you from falling out, with chest/back straps to keep you snug & not squirt out the neck opening.
Imho, the ideal, is to combine the two approaches. Have a leg support to index your feet at the controls, and support their weight. And use a simple harness that clips to the airframe ( roughly above hips & shoulders ) that secures you in the cockpit. That has the advantage of eliminating the need for a big padded "chest seat" and it's weight and interference in vision. ( might as well make everything in front & below, back to your waist, transparent. ) You still need some fixed pads to rest your arms on to index your hands to the controls, like your feet.
One seldom noticed advantage of "hanging in the frame" is egress and entry. You just have a "bomb bay" door you stand up in. With no seat structure nothing blocks your way, you strap on the harness ( maybe with parachute attached ) out side the craft, and clip in, into the airframe, with appropriate quick releases. ( a one handle release for emergencies is easy, with egress down through the doors. ( since they support no weight, they can be simple sheets of plastic, closed and held closed by bungees. )
I have tried having the pilot laying down forward in an early design of mine. I can definitely recommend AGAINST doing this with your design!
I tried how the Hortens had their pilot which was to have the head quite high and the knees up underneath the shoulders. The biggest problem was holding your head up and that breathing became difficult. The worst thing was landing when it would nearly break your neck and your ribs which aren't meant to take that sort of impact. I had thought that suspending the pilot from an overhead frame ( like a hang glider) in a cocoon or harness would be a lot more comfortable.