The P-2 "Carbon Condor" patrolling the neighborhood
This one-of-a-kind proof of concept prototype has a 5 ft span with an area of 540 sq. inches giving it a wing loading of less than 4 oz per square foot. It was the test-bed of the "Flex-Soar" series of Pocket Planes. Only a couple minute setup and no control surfaces. It's being flown here with a homebuilt dual IPS A drive with 10x7 APC sf prop and 7 cell 700ma Maxell NiMHs. There are video clips below showing it flying in about a 5 mile breeze.
Flies very nice on the GWS EPS-300C "BS" with 9x6 APC sf prop also but was limited with the 100C motor.
Control is mixed pitch and roll via true wing warping using 2 HS-81 MG servos. No strings, pulleys, weight shift, vectored thrust, or other cheesy control methods. Just simple, direct, and effective. I call them "Warperons".
This is not a kite. Although it uses lightweight ripstop kite fabric and CF tubes and collapses into a skinny bundle, that is where the similarity ends. The wing holds its airfoil shape at all times with only the washout being controlled via twist at the wing tips.
Wing shape is fixed except for the washout.
I originally tried weight shift control with limited results over 25 years ago and shelved the idea of an effective RC hang glider until now.
Weight Shift Controlled RC hang glider from 1976
The robot pilot did his job but rudder had to be added to assist turns.
Pitch control worked fine but landings stripped lots of servos.
The research I did off and on since that time for this project stated that effective control couldn't be done without hydraulics or other powerful driving forces. I also read that I couldn't use an undercambered airfoil without a horizontal stab or lots of reflex yet I had neither on my real hang gliders so I knew it could be safely done. For it to be a true flying wing I learned that it couldn't even have any vertical surface.
After seeing a seagull that had lost its tail still flying effortlessly with complete control, I was re-inspired to finish the project. Watching what he did for pitch and roll while soaring over the top of a sloped roof told quite a story so I gave wing warping a try. Hey, it worked for the Wright brothers and I've never seen a bird with ailerons, have you?
In all fairness, I had my doubts as to the control effectiveness prior to its first flight. However, as you'll see in the videos, It achieves a good roll rate for a slow flying 5 foot span wing. I did get some adverse yaw at low speeds but it has since been eliminated with some aileron differential.
Note the wing shape as it comes out of a zoom.
The stick here is back to pull out with some right bank to level.
Since this bird will quickly fold down to a skinny bundle, size isn't an issue any more for transport, only fly-ability.
Foam training bra optional!
Carbon Condor SPECS
Span - 60"
Area - 540 sq. in.
RTF weight tested - 14 to 15 oz.
Wing loading of about 4 oz per sq. ft.
homebuilt dual motor IPS "A" w/ 10x7 APC sf
also tested with
Johnson 250 w/MJ 5:1 GB - 10x5 APC folder
GWS EPS-300C "BS" with 9x6 APC sf prop
Batteries - 7 cell 700mah NiMH Maxell AAA pack
Radio - GWS R4PJ with 2) HS-81 MG servos
also used HS-555 for full range soaring
ESC - GWS GS-100 (w/brake)
Wing shape and angle of attack during cruise.
CARBON CONDOR MOVIE CLIPS
Movie (1) - Quick Time .MOV file - 3.7 mb - showing overcontrolled flight test:
Wing Waggin' (from clip #2)
Right click to download and save to hard disk and then open in media player.
This flight was one of its first. The CG was too far forward limiting pitch control and reducing performance. I couldn't even stall it with full back stick. Although it appears to be out of control toward the end of the clip, I was trying to do this only I was way over controlling and lost it just when the clip stopped. It just plopped uneventfully to the ground a second later.
Movie (2) - Quick Time .MOV file - 3.8 mb - circling, and testing roll response with wing wags:
This flight is feeling her out circling and wing wags. With the speed up, nice roll rate. When slowed down, you can yaw it around almost within a half wing span with no tip stall!
Movie (3) - Quick Time .MOV file - 6.75 mb multi loops, tight turns:
This flight was with the CG back where it should be and as you can see it will easily loop from level flight (twice!). Control is much better due to the increased pitch range. Stalls are just nose high mushes with steep descents being possible.