Posts: 99
Joined: 12/9/2002 From: Muncie,
IN, USA Status: offline
I built a 76 inch flying wing based upon the Northrop N9M. Scratch-built. The wing weighs 3 lbs 1 oz. It is powered by two Speed 400 motors (pusher configuration), two BECs and an 8 cell 2400 mAh battery pack. It will fly for 8 minutes at full power and about 12 - 14 minutes with throttle management.
Today was its maiden flight. Winds were out of the east at 15 mph gusting to over 20 and the wing flew great. No noticeable adverse yaw.
Many improvements learned with my first two wings (96 inch, single .46 size engine pusher version and 48 inch single engine electric) were incorporated into this wing. The elevons are longer and I have learned to build wings in such a way that most of the heavy stuff will fit into the nose.
Time to get some stick time on this plane while we design and build the 14 foot wing for Toledo 2004.
Posts: 99
Joined: 12/9/2002 From: Muncie,
IN, USA Status: offline
I appreciate the encouragement. This is the 4th pure flying wing (pure = no vertical surfaces) I have built since last December. While I used John K. Northrop's patents to design these planes, there was quite a bit of "try and die" experimentation involved. What I have now is a pure flying wing that can be flown within the confines of a 600 foot x 300 foot field. There is plenty of lift for a normal person to hand launch this plane and have plenty of time to hit the throttle before it gently glides to the ground.
I built this particular wing so I could fly it at a local field, less than 1/4 mile from my home. Electric power allows me to spend more time flying and less time preparing to fly. Maximum stick time per flying session.
Now we are working on wing number 5....the 14 footer, twin engine glow.
Posts: 401
Joined: 12/4/2003 From: River City, TX, USA Status: offline
Jeff...I really like the wing you built...I don't know if you remember the Klingberg wing's that were out several years ago built I built one and installed an Astro .05 FAI and was using Sanyo 1400 mah SCR batteries and a Corelli car type speed control and it was the most stable plane I have ever flow. It was semi aerobatic and I was getting about 5 minutes AFT, It was very easy to fly but it would disappear if you were looking at the cross section for very long in a flight but It sure was a crowd pleaser. I lost it at the grand opening of our flying field...it was real windy that day and I had it sitting on top of the motor on my truck charging the batteries when it was lifted off the truck and slammed into the parking lot. I looked it over real good and when flying it the next time the right aeliron came off and that was all she wrote. It would sure be nice if you had a set of plans ...I really would like to build another one someday. C.W.
< Message edited by Boss248 -- 12/14/2003 9:52:56 PM >
Posts: 99
Joined: 12/9/2002 From: Muncie,
IN, USA Status: offline
Paul,
Thanks so much for your comments and feedback. The wing does look very majestic in the air. There is just nothing like flying a pure flying wing. I quickly learned this spring and summer that when I take a flying wing to the field be ready to answer a lot of questions and be prepared to always fly in front of a crowd of spectators. It does attract attention because it looks so unique in the sky.
There is plenty of yaw control. When the CG is properly set and the correct amount of differential is mechanically set-up in the elevons, you will find the wing to have little adverse yaw. Plus, the spinning prop(s) provide yaw stabilization through the gyroscope effect. The CG range on this flying wing is 1/2 inch....and that is typical for a wing of this size.
I plan on offering plans for an IMAA-legal version of the wing. It will have at least an 80 inch wingspan and offer the builder powerplant options (electric or glow) and landing gear options (hand launched, fixed gear or retracts). Since I insist on building and testing everything I design, it will be this summer before plans are available. I will put you on my mailing list.
Posts: 99
Joined: 12/9/2002 From: Muncie,
IN, USA Status: offline
Paul,
Sorry, I mis-understood what you were asking.
Yes, through the use of clamshell drag rudders your can add yaw control to the wing. The drag rudders are are toward the tip of each wing. They open up and the wing slows down allowing the other wing to travel faster and yaw. Attached is a picture of a drag rudder.
Adding drag rudders does add some complexity. The ends of the wing get pretty thin and housing a servo small enough to fit and strong enough to operate the drag rudders is an interesting project. On larger wings (12 foot and above) this is not an issue.
Posts: 21
Joined: 11/20/2003 From: lakeland, FL, USA Status: offline
quote:
ORIGINAL: NorthropN9M
I appreciate the encouragement. This is the 4th pure flying wing (pure = no vertical surfaces) I have built since last December. While I used John K. Northrop's patents to design these planes, there was quite a bit of "try and die" experimentation involved. What I have now is a pure flying wing that can be flown within the confines of a 600 foot x 300 foot field. There is plenty of lift for a normal person to hand launch this plane and have plenty of time to hit the throttle before it gently glides to the ground.
I built this particular wing so I could fly it at a local field, less than 1/4 mile from my home. Electric power allows me to spend more time flying and less time preparing to fly. Maximum stick time per flying session.
Now we are working on wing number 5....the 14 footer, twin engine glow.
Jeff
Hi Jeff,
You are flying my kind of bird - all (or at least mostly) wing and engines pointing the "wrong" way. What type of airfoil(s) are you using. My experiments have been limited to simple symetrical NACA types. However, I have never built a flying wing with the aspect ratio of the N9m. Attached pic of my latest is about 3:1. I salute you on your design abilities, that looong wing and all those ribs, outstanding work.
Posts: 99
Joined: 12/9/2002 From: Muncie,
IN, USA Status: offline
I don't know about controlling yaw with varying the speed of each engine. They did not use this technique on the full scale Northrop planes and they do not use this technique on the B-2. Drag rudders have been the choice for yaw control.
However, this is model aviation and you can do whatever you want. Experiment and enjoy!
Posts: 99
Joined: 12/9/2002 From: Muncie,
IN, USA Status: offline
Scotty,
Thanks so much for your kind comments.
I am using an Eppler 334 airfoil from root to tip. This is an airfoil made specifically for flying wings. It delievers high lift...and wow...does it ever.
Last week when we tossed the plane for initial CG testing, it flew for over 100 yards into a 10 mph headwind.
Printable Version
All Forums >> RC Airplanes >> Scratch Building, Aircraft Design, 3D/CAD >> Flying Wing -- 76" wingspan -- Maiden Flight Today 
Flying Wing -- 76" wingspan -- Maiden Flight Today - 
Experiment and enjoy!