Does anyone know of any sources for designing flying wings ?

I'm wondering how easy/stupid it would be to design a flying wing with dihedral and rudder/elevator control (rather than the usual elevator and ailerons).

I never see any flying wings trainers and I wondered why that was.

Thanks,
Nathan

Can be done... however, the rudder control would always be marginal.

The problem cones from the rudder being close to CG... very small moment arm on the rudder's force applied means... it takes a heck of a rudder to get the thing to turn.

Spoilerons work better for yaw on a flying wing. You just lift the spoiler on the wintip of the wing you want to slow down... the plane can pivot around the wingtip. (the spoiler also drops the wing a bit and gives the bank desired)

Now... the problem becomes one of... making the linkages.

Would substituting ailerons for rudder control work ? So have dihedral to give stability and turn using ailerons ?

HI DIGSY! Flying wings perform so well with elevon control, that it seems you are only shooting yourself in the foot by using a close coupled rudder. Now if you were to hang a rudder off of a fairly long boom, then you could use the wing flaps for pitch control. If you do a search on BILL EVANS and his SCIMITAR designs you will run across some planes that should be right up your alley.

Check out this site for all thing flying wing oriented. http://members.cox.net/twitt/
Models to full sized, GREAT SITE, and quite a bit of info!

Jetts

Note the Stealth bomber: for Yaw control it uses airbrakes at the wingtips... doesn't even HAVE a rudder. It uses elevons.

Note the Gremlin Combat models: they have dual fins... no rudder, and uses elevons.

Note the Zaggi: (considered by some as a trainer in flying wing configuration... ) It just has some wing tip fins (if you bother to put them on..) Again... elevons.

They ALL do it this way because... it works.

There are others...

There have been a few flying wing gliders that use dihedral and rudder-elevator control. The Raven is one and the designer of that model has a few others like it. The Windlord is another. Plans for that one are available from RCM. A buddy of mine built one and it flew great. Large rudder though... VERY large rudder.

Trainer? A properley designed, built and trimmed flying wing would be fine as far as control response is concerned but perspective to determine what the model is doing in the air would be MUCH more difficult. Conventional designs just have much more bits that can be used for visual cues to allow the student to see what the model is doing at some distance. So while it is possible I truly don't think it's a great idea.

An interesting side note... When he built his version of the Toucan forward swept flying wing, MAN Editor Tom Atwood added a rudder control just to see what it would do. Since you should, theoretically, get reverse roll with rudder on a forward swept wing, he thought it would be very interesting.

In flight - nothing. Nada, zip, zero, bupkas. The airplane yawed a bit, and proceeded to fly straight and level with no correction required. Strange!!

Larry

I read somwhere years ago that the stability equivalent between dihedral and wing sweep was such that it takes roughly 30 degrees of sweep to equal the effect of 5 degrees of dihedral.

The Toucan has a straight leading edge with a swept forward trailing edge. As such the sweep angle of the 25% chord line is very slight. Certainly not enough to be a factor based on that sweep to dihedral equivalency of 30 to 5. So it's no wonder that they would not have noticed anything.

Tried rudders on a Zagi one time. Kept flying wings level with a bit of a yaw. Useless too, but just an experiment.

Flying wings can be designed the same way you design an airplane that has a horizontal stab and elevator.

I have taken a standard airplane and chopped off the horizontal stab and elevator, moved the CG forward to 15% of MAC and then had a great flying model. If you want dihedral, put it in. Do whatever you want. Just remember to move the CG forward.

Build a free flight profile model glider of your proposed design. Launch it using a catapult. That model will show you where the CG should be. Attached photo of some cat launched styrofoam free flight glider.

Rudders work fine on a flying wing. The attached model can do knife edge flight the length of our flying field.

If you want a trainer with rudder and elevator, do a flying wing glider as shown in the attached photo.

Build all models in foam.

My background is 30 years of designing building and flying Flying Wings made from Styrofoam.

Attached is my latest project. Vulcan Bomber with a 36" wingspan.

Ive read a couple of articles from the early 50's on swept-forward flying wing rubberpowered and glider free flights. @ 15 degrees forward sweep on the leading edge, some dihedral, symmetrical airfoils, elevators (adjustable for trim) and a huge vertical rudder. As I recall the airplane would dutch roll with a smaller rudder. I think I remember a few degrees positive incidence on the wingtips.

Jim

Hi DIGSY
I have built the Slow Motion 40 from plans of Model aviation, a plane from Bill Evans Simitar series.
Check the RC modeler site in plans site for Simitar, Polar Star , Desperado and Desperado Three Thousand.
The Slow Motion is for beginners, I am, you can buy the foam cores in USA and make wings , the fuse is very easy box, have only rudder.
Fly like a trainer with a Tower 40 engine and manage wind very well.
All the Bill Evans say is true gentle stalling only drop a bit the nose, sharp turns , good speed etc, I highly recommend you
Also you can see the faces and comentaries in the flying field.
I am making an enlarged version of a Bill Weedwacker of Flying models magazine with a Weedeater 25 cc engine.
Good Luck
Jose

The Slo Motion is a relatively tame airplane when underpowered. Put on a snortin' 40, like the piped MVVS on this one, split the elevons into ailerons and elevator, and it kicks!
Flown this with a K&B 28.. yawn!.. Johnson 36 R/C.. OK, and the MVVS...Ideal!

OK, my mistake. It DOES have a sharply swept forward shape and that would imply that it should have reacted to the rudder by rolling. Either the dihedral effects due to sweep angle are not as strong as my old information suggested or there was something else at play with the Toucan.

Did you ever get yourself squared away with flying wing designs?

Paul

Check out the models and videos on TufFlight's website www.TufFlight.com.

They make combat and sport models, and do a lot of stuff with flyings wings. They have (or had) a trainer version.

They also have a version with a rudder called the Enduro .40 that does some wild flat spins, including a flat-spin-landing you have to see the video to believe.

MY 2c about flying wings
I think the more practical application of rudder would be to istead of using the conventionally, deflect them and use them as spoilers
I have flown the SPAGI or Coroplast Zagi. Swept flying wings have some interesting characteristics
Bad Looping(Unless you have unlimited vertical
Roll- not so hot
high aoa stall qualties-[:'(] I have had a zagi spiral in after a stall after a rol. it cartweeled on the ground-first time I have seen a zagi flat-spin This is because swept-wings inherently have tip-stall

I believ it does not use airbrakes, because in order to make them effective (get them out of the boundary layer, so that they actually contact the air) The penalties in stealth would be considerable, so it uses differential engine thrust for yaw
As for the advice to build fying wings out of foam, I agree, but coroplast is nearly indistructible, and you can build a zagi in 2 nights. Because of this, you can mess around with it more and try ideas.

I am also looking into building a flying wing. does anyone have any comments on the possibility of a ducted fan flying wing constructed from reinforced low density moulded foam.

I realsie this is a pretty unspecified (and unknowledgable) question but i am trying to get an idea of what problems i am likely to face.

Thanks

Ducted fan in a flying wing?

No problems at all other than the usual structural engineering concerns.

Here is a pic of my scratch built wing it loops very nice and tight but with to much elevator it can still be "snapped" out , it has a very fast roll rate. I have seen the zagi "death spiral" also, thats the reason the verticals are swept back. It should be fairly easy to design one for a ducted fan. go for it and have some fun.

HEY KENNY! That's a great looking plane! How big is it, and what is it powered with?

Its 48" with an OS 15. It was foam and sheeted wing. It has a very thin semi symetrical airfoil. A good 46 and a carbon spar might be lotsa fun

TufFlights airplanes remind me of a penguin hopping in and out of the ocean onto a snow bank. The airplanes are the closest thing to an "organic" feel I have ever seen. I think big gliders certainly are graceful in the air as are a lot of other airplanes but they are still very much an airplane. The TufFlight designs just hop around with a sense of complete animal freedom. Landing on its nose in the snow, bouncing and still keep on flying was a very trick. Well worth visiting the web site.

Hi guys I just finished a Komet 163 and am looking for any help in setting it up. ie up reflex in elevons? any an or all help much welcomed thanks C.G. I blew it up from 3 views so I dont have any of this stuff and it is my first delta wing