Posts: 4770
Joined: 4/28/2003 From: Brunswick,
GA, USA Status: offline
holy crap dude! That's awesome! But it's not a delta. That's a little important. Check this site out for a great graphic showing how to get close to the cg.
That'll help but most flying wings use a lot more than that. The real Komet had the tips washed out about 5 or 6 degrees IIRC.
But what about some description of the airfoil? When I look at the picture shadow and highlights on the upper surface seem to show a high point back quite a ways. If you made this model with a symetrical airfoil then it's not a problem but I can tell you that if you made it with a flat bottom shape and the high point is that far ahead I see nothing but problems in your future. Flying wings are very sensitive to airfoil shape when it comes to the camber line shape. If you don't know the camber line is the imaginary curved line that runs half way between the lines of the upper and lower surfaces. On all the self stable or low pitching moment airfoils this camber line has the high point further forward than on "regular" airfoils and then the camber line reflexes up again at the trailing edge. That reflex is what you're adding when you reflex the control surfaces upwards to change the shape of the airfoil. You can always add more reflex to make it fly but at some point there will be so much reflex that the model won't be all that happy about the whole thing. Symetrical airfoils or those that are close to being symetrical (low camber %'s) don't suffer from this problem as much. The Zagi airfoil is an example. It's not stable by itself but it's got a low camber value so a little reflex on the control surfaces that are always tacked onto the rear does the job.
Can you take some more close up pictures of the wing root upper and lower sides? Try to use an angled light as well as the flash so we get more of a 3D look to it. Depending on where you wing section fits into the above we may be able to help more.
Posts: 59
Joined: 2/1/2004 From: , ON, CANADA Status: offline
Thanks for all the helpful suggestions guys the time has come Its Sunday morning here and the skys are clear the winds are good and ITS WARM!!! [north of the 48th] time for talk is over the sh## is about to hit the fan Rubber meets the road. Hopefuly the Corro gods are smiling.Will have some video of the test ,its gona be here in triumph or on the worst crash thread. Wish me luck ,I'm outa here.
Posts: 528
Joined: 7/23/2002 From: Elko, NV, USA Status: offline
quote:
ORIGINAL: Tall Paul
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!
Just to let you know, the Slo Motion has at least 5 variants that I know of. This includes the electric and comes in lots of sizes. I mention this only because of the FBI variant, Call that because it is said to fly by itself. It has a larger wing and really is a floater. It is so slow you can walk beside it! Also the Slo motion has a clipped version and it is the racehorse of the whole line of Simitars! It will bust the 100 mph barrier with out even breathing hard and a dirty version (stock, not cleaned up) was clocked at over 125mph. Quite a range for one type of plane. We just received about 30 wing core sets for our Simitar fun fly we have in the summer. Hopefully (depending on health) Bill Evens and entourage will make it down again. I just got some tapes from him showing his whole line, and it is something else. They even have a twin fuse Pole Star pulled around with two Super Tiger 3000s. Just seeing that tapes has me a little fired up, and reading this was too much for me and I just couldn't keep quiet,,,,, sorry. I am going the other way and am building half A sized ones to go with the regular size ones I have.
Hey Canadianice, Just to give you my insight on your plane. The smaller the plane the less deflection you need in the flaparons, in the little ones, you can almost set them at zero and use the trim to make any adjustments. As far as washout, none of the Simitar Series has any, and you cannot get a tip stall from them. He even took a CAP 21 and cut off the elevator and horizontal stabilizer, changed the CG to reflect the flying wing it had become and flew it, again no tip stall what so ever. It may just be the flying wing type, but I don't think tip stalling is a problem, so I wouldn't worry about washout. Just my two cents, MR Flyer57
Posts: 4701
Joined: 6/23/2002 From: Palmdale,
CA, USA Status: offline
I did the "remove the horizontal on a CAP, rebalance etc..." unfortunately the moment arm of the motor over the landing gear resulted in nose-overs, as the "elevons" weren't in the prop blast to keep the tail down at power application. At two props destroyed, I gave up and went back to a tailed configuration on that plane. No reason it can't work though, with enough control authority at low speeds to keep the nose off the ground.
Posts: 528
Joined: 7/23/2002 From: Elko, NV, USA Status: offline
Hey Tall Paul
Small world, I most likely have you on tape. I just got the one where he is out at the field flying it. Also have a segment where he is outside his house showing the planes and mentions it. These tapes talked a lot about Australia and were made in the late 90s. Also got the tapes of them flying above 10,000 feet, though I don't know just where it was at. I hope to get up there to fly sometime. If you see Bill, ask him about his Elko Buds, Marshall MR Flyer57
Posts: 269
Joined: 10/11/2002 From: Cerritos, CA, USA Status: offline
Sorry, the Toucans have a 15 degree swept forward leading edge, not straight. Should be equal to a couple of degrees of dihedral at least. But since the wing is flat, perhaps it can't decide which way to adversely roll?
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RE: Flying wing designs - 
