I should have posted here first but my plane seems to have reverse airfoils in the wings possibly caused by the drying process of the paint on the wings. I was wondering if I put both ailerons down somewhat a couple of degress would it give it a better/more stable airfoil? This thing is just too wild for me. I tried 40% expo and maybe need to add more and maybe I just need to reduce the aileron travel. If I can't smooth it out some I may sell or trade it. Actually come to think about it to get more of a flat bottom wing they would need to go up like a trainer. Please straighten me on on this before I sell the plane.

Thanks,
Jim

wholes thread on this at RC groups.com  http://www.rcgroups.com/forums/showt...20&page=53


link to Wattflyer discussion http://www.wattflyer.com/forums/showthread.php?t=56850

This model is simply a faster flying model -compared to the VAPOR
Your problems are in basic setup for THIS type model -
By reducing throws to aprox 50% and adding aboout 35% expo it will be much easier to fly- However you need aprox 50 ft by 50ft airspace to get aquainted with how it flies
If all yo uwant to do is hover and turn fast - MUCH less space is needed but to cruise around - yo will use at least the space I noted
No amount of airfoil reshaping will cure your problem - Loosing 10 grams would make a huge difference - but you simply can not remove that much weight!

Stability and speed is not set by the airfoil. It's set by the location of the balance point for the stability issue and the wing loading for the speed.

But if the paint you used on this wing has resulted in the shape deforming a lot then the differences from one side to the other will produce effects similar to warped wings or misadjusted ailerons. In some cases it'll also lead to one wing stalling before the other when trying to fly slowly so that you find that the model is extremely difficult to control.

You don't provide any details on what model it is or what paint you used or pictures. Without all that it's hard to say more about it. If it actually is the HH Extra model that is the subject of the other threads that you have then even if the wing were the right way up or properly symetrical it sounds like it's just more model than you're ready for at this point. What you need instead is another model that is more of a trainer. If you take this one back to exchange it or decide to put it on a shelf for later that's fine either way. But from your description you jumped in at too advanced a level of model for your present skill level.

Yes, the flight sims make it look easier than it is. If you based your choice on success with them then you just got bitten by the reality bug.

I looked again at the first post and apparantly the model is the EXTRA 300 by Parkzone which is NOT the UMX300
It is injected molded foam ,spray painted. The model is not intended to fly slowly like a Cub. And it won't
I als ohave th new UMX 300 (32 gram model) and tho one would think it flies in a manner similar to the VAPOR (18 gram)- it is not even close to being of the same character .
The advent of the ARF "whatever you want" designs has spawned a number of situations whre the new flier thinks that because th model is small and light -it is easy to fly
If you do some quick math -you would see that wingloading of these Micros can be (and some need to be) -in to one ounce to the sq ft catagory. As another example the tiny UMX Beast is a 2.5 ouncer and has 80 sq inches -and th wing loading is realatively high (do the math).
Ihave the UMX 300 and it flies like a larger say 1400 sq in model weighing 23 lbs.
It ain't a trainer!!

Thanks guys yes it's the foamie Extra 300 and main problem is the more flat on top and more rounded on the bottom airfoil. It's very twitchie even after 40% expo and if over or at 50% throttle it pitches wildly up and down. I have flipped the wings upside down to try but may see if I can trade it with someone for a T-28 Trojan before I crash it. I've flown it 3 times and don't find getting any better. I'm not the wildest flyer around but have flown 10 years or so. Dont' know if I want to try it with the wings flipped or not. Not the 3-D type of flyer. More scale like for me. I won the plane at a fly-in! Would not have bought it.

Thanks,
Jim

If the servos n linkages are all soli and smooth- then I would simply shove things forward in th fuselage ad try to get the CG at between 20-25%
I Know sounds like overkill but that will make the model much more stable - if all else is correct.
I have done a fair bit of flyin this type stuf as well as having built and reviewd them for magazine -
-The twitchy problem is rooted in th quest for so called 3D type performance -and the more aft cg -which helps that type flyin - can produce a fairly sensitive model
avoid any ballast the model is heavy enough as it is.
PS the airfoil means very little here.

The 260 has the same wing and same issue. I have heard of people mounting the wing on upside down and it flies better but I doubt that even after all that work you would be happy with it.

Exactly. Turning the wing over will help a LITTLE but it sure won't turn a fast "stally" model into a soft trainer like kitten. Espeically if they are overly heavy already as rmh says. Moving the CG forward by shifting the battery back is likely your best option. I don't know if you would need to go as far as to 20 to 25% but you certainly want to move it forward about 3/8 to 1/2 inch from where it is now. If that puts the balance to around the 25% point then so be it. It all depends on where it's starting from now.