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Old Jul 18, 2003, 10:43 PM
Missileer Extraordinaire
Mel Duval's Avatar
Joined Jun 2001
2,050 Posts
Tip stall on GWS Spitfire???

I have been flying a GWS Spitfire and it has an odd tip stall problem. It is completely stock, has plenty of power and weighs about 15-16 ounces, so I don't think it is too chubby. If you turn it too hard, or loop it too hard or just pull the elevator too hard, it tip stalls. It always goes right. It is also real sensitive in pitch. I have tried moving the CG way forward up well past the spar towards the LE and raising the ailerons about 3/32. Better, but it does not go away and it flies very noseheavy. I am about to try blunting th outer leading edges on the wing and then raising the trailing edges out past the ailerons 1/8" or more. Any thoughts or suggestions?

THX,
Mel Duval
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Old Jul 18, 2003, 11:09 PM
Burnin' holes in the sky!
SkyPyro's Avatar
Gilbert, AZ
Joined May 2003
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It sounds like you should check your elevator, this seems like a case of different left/right side of the elevator deflection, not tip stalling. Also check the vertical CG by holding the plane up by the prop and the rudder. Just weight the wing that goes higher.
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Old Jul 19, 2003, 02:06 AM
Tassie Electric, Heli, Glider
ChrisJ800's Avatar
Hobart, Australia
Joined Oct 2002
2,559 Posts
Have you tried reducing your elevator throw. My spitty is using less elevator throw than recommended but more aileron throw. Even so it can still tip stall if the loop is too tight, but so can most planes
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Old Jul 19, 2003, 06:40 AM
Crazy Cessna Owner
Robbie d's Avatar
Australia, SA, Windsor Gardens
Joined May 2001
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that good old elliptical wing, a tip stalls paradise. keep the speed up and don't turn too sharp
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Old Jul 19, 2003, 07:05 AM
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United States, NJ, Fair Lawn
Joined Nov 2002
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Compared to my Astra Spitfire, the GWS Spit has almost no tipstall tendencies. Every now and then it kinda wants to tip stall coming out of a loop but very gently and easy to recover from... I've found out that it you relax the elevator a little (i.e. don't hold it all the way back) when coming out of the loop, no tip stalls occur. Hope this helps.
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Old Jul 19, 2003, 07:08 AM
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London, England
Joined May 2003
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My Alpha Models P-51 Mustang is the same, you have to be relatively experienced and concentrate while flying it. (Well, I do!)
I'm going to only try to fly mine over long grass or even crops from now on, I've damaged it a couple of times when losing speed and stalling at the last minute when landing. It's pretty intense!!
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Old Jul 19, 2003, 09:00 AM
Burnin' holes in the sky!
SkyPyro's Avatar
Gilbert, AZ
Joined May 2003
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Also, instead of adding a ton of expo, decrease the overall throw. If you have over about 50% expo, it gives you a false sense of security on how much throw you have.
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Old Jul 19, 2003, 06:18 PM
Missileer Extraordinaire
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Joined Jun 2001
2,050 Posts
Thanks!

Thank you for the suggestions. I have reduced the elevator throw and checked the side to side CG as well as the elevator throw for eveness. All look good. If you've ever flown a Hobie Hawk with a too far aft CG, that is exactly how it flies. The weather here went to pot today and any testing is off till at least tomorrow.
thx again,
Mel Duval
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Old Jul 19, 2003, 06:31 PM
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Joined Feb 2002
295 Posts
I just maidened mine today and the first flight was almost it's last! The CG was back 65mm and it was all over the sky, after I got it down I taped 2 pennies to the nose and it was a lot better.
About 1/2 the roll rate of my P-51 and it wouldn't even start to loop before it would flop out. I've reduced the elevator throw from 10mm to 8mm and maxed out the airlerons.
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Old Jul 20, 2003, 09:39 PM
Missileer Extraordinaire
Mel Duval's Avatar
Joined Jun 2001
2,050 Posts
Getting better

Flew it about 6 times today and had at least 3 unexpected arrivals and ripped the gear off again. It is staying off this time. I will say one thing, it is a tough bird. The blunt wing tips helped just a little. I tried a piece of 1/16 tubing on the leading edge of the stab to see if the blunt stab airfoil was causing problems. No change. Finally raised the outer tips out past the ailerons about 1/4 inch and now it is manageable. It will still tipstall and go right, but you have to wind it up fairly tight to cause it to snap. It will not do it in a right bank unless you wind it up real tight and then it spins into the turn. It is very odd beast. It looks good in the air but flies and lands faster than I like for the small field we have.

later,
Mel D.
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Old Jul 20, 2003, 10:19 PM
Live to fly!
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United States, NJ, Fair Lawn
Joined Nov 2002
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Check out the video I just posted (http://www.rcgroups.com/forums/showt...hreadid=135385). As you can see, there's almost no tipstalling as long as you relax the elevators coming out of the loop. Sorry you are having such a bad time with the Spit. I love mine dearly, but I know how you feel because I went through the same with the Zero last year - seemed like everyone had theirs flying nicely and mine was tipstalling like crazy... My CG on the Spit is at 62mm and the bird weight 14.75oz with an 8cell 800mah pack... Hope your luck improves!
Doc
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Old Jul 21, 2003, 05:58 AM
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London, England
Joined May 2003
1,597 Posts
Solution?....

Hi guys,

I was at the LHS the other day talking to some of the guys there and they said these warbirds can be made much nicer to fly if you raise both the ailerons 1 or 2 mm to add a bit of wash-out. This helps to dampen down tip stalls and makes the plane a bit easier to fly. The plans for my Alpha models P-51 suggests doing that for the first few flights to get used to it. I've done it to mine now, I'll let you know how I get on next time I go out for a sortie!
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