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Stick won't take off

Old 06-18-2008, 06:38 PM
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flyhi
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Default Stick won't take off

got a stick arf from ebay, it's 55 inch wing, 43 fuse, don't know weight, got a tt .46 on it and it just won't leave the ground. I'm an experienced flyer. balanced it 4" from le as manual says, but guessing the cg is not right. seems like the mains may be a little forward, also. any ideas? thanks
Old 06-18-2008, 07:14 PM
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Villa
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Default RE: Stick won't take off

I saw this same thing at our field the other day. The prop was on backward. Happens occasionally.
Old 06-18-2008, 09:35 PM
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ChuckW
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Default RE: Stick won't take off

Does it seem to have plenty of forward speed?
Old 06-18-2008, 11:26 PM
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flyhi
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Default RE: Stick won't take off

ran right down to hanger to check prop, it's on ok. but good suggestion and i must admit a couple years ago i did put one on backwards. anyway, it seems to have enough forward speed. even tried to tap down elevator to get tail off ground and it still would not get airborne. maybe engine speed is low, didn't sound like it, but will check that. thanks
Old 06-19-2008, 01:46 AM
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sscherin
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Default RE: Stick won't take off

what is the incidence of the tail and wing?
It's really odd that the tail won't fly.. it's a tail dragger right?
Old 06-19-2008, 02:09 AM
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Default RE: Stick won't take off


ORIGINAL: flyhi

got a stick arf from ebay, it's 55 inch wing, 43 fuse, don't know weight, got a tt .46 on it and it just won't leave the ground. I'm an experienced flyer. balanced it 4" from le as manual says, but guessing the cg is not right. seems like the mains may be a little forward, also. any ideas? thanks

G'day Mate,
Make sure that the tail wheel is not keeping the wing & tailplane at 0 degrees angle of attack, it should sit on the ground with the wing at a positive angle of attack, if not, it won't lift the tail, & it won't be able to rotate.
You may need to bend the tail wheel up a bit to drop the tail.
It happened to one of our club members, with his new Excelleron, it would taxi all day at a great speed, but the thing would not lift the tail, so it couldn't rotate, & the wing would not produce lift.
Old 06-19-2008, 05:40 AM
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Default RE: Stick won't take off

What prop size are you using? Be careful about what these ebay products say in their manuals. The recommend C of G is probably way off. Make the C of G just forward from the center of the middle of the wing and try again.
Old 06-19-2008, 05:46 AM
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Default RE: Stick won't take off


check that both of your ailerons are not slightly "up". If anythig they should be slightly "down". If they are slightly both up it will pin the plane to the ground. Slightly both down will decrease takeoff roll.......Gene
Old 06-19-2008, 09:40 AM
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Default RE: Stick won't take off

I finished someone elses Jenson Stick and I accidentally made the wing incidence too low. it makes the roll out a bit longer. if there is anything you can do to get the wing incidence up like larger wheels smaller tail wheel etc. or if its a trike then increase the length of the front wheel.
Old 06-19-2008, 12:54 PM
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Default RE: Stick won't take off

One thing that occurs to me, that has yet to be mentioned - is DOWN THRUST. []

IF the Firewall is incorrectly installed the engine could be pointing DOWN a few degrees, as you power the engine up, the plane is literally being pulled into the ground and... you cannot lift off. [:'(]

Loosen the engine bolts and insert a washer between the mount and the engine. This will lift the thrust line and (hopefully) correct the problem.

BUT! use thin washers - it dosen't take much to change the thrust line. Too much 'UP Thrust' will simulate a tail heavy condition, More washers can be added later if needed...

Good Luck!
Old 06-19-2008, 09:14 PM
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flyhi
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Default RE: Stick won't take off

thanks to all, love the advice, i'm going to try the incident and the tail wheel both and see if it works. i will also check the engine thrust line.
Old 06-20-2008, 09:45 AM
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carlosponti
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Default RE: Stick won't take off

most sticks arent built with any down thrust. if there is it will be minimal.
Old 06-20-2008, 11:09 AM
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Default RE: Stick won't take off

I've seen happen more then once. Make sure the elevator is moving in the right direction. If it is, do you have enough throw in the elevator? Last fix is to get a new plane or call this one a three wheeled car. Dennis
Old 06-20-2008, 11:46 AM
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Default RE: Stick won't take off

I would agree with Dads, something is wrong with this picture. First balancing at four inchs aft on a 55 inch wing unless its a severely low aspect ratio wing is much too far aft and likely a good thing you never got it off the ground.

Problem is with the CG that far back if you can rotate that thing is likely really jump off the ground possibly uncontrollably. But you can,t which seems to say you either have the elevator responding backwards or some thing is preventing the airplane from rotation like main gear far to short and unable to acheve a sufficient angle of attack for take off.

You got everyone just speculating if you want help then post a good side view of the airplane (profile) and then things can be chased down or at least a link to where you bought this thing.

John
Old 06-20-2008, 12:00 PM
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flyhi
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Default RE: Stick won't take off

hey, thanks for all the great ideas this weekend i'll take it out and check aoa and will move cg a little forward. i thought 4" was too much, thinking of starting at ab 3 3/4 to start. and, hey, if it crashes i'll get something else.
Old 06-20-2008, 12:39 PM
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Default RE: Stick won't take off

You don,t need to take it out to check the a.o.a. Sit down on the ground, now what kind of deck angle do you have?

Agine a link or picture would help.

John
Old 06-20-2008, 01:05 PM
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sscherin
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Default RE: Stick won't take off

The GP Big Stick 40 (58" spam) has a CG range from 3 3/4 to 4"
I'm at about 4" on my old Midwest Stick and might move it back more..
It sounds like allot but remember that this wing has a big fat 13" cord.
That puts the CG right around 25%-30%
Old 06-21-2008, 10:10 AM
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eagledancer
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Default RE: Stick won't take off

more then likely alan0899 has hit on the problem, make sure your gear is letting the bird sit on the ground slightly nose up, have had this before on a few planes, one that i remember well was a nitro p-38 didnt want to rotate and when it finally did was like getting sling shotted into the air at about a 45 degree angle, a change in landing gear lengths cured that problem
Old 06-22-2008, 04:33 PM
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flyhi
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Default RE: Stick won't take off

things didn't work out to go to the field this weekend, however, i took the fuse, minus wing, on flat surface and the tail is definitely way too high, there is zero aoa so i'm going to shorten the tail wheel and hope that fixes it. thanks to all for the great suggestions, this is an amazing hobby where we all pitch in to help others, that's one reason I like it. plus, the sound of balsa hittin' the ground at about 90 degree angle is so heart warming.
Old 06-23-2008, 04:47 PM
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flyhi
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Default RE: Stick won't take off

Success, I lowered the tail wheel about 1/2 inch, put cg at 3 3/4 and it took off and flew fine. again, thanks for the input it would've taken me a long time to check the aoa on this.

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