Calling al GP Stuka owners

Anybody ever try to balance the Great Planes 70 inch Stuka where it
didn't practically fall off the balancer because it's so nose heavy?
Just curious as to what you have done to balance it. I could do the
obvious but I only want to add lead weights as a last resort. Here's my
set up.
I have a OS 91FX for power. According to the specs it weights the same
as the recommended OS 61FX. (550g-19.42oz) (too much power is almost
enough) I have the smaller 61 FX muffler on it. It weighs less and fits
better in the cowl. I have a 3 blade 14/7 master air screw prop on it. I
could use a lighter wood prop but I want to keep it as scale as
possible. I have a five cell, 6 volt 1800 mah ni-mh battery installed
aft of the servos. You can't put it any farther back without cutting a
hole in the bottom of the fuse to re-locate it. I also scratch built the
horizontal stab struts out of ply wood for scale reasons and for the
weight. I also used dubro ball joint clevises instead of the cheap
plastic ones that come with the kit. They weight more as well. I also
installed an I4C air whistle on the bottom of the fuse just before the
tail wheel. After all that it's still VERY nose heavy. I suppose I could
mount the rudder and elevator servos in the fuse, near the tail, but I
really don't want to go through all the hassle. What did you do to
balance it?
Reply to
K & C
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On 4/30/2004 6:24 PM Ted shuffled out of his cave and grunted these great (and sometimes not so great) words of knowledge:
Do you have room to move the engine rearward on the mount ? Another possibility are the wheels. If they are not of the foam type, try using the foam. That should remove about 1/2 oz from in front of the CG.
Hope this helps.
Reply to
Ted Campanelli
Ted, Thanks for taking the time to respond to my post. I have the motor mounted as far back as it can go on the mount. I used the foam wheels that came with the kit but since then I have replaced the foam tail wheel with a solid dubro wheel. All to no avail. Thanks anyway, Kevin
Reply to
K & C
I guess my first thought was do you have the right balance point? Kind of odd to me that it would be that far off and nose heavy to boot!
I'm not saying you hav'nt already checked it, but you may want to double check the measurement and verify it on the wing planform.
You sound like an experienced modeller, so maybe you already tried it. Use the CG calculator method from alan's R/C links and compare that measurement to your kit measurement. Be sure to include the ailerons in your calculations.
Good luck!
Reply to
Yep, I've triple checked the manual. Four inches from the LE. Haven't checked the calculator method yet. Looks like I will now though. Thanks for responding, Kevin
Reply to
K & C
Have you tried getting in touch with GP? Maybe there's a misprint in the manual.
K & C wrote:
Reply to
Charles & Peggy Robinson
"have the smaller 61 FX muffler on it." not recommended. The .91 FX will overheat and you will have frequent dead stick landings. Motor will not last long. Refer to previous comments on this NG from Great Planes/Tower and other .91FX owners. Fit the recommended .61FX with that muffler (or use correct size muffler for the .91) and you will have more enjoyable flights. regards Alan T. Alan's Hobby, Model & RC Web Links
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Reply to
Just wondering how much weight on the tail is required to balance your plane ?
Reply to
Charlie H.
Iadded lead!
Reply to
What's the chord of the wing at the root and tip? Four inches from the LE is a lot and might apply to a realy long chord.
Reply to
Dan Thomas

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