SuperCubGuy

This Thundertiger Lazy Tiger 51 ARF went together pretty well but the instructions were really vague on the CG. Plans said "4 inches from the leading edge (at the main spar)". Well, the main spar is closer to 5" from the leading edge AND 4" from the leading edge gives a different CG depending on where along the tapered wing I measure from. If I use the middle "apex" and measure back 4", it gives a CG that needs a bowling ball in the nose to balance. Any help on this would be greatly appreciated.

n7tb

Flip the plane over and measure from the front edge of the wing on the flat surface back to the wing spar. this is the support that runs from the fuse to the end of the wing. It should be about 4.25 in. back. Balance to that point.

I flew my Lazy Tiger with a OS MAX25 for a year and it flew fine. A little underpowered but fine. I put a TT PRO 46 in last night. I was afraid it would be too much engine. I had to put 4.5 oz in the tail to balance the bigger engine. Amazingly, it flies fanastic. Unlimited vertical, but slows down fine for landing. It flies like a whole new plane!

Enjoy your Tiger and use plenty of exponential if you have not flown a plane with such big control surfaces before.

Terry

SuperCubGuy

Thanks, Terry

I assume you measure the 4.25" back from the "apex" of the wing at the middle of the fuse. I'm not too happy with the way my Saito 30 four-stroke runs so I may use your suggestion and go with a 40 two-stroke. That should add the extra weight in the nose that it seems to need for CG balance. Sounds like it'd be even more fun to fly....

Roger

n7tb

No, turn the wing over to get to the flat bottom side. You should be able to feel the spar running lengthwise across the wing half. If you measure from the FRONT EDGE of the wing to the spar it will be about 4.25 in or thereabouts.

that is the balance point. I flew my lazy tiger tonight with my 46 in it. the key is to use a lot of exponential and fly with no more than the recommended throws for low rate to start with. Then change from there. I have had to reduce the throws of the elevator more than the ailerons.

The plane is a blast to fly with the right setup.

I had to add 4.5 oz to the rear of the plane with the 46 engine in the nose.

Terry

glowplug

My Feedback: (1)

SuperCubGuy,
I flew mine with an OS 40FP bushing engine. It was a perfect match for the plane....balanced out perfectly and had plenty of power. I think a low-cost TT GP .42 or OS 40LA would work very well in this one.

Mike

DBCherry

My Feedback: (4)

Typical point for measuring CG is where the wing meets the fuselage. (Balance the plane inverted if low wing.)
Dennis-

SuperCubGuy

Thanks to all you guys for your generous input. I bought a 40 size OS at a fly in a couple of weeks ago (one of those blue colored ones). If you guys think it'll dazzle the kids and little old ladies, then I'll go for it.....

Roger

glowplug

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oh yeah, it'll dazzle 'em