How much weight is too much?
 

I just got done building my Avistar but it is very nose heavy. I moved the battery and receiver back to just in front of the servo tray but it's still nose heavy. I added about 6 oz. of lead weight right behind the servo tray but it still needs more. This is with an empty fuel tank. Is there any way to add weight further back in the tail or should I continue to add weight behind the servo tray until it balances? The plane weighs about 5 lbs. and is powered by a TT .46 engine. Thanks.

RE: How much weight is too much?
 

Take out the weight in the fush and put under the elavator, this way you will use less. If at all possable move the batt. behind the servo tray first. Next try and move the engine back as far as you can. staying under 6 lbs this plane will fly great. A little extra weight will not hurt the plane. Dennis

RE: How much weight is too much?
 

What point are you using for CG. It should be acceptable if it balances between 65-90mm from LE.

RE: How much weight is too much?
 

I ended up putting my battery pack on my Avistar aft of
the servos.. Just after the fuseage (not sure what its called)
spar/rib.. I put it between the rod guides of the rudder and
elev. foamed wired tied it in.. It came out great on my CG

RE: How much weight is too much?
 

I thought about placing the battery behind the servo tray, I'll have to try that, was any other weight needed? The manual reccomends the C.G. at 83mm from the leading edge. How would I add the weight to elevator? Thanks for the responses.

RE: How much weight is too much?
 

You don't add weight to the elevator he said under the elevator.

You can buy stick on weight just add it to the bottom of the fuse under the elevator as far back as possible. The reason for this is that it will require less weight to balance. BTW that also why someone reccomended moving the engine back towards the fire wall

RE: How much weight is too much?
 

Great Planes offers lead strips with double stick foam tape. Cut off about 1/2 to 1" section and stick to the side of fuselage right under horizontal stab. Try moving the batteries first; sometimes the lead on tail trick is unavoidable.

RE: How much weight is too much?
 

Thanks for clarifying, I thought about sticking some weight back there but I was worried that it would come off in flight. I'll do that then if needed, after I move the battery.

RE: How much weight is too much?
 

I've been using the stick on weights (I prefer the other brands besides GP, but I suspect they are all close enough) for quickie CG adjustments, they generally stick through most things you'll do as long as the surface you are sticking it to is clean and dry.

If you want it to look nice, cut a small hole in the bottom of the fuse covering way back, and epoxy the weight inside where it can't be seen.

RE: How much weight is too much?
 

The problem with the sticky weights is the can come off, dramatically changing the CG as you fly. I don't have an Avistar, but most trainers aren't all that sensitive to CG anyway, and nose heavy is always better than tail heavy. (I assume you're testing with an empty fuel tank.) If possible, I'd have an expert fly the plane with the engine mounted as far back as possible, and no added weight. My guess is that with the TT .46 (a very common combination), it will fly fine.

RE: How much weight is too much?
 

You should be able to balance that plane without adding any weight. That battery pack can be moved all the way back till the fuse is too narrow to accept it. Just move it back along the fuse till it ballances, cut a hatch, snake the cable & any extention required, install and replace the hatch. Heck, I had to surface-mount my elevator & rudder servos way aft on my .40-size plane when I mounted a .61 in it.

RE: How much weight is too much?
 

I did add another big washer just on the side of the battery..in the
pic you can see the other wire tie... As I started flying the __ll out
of the Avistar I did end up with stick on weights at the end of the
fuse just under the rudder... I removed the covering and C.A'd
the stick on weights there then I covered with white sticky
covering, there still there.... Now I added the washer and tail
weights just to make the plane tail heavy to see how it would fly..
It did respond somewhat better in hovering,snap rolls and such
But it was a little more touchy on landings.. But I liked it.. And
better yet it's still in one piece:-)