Ok I am going to try and get my Avistar to balance because it is pretty nose heavy. I noticed it sets a little nose high on the table. Would I be better off adding larger main wheels to level it and for a little more weight behind the CG to get my balance closer. I am using an OS 46 AX on the nose. I have about a 35-40 degree down angle on the front. And if I add the self sticking lead weights do I just take some monokote and tack over it to cover it up? The inside compartment is so tight there is not a lot of room to move the battery and keep it secured, so I am hoping that the bigger wheels will do it, but its so close to the CG I dont know how much that will help.

Separate balancing the plane (CG adjustment) from the angle it sits at on the ground. The Avistar should have it's center of gravity 'BALANCE POINT' at a distance between 25% to 30% back from the leading edge of the wing to the trailing edge of the wing. Having fixed that, the plane should rest level to slightly nose down on it's gear when it is a tricycle gear setup, 35 to 40 degrees is way too much. Try bending, adjusting, or replacing the gear wires until you get it right. If for some reason you must add weights to the plane because the CG is off (note - not related to the angle at which it sits on the ground), it's OK to just tack them on to the outside, but do try to relocate radio gear first before adding weights.

quint

Hi crashburn69, if you are using grass runways the nose up angle you have may actualy help,
I have trained a lot of people on the Avistar, personaly its one of my favorites to train on, and I do recomend it to everyone who asks. I think you may like it alittle nose heavy, I dont think I have ever seen a Avistar that needed weight to be balanced, not to say yours doesnt.If it does I would try to relocate the rx battery, you can get that sucker behind the radio tray with a little finagling.
You will not only have a lot of fun training on the Avistar, once you learn, the plane is capable of a lot of fun stuff.
Good Luck Dude!
Never add weight to a plane unless it is absolutly necessary

Sorry I just reread my first post. When its just setting is when its nose high. When I check it at 3.5 inches behind the leading edge as per instructions is when the nose drops. The reason I talked about it was to ask if adding larger wheels on the back of the tric gear to level it on the ground and adding a little rear weight to balance it when I hold it up. Kinda killing two birds with one stone type deal. One reason it might be nose heavy is I padded the tank area with a lot of thick foam. The instructions dont call for it, but most any other aplication I have ever seen recomending padding the tank. And I am also using the thick foam to pad my reciever and battery's. Most of the time it shows the thin foam but I like a lot of padding. That may be the cause of my unbalance.

I forgot to ask. Does 3.25-3.5 sound right. I noticed the manual was not right about a few things and wanted to make sure this was right.

Move the battery as far back as possible until the plane balances. It can be secured with a balsa stick between the fuselage sides, after you pad it with a little foam.

Right now I am looking at about 3 1/2 oz. on the tail to balance it, with stock tires, and stock battery location.

I swapped for the larger rear wheels and now I am down to about 2oz. Is this still too much? I had to use a 2 1/4" spinner to accommodate my prop.

Try and move the battery behind the radio compartment. If you need more weight than the stock battery, talk to your LHS and buy an 1100 mAh battery, it will weigh more and help balance the plane, and also give you a lot more cushion on battery charge. I did this as well, and stuck it in place with some double sided foam tape.
Only problem with the Avistar sitting nose high on the ground is if you touch down fast, like I manage to do most of the time, the wing is still flying, and still has angle of attack, so the plane will lift off and bounce. I put a much smaller nose wheel on mine once, and it helped immensely with keeping it on the ground, even when I smoked it in.

Andy

Not trying to hijack this thread or anything. I took a eyehook screw, and screwed it right into the top of my wing of my Nexstar at about 25-30% CG. When I hang the plane by this hook.... In order for it to be perfectly balanced, I should basically take a torpedo level to the bottom of the wing, since its flat, and make it a dead bubble? Correct? The bottom of the wing should be level?

what size prop are you using that you need a 2 1/4 spinner? i run an 11x4 with no proplem and it flies great.

The 11x4 worked on the stock one, but I turned it into swiss cheese trying to balance the spinner backplate. So I bought a dubro 2" spinner and it would not accept the 11x4. It would take a 10x7 easy, but not the other. I put 10 or 12 holes in the backplate and it would not even come close to balancing.

Body pilot, what did the eye hook sink into. I hope it did not weaken the main wing spar when you did.

No not correct. most trainers have a positive wing incidence. The datum line must be level, this is usually shown as a line on the plans, and is generally parallel with the hoiz stab. The balance point is about on the spar so I wouldn't screw anything into the spar. The easiest way is to put two small pieces of tape on the bottom of the wings at the balance point and see if the horiz stab looks level.

This is a trainer not rocket science... Pick it up with your fingertips at the expected CG and look to see if it looks level to you. Do your best like the gentleman above sugested and enjoy. Yes I build scale and 3D ships and yes, I have the laser incidence and CG machine goodies, but don't worry on the Nextar, just enjoy.,

quint

I agree on that balance point I have always found that with high wing trainers you need to put your finger tips under the wing at about 1/3 of the way back from the leading edge (front of wing) , the nose should drop slightly(hell it can swing way forward and still ok) if you have this fly that sucker!
Remember nose heavy is ok to fly, tail heavy you better have some experience.
I once put a supertigre .51 in an avistar .40 I didnt add a drop of weight to balance it, it flew great always on the verge of ripping the wings off , although when i would run out of fuel it would drop like a rock, just head for the runway.
Good Luck Dude

OK I got it balanced. 3oz. in the tail and and 1/2oz on left wing tip. Now all I need do is patch the wing tip, and cover the tail lead. It balances just a little nose down. I now want to find a scale to see what I am weighing in at.

Just to share a few things you might want to do with the Avistar.

One, the extra weight shouldn't be a problem as it looks like you only added maybe 7 to 9 oz with the bigger engine and balance weights.

Two, if your radio supports it (don't know if you have the stock Avistar radio or not) install two aileron servos and set up for flaperons. I have this done on mine and it makes a big difference on landing speed. It really just floats along. This can be done very simply by using slightly smaller servos. I used HS-81s and they fit side by side in the stock servo mount at the wing join. No adjustments to the control linkage required or anything, pretty much plug and go.

I picked up mine from a guy who had crashed it and broken of the firewall. After fixing that, I find that even though its a 'trainer' this is one of my favorite planes.

Duke

Re sitting level -- my Avistar was "tail low" after assembly too. Flew it some and had lots of trouble landing (could have been pilot experience level too ) Anyhow, fellow flyer at the field mentioned the "angle of attack" issue. I went home, removed the landing gear, placed each piece in a vice and "hammered" a little more angle in them to "raise" the tail (actually wound up with tail sitting high). Yes, this made a nice difference--made it easier for main gear to touch and roll out. I had considered bending the gear pieces after initial assembly when the plane looked as if it sat "tail low", however, initial attemps to bend the gear pieces seemed to take more "force" than I thought appropriate, so I left it be. When I finally did bend them, it took some pounding, but at this point I was more confident that it was necessary.

Re adding weight--I too had to add lead to the tail of my Avistar to balance it (three ounces I think it was)--I had it balanced to what I thought was "perfect" but when the insturctor at the field picked it up at the "balance point" he said, "Take a third of that weight off!" Didn't bother to cover the lead, it makes a nice skid if the tail happens to skid on the runway