Balancing LT-40
#1
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From: Alexandria, VA
Ok, so I am going to do it, and I did a trial run, Tail Heavy which totally shocked me. I figured that by converting it to a taildragger (and moving the landing gear forward) the .46 Engine, and the fact that the Batter and the receiver are already in the front that I would have to add weight to the tail.. WRONG..
So, where and how is the best weight placement? I have some lead I bought specifically for this purpose...
So, where and how is the best weight placement? I have some lead I bought specifically for this purpose...
#2
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From: Brick, NJ,
There are 2 things I would try to get in balance.
1. Try a 1 ounce prop nut. If you are close, it should bring you in tolerance.
2. If necessary, add weight to the nose to the left and right of the engine. Be sure to epoxy it in place when you have determined the proper amount. If you need more than 2 ounces, consider moving the landing gear forward a bit.
Good Luck
Mike
1. Try a 1 ounce prop nut. If you are close, it should bring you in tolerance.
2. If necessary, add weight to the nose to the left and right of the engine. Be sure to epoxy it in place when you have determined the proper amount. If you need more than 2 ounces, consider moving the landing gear forward a bit.
Good Luck
Mike
#3
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From: Alexandria, VA
Turns out I need 4.25 oz. It balances perfect with that. Seems like alot of weight though. As it stands now, my landing gear (the front) is even with the leading edge, I don't have alot of room to move it forward any more...
Any suggestions? I don't mind adding a few ounces, but this seems ridiculous..
Any suggestions? I don't mind adding a few ounces, but this seems ridiculous..
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From: Brick, NJ,
You probably have already done this but here goes.
I located my battery and reciever under the fuel tank, that helped.
I am powered with a .52 4 cycle which is the same or lighter than a .46, so I added a one ounce spinner nut on the prop shaft rather than a spinner.
Just to be sure, I epoxied 2 ounces of weight up by the engine and when I hold the wing tips, (actually 2 of us) at the main spar the bird just tilts it's nose gently forward.
If you have to, 4.5 ounces is not a lot of weight and the bird won't notice it too much.
VR Mike
I located my battery and reciever under the fuel tank, that helped.
I am powered with a .52 4 cycle which is the same or lighter than a .46, so I added a one ounce spinner nut on the prop shaft rather than a spinner.
Just to be sure, I epoxied 2 ounces of weight up by the engine and when I hold the wing tips, (actually 2 of us) at the main spar the bird just tilts it's nose gently forward.
If you have to, 4.5 ounces is not a lot of weight and the bird won't notice it too much.
VR Mike
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From: Alexandria, VA
I am just about there with the battery and reciever now. I think I am going to go with a GP Spinner weight, seems like the best solution, adds 2 oz, then I'll need to add the rest in lead in the engine area, I'll epoxy them in and hopefully be able to paint them or something to keep them from being conspicuous..
#6

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You said you have the battery forward but never said whether you meant forward in the radio compartment or forward in the nose compartment up to the firewall. If it is not all the way aginst the firewall under the tank then that is where it should be and do not add any weight untill you,ve moved it there. If there is no access then make a hatch, If the switch cord is to short then us a 6 inch extension.
Also do not move the gear forward from where you have it in an attempt to balance. That will make the airplane very bouncy on landings and difficult to land (even less directional stability). The gear has to stay in a given range of the target CG.
John
Also do not move the gear forward from where you have it in an attempt to balance. That will make the airplane very bouncy on landings and difficult to land (even less directional stability). The gear has to stay in a given range of the target CG.
John
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From: Alexandria, VA
I like the idea of moving the battery, but what about leaked glow fuel? That is why I didn't put them under there in the first place (even though there is a ton of room under there). I was told not to put anything under there (especially the reciever) because of the possibility of glow fuel getting on them..
I would like to put the battery at the firewall, but how can I secure it there?
I would like to put the battery at the firewall, but how can I secure it there?
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From: Woodward, IA
As long as you are using a proven tank (seal it, put it in water, blow into the fuel lines. You shouldn't see bubbles.) you don't need to worry about spilled fuel.
#9

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Dittos to what Phayd said. I have in some extreme cases mounted the battery externally in front of the firewall or under the engine mount beams, just slip it into a baggy.
I don,t know if the LT-40 has a tank hatch or not but if it does just remove the tank, wrap the battery in a little foam and slid it into a baggy and tape the baggy opening to the rear around the wire. Lay it in the bottom up aginst the firewall or thereabouts.
cut a piece of 1/4 square balsa stick the width of the compartment push it down over the battery and CA the ends to the fuse sides, put another at the rear to keep the battery from sliding to the rear, reinstall the battery and your done. If you don,t have a tank hatch I highly recomend you make one all sport airplanes really should have one and particularly trainers. About the only airplanes I do not use a hatch is my pylon racers and thats only because of the need to keep a very strong nose box to carry power loads.
John
Oh almost forgot, Never put a Rx in that area.
I don,t know if the LT-40 has a tank hatch or not but if it does just remove the tank, wrap the battery in a little foam and slid it into a baggy and tape the baggy opening to the rear around the wire. Lay it in the bottom up aginst the firewall or thereabouts.
cut a piece of 1/4 square balsa stick the width of the compartment push it down over the battery and CA the ends to the fuse sides, put another at the rear to keep the battery from sliding to the rear, reinstall the battery and your done. If you don,t have a tank hatch I highly recomend you make one all sport airplanes really should have one and particularly trainers. About the only airplanes I do not use a hatch is my pylon racers and thats only because of the need to keep a very strong nose box to carry power loads.
John

Oh almost forgot, Never put a Rx in that area.
#10
Wrap battery and receiver in a sandwich baggy (plastic) tape around the wires where thay protrude through the bag with masking tape. That will protect those items so you don't have to worry about fuel leakage.
#11
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From: Alexandria, VA
Well, it looks like I have a plan of action then. I am going to move the battery to the front, I don't think this will totally solve my problem, but it will come close. Thanks for all of your help guys, as always, you're very helpful..



