raron455

My Feedback: (38)

Iposted this in the giant scale and have not had much luck, then I thought about this forum and with all the aerobats here, surely I will have better luck So here is the situation


I am finishing up my build on my GP 1/3 scale pitts special, I have a question about the location of the smoke tank, I have all my accessories located, batteries, ignition, etc,,
Here is my question,, Where should I put the smoke tank in regards to CG,, I have the plane balanced right now with the engine (dle-55), smoke pump, and batts,,
I was thinking of putting the center of the smoke tank right on the CG of the plane, that way It would not throw the plane out of balance when it gets filled, I balance the plane with an empty fuel tank, and it is located in forward of the cg, So I know I dont want any more weight on the nose after the fuel tank is full, thats why I was thinking center the smoke tank right at cg,
If my thinking is wrong please help me out, I am asking for advice, I know plenty of you guys have probably figured this out the hard way, and I am wanting to learn from your experience,, thanks fellas

zx32tt

My Feedback: (9)

Your thinking is exactly correct for the smoke tank. I usually try to do that for my gas tank on the cg as well, but its not always possible.

daveopam

My Feedback: (9)

If you can get it right on the CG it's the perfect spot. Second best would be just in front of the CG.


David

raron455

My Feedback: (38)

thanks fellas, I wanted to get all the advice I could before placing it,,

daveopam

My Feedback: (9)

Never hurts to have a second opinion. None of us are so smart we cant learn.


David

RBACONS

My Feedback: (3)

A minor point but I would recommend swapping the 2 fuel tanks. You want your main fuel tank for the engine on your CG as you will always need to be flying with fuel for the engine. That way, under normal circumstances, there is no CG change when your flying without smoke. When you do use smoke, your CG will be forward but you probably don't fly with smoke all the time and when you do, the smoke oil tends to be used up quicker than the engine burns fuel so you'll be nose heavy a smaller percentage of your overall flying time (rather than always).

Lnewqban

The reason to balance with empty tank(s) is to avoid a tail heavy condition by the end of a flight, when the fluids have been burned.

If you cannot place the fuel and smoke tanks in the CG, but forward; then, both should be empty for balance.

Yes, the plane will be nose heavy for take-off, but will be balanced for landing.

The inverse applies for tanks that need to be placed aft the CG (they should be full for balance).