Balancing a spitifire

session savage

Hi folks. Another question for ye.
I have completed a deagostini spitfire. ANd as I have said on previous posts I managed it even though I was missing a good few issues. I was talking to a guy who flies near here and he mentioned that I would need to balance the spitfire. He said there should have been a diagram showing where the centre of gravity on the plane should be. Problem is I searched high and low and its not in any of the issues I have. I presume that vital piece of info is in one of the issues I'm missing..typical. One issue I have has a sentence just thrown in at the end of an unrelated paragraph. It says the centre of gravity should be 95 mm back from the leading edge. Does that sound about right. If it is, its not too far off just a little tail heavy but a fishing weight would sort that out. The wings however are way off. The right wing seems to made from granite while the left wing is made from spaghetti. Are fishing weight or something similar at the end of the light wing (and on the nose) the right way to go about balancing?
What I have done is put a screw on a pedastel and marked a point on the undercarriage 95mm back from the leading edge. Then I try to balance the plane on this screw. This sound right or am I fooling.
Can anyone help me?

Cookie_Monster

sounds reasonable to me. (not familiar with model planes) but how you're doing it sounds like common sense.

coolwings

95mm from leading edge, if that is what it says, would refer to measured at the root of the wing.

Either way it should be slightly forward of the thickest part of the wing ribs, just forward of the point where the air ceases to rise to pass over the wing's upper surface.

If one wing is heavier than the other, an instant fix is to tape a coin under the lighter wingtip. When wanting a permanent cure, drill the wingtip and post in a steel wire or rod with epoxy rubbed on.

Most Spits are tail heavy, due to being a short nose design, and they benefit from a powerful (heavier) engine than that recommended - since that uses extra weight in the nose for power creation. But a little lead in the nose together with the normal engine will be fine, just a longer takeoff roll when grass needs cutting!

Bruthal

session savage wrote: »

Hi folks. Another question for ye.
I have completed a deagostini spitfire. ANd as I have said on previous posts I managed it even though I was missing a good few issues. I was talking to a guy who flies near here and he mentioned that I would need to balance the spitfire. He said there should have been a diagram showing where the centre of gravity on the plane should be. Problem is I searched high and low and its not in any of the issues I have. I presume that vital piece of info is in one of the issues I'm missing..typical. One issue I have has a sentence just thrown in at the end of an unrelated paragraph. It says the centre of gravity should be 95 mm back from the leading edge. Does that sound about right. If it is, its not too far off just a little tail heavy but a fishing weight would sort that out. The wings however are way off. The right wing seems to made from granite while the left wing is made from spaghetti. Are fishing weight or something similar at the end of the light wing (and on the nose) the right way to go about balancing?
What I have done is put a screw on a pedastel and marked a point on the undercarriage 95mm back from the leading edge. Then I try to balance the plane on this screw. This sound right or am I fooling.
Can anyone help me?

I usually balance about 10 mm or so forward of the recommended position. A bit better to be nose heavy than tail heavy. Nitro planes usually have the fuel tank forward of the wings as well so it should balance forward of the recommeded point when full of fuel anyway as the weight of the fuel reduces. Empty i balance them the 10mm forward of recommended position anyway. Tail heavy planes become more unstable, and unflyable when over tail heavy. One wing heavier should still fly grand, but a bit of weight on the tip of lighter one works fine, and weight in nose or bigger engine. Although bigger engines dont always work out heavier, some use the same casing with bigger bore for the next size up and are not always heavier, but it is a good way if the bigger engine is heavier, and i nearly always went up a size in nitro engine size from recommended and never needed to add weight. But a bit of lead weight in the nose works perfect,

session savage

Thanks everyone.
I was told that nose heavy was better allright.
I'll have her flying yet

Bruthal

session savage wrote: »

Thanks everyone.
I was told that nose heavy was better allright.
I'll have her flying yet

I dont fly the fast nitro ones as much now myself, have a p51 mustang which flies the odd time, im onto the glider type ones these days, it must be the old age gettin me.