raveco

Hi All,
New to electric planes, I have just bought a Flying Dreams Extra 330 LP from a swap meet. It looks not to have ever been flown and in perfect order. Unfortunately there was no instruction manual with it so I am a bit stuck with critical information such as recommended control throws and more importantly the CG. ( I would guess at 25% back from front edge of wing but???)
Anyone out there who has had one of these and can enlighten me?
Many thanks in advance.

R.

RBACONS

My Feedback: (3)

Most extras have tapered leading edges and trailing edges. You need to find the mean area cord and take 25% of that. 25% of the cord at the wing root won't give you the proper CG.

raveco

Thanks for the info. In the absence of the original instructions I guess this will be a good place to start.

JohnBuckner

My Feedback: (1)

And here is a simple way to find mean or average chord to measure back from for your CG. It is called mid span averaging and works quite well with any monoplane wing that is single tapered, leading edge or trailing edge as well as a double tapered wing, heck even with an elliptical wing.

All you need to do is to measure the distance between the leading and trailing edges out half way between the fuselage and the wing tip. This will be your mean (or averaged) aerodynamic chord for weight and balance purposes. Now if you want to balance at 25% mac (a figure that I definitely agree with for that airplane for first flights) then all that is needed is to divide that measurement out there half way between the fuse and wing tip by four. And this sum is measured back from the leading edge out at that half way point then just projected straight into the fuselage side for balance purposes.


John