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Old Mar 25, 2004, 09:27 PM
Maz
Mig Killer
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Broadview Heights, Oh, USA
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CG question

I just finished building my first plane yesterday. My planes say the CG is 50mm back from leading edge. My question is,when I put my fingers at that point and lift the plane should the plane move at all? When I do this it stays pretty level. I just need to know how you determine what level really is. Is using your fingers OK or is a CG stand the best way to go or maybe something else? I hope to take the maiden voyage this weekend(weather and wind permitting).

Thanks,
Maz
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Old Mar 25, 2004, 09:37 PM
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Chattanooga, Tennessee, United States
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Two fingers, a couple of pencils or a fancy CG stand - as long as it balances at the correct position it will be fine. If anything, for a maiden flight. have the plane a fraction nose down when you are balancing at the prescribed CG point [a little nose heavy never hurts: a bit tail heavy, and you could really get into trouble].

Cheers, Phil
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Old Mar 25, 2004, 11:21 PM
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Riverview, FL
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nose heavy flies poorly - tail heavy flies once
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Old Mar 26, 2004, 04:40 AM
Dead stick!!
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Joined Mar 2002
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Welcome to ezone Maz

It depends a little on the style of plane. I got caught out with a taildrager - I balanced it so that when I lifted it at the balance point it retained the same attitude as when sitting on the ground (i.e. nose up). I later realised that the balance should have been level as in the position in flight.

nose-first is right - a very tail heavy plane is a real handful. Mine flew ok (although very twitchy) until I went to land. As soon as I backed off the throttle it was like a stall. Eventually I landed it under power (the thrust from the motor was the only thing keeping the plane in the air). Hair raising stuff!

Peter
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Old Mar 26, 2004, 05:38 PM
Maz
Mig Killer
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Broadview Heights, Oh, USA
Joined Mar 2004
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Thanks for the input everyone. From what I gather as long as the plane tilts just a little to the nose heavy side,then I should be OK. I have a Stinson Voyager from hobby lobby. Top wing design, but has ailerons. I`ll let you know how the first flight is.

Thanks,
Maz
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Old Mar 26, 2004, 10:01 PM
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If the plane is a high wing tail drager then the bottom surface of wing should be parallel with the ground. That means that when you pick it up at the balance point the nose will come down a fair way. Maybe this is what you mean.

The problem with a tail drager is that you pick it up at the CG points from a nose-up attitude on the ground. My mistake was thinking that as long as it stayed in this nose up attitude that it was balanced. In fact you want it to balance as it will fly - tail up so the wing and tail surfaces are moving parallel to the ground.

I hope this makes sense. I just know how easy a mistake this is to make.

Looks like a nice plane.

Peter

http://www.hobby-lobby.com/media/GR6252-Stinson.wmv

BTW this looks like a pretty challenging first plane. I hope you've got an instructor? Maybe it's your first build job, not first flying experience?
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Last edited by Peter Young; Mar 26, 2004 at 10:08 PM.
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Old Mar 27, 2004, 06:07 PM
Maz
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Broadview Heights, Oh, USA
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Thanks Peter that is exactly what I mean. I didn`t know if it should stay level when you pick it up off the ground. I guess it only makes sense that it should be level while in the air. I`ll work on getting the plane somewhat nose heavy.
Yes this is my first plane. No I do not have an instructor, but I bought Aerofly Pro a few months ago and have been practicing with that. Hopefully that will help me out. I`ll balance her out tonight and hopefully fly tomorrow. I`ll let you know.

Thanks,
Maz
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Old Mar 27, 2004, 07:25 PM
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Interested to hear the first flight report. Make sure you start on a very calm day, and pick a big field so you don't need to worry about trees etc. My first flight was a tight little field on a windy day - the plane blew away like a kite with a cut string....
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Old Mar 29, 2004, 09:46 PM
Maz
Mig Killer
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Broadview Heights, Oh, USA
Joined Mar 2004
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Well yesterday was my maiden voyage. It didn`t go exactly as planned. I tossed it into a slight breeze,it went well for the first 20-30 feet,I gave a little up elevator and then it started banking to the right and went right into the ground. The wing popped off and the shaft of the motor was bent. Today I straightend the shaft to almost perfect. Hopefully good enough to fly. The reason I think it banked to the right is that the left wing seems to be a little higher than the right. When I put it together I noticed it but I had it on a table and I thought that the landing gear was a little croocked. After really checking it out today I think the wing actually sits a little higher on the fuselage on the left side. I`ll probably shave down the fuselage some on the high side,then I`ll try her again. I`ll get it flying sooner or later.

Maz
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