How does a nose heavy plane react
06-08-2008, 04:43 PM
#1
How does a nose heavy plane react
I built this trainer type plane from parts of other planes, and it has a peculiar flying behavior, it want to rise upward and towards the right have added rudder trim and aileron trim it got a little better but when I give it full throttles it flies like before crooked and unstable, could it be over nose heavy or not enough?
06-08-2008, 06:41 PM
#2
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RE: How does a nose heavy plane react
I'm sure someone will correct me - engine thrust line alignment is quite important. In general, the thrust line of the engine should be no more the 2-3 degrees down and 2-3 degrees to the right. From what you have described, it appears that the thrust line needs to be adjusted, as well as ensuring that the acft is within CG limits (in general, 1/3 the chord length back from the leading edge of the wing). It's better to be a 'bit' nose heavy than have it being tail heavy.
06-09-2008, 03:43 AM
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RE: How does a nose heavy plane react
The pulling to the side is related to the thrust line or over all airplane alignment. The nose wanting to lift is normal unless it's a very strong tendency to lift in which case it is due to being nose heavy and the need for elevator trim to balance this. Downthrust is often used to somewhat compensate for the tendency of the model to climb with added power.
There is a link to a site where you can input some measurements of your model and find the CG you should be using. Be sure to include the wing's sweep angle as that makes a difference to the CG location.
http://www.geistware.com/rcmodeling/cg_super_calc.htm
There is a link to a site where you can input some measurements of your model and find the CG you should be using. Be sure to include the wing's sweep angle as that makes a difference to the CG location.
http://www.geistware.com/rcmodeling/cg_super_calc.htm
06-09-2008, 12:24 PM
#5
RE: How does a nose heavy plane react
ORIGINAL: mjfrederick
It looks like the airplane is held together with bumper stickers... that could be your problem too.
It looks like the airplane is held together with bumper stickers... that could be your problem too.
06-09-2008, 12:58 PM
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RE: How does a nose heavy plane react
I believe you took offense when none was intended. I guess my point was, if it's just a knock-around, pieced-together project, it's going to be tough to get it to fly just right.
OK, let me give this a sincere effort... I would guess the horizontal stab has negative incidence in it. You can trim for level flight at one throttle setting, but the second you add more power, it's going to force the tail down, and shoot up again. The problem you are describing sounds like the horizontal stab has both negative incidence, and is probably twisted a little bit, causing the rolling effect you are mentioning.
OK, let me give this a sincere effort... I would guess the horizontal stab has negative incidence in it. You can trim for level flight at one throttle setting, but the second you add more power, it's going to force the tail down, and shoot up again. The problem you are describing sounds like the horizontal stab has both negative incidence, and is probably twisted a little bit, causing the rolling effect you are mentioning.
06-09-2008, 01:24 PM
#7
RE: How does a nose heavy plane react
ORIGINAL: mjfrederick
I believe you took offense when none was intended. I guess my point was, if it's just a knock-around, pieced-together project, it's going to be tough to get it to fly just right.
OK, let me give this a sincere effort... I would guess the horizontal stab has negative incidence in it. You can trim for level flight at one throttle setting, but the second you add more power, it's going to force the tail down, and shoot up again. The problem you are describing sounds like the horizontal stab has both negative incidence, and is probably twisted a little bit, causing the rolling effect you are mentioning.
I believe you took offense when none was intended. I guess my point was, if it's just a knock-around, pieced-together project, it's going to be tough to get it to fly just right.
OK, let me give this a sincere effort... I would guess the horizontal stab has negative incidence in it. You can trim for level flight at one throttle setting, but the second you add more power, it's going to force the tail down, and shoot up again. The problem you are describing sounds like the horizontal stab has both negative incidence, and is probably twisted a little bit, causing the rolling effect you are mentioning.
