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Iso Octane
Feb 09, 2005, 08:24 PM
In the context of pattern planes, how does the location of the horizontal stab and wing with respect to the thrustline affect the handling of the plane?

I've read many times that a good starting point would be to have the wing and stab on the thrustline, but pattern planes don't seem to use this configuration. Most have both the stab and wing below the thrustline, with the wing somewhere halfway between the thrust line and fuse bottom, and the stab slightly above the wing.

What determines this location? And how does moving things around affect the flight characteristics?

Haven't been able to "Google" any info about it. Thanks. :)

Sparky Paul
Feb 09, 2005, 10:26 PM
Most top of the line pattern planes I'm familiar with have a high thrust line, but wing and tail inline.
The "PARTNER" illustrated was 2nd in Masters at the 2004 Nats...

Berdie
Feb 10, 2005, 06:30 PM
I've read this is a book so I don't how useful it'll be. The positioning of the wings and the thrust lines has to do with the static stability of the airplane. In a normal aircraft the thrust line is usually in line with the center of gravity.

If we say the aircraft is flying level and trimmed and it undergoes a disturbance changing the angle of attack the wing will tend to gain lift while the hoizontal stab loses lift. The overall effect sets the plane back into its original position. By changing the position of the thrustline it takes load off of the wing and stab by providing a restoring moment. If in the case of a pattern plane you want it to be very manuverable then a disturbance in the angle of attack will make the plane unstable because there isn't enough restoring moment. A thrustline displaced from the centre of gravity can help destabilise this further making even more manuverable.