Biplane Stab Incidence Question
11-18-2002, 12:09 PM
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Biplane Stab Incidence Question
I am scaling down a set of plans for Ultimate Bipe. The plans were for 35% and I am going down to 25%. There is 1.5 degrees of down thrust on the stab with the motor at 0. I am interested in your comments on this setup as this is my first biplane.
11-18-2002, 02:42 PM
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Biplane Stab Incidence Question
The angles between the wings, tail and thrust line plus the CG location (as a percentage of wing chord) will determine the pitch trim for a particular throttle setting. This shouldn't change appreciably with a 25% decrease in size.
11-18-2002, 02:49 PM
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Biplane Stab Incidence Question
Originally posted by Ollie
The angles between the wings, tail and thrust line plus the CG location (as a percentage of wing chord) will determine the pitch trim for a particular throttle setting. This shouldn't change appreciably with a 25% decrease in size.
The angles between the wings, tail and thrust line plus the CG location (as a percentage of wing chord) will determine the pitch trim for a particular throttle setting. This shouldn't change appreciably with a 25% decrease in size.
11-18-2002, 03:18 PM
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Biplane Stab Incidence Question
Yes, if it worked for the original size model it will work for the 25% smaller version.
BTW, incidence (angle to an arbitrary reference line) is no more than a convenience in establishing the angles that count, which are the angles between the thrust line, wing chord lines and tail chord lines. Keep the angular relationships that count and draw the arbitrary reference line any way you like. You could draw the arbitrary reference line parallel to the fuselage center line, thrust line, either wing chord line, the tail chord line or any other way and it wouldn't matter as long as the wings, tail and thrust are in the proper relationship.
BTW, incidence (angle to an arbitrary reference line) is no more than a convenience in establishing the angles that count, which are the angles between the thrust line, wing chord lines and tail chord lines. Keep the angular relationships that count and draw the arbitrary reference line any way you like. You could draw the arbitrary reference line parallel to the fuselage center line, thrust line, either wing chord line, the tail chord line or any other way and it wouldn't matter as long as the wings, tail and thrust are in the proper relationship.
