Aerodynamics & Flight Mechanics Troubleshooting Guide
This page helps you to cure the most common problems that you
may encounter when flying your precious model airplanes.
The model airplane depicted below has some problems.
Photo taken during an F3A-X contest in
- inappropriate flight attitude:
most planes are designed for flight with the wings in a
level position. The fuselage is poorly shaped and does
not create enough lift to counteract the weight of the
Remedy: use a better fuselage shape
and increase the fuselage height.
- center of gravity too far aft:
removing the engine during flight shifts the center of
gravity too far aft. This results in reduced longitudinal
Remedy: move the wing back towards
the tail plane until the center of gravity reaches the 25%
chord line of the wing.
- front end of tuned pipe open:
The conical end of the tuned pipe should be connected to
the exhaust of the engine (where the oily, hot mess comes
a fuel injection and ignition system to use the pipe as a
ramjet engine when the piston engine drops off.
- asymmetric horizontal tail plane with pointed wing
cutting away part of the tail does not improve handling
capabilities. Pointed wing tips may be a means to reduce
induced drag, if there is any.
Remedy: To compensate for the
asymmetric drag, offset the engine to the port side.
- reduced aileron area:
chopping off half of the aileron reduces roll rates. The
drag reduction due to a smaller wing surface is quite
Remedy: increase aileron deflection
and add a wing warping servo.
- flying close to neighbors:
the trees and houses are dangerously close to the model
Remedy: cut the trees and demolish
last modification of this page: 21.08.01
[Back to Home Page] [Index of all Pages] Suggestions?
Corrections? Remarks? e- Martin Hepperle.
As I get quite a number of messages, it might take some time until you receive an
answer and in some cases I get lost in the flood and you may even receive no answer at
all. I apologize for this, and if you have not lost patience, you might want to send me a
copy of your e-mail after a month or so.
Copyright 1986-2001 Martin Hepperle
You may use the data given in this document for your personal use. If you use this
document for a publication, you have to cite the source. A publication of a recompilation
of the given material is not allowed, if the resulting product is sold for more than the
production costs. Some names appearing on this web are trademarks or registered names whose rights belong to their owners, even if not explicitely stated. This document
can be found by navigating from the Web site http://www.MH-AeroTools.de/