Ailerons come in all shapes and sizes
In this section I'll deal with adding simple strip ailerons
to a wing. These have worked fine for me on many aeroplanes
and, while maybe not the neatest or most aerodynamically efficient
ailerons, they more than make up for it in their ease of construction.
Once the techniques are familiar and understood, it's just a
short step up to customising the ailerons to fit your own plans,
whether they're to give a more scale appearance or to make room
for flaps etc.
Simple trailing edge ailerons
The simplest way to put an aileron on your wing is to simply
cut an aileron to the desired length and then to tape it to
the trailing edge of the wing. This sounds rather more crude
than it actually is, as with a little effort , a very neat looking
aileron can be produced.
Note: the following diagrams show a right hand
wing (starboard) as viewed from above. The left side of the
diagram represents the centre of the wing.
Fig 1. (above) shows possibly the most simple
of all configurations - basically a near full width strip aileron.
The aileron stops before the centre, or root, of the wing in
order that the ailerons do not contact the fuselage. Also, the
ailerons will have more effect the further they are towards
Fig 2. (above) shows a neater form of aileron
installation. Instead of simply taping them to the rear of the
wing, a bit of planning during the wing building stage has left
a gap for them to fill neatly. There are far too many different
possible configurations to show here, but hopefully you'll be
able to have fun experimenting and finding your own way to aesthetic
Fig 3. (above) is a close up of the small
gap between wing and aileron - the simplest way to hinge the
ailerons is shown. Just lay a strip of clear self adhesive tape
across the surfaces. This provides an extremely free moving
hinge and can easily be replaced in a matter of minutes any
time you need (for example if it has become totally encrusted
with dust and grass)
I've tried a good number of different hinges but the one I keep
returning to, for its ease of construction and maintenance, is
sticky tape. It also adds a negligible amount of weight.
Fig 4. here shows a cross section of the hinge.
Notice the gap between the double surface trailing edge of the
wing and the aileron. In practice, this gap should be no more
than equal to the thickness of your twinwall sheet. This allows
for a good range of motion, though you might like to close up
the gap if you don't need massive deflection on your flying
What size ailerons to use
There are several really quite dull formulae around to calculate
the best area of aileron for a given wing. I however, choose
the old 'suck it and see' formula.
Let's face it, those equations probably matter if you're building
in balsa but for the twinwall modeler, all you need to do is
to attach ailerons as big as you think you might need, and then
trim them down if necessary following empirical evidence from
a first test flight. If they really are wrong, simply untape
them, cut some new ones and try again.
As a general rule, I make ailerons pretty large and with really
extreme deflections of >45 degrees. That suits my style of
flying and, after all, you can always reduce the movement mechanically
or on the radio, but it's a whole lot harder to increase the