On 2006-10-09, Mxsmanic wrote:
Robert Chambers writes:

The discussion of trim in a flight sim on a PC is academic.

Hardly. Trim does the same thing on a simulator that it does in real
life.

Not really. In a real aircraft, you trim out the forces you're feeling
without actually moving the control itself.

However, controls for a PC don't work like this - so you have to feed in
trim to the simulator, while gradually moving the joystick to the centre
position - because all that's providing resistance is a set of static
springs.

It would be possible to design flight controls for a PC simulator (which
are inadequate on so many levels - even the expensive ones) which work
just like trim works on a real aircraft, but it would be extremely
expensive. The other problem with PC controls is that they don't move
nearly far enough. The CH yoke for example, goes in and out (for pitch)
about 3 or 4 inches, and turns about 45 degrees in each diretion. The
yoke on a Cessna 172 has probably 18 inches of fore/aft travel and turns
through about 120 degrees in each direction. CH rudder pedals maybe
displace an inch or so, but the rudder pedals on a C172 probably
displace a good 5 or 6 inches. This means that the controls on a
simulator are _insanely_ sensitive if you want them to be able to make
full control deflections.

In an aircraft, trim is not so much a "convenience" as you seem
to think.

A lot of aircraft and pilots seem to do without it, so obviously it is
not necessary.

Name ten!

If you're doing without trim in a real aircraft, you _are_ doing it
wrong, at least for any conventional light plane right up to airliners.
Trim is absolutely essential in pitch.

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