New from Canada

[pbhead]

i have just joined. I am a novice level FSer although have ben using it on and of for years.
My biggest problem is in the proper use of the trim. I know I am supposed to use trim so I don't have to hold on tight to the yoke but how much trim do I use. does up make the plane go up or down? Is there a neutral setting on the trim wheel( I don't think there is) so how do you know at a glance how much trim you have aplied?
Signed Confused.

[Paul G]

Hi and welcome.

On sophisticated aircraft there are trims for all axes. The one on just about every aircraft and the one to which you are referring is the elevator trim. As you say it controls the 'up and down' of the aircraft.

The elevator trim relieves the pressure you have to apply to the yoke control, to maintain your desired aircraft attitude. So if you're in a climb, you will probably be applying back pressure to the yoke to keep the nose up.

The way trim works in a real aircraft compared with a sim, makes it considerably easier to use and intuitive. In a flight simulator, the elevator trim is perhaps the least realistic of all controls. The reason? Well most flight simulators cannot replicate the control forces on the yoke or joystick that you would experience in flight.

So your question about how much trim to use is one that is more difficult to answer in the context of a flight sim, like you or I may be building. The answer is enough trim so that you don't have to hold the joystick or the yoke to maintain the desired pitch (climb or descent).

And swiftly onto your second question about neutral point. Technically trim is calibrated and on airliners this is crucial as it has to be set in advance for take off. How much is set depends on the aircraft weight, weather conditions etc, but an example would be 4.2 degrees nose up.

For a general aviation aircraft there is no neutral point so to speak. However, many aircraft have a fixed mark on a calibrated gauge, labeled "take off". Of course this is an approximation, and no doubt based on maximum weight and standard conditions. However, unlike their big relatives, a small aircraft gets away with an out of trim situation a lot more. So approximations can be made.

More complex aircraft also have trims for rudder and aileron. Rudder is particularly important for multi engine aircraft, particularly where there is an imbalance in the power of the engines, most notably because one has stopped working or is at low power.

Hopefully this answers your question and provides a bit of additional info. Tell us more about your specific goals or sim and there will be people who can answer your questions more specifically.

[Michael Carter]

And on the yoke up is nose-down, and down is nose-up.