I am fairly new to Flight Simulation. When I trim the Piper Cub it is quick,easy and stays trimmed. However, when I trim the Cessna Skyhawk 172 SP it is difficult and tends to drift off even if I continue flying straight and level.
Is this true of the real aircraft, is it a problem in FSX or is it me?
All FSX aircraft are different, some trim easily, some don't, and this to some degree is true in real life, but not to the extent that you see it in FSX.. Find an aircraft that you are comfortable with and fly that whenever possible.. I find the Carenado C206 as good as any for GA flying.. and tend to stick with that or their 182RG.. Many simmers adjust the aircraft .cfg file to get better responses from their aircraft, and you will occasionally see these posted on the forums, or at the big simming websites such as Avsim, and Flightsim.com. Teecee.
There is a useful technique to trimming...
For example, you have just taken off from an airfield and you are climbing away. You will have your power set. You then need to set your attitude to get a good climb speed (75KIAS is good in a Cessna). You then need to hold that attitude to get a feel for what the aircraft wants to do. If it wants to pitch down, add some nose up trim and vice versa. It is that holding of the controls to work out what trim you need and how much trim you need that will save you the pain of a bumpy journey.
When coming out of the climb and levelling off:
You need to adjust your attitude to maintain level flight. You then need to readjust the power to a cruise setting. You then need to hold the controls required to maintain straight and level and you can then trim out any forces you are having to hold yourself.
Never try and fly the aircraft's pitch axis using trim - you'll end up with a horrible sine wave flight.
99joleg's right. The amount of lift your wings generate is dependent on your airspeed, so whenever that changes you'll need to adjust your trim.
With single engine prop aircraft, you also have to adjust your aileron and rudder trim whenever you move the throttle to compensate for the change in gyroscopic forces you get from the prop. That sounds like the problem you're having- it'll cause your plane to want to roll to one side or the other. Easy way to fix that is to look down at the turn indicator (The one with the bubble level at the bottom) and adjust your rudder trim until the ball is in the middle when you're flying straight and level, then adjust your aileron trim until the plane doesn't want to roll anymore.
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