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Chock · 07-08-07, 06:02 PM

If you have the flaps up and gear up etc and you are set for cruising along, you will need to 'trim' the aircraft, as you have to with real thing.

What this means in real life is that the control surfaces on most aeroplanes (i.e. the elevators, ailerons and rudder) have either 'trim tabs', or a similar device to partially move the control surface a little bit, in order to steer the aircraft up or down slightly without you having to constantly keep the stick deflected for whatever your engine power setting is (that's what all those handwheels in the cockpit down near the floor are, you'll see them move if you adjust the trim). Doing this is called 'trimming the aircraft to fly hands off'.

A common misconception with inexperienced flyers is that you use the stick to control the height and the engine to control the speed in level flight, in actual fact, it is the other way around, with engine power settings used to climb and descend, and the stick (elevators) to control the pitch, which affects the speed (in truth this is sometimes interchangeable). This means that it is technically possible to make the aircraft fly perfectly straight and level by finding the exact throttle setting which makes this happen (i.e. having all the forces of weight, drag, lift and thrust in equilibrium, but, you might want to stay level at a different speed, and so that's where trimming comes in). Of course in combat, you might find that you have to throw these rules out of the window, but if you ever learn to fly on a Cessna or whatever, that is what they will teach you.

Trim tabs are like a miniature version of the control surface situated on the trailing edge of the main control surface. You can see a trim tab at the back of the elevator on this picture of a B737's tail, the small tube on top of it is a fairing over the pushrod that actually moves the trim tab:

http://www.b737.org.uk/stabprofile.jpg

So, without a joystick you will need to set up a couple of keys in the options for positive and negative elevator trim. Note that you can also trim the rudder to stop the aircraft's tendency to yaw in a direction opposite to the propeller's rotation if you like, or you can use the aileron trim to do this (although technically, the aileron trim tab is for trimming out any tendency to roll). Which you should use really depends on the aircraft, as some aircraft have no rudder trim tabs.

When you get a stick, I'd recommend setting the 3rd and 4th fire buttons as the up and down elevator trim, as this will make flying 'hands off' a lot easier.

Unfortunately, without a sliding control (such as the throttle control on a joystick) assigned to trim, it will not be as easy to use as it is in real life, where it is usually just a case of moving the stick until you are flying level at the speed you want, and then taking up the slack on the trim control and that's it, you are trimmed. With a sim, you will have to keep pressing the positive or negative trim keys (that you have assigned) until you 'hit the sweet spot', which is easy enough to do once you are used to it. If you have more than one rotary or sliding control on your joystick, of course you can have the throttle and the trim assigned. You may possibly be able to assign the mouse wheel to elevator trim, in which case it would be very similar to how the real thing works, but I have never tried that, so I don't know if it is possible in IL2.

Chock

07-08-07, 06:02 PM	#7
Chock Sea Lord Join Date: May 2005 Location: Under a thermal layer in chilly Olde England Posts: 1,842 Downloads: 0 Uploads: 0	If you have the flaps up and gear up etc and you are set for cruising along, you will need to 'trim' the aircraft, as you have to with real thing. What this means in real life is that the control surfaces on most aeroplanes (i.e. the elevators, ailerons and rudder) have either 'trim tabs', or a similar device to partially move the control surface a little bit, in order to steer the aircraft up or down slightly without you having to constantly keep the stick deflected for whatever your engine power setting is (that's what all those handwheels in the cockpit down near the floor are, you'll see them move if you adjust the trim). Doing this is called 'trimming the aircraft to fly hands off'. A common misconception with inexperienced flyers is that you use the stick to control the height and the engine to control the speed in level flight, in actual fact, it is the other way around, with engine power settings used to climb and descend, and the stick (elevators) to control the pitch, which affects the speed (in truth this is sometimes interchangeable). This means that it is technically possible to make the aircraft fly perfectly straight and level by finding the exact throttle setting which makes this happen (i.e. having all the forces of weight, drag, lift and thrust in equilibrium, but, you might want to stay level at a different speed, and so that's where trimming comes in). Of course in combat, you might find that you have to throw these rules out of the window, but if you ever learn to fly on a Cessna or whatever, that is what they will teach you. Trim tabs are like a miniature version of the control surface situated on the trailing edge of the main control surface. You can see a trim tab at the back of the elevator on this picture of a B737's tail, the small tube on top of it is a fairing over the pushrod that actually moves the trim tab: http://www.b737.org.uk/stabprofile.jpg So, without a joystick you will need to set up a couple of keys in the options for positive and negative elevator trim. Note that you can also trim the rudder to stop the aircraft's tendency to yaw in a direction opposite to the propeller's rotation if you like, or you can use the aileron trim to do this (although technically, the aileron trim tab is for trimming out any tendency to roll). Which you should use really depends on the aircraft, as some aircraft have no rudder trim tabs. When you get a stick, I'd recommend setting the 3rd and 4th fire buttons as the up and down elevator trim, as this will make flying 'hands off' a lot easier. Unfortunately, without a sliding control (such as the throttle control on a joystick) assigned to trim, it will not be as easy to use as it is in real life, where it is usually just a case of moving the stick until you are flying level at the speed you want, and then taking up the slack on the trim control and that's it, you are trimmed. With a sim, you will have to keep pressing the positive or negative trim keys (that you have assigned) until you 'hit the sweet spot', which is easy enough to do once you are used to it. If you have more than one rotary or sliding control on your joystick, of course you can have the throttle and the trim assigned. You may possibly be able to assign the mouse wheel to elevator trim, in which case it would be very similar to how the real thing works, but I have never tried that, so I don't know if it is possible in IL2. Chock __________________ Last edited by Chock; 07-08-07 at 06:53 PM.