I just finished a global RCM trainerand I need to trim it out for it's maiden flight. I was just wondering what to expect on takeoff. I trimmed out my previous trainer but I kinda forgot what to do. In case you're wondering what I did to it, I was doing full throttle strafing turns with it and the aileron ripped out. I probably should've used the rudder but I panicked. From now on my philosphy on R/C planes will be "fly em the way you would fly the real one".

"I was just wondering what to expect on takeoff."

Well that is a question that does not really have a definite answer other than provided the model is set up correctly. Such as C,G correct control throw and deflection, you should be OK. When setting up controls for a first flight i just set therm so they are parallel to the flying surface when in neutral.

Here's my routine for maiden flight, or any time trimming might be needed. First, you assure the cg is where it ought to be, according to plans or previous experience. Second, you have all the control surfaces as close to neutral as you can tell by eyeball or measuring device. Third, you do the nose-up test on less than a half-tank of fuel, be sure it will hold wot with the nose straight up. If it poops out, open the nv a click or two and test again. Then you can fill the tank and prepare for take-off.

Before you take off, stop and think of what you're going to do, and limit your moves to what's on the trimming agenda--no ad-libbing.

You did your range check, right? Throw all the sticks, see that surfaces go where they're supposed to go?

Taxi around a little bit, with maybe a touch of down elevator to keep the nose-wheel to the ground for tri-gear, or a bit of up elevator to keep the tail-wheel on the ground for a taildragger. Give it a quick short burst of power to see what the torque does. Be ready to hold just a bit of right rudder when it starts rolling until it flies straight by itself. By that time, it's probably coming off the ground.

It's not likely that your rudder will need any immediate trimming. Concentrate on getting your plane up and turning into the pattern, get some altitude and get on your down-wind leg. All this time just concentrate on elevator and ailerons to make your turn and get altitude on the down-wind leg. When it's up and flying straight, back off on the throttle to maybe 2/3 or so, and come around for your up-wind leg. Level the wings, level the pitch. Now comes the moment of truth. Relax your sticks, but be ready to pounce back on them if the plane starts rolling or pitching. If it's out of trim much at all, then back off to maybe 1/3 throttle and make your trim adjustments. If both elevator and ailerons need trimming, I usually do the ailerons first, and just keep flying until the wings will stay level by themselves. Then do the elevator, and you're good to go.

This flying pattern basically means two long legs and two short legs, which some folks simplify into an oval. The main thing to keep in mind with a newly minted model is you should be able to dead-stick down from a power loss anywhere over the course of this pattern. If you have trees, don't take excursions out over the trees any more than you can help. Save that for when you know your engine won't quit. (Which for me means never.)

If the wind is across the field to any extent, I usually take the liberty of running straight upwind for my trim-setting legs.

When it's time to turn downwind again, I forget about trimming, and just hold the plane in the pattern. Wait until you're coming back upwind, where your plane is flying a bit slower relative to the ground, and it's closer to you where you can better see what's happening. That's when I make my trim adjustments.

What you're after is straight & level at 2/3 throttle. Save the top third of throttle for climbing, going up into a loop or other vertical maneuvers. For going around in the pattern you should be about 1/2 throttle downwind to 2/3 throttle upwind.

A model that needs a lot of trimming may take three or more trips around the pattern before it will fly straight, hands off. If you're lucky, one or two passes will do it.

Now, if you care to, you can put it in a steep climb and see if it veers to one side or the other. If so, a bit of rudder trim will enable it to climb straight. This is a cheap substitute for side thrust offset on the engine. (Just remember though, that when you're flying inverted, you're twice as far off in the other direction.)

Before you think about some trial low passes and landing, you ought to get it up high and out where you have a good side view, cut the throttle and feed in up elevator until it stalls, just to see how it stalls--straight ahead hard, or soft, or rolling off into a spin. If it rolls off, be extra careful when you're setting up your landing that you don't get into a situation where you're flying at low throttle with elevator and rudder both deflected. You need airspeed to keep from stalling with two control surfaces deflected.
If your wings are banked much at all, straighten them out and keep them level when setting up your landing. Once you're over the field on final, forget any further use of ailerons. If the wings tip into a bank, using ailerons at low speed will be somewhere between ineffective and crashful. Once on final, use your rudder for any correction on banking or heading. Acting way out on the end of the tail, rudder will be effective at low speeds in a way that ailerons can't match. Using ailerons at low speed will cost you lift, at a time when you need all your lift to keep from stalling.

Just to reinforce this rudder business at low speeds, ease your way into landing with a few low and slow passes, then a few touch-and-go's, and test your rudder action (gentle nudges, please--don't hold it over!) at maybe 10-15' altitude, then 5-10' altitude, and see how it acts. That will settle your mind on how to use it when you finally decide to bring it down.

Man! Just writing this has my nerves all frazzled! Time for a beverage! Upwind and high, ailerons first, then elevator, 2/3 throttle. Once you've done that, the rest is a piece of cake.

thank you both for the help I appreciate it

Xtratorque,

Just thought I would add a little tip in here...

MajorTom mentioned getting the control surfaces at zero to start the maiden flight ritual... The best way I found is to disconnect the pushrods (assuming you've already connected them) and use those snack bag clips across the fixed surface and spanning to the control surface. Those things work great, they generally have a piece of rubber tubing on the gripping surface and don't have too much spring poewr. They hold the control surface at neutral while you fiddle with the clevis end. Adjust the clevis until the pin lines up with the hole in the control horn with the clevis closed, then simply make the connection.

Using those chip clips have made final assembly alot easier and generally, you don't need more than a click or two of trim to get the model to fly straight, assuming of course, that everything else is straight.

Hope this helps...

Ed