Trimming a plane

[alan0043]

Hi Everyone,

I understand this is a basic question on RC planes. I have done a Google search and could not find the answer that was helpful. I understand the trim tabs on the radio do. But no one talks about throttle speed when trimming a plane. So what throttle speed do you use ? 1/2 throttle or 2/3 throttle maybe 3/4 throttle ? I can't believe using full throttle to do trims. I understand how important speed is when flying. So what do you say ?

All input is welcomed,
Al

 

[Obi-Wan B.O.B.]

I’m a newbie as well so I’ll be interested in hearing the responses from more experienced pilots.

As for myself, right or wrong, I decided to do it at my “cruising speed”, i.e. the speed that I feel comfortable buzzing around and trying basic maneuvers as I learn to fly. For me that has turned out to be around 30-35% throttle, depending on the plane. right in the region that I can generally maintain flight without elevation change.

 

[Pieliker96]

Cruise throttle is a good start for trims. If you really want to get into it you can set up mixes for all three axes to compensate for any power-induced trim changes. For further reading there's Peter Goldsmith's guide to trimming - a fantastic resource.

 

[tamuct01]

Are you talking about "at what speed (throttle setting) should I trim out my plane?" or "how should I use the throttle trim switch?"

For the speed question, there is no specific throttle setting (1/4, 1/2, full, etc) to trim out (aileron, elevator, rudder). Usually, the process is as follows: Get the airplane in the air and into a stable position. You may have to hold some aileron, elevator, or rudder input to do this. Working aileron, elevator, and rudder trims (usually in about that order) adust the trims to where it will fly straight and level with no stick inputs. Speed is kept at a cruising speed well above the stall speed, but usually not full throttle.

As for what are the trim switches for on the throttle channel - these are usually not necessary on electric planes. I, in fact, remap this switch to adjust a mix rate on my flaps and elevator, but that's a different topic. On nitro and gas planes, you may need to adjust the idle speed depending on temperature, humidity, or altitude. The throttle trim is used to do this. It artificially adjusts the servo positioning up or down to get that idle correct. Also, in the past, it's been used as an engine kill. You set the throttle servo trim fairly high under normal operation, and when you need to kill the motor you pull the throttle trim all the way down to stop the motor.

I hope that helps!

 

[Merv]

...So what throttle speed do you use ? 1/2 throttle or 2/3 throttle maybe 3/4 throttle...

Trim your plane to fly, hands off, straight and level at the speed you spend most of the time flying at. As you progress in your flying journey and you gain more skill, you will likely increase the speed you spend time at. As you increase your speed from where you trimmed it, the plane will tend to climb, you will need to add down elevator to hold altitude. As you decrease speed, you will need to add a bit of up elevator to hold your altitude. It’s difficult to have a plane fly, hands off, straight and level at all speeds.

Myself, I trim my planes to fly at full throttle.

 

[JasonK]

Trim your plane to fly, hands off, straight and level at the speed you spend most of the time flying at. As you progress in your flying journey and you gain more skill, you will likely increase the speed you spend time at. As you increase your speed from where you trimmed it, the plane will tend to climb, you will need to add down elevator to hold altitude. As you decrease speed, you will need to add a bit of up elevator to hold your altitude. It’s difficult to have a plane fly, hands off, straight and level at all speeds.

Myself, I trim my planes to fly at full throttle.

you can add a small mix from throttle -> elevator to increase that range - or make the amount of elevator add less.

 

[Tench745]

I will differ slightly from the advice of others here. I would recommend trimming the plane for the airspeed/ flight regime where you need it the most. For most people that is at cruise speed where you will spend most of your time flying.
However, if the plane is really difficult to land maybe you want to trim the plane to fly a stable approach and allow you more brain-space to set up for a good landing. But, you'll probably have to hold down elevator the whole time you're flying at cruse speed.
Similarly, if you've got a speed machine you may want to trim it out at full throttle so you don't have to be fighting anything on fast passes.

Depending on your transmitter, and if you feel like playing with mixes, you can set flight modes with different trims for each phase of flight.

 

[skymaster]

Sorry i could not resist. Does it have to many leaves

 

[Bricks]

If you want your plane to fly level at all speeds once trimming is done set up a throttle to elevator curve.