When I first take off , I trim my elevator at full throttle to 3/4 throttle. And that is were I leave it. Is this correct ?
Or should I learn to adjust as fuel level goes down. and again for landing.

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I'm going to wait and read what others have to say about this. I was taught to trim {not trainers} at full throttle but I started to trim my planes at half throttle and like it better. I trim and never bother changing after they are set. This works for me very well but my planes usually have the fuel tanks over the CG. My students trainers I just trim at half throttle and leave them there. My thinking is it's better to just leave things alone and fly the plane. I don't know anyone doing any trim work during a flight like you are asking about but I guess it happens?

I usually trim my planes about once a year. I don't really pay attention to what throttle setting it is at unless I have a thrust angle problem. I do like my planes to glide with minimum input, so if my initial high throttle trim isn't what I like I will retrim for low speed. When I have throttle on I am always flying the plane anyhow so the elevator trim isn't as important to me as rudder and aileron.-BW

I like to trim my planes out for level flight at about 80-85% of full throttle.

Since this is the range I use for most normal flight modes, it permits me to let go of the sticks to make adjustments, scratch my head, etc.

Lots of different opinions on this. Depends on kind of aeroplane and flying style too.
I tend to trim the airplane to fly straight and level at the flying speed used for the day.
In time for landing I trim the elevator for aproach speed and then adjust the descent rate with the throttle.
I find it easier to get the plane down this way, but it is only my personal opinion.
Guding a glider floating around I might use the trim almost as much as the sticks, again personal flying style.

Hi!
You always trim at full throttle!
That way your plane flies straight as an arrow when you want it to (at take off and during high speed runs) .
It also makes the plane more easy to control as you don't have to worry what happens when you give full power in a emergency situation.

In all other flight situations the plane will decent slightly but this is so slight that it's easy to adjust with a little up elevator.

I never do!

I guess I trim at the throttle setting that I fly at most of the time. Usually 1/2 throttle. But I guess that is just me.

To me it depends on the type of plane and how I want to fly. If it is an aerobatic plane with a symmetrical wing, I trim the elevator at full throttle, trying to find a setting where the plane behaves the same upright and inverted (assuming the CG is correct). If I fly "right side up" most of the time, I trim the airplane to fly hands off at the speed I want. Some people prefer to fly landing approach with a little backpressure on the elevator, others like to adjust the trim for a nice approach speed with the stick in neutral. Do what feels right to you. There is no right or wrong, just personal preference . Your transmitter, your rules. Experiment and have fun.

Well, I was taught how to fly by a Pattern Pro. He taught me that every time I change the throttle setting, a minor trim is usually necessary for straight and level flight. So, that's what I do. After practice, if you do a maneuver that requires a throttle change ( as most do ), You do the maneuver with the throttle change, then once finished, you get back to straight and level flight at the previously set throttle setting. It becomes automatic after a while, you just learn where to set the throttle after the trim setting and then fly. If you add or reduce throttle, to get straight and level, you adjust trim accordingly.

CGr

Well Dick, I too was taught by a pattern guy and he taught me to trim at full throttle and forget about it from then on, Even pattern guys seem to do things differently. Jan, always is a very narrow term and I try not to use it too much. I see too many people doing things that work more for them then etching one way in stone. Because it doesn't work for me doesn't mean it doesn't work for others. I'm too busy flying to be moving my trims like Dick does but it seems to work for him. My planes work much better for me when I trim them in flight at around half throttle, you may not like flying any of my planes though? Works for me!![8D]

Gray.... You are so right. We all learn differently from different instructors.. the benefit for new-comers to take heed... you gain an awful lot from the experience from others. It all boils down to what works for the individual.

There are some that have an on-off switch rather than a proportional throttle... and don't need to worry about throttle trim, I'm sure we've all seen them fly. Then there are the more conservative of us that DO trim our controls from time to time.

If you trim it right, though, you should be able to make a turn, head straight across the field, and let go of the sticks going "hands off" and it should do nothing but fly straight and level. If you do that, then, in my humble opinion, you're trimmed correctly.

CGr.

I guess my only question is, does the way you trim work for the plane and the way you fly? If it does, and you enjoy flying the way you set up trims, then there really isn't a reason to change the way that works for you. Keep it simple.

As for myself, once I have the trim set up for the way I fly that plane, it's there and I don't change it.

Hi!
Same here! Once I have trimmed the plane ,at full throttle (which means moving around the servos and battery,never ever adding lead) I rarely touch the elevator, side rudder and aileron trim.
That's how all of my pylon racing friends trim a plane!

I trim at my normal cruising speed.
If I change speed or do a maneuver
I know I will be returning to cruising speed.
Once a plane is set up I try and leave it alone.
Constant trimming takes time and you are apt
to be trimming for some anomaly that may not
re-occur.
Do what ever you are comfortable with.
Good Luck,
KW_Counter

<span style="FONT-FAMILY: Arial; FONT-SIZE: 9pt; mso-fareast-font-family: "Times New Roman"; mso-ansi-language: EN-US; mso-fareast-language: EN-US; mso-bidi-language: AR-SA">To me it's obvious, with all these replies there is only one way to trim your plane. That is the way you like it for your style of flying. I over heard a guy the other day say that he had his elevator trimmed to fly level when inverted for practicing inverted flight. Unless you set up a good computer radio to compensate for throttle to elevator position, you wont get good trim all around and still it wouldn't be perfect cause its throttle position not air speed. So I say do it however your most comfortable.

A flat bottom or semi symmetrical wing will have more variant elevator trim with airspeed, when you fly a full symmetrical wing the trim will become more stable with airspeed. I am not sure why they don't make high lift wing aircraft like trainers with lifting tails.</span>

Dick {CG} brought up the switch, another good point. At one point in my flying, I call them my Bipe days, I had several bipes that were hard to control on the ground and when landing. I did end up using a programed switch for them so I had just enough up elevator when the switch was on so the tail would stay on the ground for steering. It was my lack of control on the elevator {read dumb thumb} that would allow the plane to go onto step before it or I were ready. The switch cured that little operator problem until I got better at control movement. It worked well for landings too, it corrected my bad glide slope. I don't do anything like that these days but it can be of help to newer pilots, it worked for me. All my race planes were in trim for full throttle, up until a year or so ago all my stunt planes were too. When I go into a stunt I want my wings straight and level at half throttle, that's why today I trim the planes at half, I tended to over control so now I just take my hands off the sticks when I have the plane the way I want then go into the stunts I want. It works for me. My students trainers I trim at half throttle too but it's beacuse I have them flying the plane at half power. How we trim a plane is just that pilots choice thing so what ever works is correct, sort of like the thumb or thumb and finger on the sticks question we see a lot.

I was taught to fly with a little bit of down trim. This gives the plane a built in tendency to avoid stalls. For the pilot, relaxing a little bit of back pressure to allow the plane to descend is a smooth way to bring a plane in. When you flip the plane for inverted flight, the down trim is also a built in reminder as to which way is up, because now the plane will be climbing.
As you gain experience and transition to 3D or pattern, you'll want to fly with nuetral trim...but bear in mind that for some types of flying down trim has certain advantages.

For planes with flat bottom or cambered airfoils, setting the wing at the proper angle will greatly reduce the need to trim and re-trim the plane for different airspeeds. I've seen ARFs that you would expect to be totally R&D'd and wrung out by the MFG that needed the wing's trailing edge raised a considerable amount.

"CORRECT" is what you find that suits your personality and style. I never had a chance to learn any procedure in RC flying as I only had 2 "grab the transmitter" lessons back in 1971. Then I was on my own.

I always associate "TRIM" with whatever I need at the moment and holding pressure on the stick to attain that point until I can trim out the pressure. That came from full scale flying.

I hate, despise, abhor, and other not-nice terms digital trim on toy airplane RC Transmitters. If I need a lot of trim I want it NOW. If I need a teeny-tiny amount I want to select that amount, NOW!

For a new airplane, I set up everything as close to straight and level as I can determine on the ground. On that first Take-off, I use rudder to maintain directional control - if the machine wants to roll - until I am a safe distance up, say 8-12 feet. I hold pressure in pitch to maintain a climb angle of from 10-15° nose up (heavier airplanes the lower) until good airspeed is established. Once a turn away from the flight line is made and a downwind line established, I trim for straight and level. As the flight proceeds, then I check things out and go from there.

I don't do any competition aerobatics so all those things that are published I do not do much of. OTOH, when in the USAF and doing a considerable amount of formation flying, I wore out flying glove right-thumb positions every 3-4 flights. Doing formation aerobatics, I kept my airplane trimmed as much as possible, as all those small corrections could be accomplished with the lightest pressure when the machine was in trim. That little trim button on the stick always got a real workout. [sm=tongue_smile.gif]
As an airline pilot I hand flew my machine a good bit of the time at level and also all the time from T.O. to level and all descents.
Did you know that just a flight attendant walking back and forth can cause a real change in trim? It does. [sm=shades_smile.gif]

A well-trimmed machine makes flying much easier. I do trim for my final approach airspeed. Sometimes a tad extra up, because as you break the descent for roundout and the model starts to slow, that requires additional nose-up control pressure. I see many nice approaches resulting in a very bad "landing" because the RC pilot ignores:
1. The use of more up elevator in the round-out will cause lower airspeed which results in loss of wing lift resulting in a nose drop with more up needed.
2. So many RC pilots, especially newer ones, will release any nose-up pressure when making some small aileron correction. OOPS, nose first landing.
3. Pilot has some power on and pulls throttle to final idle, with no increase in up-elevator. Remember that during the landing process, when the final reduction in throttle is made, the loss of that accelerated air-flow, reduces the stabilizer-elevator's lift force downward that holds the wing in its lifting Angle-of-Attack. Airplane drops, usually nose first.

Good Trim and good feel of Control Pressure significantly reduces the number of these bad landings.

I prefer to set my trims for level flight at the cruising speed of the airplane. If I need to climb I add power, if I need to decend I reduce power. Set up this way, take-offs at full power need little to no input from the elevator for a nice climb-out from the runway. Landings are controlled by a combination of power and elevator. On really 'floaty' type of airplanes, I might add a couple of clicks of down trim on the elevator to aid in landing and dealing with ground effect.
I like to fly in a scale manor, and this 'system' has worked well for me. It really all comes down to what works for you and what helps you to fly better.
Cheers!! BH

Use the trim to set hands off straight and level flight at your desired power setting. If you need to maintain a different setting for any moderate length of time change the trim.

Im just setting up my DX6i for my New GP Cherokee for its Maiden, what i plan too do as a test, is at first cruise 50% throttle let go stick and see how it fly's,and do trim adjustments as needed,as of now i needed 1oz too the tail cause i decided too get a 6v 5C 2700Mah for the receiver/servos which added Weight up Front , im getting a Du -Bro 1oz Spinner nut, cause the Plastic one that came with it,ant going too last i can tell lol,...so looks like ill have too add another oz.
Every Plane Fly's different and as stated before its kinda Fliers Preference on what throttle Percentage too adjust trim. But seems like what ever you Cruise at would be the best option,lol its kinda a rule of thumb when flying a real Plane.
What im Planning on doing (Which Ive looked for and haven't came across in these forums) is enabling about 2-3 degrees of elevator up with the first notch of Flap,for ease of lift off,i know its not going too be necessary too have my 1st notch of flap for Climb out,but i think it'll add too realizam of flying,and when coming in for landing doing the opposite of 2-3 degrees of elevator down with full flaps,which well be enabled when i hit my toggle for the first notch of flap Via D/R Combi options in the Dx6i and im assuming many other higher end TX's.

Has anyone else experimented with setting D/R's and tieing the flaps/elevator?Just Curious.

Thanks

Lots of good replies and advice.

I don't know for what I trim to be honest. I take the plane up, trim ailerons and rudder and then I wil start trimming the elevator - by this time - I will have a fairly good idea of what speed I want to fly the plane normally and I trim according to that. I hardly ever know at what % my throttle is during flight...no wait correction...about 10% of the time I know. So it's all about personal preference.

What many consider a trim issue with elevator trim can be exasperated by problems with engine thrust lines (down and side), decalage of the wing and tail and overall balance of the model. There is no simple answer other than to learn about these issues and do the adjustments to your models.

Bump!!!