Just got my Hangar 9 Pulse XT 40 built and I am working on breaking in the engine. I figure i will get it in the air by next weekend, and I was curious how trimming everything out is supposed to be done. When you get the plane into the air, do you adjust the trim when at full throttle?

Hi quore,

You may find this site of assistance in providing info on how to trim your model.

FWIW I generally trim my models out at the throttle setting that I will fly the manouvers at, usually 1/2 to 3/4 throttle. If you don't learn throttle control, particularly on the "down lines" and you are flying an ARF the sound you hear immediately before impact is "flutter"[&o].

http://www.palosrc.com/instructors/trim-chrt.htm

Cheers,

Colin

First, on the ground, you trim everthing to neutral positions, adjust the endpoints so they don't strain the control surfaces, hinges, or the servos, and set your dual rates to the recommended throws. In the air, you just trim it out at a reasonable cruising speed. A properly designed/built plane will not have any throttle to aileron or rudder coupling, but some may have throttle to elevator coupling (e.g. climb more at full throttle). This means the elevator is the only trim that is likely to vary with speed, but with a Pulse XT, I doubt you'd get much of that (some trainers like to climb more at full throttle).

After you have set everything on the ground, throws, or dual rates if you want, whatever.....now you go fly....have a bud stand out there with you in case the trims are off bad enough you can have help trimming while you fly the plane......1st order of business is fly the plane...2nd order of business is trim the plane....I trim at 1/2 throttle or a tad above half....I trim the surface that is giving me the most problems first....bottom line is with no wind you trim the plane to fly straight and level thumbs off the sticks
Good Luck

What does flying an ARF have to do with flutter?

One thing to add to what has been said above........

If you set your linkages up properly, with the servos centered, the surfaces themselves centered and the trims on your Tx centered, hopefully the in-flight trim adjustments will be minimal. If I have to make significant trim adjustment in the air, I usually readjust my control surfaces so that they are at their trimmed position with the Tx trim settings near neutral. This will require noting the relative position of the surface, neutralizing the trim control and then adjusting the clevis to put the surface back at it's noted relative position where it needs to be for straight and level flight. It's not absolutely necessary, but I prefer to have my trim settings within a few clicks of neutral with the plane properly trimmed. If you're way out near the end of the trim adjustment you're probably better off making the mechanical adjusment and then flying the plane again to finalize your trim settings. I think it's a good habit to get into.

Good luck with your plane.

Thanks for all the advice. Currently, everything is centered and I have the low and high rates set per the instructions. the only servo adjustments i had to do was on the throttle. when I put the throttle stick to full, the servo was moving more than was needed and when the carb. was fully opened, then the push rod just started to bend/flex. I set the throw on my radio on the high setting from 100% to about 35% (going off of memory). That seemed to fix that issue. The other thing I had to do was the throttle curve. When I had the throttle stick at half, the carb was almost fully opened. I have it set now that half throttle stick is about half opened on the carb. The low end is gradual on the throttle curve, but the high end is steep. I think I have it set ok. Thats all I did on the radio so far. Everything else, I just adjusted the clevise (sp) to make the control surface be at the center mark, and the position on the control horn.

Well said, in fact, I use to look for the neutral point of all of my servos with the exception of trhottle after all trimming, then my batteries will last longer.
Also remember that Rudder should be trimmed in a vertical line (maybe at full trhottle or enough to perform a vertical line), ailerons and elevator at the flying speed of your choice (avoid always full trhottle) and use wind speed.
Good luck.

Hi!
Trimming out in flight is best done at full throttle! That is the way all competition fliers do it...!

I too trim at full throttle. I use pattern and IMAC trim charts for doing all the fine tune stuff. I think if you look on the AMA site there may be trim charts there. The trim charts are for in flight trimming, very simple things like nosing over the plane and letting the sticks go, watch what the plane does, if it trys to pull up towards the canopy it shows nose heavy, if it tucks in towards the LG it is tail heavy. These are done after in flight radio trimming for straight and level. Lot of good info in these charts. They also give you the fix to the problems.

Hi CGretired,

I'm retired too. I put in my comment regarding flutter and throttle control as the only models I have seen suffer catestrophic failure through flutter have been ARFs, one from the same stable as quore's model. I have seen the occassional kit or scratch built model suffer from flutter but not to the extent of destroying the airframe.

Cheers,

Colin

what is imac I tried to google it but only came up with apple computers "I use pattern and IMAC trim charts for doing all the fine tune stuff"

For the average flier I disagree with trimming at full throttle...but the nice thing with our hobby is you can do what you wish.
I'll give you the reasons I trim at 1/2 throttle.....I want a tad bit of climb with power on....for if I add power that is exactly what I want to do is climb.....I cannot think of a single time where I reduce power to gain altitude.....trimmed at 1/2 throttle is "cruise" where I do most of my flying...very little input from me to fly straight and level....with power off I want to descend....lastly on approach I don't have to hold in alot of up elevator where if for some reason my thumb slips I didn't re-kit an airplane.
One of the advantages I see in trimming at full power is doing alot of aerobatics.....you don't have to be on the elevator as much on the down lines of loops and bowties.
just my opinion.....Good Flyin to all

Hmm.. ok. All but one of my planes are arfs and I have NEVER experienced a wrecked aircraft due to flutter. My Goldberg Wildstick, which is an arf, (and retired at this point) used to flutter when I pushed it to hard.. but I always caught it right away (lucky me) and landed it. The control surfaces were all intact as were all their hinges.

I would turn around and put it right back in the air.

I retired it because I needed the servos.. the thing had 7!!

CGr.

International Miniature Aerobatic Club

http://www.mini-iac.com/

Only if you fly at full throttle ALL the time. Many competition pattern pilots do not fly at full throttle in level flight, they will try to keep a constant speed with throttle management esp. on the up lines and down lines. Using around 1/2 to 2/3 throttle in level flight.

Trimming can stop at getting the plane to fly straight and level at "normal" throttle by setting the elevator and aileron trims [ many pilots do this and stop there] OR it can involve adjustements to CG, lateral balance, engine thrustline, aileron differentials, THEN you work on max movements required for specific manouvres and set rates accordingly perhaps with added mixes like rudder to elevator to correct knife edge problems.

Here is a link [link=http://home.comcast.net/~scottcov/]CLICKY[/link]

CG adjustement is an important part of trimming an aircraft out. Many people do not bother with this one but it can turn a dog into a pleasant flying aircraft.

I like setting a plane up, trimming it to behave the way I want, it takes time and make ONE CHANGE AT A TIME.

I'm watching this thread to see how long it takes...

to?

for someone to say 'find an instructor'

You know its coming, 'find an instructor' is the one of the most common answers give to the widest range of questions here.

So I'm waiting for it.

this post doesn't count.

OP, you should really find a good instructor to teach you how to trim a plane the proper way!!!
Done Deal!!!!

unless your an experianced pilot, I wouldnt consider trimming a plane. there no way to explane it here. things happen so fast in the air and if your not on top of it, its going down IMHO

I don't quite understand that. One of the very first "lessons" we learn and that instructors teach, is how to trim the plane and why. It does not take an experienced pilot to trim out a plane in flight. You simply point it right to left or left to right, then adjust it for straight and level flight. How difficult can that be? The trim slides are right next to the transmitter sticks.

Do you take off, then hand your tramsmitter to someone else to trim it up for you? I don't think so. Neither should a novice. That should be almost automatic once the plane is in the air.

CGr.

cgr, it is automatic, however there is a huge difference between someone experienced doing this and someone that has their hands full dealing with a slow steady trainer that is already trimmed out.
You don't always know that a plane is grossly out of trim until after the wheels leave the ground, right after takeoff low speed, high angle of attack, low alt. all means there is only one shot to get it right.
Nothing hard about it, but nothing forgiving about it either.

I flew quite awhile after soloing before I was comfortable maidening and trimming a plane. With my first few planes, I had an instructor maiden them and trim them out for me.

well with experiance, you will know what to do in a slpit second, I do agree that learning how to trim should be taught when teching a new flyer. What I have found out is that new pilots, even after they have soloed are way to scared to take there hands of the stick to hit the trim levers, they have to look down to find them. so thats why I feel a new pilot shouldnt be trimming a plane that has never flown before. they would really need to get comfortable on an already trimmd plane and make minor adjustments to it