[Canhos]

Let's keep it simple.

First build the plane.

Then get it covered.

Then get it ready to fly.

Then balance for C of G front to back.

At this point, with a trainer, I'd not worry about lateral balancing. For most sport flyers, it's not going to make a difference. If you find that it is carrying alot of aileron trim in flight, then look at balancing the plane laterally. Some may disagree (I trust Chad will slap me for saying this), but most of us won't really notice a big difference.

Being that the wing isn't covered, you can lighten up the heavy wing. Either check for globs of glue, and sand them off, or drill some lightening holes in the wing tip. This is almost overboard for a trainer. regardless of what you do, don't bother adding weight until the plane is finished.

I remember my first kit. I was so meticulous about all the details. Then I crashed it. I bought a second one that was ready to cover. It crashed the same as the first. Third one, I threw togetther with whatever gear and glue I could get my hands on. It lasted for a long time, and was finally retired after sitting in a storage facility for 8 years (I flew it 4 or 5 times with the fuse twisted. Front to back, it probably had about 10 degrees of twist, it also had about 3 lbs, literally of glue from repairs). It broke under my feet the same as the first 2. My latest "trainer" was doing "snap" rolls 10 feet off the deck yesterday. It didn't break. I suspect it will eventually find the trash barrel in much the same fashion as the first 3, but I'm hoping it won't be for a long time.

[michel gravelle]

Hi Micheal

I get the point I won t add the weight .

THANKS

MICHEL ( MIKE )

[Guest]

Originally Posted by Canhos

At this point, with a trainer, I'd not worry about lateral balancing. For most sport flyers, it's not going to make a difference. If you find that it is carrying alot of aileron trim in flight, then look at balancing the plane laterally. Some may disagree (I trust Chad will slap me for saying this), but most of us won't really notice a big difference.

Nope You are quite right, most wont notice

The reason for laterally balancing the wing is so that the plane will be trimmed in roll for both upright and inverted. What you will find is that if your plane is trimmed hands off upright, it may roll inverted. Then you add weight to the tip to counteract and balance upright/inverted flight.

Thats how I check lateral balance...and often find that my plane when balanced laterally for perfect flight, is not balanced statically at all....so in general its a waste of time doing it on the bench.

I dont bother doing these steps for anything but my competition models...sport planes dont get this treatment from me

[hillmanr2]

The best way to test for lateral balance I have come across involves flying the plane. You may not have to put weight in it at all. Take into consideration mufflers, batteries,etc.

To balance it put the plane into a dive and pull up as hard as you can without snapping it. If the plane is out of balance it will drop the heavy wing more than the light wing. Repeat this test at least 12 times to be sure.
In a dive with a straight pull up the wings will always start level at the beginning of the pull no matter how the plane is oriented. If you cannot tell the difference then don't worry.

I commend you on being aware of balance throughout the build stage!

[michel gravelle]

Hi
Thankyou Hillmanr2 I will be doing what the thread has sugested .
Thank you gentelmen

Michel ( Mike )

[Guest]

Originally Posted by hillmanr2

The best way to test for lateral balance I have come across involves flying the plane. You may not have to put weight in it at all. Take into consideration mufflers, batteries,etc.

To balance it put the plane into a dive and pull up as hard as you can without snapping it. If the plane is out of balance it will drop the heavy wing more than the light wing. Repeat this test at least 12 times to be sure.
In a dive with a straight pull up the wings will always start level at the beginning of the pull no matter how the plane is oriented. If you cannot tell the difference then don't worry.

I commend you on being aware of balance throughout the build stage!

I am going to beat this one a little more I think a lot of trim charts, trim steps have led people down the wrong path.

There are a few problems with doing the sharp pull to test for in flight lateral balance. A number of trim charts use this as one method, however more times than not you will be adding tip weight to counteract some other issue and not a tip weight issue...here's why.

During a sharp pull a number of things are going on.....
1. you are usually at high (relative) elevator deflection
2. you will have high loads on the surfaces, therefore linkages
3. you wing will be heavily loaded, therefore your ailerons and linkages will be heavily loaded, incidence will play a huge roll, both wing and stab.
4. you are already trimmed for upright flight, and most likely pulling an upright corner, tip weight shows up predominantly between upright and inverted flight
5. it happens extremely fast, and is difficult to see exactly what is going on, there is little time to make good choices about what the plane is doing.
6. how often do you actually do this? Usually rarely in any precision type aerobatics

So, what I do, and teach to anyone who cares Is the following,

1. Trim model for upright flight
2. Adjust wing incidence to remove trim as close as possible....if you cant adjust your incidence then you better build it straight to start with!
3. Ensure elevators are aligned correctly, large loops will help with this.
4. Roll inverted and fly extended horizontal lines, watch for the plane to roll....do not correct the roll, note direction.
5. If model rolls right while inverted add weight to right tip, and vice versa.
6. Re-trim for level, and repeat inverted step until model will hold both upright and inverted hands off without rolling.

Doing this minimizes deflection of surfaces due to G loading, and yes they will move! Also minimizes and roll changes due to elevator misalignment....as the misalignment is more likely to be at high deflections than near neutral while holding inverted.

It provides nice extended time to see the problem.

It provides you with a trimmed model in an attitude that you are likely to be in for a long period of time a lot of times! Also the engine is operating and generating its slipstream and inducing a torque on the fuselage, something which a test at idle wont do.

I am sure this is not the only method, but its the only one I know of that I have had any success with.

Generally once I complete this and a few other trim steps, I can apply full elevator deflection from a dive and end up with a perfectly straight exit.

[Guest]

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[moo]

Originally Posted by can773

....

Do you teach classes in aerobatics?

[Gabe]

Mike ....michael is right don't worry too much trim can do wonders , As for the plane my first trainer saw ground so many times and got repaired often, the guys at the club called it the brick and you know what it still flew and I still had allot of fun with it......If its your first plane , things will happen to it, its all part of the hobby... Built it, fly it ,repair it and have fun.....Gabe......

[Guest]

Originally Posted by erg

Do you teach classes in aerobatics?

If you happen to be out at the field when I am there practising, and you have a question, I will show you whatever you want to know.