Well let me first say that I wasn't sure where to start this thread but it seems to me the pattern community should be the ones with the answers.

Here's the deal, I have searched all over RCU and found only little bits and pieces of the answers. What I would like to see is a method to the madness in trimming out a new plane. I've been in the RC game 40 years with a recent 10 year hiatis. I found that I have forgoten a lot of what I need to know about triming out a new plane. I have some specific prblems as well as I would like see a good checklist and correction method. Sure most all of todays ARF's have a basic trimming chart but I don't see it as having the answers that many need. So with that said where do we start? CG, Latteral CG, first things to try while in the air, how props might affect trim etc.

I have built and flown a Model Tech Paramount 52/70. This is a midwing plane with rather large control surfaces and weighs in at 5.75lbs AUW. I have a Magnum 70 4s running a 12X8 prop. Pulls a pretty nice vertical but not unlimited. It has a fairly tall fuse. Attached is a basic picture of the ship.

There was a misprint in the manual and I built it originally to the CG specified. Whish I hadn't but that another story. The wing cord is 14.5" and I have the CG @ 25% of that now. The plane seems nose heavy.

Right now I have a fairly good vertical not falling off to one side or the other and it fly's straight and level under power hands off in calm weather.

The biggest concern I have at the moment is if I apply ruder in either direction it noses down and rolls to the input direction. I mean this thing wants to roll. Knife edge is out of the question it's so bad.

Thank you to all in advance.

Mike,

Check the wing's dihedral. Usually, if it rolls the same direction with rudder, its too much dihedral.

However, you can counter it with opposite aileron mix.

Good luck.

This is a ARF kit and I respect checking the dihedral, but this plane is not worthy of cutting the wing in half and adjusting that.

I would also think that if the dihedral is out that bad(I'm waiting for other comments)that I will be having a serious talk with the manufacture.

Mike,
Use this link to the NSRCA (pattern site)site that will give you everything you would want to know about trimming and balancing a new bird. Good Luck.

http://nsrca.org/trimA.htm

You can lay one side down on a table and measure the dihedral on the other wingtip after dividing that by half.....

Hello Mike,
there are many trim guides on the net, as the one that has been suggested. IMHO it is important to point out that trimming is a process, i.e. there are several steps to perform in a particular order, since many variables interact with each other.

For example, your problem could be due to CG (pitch with rudder I mean), which is the first thing to check, as the experts suggest. Moving it forward will reduce the need to a mix, but the best thing is to follow the trim guide from the beginning to the end. The most subtle settings are CG, incidence and thrust angles, since they all play together. Then you might want to think about mixes, but not before!

Hope this helps!

That trim chart on the NSRCA page is a little dated, but it's a GREAT place to start. One thing I don't like is changing wing incidence to affect KE performace. If you do that, it messes up a lot of other stuff, and you end up chasing your tail.

We really need a new chart that's more tailored to the planes of this century. But with a plane like the one in the first post, that NSRCA chart is still about the best there is, and even then that particular plane isn't going to trim out quite like a modern 2M plane. but it will get so close it'll be the best flying one out there!

Good luck with it,
-Mike

Thanks for all the input, I have printed the charts for reference at the field and I will begin with that.

Mike