I hate to bust your bubble here...but it just ain't that technical.

That era of planes was simple.....Stick it around the wing tube...Like right on it....Then fly it.

Go to the NSRCA web site www.nsrca.org

There is a trim chart under technical stuff....It has some trimming tests to setup the CG properly. CG is a feel thing.

I like a plane to have a feel....Others seem to measure it by the amount of down elevator needed to hold inverted. I guess a good rule of thumb I use is Pull 45 up line roll it inverted and see how well it holds the line....If it maintains the line without any down elevator needed its tail heavy. It should arc slightly shallowing the 45 deg line.

Another thing is the amount of pitch coupling associated with rudder input. Fly Knife edge and if the plane pitches to the belly its tail heavy and pitching to the nose is usually nose heavy....There are other factors that can cause this so I usually play with it until I find the best feel and best other attributes.

You should find that pattern planes are very tolerant of CG location.....Everybody likes their planes a certain way and not everyone feels the same about CG...In fact most people like their planes too tail heavy for me....The more nose heavy a plane is the better it will hold heading in a snap...But you get to a point where the the plane takes too much control surface throw to achieve the stall in a snap roll.....

Since your just starting out don't worry about the snap rolls. It will not be an issue for you for a while yet.

My best advice is to get with a local pattern flier or go to a contest around that area and get a pattern flier to fly your plane.

I had a Summit but it was a long time ago and I don't know where the CG is noted on the plans....If you have this number then use it. Many people flew those planes it was a very popular and great flying plane for its day.....

Its generation was the last of the 60 sized pattern models and it was a very good combo and very competitive in its era. Most designs in this era had the wing tube on or very near the CG...So use the wing tube as a starting point if you don't know....

The CG will always need to be tweaked to meet your needs....Try the 45 upline with the 1/2 roll....and this will give you a good feel...my personal opinion.


Troy Newman
Team JR