GP Easy Sport balance.
 

I just finished assembling a Great Planes Easy Sport with an OS 46 engine mounted as per the instructions. A 600 mah battery mounted right behind the tank and the RX behind that. Now in order for it to balance at the 105mm called out in the instructions I would have to add 3 oz of lead to the tail. I've been doing this RC thing for 40+ years and I know all about moving stuff around , that's not the question. The question is, is this just a short coupled poorly designed model or am I missing something else here. I'd really like to hear from someone who has assembled this model.

RE: GP Easy Sport balance.
 

I just can't believe that in the whole RC Universe, Universe that no one besides myself has assembled this model! Unbelievable!

RE: GP Easy Sport balance.
 

Well guess what? I've built two of these guys! I love to start off the season flying the ES first before going on to my other models. The reason - less stress. And I get more confidence with our windy weather starting off EASY (Ha HA).

I don't know must about the design but I too had to add about 3 ounces to the tail in order to get it to balance at the given CG. I have an OS 46 installed and placed the battery and receiver as far forward as possible.

RE: GP Easy Sport balance.
 

Thanks, that's what I was looking for. I feel so much better now. This model was not for me. I assembled it for another modeler.
I do a lot of my own design work (Pylon Racers) and the first thing I do is determine what tail & nose moments to use that will result in a balanced model without moving anything around or, god forbid adding any weight. Looks like Great Planes missed the mark on this issue. 3 oz of tail weight in that size model is really not that big of deal. It's gotta balance to fly it. Left as it was it would have had the glide of a rock.
I was just hoping I hadn't made a mistake. I'd hate to charge to do the work and have it go in on the maiden flight. I'd help him with the maiden but for some strange reason he flies on mode 4. You know aileron and throttle on the left stick and elevator and rudder on the right.
Gawd I hate ARFs.

RE: GP Easy Sport balance.
 

double post -

RE: GP Easy Sport balance.
 

I have  3 of these aircraft, best and easiest plane I have ever flown. I made one a taildrager and had to make a larger rudder for ground control. T get all three of mine to ballaqnce I cut a hatch as far back in the bottom of the fuse to get the battery as far bac as possable. By doing this I only had to use 1.25 oz. of lead to ballance ,again in a hatch on the botton of the fuse at the tail.

RE: GP Easy Sport balance.
 

I am inclined to think that this plane was originally designed around a bushing .35 or .40 that is somewhat lighter than a ball bearing .46. That might account for the tail heaviness.

RE: GP Easy Sport balance.
 

I am thinking about putting a Rossie .45 in the tail dragger version to see what it will do. If thiws happens I will certainly beef up the firewall.

RE: GP Easy Sport balance.
 

AND be prepared to either move the servos to the tail or add a lot of tail weight. Or maybe even both. A Rossie .45 is a great engine but light it ain't.