I have a dilema with a Warrior 61. here are the basics ws- 64 1/2", fuse 46" w/o rudder 52" with. wing chord at fuse is 16" and complete weight is approx 5 lbs. This ARF was made in India and the instructions were translated into English poorly. The instructed BP is 77mm from LE and at that point it takes 4 lbs to balance, and at 4" it still takes almost 1 lb. The plane looks very similar to a CAP 232 but for the wings. Anybody have ANY suggestions that may help other than trying different BP's and fly it?

Are the leading and trailing edges straight or tapered? Is the spar straight of angled back? It sounds like the CG call-out is wrong, but we can't tell until we know the shape of the wing.

Jim

Thanks for the reply Jim. It has a tapered wing, spars are tapered matching angle of the wing. wing is flat bottom with no dihedral. Does this help? I can post a picture if that would be helpful. Jay

Yes, that would help.

Meanwhile, here is a method that works well for any shape wing;

Take the wing off the airplane.
Measure half of the distance from the center of the wing to one wing tip.
At that point, measure the distance from the leading edge to the trailing edge.
Still at the halfway point, measure back 30% of that distance from the leading edge and make a mark or put a little piece of tape on the wing.
Now do the same on the other wing.
Use a straight edge to strike a line connecting the 30% points across the center of the wing and make a mark or put a piece of tape on the line where it crosses under the fuselage.
Put the wing back on the fuselage and measure from the leading edge to the line at the side of the fuselage.

That measurement at the side of the fuselage will put the CG at 30%, which is a good starting point for a sport aerobatic model.

Jim

Jim, thanks for the info. I will give it a try this evening. I did make a mistake on the wing descriptin, it is symetrical not flat on bottom. If this image is of no use let me know what type angle would be best and I'll post it. Jay

Clyde:

The wing looks like a typical tapered wing where the leading edge is swept back and the trailing edge is swept forward. Usually in these wings, the spar is straight across from tip to tip. If it is, then you can just measure 30% (of the root chord) back on the wing at the side of the fuselage and that will be your CG.

If the wing root chord is 16", that would put your CG at 4.8 inches (122mm).

The method I gave you in the last post will work fine for this wing and should give the same answer.

Looks like a nice flyer. Good luck with it.

Jim

PS: The airfoil looks pretty thin. I'd suggest you start out with very small elevator travel. Something like 1/2" each way on low rates. Use anything you want for high rates, but use low rates on the first flight! I have a Suchoi with an airfoil like that and it will stall instantly if the elevator throw goes over 1/2".

J

Jim. Outstanding advice. I just got to where I could try your suggestion and Viola! It measured out to 4 7/8 from LE and balanced with 1/2 oz. nose weight. We have had 25-35 mph winds for the last 12 days so I haven't had a chance to try it out yet, but I will let you know what happens when it happens. Thank you very much, you were a wonderful help. Jay

Jim, thanks for the info also. I'm using a Hitec Eclipse so I'll start with Lo rates. Thanks again, Jay