ORIGINAL: SLFlt
I recently completed a Superstar 40 and rough checked the CG (pointy finger method) according to the directions. My choice of engine was an OS .46AX. The fuel tank was empty and my measurement markings were right on (3 5/8" from leading edge). The battery and receiver placement were also according to directions. The aircraft appears to be aggressively nose heavy. Obviously my choice of engine is having an impact. Almost 3 oz of weight placed (temporarily) near the tail is starting to bring it level. I have several questions:
1) Is 3 oz or more weight excessive (when does the plane become too heavy)? What point do I stop counterweighting and start to move batteries and/or receivers instead?
2) Due to a long lever arm, the farther back I place my weights in the fuselage, the less I have to use. Does anyone have any techniques to cut into the rear portion of the fuselage and place weights there?
Any suggestions will be much appreciated. If I can crack this problem, I can "maiden flight" the aircraft as soon as the weather breaks!
Cheers,
S&L Flt
No, 3 oz is not too much weight. You place it as far back as possible which means you need to cut the tail open and glue them in the tail cone. Take a sharp x-acto knife and cut the bottom rear of the fuselage off, as if you were making a hatch. Be careful with the cuts, make them clean as you will be gluing it back on.
When you get the hatch cut off, glue the lead onto the bottom of the horizontal stabilizer or the fuselage sides. Recheck your CG before gluing the hatch back on. After gluing the hatch back on, you can leave it as is, or get some scrap covering from somebody and recover the seam.
Go Fly
Don