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[Rusty]

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[RC Storick]

It seems I must be doing something wrong.   I just built the BRM per plans and it was not even in the ball park of balancing?  (nose heavy)

Can I get some insight on this? 

If the plans are so off target, what can I do before I build the plane to get an idea of moving the nose back or extending the tail?  (or vice-a-versa)

Thanks

You can ad more finish

[Tim Wescott]

You can ad more finish

Without an "I'm teasing" smiley face, even.  Hmm.

Can I get some insight on this? 

I suspect that most commercial 1/2-A planes were nose-heavy by design, particularly the sheet-winged ones.  If you want to put a handle into the hands of a kid who's never flown CL and get successful flights, having the CG at, or even in front of, the leading edge is not a bad thing.

If you're going to fly that baby RM in Classic for points, then you need to leave the rear fuselage alone.  If it's just for sport flying, I'd shorten the nose and lengthen the tail by an equal amount -- i.e., move wing and canopy forward.  Or just the wing.

Some of my 1/2-A planes have the firewall right on the LE: on a smallish plane with a Golden Bee, that tends to put the CG about where you want it.

[Tim Wescott]

Tim, thanks.   I am building another from outerzone and will do exactly as you suggest. 

If you're building another one of the exact same thing, with the same engine, then rubber-band the engine onto the plane you have and move it back until it balances.  Measure the distance from the prop driver to the LE (or whatever), and whack the next fuselage down to fit.

If this is that Baby Ringmaster that came out at 112 square inches, you may want to consider blowing it up a bit -- a Medallion or TD ought to fly nicely on a 125 or 150 square inch plane (or even bigger -- I dunno; I could never afford the nice Cox engines).

[Balsa Butcher]

One thing to remember is the O.Z. plan is marked "modified from original".The original as kitted by Sterling had a cut-off nose for a Cox Baby-Bee. Extending the nose and adding beam mounts would definitely make it nose heavy. I would do what has already been suggested and perhaps even increase the tail moment. BTW: plane looks nice.

[Randy Cuberly]

The easiest thing to do is simply add some tail weight.  Up to and ocnce won't cause any serious overweight problems and it's far better to add some weight to the airplane than try to fly a very nose heavy one!

For future builds folleo the instructions above to rubber band the engine and tank in place and get the CG where it belongs, then simply chop off the excess.

I've never understood why folks are so hesitant to add a little tail weight to something!!!

Randy Cuberly

[Jim Kraft]

Hey Rusty.  Where does it balance and what engine are you using? Where is the balance point on the plans? I would think it should balance pretty close to the leading edge of the wing or a little behind. As Randy pointed out adding a little tail weight should get you in the ball park, and it won't take much unless it's way off.

[Jim Kraft]

Should be fine Rusty. You might even want to remove a 1/4 ounce to make it less touchy on the controls. Most of my smaller planes have flown better with the CG a little farther forward than shown on your plan, but the designer should now best.

[john e. holliday]

I have a Baby RIngmaster that almost balances on the leading edge and is fast and twitchy.  Of course mine is for the Babe Bee and I put one of my Golden Bee's on it.