Tired Old Man

My Feedback: (1)

Dan,

I can appreciate not changing what works

Rockyaged

I love threads about weight and balance. It's what I did for 24 years for the USAF.
On several logistics cargo carrying aircraft.
What's interesting in this thread, is no one stated HOW they found the balance point.
So, I suggest the following...

Weigh the plane for total weight, tailwheel weight, and measure the distance from
the main gear axle to the tailwheel axle, giving you a wheel base. The compute the
following formula.


Tailwheel weight times wheelbase divided by total weight = balance point measured in inches from
center of landing gear.

Take a square of some sort amd mark a spot on the rails that is right above the center of the landing gear,
and measure rearwards from that mark, the answer you got from doing the formula. It will be your CG
location. Next install the wings. Mark a spot on the wing tips of each wing, three inches back. Run a piece
of string or fishing line from wing tip to wing tip across the rails. Mark a line here, and compare this line to
the cg computed line. If the lines match up, your cg is at three inches. If different, measure the difference.
If your computed line is forward of the 3 inch line, your cg is less than three inches. I have done this on mine
and have come out at three and 1/4 inches. The plane flies great IMAC sequences and is easy to land. If you
want to know how my plane is configured, PM me and I'll send it to you. I have time-out problems on this site
so am going to close this post now.

Gerald

rcdude7

My Feedback: (264)

Today I skipped out of work and maidened my 300 extra special. I had checked my CG at 3 1/4 inces just before flight. Only required one click of aileron trim when airborne and it was "steady as she goes". I called it quits halfway into my second flight when the G-62 flamed out. I had lots of altitude so I brought it in for a nice easy deadstick. My engine ran fine at all throttle settings on the ground. Once in the air though it is rough at any setting below 3/4 throttle. I have a velocity stack sticking through the cowl that I suspect may be causing this. Tonight I soldered a brass tube onto the carb diaphram plate and ran a piece of tygon tube into the fuse. I'll try this trick first before I pitch the stack.

psk560

My Feedback: (12)

RCDude,

Congrats. I love my hare and you will too.

Craig

Bob Pastorello

My Feedback: (198)

Gerald - great technique, thanks for posting. When measuring "up" from the landing gear/axle, isn't it necessary that the fuse be sitting with horizontal datum level (zero)? If I recall, that's important...

Also - balance wasn't an issue on mine. Flew great for it's forty seconds of life. Went in at show center in a most spectacular semi-knife edge at about 1/2 throttle....looked like a tv-movie crash scene. Have no idea what happened, but it wasn't airframe related, and OF COURSE everything worked when I got all the pieces home.

Think I'll try a Yak.

Rockyaged

Aerobob;

Yes, you are correct. The rails should be level at "0" degrees when you
use the scale to transpose the center of the landing gear to the rails. This
allows you to use the square on the rails gauging down to the landing gear.

Sorry to hear about the crash.

Gerald