Champ C.G. Limits

[navyav8er]

I have a new to me Champ (7BCM Conv) that has been converted to a C-85-12F using Bill Pancake's STC. I just did a new weight and balance I had a question about the C.G. limits. I'm a big guy (230lbs) and if I fly by myself in the front seat with full fuel (13gal), my calculated C.G. is pretty far forward (12.3"). The STC lists two C.G. limits:
(+16.8) to (+20.4) at 1320 lbs (max gross weight)
(+10.0) to (+20.4) at 1087 lbs or less

Can I plot a line from the 10" weight to the 16.8" weight and use that as my forward C.G limit when my weight is less than max gross? Or am I limited to 16.8" at all gross weights? I'll attach my weight and balance plot for a visual of what I'm asking. I'd hate to have to add ballast, I live in CO and need all the performance I can get.
Thanks,
Scott

 

[Bob Turner]

Legal answer is no - just like the rule that says do not fly overweight.

Nothing actually happens at breakpoints - an airplane cannot be perfectly safe at 1320 lbs and 16" and at the same time deadly at 1321 and 15.9" - you just go from legal to not legal.

 

[navyav8er]

Ok, but what I'm asking is what is the forward C.G. limit when your gross weight is.....say 1100 lbs? The limits I posed above don't seem to define a forward limit when gross weight is between 1088 lbs and 1319 lbs.

 

[Bob Turner]

I think I see your problem. This is a poorly worded restriction. You might want to check with Bill Pancake. He is easy to talk to. Jot down the time and date of your call, and the results, date and sign it, and keep it in your paperwork.

 

[Sully]

Can't answer your question directly for an STC'd 7BCM but:
Look at later POH which are on the same TCDS.

 

[Sully]

Additional Info.

 

[Thedude]

Most CGs (including Aeronca/Champion/etc) with two weight ranges will specify a “straight line variation between points given” which is exactly how your chart is drawn.