Russ McCutcheon
Well Known Member
Quick question for you -7 guys. Am I correct that the pilot and passenger move the C of G aft? I was told recently that only baggage will move the C of G aft in the -7, I don't believe this to be true. What say you?
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Weight and Balance
- Thread starter Russ McCutcheon
- Start date
Russ McCutcheon
Well Known Member
Thanks Alton.
I had the same question
I posted pretty much the same question on the RV-9 page, but didn't express myself as well as AltonD. My thought was that the engine choice has most of the CG impact and might counteract the effects of overweight PIC + pax, but couldn't locate arms for different models. I was looking for a fuel-efficient configuration to cut ROI costs and the 9 looked attractive. My concern was the -9 might be more sensitive to aft CG with smaller engines, but this post suggests the culprit is luggage. Then I read an NTSB report of a 7 with intricate paint (the green one with shark teeth on the cowl) that might have also set CG way back and was a contributing factor in a crash in formation flight. My goal is selection of model, engine and paint (or probably no paint) that results in a CG-stable configuration that is relatively insensitive to overweight PIC+pax. What I'm reading here and with my own limited research is the 7 probably has better CG resilience due to the heavier engines and longer chord, with the significant arms of seating, luggage and paint all aft (in that order).
I posted pretty much the same question on the RV-9 page, but didn't express myself as well as AltonD. My thought was that the engine choice has most of the CG impact and might counteract the effects of overweight PIC + pax, but couldn't locate arms for different models. I was looking for a fuel-efficient configuration to cut ROI costs and the 9 looked attractive. My concern was the -9 might be more sensitive to aft CG with smaller engines, but this post suggests the culprit is luggage. Then I read an NTSB report of a 7 with intricate paint (the green one with shark teeth on the cowl) that might have also set CG way back and was a contributing factor in a crash in formation flight. My goal is selection of model, engine and paint (or probably no paint) that results in a CG-stable configuration that is relatively insensitive to overweight PIC+pax. What I'm reading here and with my own limited research is the 7 probably has better CG resilience due to the heavier engines and longer chord, with the significant arms of seating, luggage and paint all aft (in that order).
AltonD
Well Known Member
For me. . .
I have a IO-360 with constant speed Hartzell. With me and the wife, I cannot drive the CG out aft, even with empty tanks. I cut the baggage load to stay within gross. And even if I exceeded gross, but still maintained the max 100# baggage limitation, I would still be withing CG limits. (I would never exceed gross, just sayin, if I did).
I think it has to do with the Hartzell prop.
BTW, full IFR panel
aviator interior - leather
My empty CG is at the forward limit (no baggage, fuel, personnel). Everything added moves the cg rearward.
I have a IO-360 with constant speed Hartzell. With me and the wife, I cannot drive the CG out aft, even with empty tanks. I cut the baggage load to stay within gross. And even if I exceeded gross, but still maintained the max 100# baggage limitation, I would still be withing CG limits. (I would never exceed gross, just sayin, if I did).
I think it has to do with the Hartzell prop.
BTW, full IFR panel
aviator interior - leather
My empty CG is at the forward limit (no baggage, fuel, personnel). Everything added moves the cg rearward.
Last edited:
lostpilot28
Well Known Member
I don't know if I'd say it's "just barely"...just glancing at my W&B sheets, the addition of a passenger only, moves your CG back 1.5 inches. That's quite a bit, especially if you're starting off with an empty airplane who's CG is 2 inches aft of forward. In the grand scheme of things, 1.5 inches isn't a lot, but if you're on a long flight and tanks start getting real low, that will probably put you to the aft end of your CG range. Mine does.
