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W&B tiedown arm

AltonD

AltonD

Well Known Member
Anybody have the arm for the wing tiedown station? Inches behind the leading edge?
30 min. Drive to the airport, looking for the shortcut.
 
Probably in the middle of the fuel arm and pilot/co-pilot arm, if a ballpark figure gets you close enough.
 
16" aft of Leading Edge.

Derived from plans, DWG 9 - 1/4 scale - zoomed to 800% and measured; checked against known measurement on plans.
 
bjdecker said:
16" aft of Leading Edge.
Derived from plans, DWG 9 - 1/4 scale - zoomed to 800% and measured; checked against known measurement on plans.
Click to expand...

Be careful here. The -9 uses a different wing. Is the leading edge "D" cell the same dimension as the -7?
 
bjdecker said:
16" aft of Leading Edge.

Derived from plans, DWG 9 - 1/4 scale - zoomed to 800% and measured; checked against known measurement on plans.
Click to expand...

Thanks, dug out my drawings. 4.125 x 4 = 16.5"

Mel, he was referring to drawing #9. Saved me the trouble is going through all of them.

I am what-iffing changing out from a PC680 battery to a ETX900. 10 pounds off the firewall (13" in front of the leading edge). My raw W&B numbers were taken on jack stands at the tie down.
 
AltonD said:
Thanks, dug out my drawings. 4.125 x 4 = 16.5"
Mel, he was referring to drawing #9. Saved me the trouble is going through all of them.
I am what-iffing changing out from a PC680 battery to a ETX900. 10 pounds off the firewall (13" in front of the leading edge). My raw W&B numbers were taken on jack stands at the tie down.
Click to expand...

Sorry about that. I misread the post.
 
I did the same on my -7, swapped out the PC680 & steel box and installed a ETX900 + BBMU.

I went through the math and figured the C.G. moved aft a little bit (read: ~1")
 
Thanks for the help guys.

Final what if, moves my CG .46" aft, still within limits, worst case.
 
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bjdecker said:
I did the same on my -7, swapped out the PC680 & steel box and installed a ETX900 + BBMU.

I went through the math and figured the C.G. moved aft a little bit (read: ~1")
Click to expand...

If I do the deed, I'll put mine back up on the scales to verify. Went in with 5 local builders and bought a set of scales. Money well spent.
 
I wasn't worried about the CG limits, due to the fact that my weight varies by at least 10 lbs during the course of a year :)
 
bjdecker said:
I wasn't worried about the CG limits, due to the fact that my weight varies by at least 10 lbs during the course of a year :)
Click to expand...

Hang a Hartzell constant-speed, non-composite prop on the front of an A model 7, unless you are loading lead bricks and exceeding gross, darn near impossible to drive the CG out aft.
YMMV
 
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