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Does this look right? EWCG

adamgrenda

Registered User
King Salmon, AK
Pictures attached of empty weight CG. 15.33 on skis ,14.35 on 35s. What is everyone else CG empty? Is this too far aft? I've researched a while and found that CG can be very convoluted topic as well...

Also pictures attached of a W&B calculated for my cub. I'm 260 with a 260 passenger and full tanks nothing else puts me at 18.7 on skis...Does that seem right?

I always seem like I'm pushing aft CG limit

Thoughts?

Thanks



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You used the wrong arm for the bushwheels. It should be +2". You used -2". That's a 4" error.
I get 1280 lbs @ 15.82" empty with the 35" wheels.
Loaded two 260 pound people and 36 gallons gas = 2016 lbs @18.81"

The aft limit for the PA-18 is 20".
 
You used the wrong arm for the bushwheels. It should be +2". You used -2". That's a 4" error.
I get 1280 lbs @ 15.82" empty with the 35" wheels.
Loaded two 260 pound people and 36 gallons gas = 2016 lbs @18.81"

The aft limit for the PA-18 is 20".

I redid the figures and came up with 1235(after removing 44# for skis) 1235 at 14.57.

Am I missing something? Does that seems pretty far aft for empty cg?
 
That seems pretty heavy on the tail. I am seeing a pretty stock Super Cub on 8.50 at 1100 lbs empty and CG of 13.03" to 1166 lb EW modified SCs at 166 lbs and 13" CG, 1218 EW 11.54" CG and 1158 lb EW 13.86" CG. These are anywhere from 50-68 lbs on the tail in level attitude and I use a light weight battery in the stock location to keep the CG from going so far forward like the underseat batteries seem to do when flying at low gross weights.
 
Using your original scale weight numbers of 506 @ 2", 571 @ 2" and 88 @ 203" I get 1165 lbs empty @ 17.18". Then adding 114 lbs @ 2" the answer is 1279 lbs @ 15.83".
I misread your 35" wheel weight as being 115 lbs the first time.

Can you account for the 65 pound difference between the left and right wheel weights? Seems as though those numbers should be closer together. Not necessarily the same.
 
I recently helped a buddy weigh his almost-ready-to-fly PA12 project.
TCDS gives the datum as the wing leading edge,
but the old W&B sheet used the old "point in space out in front of the airplane".
Pretty darn confusing, I can see how these can easily be messed up.
I like Cessna, usually (but not always) it's the firewall, but the C120/140 uses WLE.
Seen a C140 W&B revision which used the firewall as datum,
IMHO might as well not even done the revision as to do it wrong.
 
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