The Cessna 120-140 Association Forum

Anyone have numbers for setting weight balance on fore flight? I keep getting error messages. “ Each fwd CG limit point should have unique weight” same message for the aft. I don’t know that number any help would be appreciated

I have not used the Weight and Balance on Foreflight as it didn't seem to work for me either. It seems like you should contact them with the issue. The app should come up with the balance point between the fore and aft limits and whether or not it is within the maximum weight limits.

WAG: you only have one fore and one aft limit, and they are both at 1450 lbs.

Maybe try making the second weight only one lb different. One would be 1450 and other 1449. Maybe that will make it work since it's looking for different weights. If successful, I would think one lb wouldn't make the computations off by enough to worry about.

Your Zero fuel weight is not correct.
By definition Zero fuel weight is everything loaded except for fuel.
Empty weight +Crew+Cargo= Zero fuel weight.

It probably won't answer your question but it should be corrected.

I don't think there is a Zero fuel weight limitation for this aircraft.
It is usually found with large transport category aircraft.

Rick

8342 wrote: ↑Thu Jun 23, 2022 1:14 pm By definition Zero fuel weight is everything loaded except for fuel.

That's a little confusing.

Zero fuel weight is a structural limitation. It is the maximum weight allowed for aircraft+passengers + baggage+ unusable fuel. Any additional weight beyond the zero fuel weight must be fuel. There is no zero fuel weight for the 140 other than what is necessary to meet fuel reserve requirements, but those limits are not structural.

Here's a good discussion.

The C of G Limits require a weight, this is because for many aircraft (not ours) the C of G envelope changes with weight. So to correct and make this work for you make the following adjustments...

1) Change one of the forward C of G to 13.5 @ 1450 Ibs and one of the Aft to 17.7 @ 1450 lbs as you currently have them set at 0 lbs.

2) Also change the MZFW to 1450 lbs (yes this 100% meets the definition of MZFW)

Kindest
Si

John, I did not include unable fuel since it is included in the empty weight.

The reason I brought it up is when you look at cpt7576's post the it has empty weight at 972 lbs and zero fuel weight as 972 lbs.
They are not the same.

Rick

Thanks for info ! I’ll give it a try.

Refer to your AC's W&B -
Empty fore & aft CGs as in the attached would likely be near 12.2" & 14.5", respectively.
Max weight fore & aft CGs as in the attached would likely be near 13.5" & 17.7", respectively.