Unknown item in W&B

[JimC]

Originally Posted by JAG

When I measured my points, I came up with:
A (front face of Fwd Firewall to main wheel centers) = 87.8 "
B (Nose Wheel center to main wheel center) = 93.7 "
I took a great deal of time doing the measurements using a plumb bob, tape on the floor, large straight edges, etc. Still easy to mess it up though...

[...]

Hope this helps.

Jeff

It helps tremendously. All I know at this point is that it's very likely wrong. Knowing where it's likely wrong will help me sleep at night. I figured the linear measurements were off - there was no effort made to record a precision of less than one inch. Also, the the weight of my front tire was recorded as 500.0 lbs, exactly. Is it possible? Yes, but I think it's more likely they were using a substandard scale with a precision of 10.0 lbs. Combine that with substandard measurement and you have my W&B.

What REALLY shocks me is that this has been the reference W&B for 30+ years! Either
a) nobody checked c.g. or
b) nobody thought having two 170 lb pilots throw the plane out of c.g. was unusual!

[JimC]

Well, it took almost a year - but I had my plane accurately weighed. As expected, I gained 60+ lbs of useful load and the c.g. moved back almost two inches. I'm still trying to figure out why the c.g. is slightly forward more than the fleet average - I'm at 139.38.

This error has been in the paperwork of the plane for over 30 years!

[patrolpilot]

My '77G just weighed in at 3068 @ 140.

[Learjetter]

Paperwork says I’m at 2968 @ 141.1 ‘77 G model.

But I’m going to weigh her this fall and get an accurate updated W&B.

[JimC]

Those G models are light! I can't figure out how they're lighter than the Es and Fs, when they have the same fuselage as a P-model.

[JAG]

Jim - what is your empty weight? E & F should be lighter than the G given the different interior...

Jeff

[JimC]

I've come to the conclusion that the unknown item in my W&B is the weight of the entire turbo system, which was installed after my airplane was weighed at the factory.

If the 2968 lbs is correct, that is a VERY light plane. I still can't figure out where I'm "fat" - the turbo is about 150 lbs, and that G is lighter than my plane minus the turbo. The 3068 lb G seems more likely.

My empty weight is 3,174 lbs.