Unknown item in W&B

[JimC]

I'm looking through my old W&B docs, and I found this line item in the original factory W&B:

"MODEL 337TURBO SUPER SKYMASTR" [sic]
Weight: 159.0 lbs
Arm: 115.5

The airframe itself is listed as "STANDARD AIRPLANE (EMPTY,DRY,UNPAINTED) ACTUAL" with a weight of 2617.5 and an arm of 141.6.

Does anyone know what that 159 lb item is? Is that the factory way of listing the turbo system? I find it odd that they'd build it, weigh it, and *then* add turbos.


At some point my c.g. jumped over an inch and a half forward and I'm trying to find out when & why. It's currently 137.5, which seems VERY far forward. I go out of c.g. with two people and 1/2 fuel. It's been as far forward as 137.2, which seems to me to be dangerously far forward. It came from the factory at 138.9. The w&b that moved it from 138.9 to 137.2 is missing.

[JAG]

Jim,
Look closely at the original factor W&B - many times the aircraft was "computed" and not "actual" weight - that could explain the turbo system being listed separate. See snap shot of my original - it calculated the paint! depending on your configuration, they are all listed in the equipment list with annotations either as installed (have an 'x') and whether it is optional or required equipment.

My guess is the 159 lbs is the extra weight for you aircraft as optioned over the standard airplane weight.

Jeff

[JimC]

Mine's listed as ACTUAL. Also, each piece of installed equipment is listed separately.

The 159 lb item in question is the last line item. The station of 115.5 is slightly forward of the average of the two engines (the average station of oil is 125.5.)

[JimC]

BTW, I found all but one of my missing W&Bs. The one where the weight seems to "jump" forward is a reweighing from about 30 years ago. The weight and c.g move as though 111.5 lbs were added right about at the pilot's knees. That's a lot of "found" weight, and very far forward. Every W&B since then has been a calculation off of that one.

I don't think the 1990 reweighing was done precisely.

[JAG]

Thanks Jim,
Interesting to see your W&B from Cessna from 1969. Mine is about 5 pages, and it is similar in the sense - but it also includes the whole equipment list for all 1966 aircraft, then and 'X' or 'O' depending on if it was installed.

I was worried about the same on my my aircraft - for the last 30 years the W&B had been amended, but I was concerned about the actual weight and CofG. My reweigh went well, and right about where I thought it would be. I removed a lot of old stuff, but added a bit with a lot of soundproofing/insulation in the cabin. Nose scale was 390 lbs, LH main 1249 lbs and RH main 1243 lbs = 2882 lbs. I weighed with fuel empty, but oil full.

Cof G is 140.2 inches.

Jeff

[TomM]

Its interesting how the static wicks are negligible but post lights are worth weighing and calculating moment arm.........I cant imagine the post lights weigh more than the static wicks....