The Cessna 120-140 Association Forum

I purchased the Tempest Oil Filter Adaptor for my C140A. C90 and have the STC, but does anyone have the weight and balance information for the W&B revision?

W&B information should have come with the STC.

Probably weight and arm, then you need to do the calculations from the last and most current W&B sheet for your airplane.

Using that information you would then make a new W&B sheet to keep in the airplane as part of the ARROW data.

Good luck,

Rick

I have a NOS adapter back before Tempest - I checked Tempest page and it is the same adapter, Model TAF. Checked the STC installation instructions and the last sheet, "SUPPLEMENTAL INSTRUCTIONS FOR INSTALLING THE MODEL TAF OIL FILTER ADAPTER", excerpt last paragraph, "Figure weight of unit at 3.5 lbs. C G Change is negligible, less than 7/16" and is forward. F & M COMPANY Revision 1 April 30, 1992."

I had weighed the adapter but reweighed today on my precision, NIST traceable, scale and the adapter alone weighs 1 lb 3.75 ounces, thus, the "figure the unit at 3.5 lbs." must allow for the filter and extra oil and weight reduction for removing the old screen.

Big Edd

I just did one recently. I got the weight from the paperwork (probably the same as above) and I used the same arm as the oil in the tank, -31.5" (on a 140 - you'll have to look it up for the 140A.).

The potential change is not negligible, although it is forward, and therefore not likely dangerous. I would be sure to compute it anyhow.

I think the A model uses the firewall as the reference point and the 120 and 140, the leading edge.

6298 wrote: ↑Fri Oct 26, 2018 8:08 pm I think the A model uses the firewall as the reference point and the 120 and 140, the leading edge.

Oops... The arm I gave is for the 140, not the 140A. Easy enough to measure from the firewall to the center of the filter.

To quote, not here but other forum, "I'm being attack" for trying to help a guy with too much detailed info.

To put my references ( identical quotes from the FAA APPROVED STC, approved by the Manager, Special Certification Office) in context, the STC is against the C-90 & O-200 series engines - not airframes, which would mean negligible CG change for engine and not an airframe. For once, at least, the FAA manager agreed with the STC "Supplemental Instructions" concerning "negligible" and that approval is noted due to the fact that it is so noted as one of the "Date Amended" notations on the face of the STC!!


In essence, does one run a new W@B if operating a quart low in an aircraft sump?


Possibly, that's why Tempest left it up to the installer to sort through the quagmire - no liability!!

In closing, it would be an interesting experiment to give three of the contrbuting "gurus" this issue and a tape and see how close their results would compare.

4004 wrote: ↑Fri Oct 26, 2018 11:41 pm"I'm being attack"

4004:
Are you referring to me? It was not my intention to attack you. Further more, it wasn't your statement I was disagreeing with, but, as you said, the statement of the previous STC holder.

The reason I said it is not insignificant is because, last time I installed one, it put the CG slightly forward of the empty CG range where "further check [is] not required." I thought that was important enough to point out.

Oh, further, it would not really be possible for the STC holder to give the arm as that depends on the airframe installation. Perhaps it was their intention that the engine weight should be increased by 3.5 lbs then the CG recalculated with the new engine weight. Who knows?