Fuel Loading Chart

cessnadriver · #1 12-18-11, 06:00 PM

Hello ALL.
Here's my question.
I have a 1965 C337. I'm going over the owner manual, specifically "Sample Loading Chart".
On the loading graph it has one line for "FUEL". On the line at the 32.3 (load moment) "36 gals Max. Aux tanks" AT the end of the line at 82.8, "92 gal Max."
When calculating the fuel load, I add the 36 gal and 92 gals, 128 gals (#768) TOTAL.
On the "Moment" column do I add 32.2 (AUX) and 82.8 (STD) together, OR do I use the 82.8 for both fuel loads. This is probably 'CG 101' for most of you but this is a new aircraft for me and I'd just like to understand better!
Many Thanks as usual!!
BILLS

Learjetter · #2 12-18-11, 07:58 PM

The attached is from a 67 Skymaster POH. Also, I'm not a skymaster pilot (yet!), so take this as you will...

The reference moment for FUEL appears to be based on a more than one WING STATION or FUS. STA. or reference datum point...whatever you want to call it. So TOTAL fuel (from EACH TANK set) is given a MOMENT. In the SAMPLE (attached), it appears the SAMPLE problem assumes FULL Standard 92 gal tanks (92 Gal X 6# per gal = 552 lbs) and EMPTY AUX TANKS, so it's given a single moment of 82.8. There's no entry for AUX Fuel, but there IS space for it on the chart, and a separate entry on the graph, so AUX fuel would have it's own moment (Full AUX Tanks would be about 33)

Confirmation on my theory (for me): reference the OIL lines on the SAMPLE--two values, two different entries for the two different locations of the oil...

That's my $.02. If I'm wrong, Mods delete this post and school me right.

Fly Safe.

cessnadriver · #3 12-18-11, 08:33 PM

Thanks Learjetter!
You Loading Graph shows AUX FUEL under the Standard fuel, mine does not. That's part of the problem for me. Your explanation is I will have to add the AUX MOMENT (@ about 33) to the moment for standard fuel (@82.8)-correct?
I'm going to copy your graphs to use in my 1965 C337(the number are the same)! I hope that I can get a bigger and more defined copy of your graphs-getting older you know.ha-ha.
BILLS

cessnadriver · #4 12-18-11, 08:40 PM

TO: Learjetter
Your attachment has three pages but the first didn't come through. I assume that the first page was the "CG Envelope"? Could you send this page again? Appreciate it. I PRINTED YOUR GRAPHS AND THEY'RE FULL PAGED- I CAN READ THEM FINE!!
Thanks, BILLS

Learjetter · #5 12-18-11, 08:58 PM

BILLS,

Here's a better copy..again from a '67 Skymaster POH. Hope this helps.

Fly Safe and Good luck!

cessnadriver · #6 12-19-11, 07:23 AM

TO: Learjetter.
Thanks for the new copy. I see that your aircraft max. weight is 100 more than mine so the CG envelope won't help. But Thanks any ways.
BILLS

Ed Coffman · #7 12-19-11, 10:22 PM

On your graph it shows full mains 92 gallons with a moment of 83000. Your aux tanks are 36 gallons with a moment of 32000. You have to add the moments together if you have both main and aux full for a total moment of 115000 and fuel weight of 768lbs. If you look on page 4-5 of you POH it actually give you moments of 82800 and 32400. Its just a little hard to discern that on the graph. Good luck.