Online weight and balance

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pcykoria
Airman
Posts: 18
Joined: 07 Oct 2013, 12:46

Re: Online weight and balance

Post by pcykoria »

CESSNA A2A BALANCE CALCULATOR

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Link

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simurqq wrote:Just to clarify: I guess the "Oil" cell requires input in pounds, not quarts. So, judging from this specification, 8 quarts of oil = 2 US gal = 14.88 pounds. Can you confirm?
The XLS file is set for LBS mesaurement only atm. Fonding proper converting rate of US Qt to LBS was quite a googletrip for me, I finaly found some University forum with a whole thread about this conversion. It was stated clearly there that 1 US QT = 0.25 LBS therefore Cessna's 172 6 oil quarts will be 1.5. I also found one other source (pilot forum) where one mentioned that 6 us qt are 1.4 lbs... I am not quite sure about this 14.88 pounds for oil conversion. It would be great if someone could confirm it for both of us please :)

UPDATES:
I have uploaded a new version with extra descriptions and I changed the max fuel quantity to appropriate number.

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Great Ozzie
A2A Test Pilot
Posts: 2054
Joined: 16 Feb 2008, 15:49
Location: KUMP

Re: Online weight and balance

Post by Great Ozzie »

simurqq wrote: Just to clarify: I guess the "Oil" cell requires input in pounds, not quarts. So, judging from this specification, 8 quarts of oil = 2 US gal = 14.88 pounds. Can you confirm?
This is getting into A&P territory... personally, I think that it is excellent you guys are taking the time to think about these things - so I submit the following:

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"For aircraft certified since 1978, full engine oil is typically included in an aircraft’s empty weight. This can be confirmed by looking at the Type Certificate Data Sheet. If full oil is to be included, the oil level needs to be checked and the oil system serviced if it is less than full."

"The standard weight for lubricating oil is 7.5 lb/gal (1.875 pounds per quart)"

Aviation Maintenance Technician Handbook - General
Chapter 4: Aircraft Weight and Balance

[From TCDS No.3A12]

Data Pertinent to Model 172R: (cont’d)

NOTE 1: Weight and Balance:
Serial Nos. 17280001 and On
The certificated empty weight and corresponding center of gravity location must include unusable fuel of 18 pounds at 46.0 inches aft of datum, and full oil of 15.0 pounds at 13.1 inches forward of datum.
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Oil (in this case) is included in the Basic Empty Weight and one would use the figure of 15lbs for full oil... but this is ONLY if you are attempting to determine the Basic Empty Weight... something you would only do as an A&P as there is going to be a logbook entry & sign-off needed by an appropriately certificated mechanic.

How does this impact your Weight & Balance calculations? In this case it doesn't -- you don't concern yourself with how much oil is in the engine for Weight & Balance Purposes.

That link Scott provided is spot on where it says, "Oil (8 Qts)included in basic empty above as per POH". And you can see there, one does not have the ability to change the "Zero" figure to anything else as it is grayed out. Hope all this helps...

-Rob
Rob Osborne
Flight Instructor - CFI, CFII, MEI, MEII
A & P Mechanic


FAASTeam - Safer Skies Through Education
Professionalism in aviation is the pursuit of excellence through discipline, ethical behavior and continuous improvement. NBAA

simurqq
Airman First Class
Posts: 79
Joined: 31 Mar 2010, 16:16

Re: Online weight and balance

Post by simurqq »

Rob,

Thank you for clarification! Basically what I did was 2 gals x 7.44 lbs/gal (density) = 14.88 lbs which is very close to the figure from your post. Checked!
But according to that line from TCDS, no need to consider oil in weight calculations since it's already in EW. Done! :)

Thanks!
Thanks!

Victor Q.

ft
Staff Sergeant
Posts: 358
Joined: 01 Feb 2005, 08:13

Re: Online weight and balance

Post by ft »

Scott - A2A wrote:Regarding the empty weight, just deduct 50lbs from the final calculation.
That'll render your calculated CoG invalid though. Not by much, probably not significant in any way in the simulator, but not OK in real world ops.
Be warned: Aero engineer, real life pilot, sim programmer. Nothing good can come out of that.

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jmann
Airman First Class
Posts: 62
Joined: 20 Nov 2013, 14:42

Re: Online weight and balance

Post by jmann »

pcykoria wrote:CESSNA A2A BALANCE CALCULATOR

Image

Link

--------------------------------
simurqq wrote:Just to clarify: I guess the "Oil" cell requires input in pounds, not quarts. So, judging from this specification, 8 quarts of oil = 2 US gal = 14.88 pounds. Can you confirm?
The XLS file is set for LBS mesaurement only atm. Fonding proper converting rate of US Qt to LBS was quite a googletrip for me, I finaly found some University forum with a whole thread about this conversion. It was stated clearly there that 1 US QT = 0.25 LBS therefore Cessna's 172 6 oil quarts will be 1.5. I also found one other source (pilot forum) where one mentioned that 6 us qt are 1.4 lbs... I am not quite sure about this 14.88 pounds for oil conversion. It would be great if someone could confirm it for both of us please :)

UPDATES:
I have uploaded a new version with extra descriptions and I changed the max fuel quantity to appropriate number.

Can we get an unlocked version so we can change the empty weight?

jsbrewster1
Senior Airman
Posts: 111
Joined: 19 Sep 2015, 12:11

Re: Online weight and balance

Post by jsbrewster1 »

I've noticed a checklist step to calculate W&B, and I remember my boom operator doing it for years in the -135, but is there actually anything built into the simulation for W&B, or should I just use this very cool Excel spreadsheet and assume it's accurate enough?
Jeff Brewster
KC-135 Navigator
US Air Force (retired)
"...and miles to go before I sleep..." - RF

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