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Weight & Balance

Download the Weight & Balance Calculator (May 2017)

Paul Mayer of Green River Composite Squadron has developed this fleet weight and balance calculator.

There is a new, improved format which includes separating the seat rows into two inputs for each row of seats, and color coded information / warnings for how much more weight you can add (green) and how much you’re over and must remove (red), or lie about.

The ‘R’ and ‘T’ Model 182’s that have a reduced maximum landing weight have two possible inputs for “Fuel Burn”.


 Clarification for the application of those options is…


Basically, the "Fuel Burn" or "Burn For Ldg Wt" are an either / or (but not both) consideration based on whether T/O weight is greater than max landing weight (i.e. 2950 lbs). There are two scenarios.


A.    If T/O weight is </= 2950 lbs and in the envelope you really don't care about anything else. For amusement you can input your ete (hrs) times your fuel consumption (gal/hrs) which will give you a value of gallons. The program will then calculate a landing weight and CG.

This is just for amusement for two reasons;


     1.   Cessna's Law (C-182) = If the T/O CG is in the envelope, then burning fuel CANNOT take you out of the envelopeIt can only move the CG forward while reducing the weight. And each reduction of weight moves the envelope limit forward. And it appears to be linear. See if you can break Cessna's Law.


    2.    If you burn enough fuel you could reduce the weight enough to consider re-evaluating some of the V speeds, particularly V/a. However, the range of Cessna V speeds throughout the entire spectrum of weights doesn't vary all that much and, except for V/a, who cares if you're a knot or two fast. There are only two pilots in all of CAP that claim they fly the airplane to a knots derriere, and they're both lying. And if flying V/a to a knots derriere is your current dilemma you have already screwed up royally.


For further amusement, entering your ete burn in gallons will reveal your ete 'fuel remaining' at landing and could help you think about your CAP required 1 hour reserve. If, for instance, it showed 7 gallons remaining at landing would that be a wake up call ? Just being shown the numbers and their relationships and comparing them with what you really burned increases your knowledge and awareness.


B.    On the other hand, If T/O weight is > 2950 lbs you absolutely want to know how much fuel you MUST  burn, and therefore the minimum time you had better plan to be aloft, to get down to legal  landing weight. So, subtract 2950 from your take off weight and enter that number in the "Burn for Ldg Wt" line and you will get the gallons you need to burn, and by extrapolation your minimum ete.


In practice, you would run the weight and balance entering your ete gallons based on your flight plan on the "Fuel Burn" line. If you get a red "OVER" in the landing weight box then you can delete the "Fuel Burn" line entry and enter what you must lose in pounds on the "Burn for Ldg Wt" line and determine your minimum ete based on Gal/Hr, and compare that with what you are planning to do.

Mon Boonprohm,
Jun 23, 2017, 12:37 AM