Online Aircraft Weight & Balance Calculator

Aircraft Weight & Balance Calculator

A spreedsheet-like tool for calculating aircraft weight & balance
during construction of home-built experimental aircraft.

This online tool can also be used for calculating aircraft weight & balance
for flight-planning purposes.

The weight/balance table allows the user to start with a basic fuselage,
without engine, propeller, passengers, fuel, or baggage. Various aircraft
components, engines, and engine placement values can be entered on
the chart and the resulting center-of-gravity determined.

( See notes * at bottom of page for more information )

Calculate

Initialize

Distance from Datum to Face of Prop-Flange
Distance from Engine C.G. to Face of Prop-Flange
Distance from Prop-Flange to Center of Prop.

Component	Weight	Arm	Moment
Basic Fuselage
Engine
Propeller
Front Passengers
Rear Passengers
Baggage
Fuel


Total Weight
Total Moment
Center of Gravity

For comparisson purposes, a copy of a page from Rober Barrows
2005 Bearhawk Patrol News Letter is shown below.

Basic Patrol limits: 10.5" (16%) - 21.5" (32.5%)

(note: There is a small error in the above W/B document; the weight of the fuel, 30#, was omitted when adding up the gross weight with one passenger and minimal fuel. The weight should have been 1257.5 and the resultant C.G should be 12.5 ... still within the Patrol's C.G. envelope)

The purpose of this project was to develop a simple spreadsheet-like web page to serve as an aid in aircraft fuselage design, specifically - construction of engine-mounts, engine-placement, and positioning of accessories.

It assumes that the weight and C.G. of the bare fuselage is known rather than weight of total aircraft as measured with scales beneath landing-gear and tail-wheel.

Default data was determined by reversing calculation done by Bob Barrows as printed in his Bearhawk Patrol 2005 Newsletter. This was accomplished by performing an online search for weight and C.G. data from Lycoming and propeller manufacturers, using Bob's documented engine location, determining the weight/balance moments contributed by engine and propeller on the Patrol prototype, and subtracting engine and propeller values to determine C.G. data for the bare fuselage.

Since the exact model of Lycoming O-360 engine in the Patrol prototype was not know, an average value (guess) was chosen from Lycoming documentation.

Good agreement of results of this online tool with Barrow's published data was achieved.

This online tool was then used to determine design specifications for engine-mounts on another Bearhawk Patrol incorporating a stripped down 0-320 and a wooden propeller. Calculated specifications generally agreed with anticipated results but engine position selected was slightly forward of Barrow's suggested engine position.