Rules of Thumb: Aircraft Weight
- Thread starter Zipper730
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Shortround6
Major General
For the engine yes. The guns and ammo were considered part of the payload so no there is no rule of thumb for that.
Rules of thumb would Break the gross weight into engine/power plant, structure (sometimes even wing and fuselage), sometimes landing gear (around 5%) and so on.
But since you can swap guns/ammo for fuel or increased electronics (night fighters) that made no difference to the basic aircraft size/structure (within reason).
It also helps to keep aircraft in certain classifications, obviously a fighter will use a higher proportion of it's weight for propulsion that a single engine transport will even though their landing gear weights might be close (assuming similar gross weights). Likewise a plane expected to pull 6-9 Gs on a regular basis will need heavier structure than a plane limited to under 4 Gs.
For a fighter the propulsion system would be in the high 20% to low/mid 30% of the gross weight.
Rules of thumb would Break the gross weight into engine/power plant, structure (sometimes even wing and fuselage), sometimes landing gear (around 5%) and so on.
But since you can swap guns/ammo for fuel or increased electronics (night fighters) that made no difference to the basic aircraft size/structure (within reason).
It also helps to keep aircraft in certain classifications, obviously a fighter will use a higher proportion of it's weight for propulsion that a single engine transport will even though their landing gear weights might be close (assuming similar gross weights). Likewise a plane expected to pull 6-9 Gs on a regular basis will need heavier structure than a plane limited to under 4 Gs.
For a fighter the propulsion system would be in the high 20% to low/mid 30% of the gross weight.
- Thread starter
- #3
So the plane will weigh around 3.13 to 5 times the engine?
Shortround6
Major General
For a fighter that is a good range.
Like an F4F-3, max gross weight clean 7432lbs
power plant weight 2432lbs'
engine weight 1540lbs.
Like an F4F-3, max gross weight clean 7432lbs
power plant weight 2432lbs'
engine weight 1540lbs.
- Thread starter
- #5
So plane as a whole weighs around 4.83 times the engine and 3.06 times the whole power-plant; fuel fraction would be 11.8676% (this configuration is in the fighter overload configuration.
Shortround6
Major General
You can forget about running things past the 1st decimal place, in fact you can put a + or - of several percent on these figures.
This was posted a while back.
Structure weight data and drag analysis.
see second sheet.
Powerplant weights for eight single engine/single seat fighter (American and British ) vary from 29.? ( can't read the last number) to 38.0%.
Single engine bombers are in the low 20s (mostly) low powered twin engine bombers are in the teens.
Structural weight for wings and fuselage and other stuff is given.
Any time your are working with a "rule" of thumb you can forget decimal points.
This was posted a while back.
Structure weight data and drag analysis.
see second sheet.
Powerplant weights for eight single engine/single seat fighter (American and British ) vary from 29.? ( can't read the last number) to 38.0%.
Single engine bombers are in the low 20s (mostly) low powered twin engine bombers are in the teens.
Structural weight for wings and fuselage and other stuff is given.
Any time your are working with a "rule" of thumb you can forget decimal points.
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