DaveB.inVa
Airman 1st Class
- 225
- Dec 20, 2004
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Soren said:So the 16,300lbs normal loaded figure for the -47N was correct afterall....I thought so
DAVIDICUS said:All performance data is for "Combat Gross Weight" which means a full internal ammunition load and a full internal fuel load.
Which is what we were looking for. (or atleast me)
For example the Spit XIV's Combat gross weight was 8500lbs, and the Bf-109K-4's was 6,940lbs. Both are with full internal fuel load and ammunition.
So to keep it fair, we should be looking at the -47N's combat gross weight aswell.
Soren said:I set up the Bf-109K-4 as an example, because these two would meet in battle under these exact conditions; The 109 would be weighing its normal combat gross weight of 6,940lbs while the -47N weighing its normal combat gross weight of 16,300lbs. Thats how it would be, now you can call that unfair all you'd like, but thats how war is.
Soren said:DAVID all else being equal, fighters did not fly out on half full or even 3/4 full internal fuel tanks, that's just not the way it was done. And they certainly didn't fly on half full internal fuel tanks coupled with drop tanks..
So while the -47N might have had an excessive amount internal fuel for 'one' mission, it would still be fully fueled up in case of any emergency.
Lunatic said:Soren said:DAVID all else being equal, fighters did not fly out on half full or even 3/4 full internal fuel tanks, that's just not the way it was done. And they certainly didn't fly on half full internal fuel tanks coupled with drop tanks..
So while the -47N might have had an excessive amount internal fuel for 'one' mission, it would still be fully fueled up in case of any emergency.
Not necissarily. The fuselage fuel would be filled to capacity, but the wing tanks might or might not be. The P-47N had fuel cells rather than normal tanks in the wings, IIRC it had 6 cells in each wing. It was entirely reasonable and possible to fill all, some, or none of the cells depending on mission parameters.
On the P-38L the fuel tanks outside of the engines were often left empty, so your contention that maximuim internal fuel was always loaded is false.
=S=
Lunatic
evangilder said:Interesting point, Joe and I will add that with our airplanes at the museum, they always fuel them after a flight before putting them away. I wondered why, but never asked. Condensation makes perfect sense, especially in Camarillo.
FLYBOYJ said:DISAGREE! You cannot continually leave a fuel tank empty - the cell will deteriorate and rot! Those aircraft with a plain wet wing will have fuel tank sealant within the wing break down as well. Additionally the seals in boost pumps and transfer valves will also rot as well. The only time fuel was left behind was to carry a load or because of density altitude performance, or both. Additionally it was SOP to top off fuel tanks after a mission to prevent condensation in the fuel tank. I've confirmed this with several WW2 wrench turners who served in both ETO and PTO.
Simple fuel tanks (Riveted aluminum) are still sealed with fuel tank sealant at the riveted seams and all the fastener heads are also sealed as well. Welded fuel tanks usually had a a seal or o ring at the outlet or the crossfeed. Once fuel is placed in the tank and contacts that sealant, the sealant must have occasional contact with fuel our else it will break down, and again you still have interconnecting plumbing and boost pumps and/or transfer valves with o rings and seals that will break down as well.Lunatic said:FLYBOYJ said:DISAGREE! You cannot continually leave a fuel tank empty - the cell will deteriorate and rot! Those aircraft with a plain wet wing will have fuel tank sealant within the wing break down as well. Additionally the seals in boost pumps and transfer valves will also rot as well. The only time fuel was left behind was to carry a load or because of density altitude performance, or both. Additionally it was SOP to top off fuel tanks after a mission to prevent condensation in the fuel tank. I've confirmed this with several WW2 wrench turners who served in both ETO and PTO.
Neither the outer fuel tanks on the P-38L nor the fuel cells in the P-47N wings were self sealing. They were simple fuel tanks. There was nothing to "rot".
Draining condensation in a fuel tank would be easy enough, if that were a problem.
=S=
Lunatic
wmaxt said:Leaving a tank empty is also a fire/explosion hazard and if the tank is less than full the remaining fuel degrades quickly. Degraded fuel can/will gum up/destroy any fuel system component as it turns to varnish. Condensation can be drained but not as effectively as preventing it in the first place, aircraft are not stored empty or even below full, minus expansion volume, if possible. Down loading fuel to taylor the aircraft for a mission is common place.
Flying with empty tanks is common with aircraft esp. airliners and cargo planes to save weight for cargo or fuel economy. These aircraft are required to fill empty fuel tanks with inert gas since flight 800 went down. Even these tanks are not empty for extended periods since seals and other flexible parts dry and crack.
wmaxt
wmaxt said:Leaving a tank empty is also a fire/explosion hazard and if the tank is less than full the remaining fuel degrades quickly. Degraded fuel can/will gum up/destroy any fuel system component as it turns to varnish. Condensation can be drained but not as effectively as preventing it in the first place, aircraft are not stored empty or even below full, minus expansion volume, if possible. Down loading fuel to taylor the aircraft for a mission is common place.
Flying with empty tanks is common with aircraft esp. airliners and cargo planes to save weight for cargo or fuel economy. These aircraft are required to fill empty fuel tanks with inert gas since flight 800 went down. Even these tanks are not empty for extended periods since seals and other flexible parts dry and crack.
wmaxt
They actually used both....I'm not sure but I think it was CO2 gas but it might have been nitrogen.
lesofprimus said:They actually used both....I'm not sure but I think it was CO2 gas but it might have been nitrogen.
wmaxt said:I belive a fuel "Cell" is lined with a compound to make it self sealing/more resilient to leakage while a welded metal tank is just that a "Fuel Tank". Not trying to be nitpicky but at this level of discussion its an important destinction.
wmaxt
FLYBOYJ said:wmaxt said:I belive a fuel "Cell" is lined with a compound to make it self sealing/more resilient to leakage while a welded metal tank is just that a "Fuel Tank". Not trying to be nitpicky but at this level of discussion its an important destinction.
wmaxt
You're on the money wmaxt - cells are also intergrated into the structure as a wet wing and can even include a "bag" which is attached to the structure.
When I was 25 years younger and 30 pounds thinner I was a fuel tank (or cell) inspector...
wmaxt said:FLYBOYJ said:wmaxt said:I belive a fuel "Cell" is lined with a compound to make it self sealing/more resilient to leakage while a welded metal tank is just that a "Fuel Tank". Not trying to be nitpicky but at this level of discussion its an important destinction.
wmaxt
You're on the money wmaxt - cells are also intergrated into the structure as a wet wing and can even include a "bag" which is attached to the structure.
When I was 25 years younger and 30 pounds thinner I was a fuel tank (or cell) inspector...
In my Dads Squadron (B-47s), they thought a man had gone AWOL, later checking a thunking noise in the foward fuel tank they found him and a ladder. Apparently he passed out, nobody checked well enough and so on.
wmaxt