Aces High Bulletin Board
General Forums => Aircraft and Vehicles => Topic started by: Krusty on August 24, 2007, 12:55:27 PM
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"An interesting characteristic of the B-25 was that its range could be extended by using one-quarter wing flap settings. Since the aircraft normally cruised in a slightly nose-high attitude, about 40 US gallons (150 l) of fuel was below the fuel pickup point and thus unavailable for use. The flaps-down setting gave the aircraft a more level flight attitude, which resulted in this fuel becoming available, thus slightly extending the plane's range."
I wonder if that's true. And if that's modeled in AH! :rofl
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So, how would it behave when climbing or diving with the last drops of fuel? If it pulled the nose up in final approach, the engine would not get anymore fuel? :rolleyes:
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I don't know.
I find it comical. I doubt they'd leave such a problem in a plane that had many upgrades. If it was such a problem they'd move the fuel pipes to the rear (lower) end of the fuel tanks.
I think Wiki's done it again, is all. Just another reason why I'm skeptical of their info!
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The only reference on the internet I can find to this "fact" is that page on wiki.
HOWEVER, it does cite a reference, complete with ISBN. Anyone care to check it out?
Higham, Roy and Williams, Carol, eds. Flying Combat Aircraft of USAAF-USAF (Vol.1). Andrews AFB, Maryland: Air Force Historical Foundation, 1975. ISBN 0-8138-0325-X.
Looks like you can pick a copy of that book up from Amazon for the low low price of $0.38. Search the ISBN on Amazon.
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all airplanes have "un-usable fuel". it helps prevent crap from getting sucked into the fuel system. so the stuff just rests on the bottom.
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Originally posted by Krusty
"An interesting characteristic of the B-25 was that its range could be extended by using one-quarter wing flap settings. Since the aircraft normally cruised in a slightly nose-high attitude, about 40 US gallons (150 l) of fuel was below the fuel pickup point and thus unavailable for use. The flaps-down setting gave the aircraft a more level flight attitude, which resulted in this fuel becoming available, thus slightly extending the plane's range."
I wonder if that's true. And if that's modeled in AH! :rofl
Did Ben affleck know that on Pearl Harbor(love triangle extravadganza).
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Originally posted by moneyguy
all airplanes have "un-usable fuel". it helps prevent crap from getting sucked into the fuel system. so the stuff just rests on the bottom.
I doubt its true, at least for fighters.
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This looks dubious.
If the fuel pickup was above a nose-up attitude, that is an alterable thing.
And for flying straight, - more speed will bring the nose down.....
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Originally posted by PanzerIV
Did Ben affleck know that on Pearl Harbor(love triangle extravadganza).
Consider yourself punched in the face.
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Tis true, Oleg. Total fuel capacity and usable fuel are different numbers even for fighters. This number can be very small as little as 1-2 gallons but it does exist.
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Originally posted by Oleg
I doubt its true, at least for fighters.
Every aircraft carries fuel it cannot use, even fighters. Many manufacturers publish the volume of trapped fuel, or its weight as part of the basic weight. Others list total trapped fluids (fuel and oil). For example, for American fighters:
P-38J: 3.5 gallons
P-39Q: 1.2 gallons
P-40E: 2.1 gallons
P-47D-25: 9.0 gallons
P-51D: 3.2 gallons
P-63A: 1.3 gallons
F4F-4: Not listed, but thought to be about 1.5 gallons
F4U-1: Listed as 88 lb of trapped fuel and oil.
F6F-5: Listed as 89.5 lb of trapped fuel and oil.
My regards,
Widewing
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Is that trapped fuel actually served for keep soiling away from engine? Or there was other purpose?
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Originally posted by Oleg
Is that trapped fuel actually served for keep soiling away from engine? Or there was other purpose?
No, its usually a figure derived to account for fuel that can't be reliably transferred from the tanks to the engine. I doesn't have anything to do with keeping trash out of the fuel supply. That's what gascolators are for.
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Originally posted by scottydawg
Consider yourself punched in the face.
:rofl
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Wikipedia sucks, find a real source.
Theoretically the flaps would cause more drag in the long run and would only reduce range. If the 40 gallons is true you might be able to use them up with the flaps technique, but how much burn time is that anyway? What's the standard GPM on a B25? Probably wouldn't be worth a loss of airspeed unless you're really bone dry.
I'm sure if there was something like this involved in flying the B25, Doolittle and his men new about it. Affleck wouldn't even have been allowed on the Hornet. Its sad how Hollywood butchers history.
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Originally posted by 68Hawk
Wikipedia sucks, find a real source.
Theoretically the flaps would cause more drag in the long run and would only reduce range. If the 40 gallons is true you might be able to use them up with the flaps technique, but how much burn time is that anyway? What's the standard GPM on a B25? Probably wouldn't be worth a loss of airspeed unless you're really bone dry.
I'm sure if there was something like this involved in flying the B25, Doolittle and his men new about it. Affleck wouldn't even have been allowed on the Hornet. Its sad how Hollywood butchers history.
Agreed, wikipedia sucks, however this particular tidbit of information appears to have a footnote referencing an actual book that actually exists.
I am inclined to believe that this is true, however, if I actually cared more than just posting on a BBS about it I would find the book and look it up. Fortunately I don't care that much.
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Actually Scotty they're citing Vol 2. Which is referenced as such:
_______. Flying Combat Aircraft of USAAF-USAF (Vol.2). Andrews AFB, Maryland: Air Force Historical Foundation, 1978. ISBN 0-8138-0375-6.
I assume the ______ is a stand in for the same editors of Vol 1. Being "Higham, Roy and Williams, Carol, eds." Their footnote is wrongly credited then too. Roy might be a nickname, but an ISBN search shows it's actually credited to a Robin Higham. Basically this is borderline plagiarism.
I wouldn't be surprised in the least to actually look up that source and find it cut and pasted. Blatant plagiarism. Given that they don't cite a page number I'd have to look through the whole 202 pages to find this info. Again plagiarism.
Too much crap is either copied onto Wikipedia or just made up because people don't care about where the info comes from. They assume that it'll be credible because its got some type of footnote. This could be a true fact, but its too bad whoever wrote this didn't give proper credit.
If you do want to assert something, check the real source. If you don't want to take the time then don't.
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I never said it was true, bro.
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No, you did qualify that, but if you want to drop out the sources the least you can do is look at how they're cited. Also you could refrain from punching people.
I also believe this could be true, but the 'author' of this wiki article seems to have committed some academic transgressions, possibly even stealing the real authors words. It could also be a complete fabrication. Because of wiki and its low standards we are left to wonder.
I'm curious now, and I might just check out the source, but if something can't be corroborated somewhere other than wiki it might as well be false.
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I agree.
I only brought it up because it was a bizarre claim.
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Wiki sucks and should be destroyed.
I still like Colbert's idea about the African Elephants. I think we should all get together and alter the thread on the B-25
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Originally posted by Oleg
I doubt its true, at least for fighters.
99% of aircraft have unusable fuel. That is where the term "Usable Fuel" comes from. It is part of the design especially considering the use of flexible fuel bags, placement of tanks, and the placement of sumps.
On the P-38's it is roughly 3 gallons a side. Going from memory, I believe the B-17's with the bladders in the outboard wing panels had about 20 - 30 gallons unusable a side.
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Originally posted by 68Hawk Theoretically the flaps would cause more drag in the long run and would only reduce range. If the 40 gallons is true you might be able to use them up with the flaps technique, but how much burn time is that anyway? What's the standard GPM on a B25? Probably wouldn't be worth a loss of airspeed unless you're really bone dry.
I'm guessing that the idea was only to fly with the notch of flaps to have access to this fuel when you were actually down to the end of your fuel, and needed that extra 40 gallons to stay in the air. It wouldn't have helped in any way to have flown with the flaps down on a full tank.
And I'm going to go out on a limb and say that if the alternative to taking a bit of a speed hit by having flaps down a notch is to run your engines dry and commence gliding, the pilot would gladly take the performance hit.