P-51 internal fuel capacity (how?)

[davebender]

For what it's worth, The History Channel stated the P-51 used only half as much fuel as the P-47 when covering the same distance.

Perhaps the P-47 really was that much of a fuel hog.

 

[MikeGazdik]

To make horsepower, you have to provide fuel, the more fuel, (along with air) the more power. Cubic inches also make power, and the more cubes, the more fuel. Simple really. It should not be a surprise that a 2,800 cubic inch engine that develops 2,000 horsepower would use much more fuel than a 1,650 cubic inch engine that developes 1,500 horsepower.

Even if they were in the exact same airframe, the P&W will in comparison gulp the fuel.

Which has lead me to another off subject thought of seeing some effieciency comparisons of the P-47 vs F4U vs F6F.

To better understand the genius of the P-51 wing, imagine the Messerschmitt 109 of having a wing of the same design. Just the layout and structure, not the Laminar flow. Obviously the wing would be smaller than that of the P-51 wing, but just imagine a wing capable of carrying fuel AND ammo on the Bf109 in 1940!!! Or during the duration of the war!

 

[drgondog]

To make horsepower, you have to provide fuel, the more fuel, (along with air) the more power. Cubic inches also make power, and the more cubes, the more fuel. Simple really. It should not be a surprise that a 2,800 cubic inch engine that develops 2,000 horsepower would use much more fuel than a 1,650 cubic inch engine that developes 1,500 horsepower.

Even if they were in the exact same airframe, the P&W will in comparison gulp the fuel.

Which has lead me to another off subject thought of seeing some effieciency comparisons of the P-47 vs F4U vs F6F.

To better understand the genius of the P-51 wing, imagine the Messerschmitt 109 of having a wing of the same design. Just the layout and structure, not the Laminar flow. Obviously the wing would be smaller than that of the P-51 wing, but just imagine a wing capable of carrying fuel AND ammo on the Bf109 in 1940!!! Or during the duration of the war!

Imagine a winspan of 20% increase, heavier structure in the wing and a lot less climb performance for the 109

 

[MikeGazdik]

Imagine a winspan of 20% increase, heavier structure in the wing and a lot less climb performance for the 109

Very true, but if a wing of similar area was used,( as to the original Bf109 wing) but with the internal layout of the P-51.

 

[Elvis]

I am not sure of what you mean by this comment. In you initial comment, you seem to imply that the aerodynamics and engine of the P-47 allowed very good cruise, which I would agree, however it could mislead someone to assume this cruise perfomance was equavlent to the P-51, which it was not. The P-51 cruise performance was not only very good but excellent. The extended range of the later P-47s were due to the massive amount of fuel carried.

Dave,

Not sure where you got that idea from, but I was referring to the P-51 in that post, not the P-47.



Elvis

 

[Elvis]

Elvis - The command radio for the P-51, A-36, P-51A and P-51B/C and P-51D/K were the SCR-274 with variations including the SCR 522 from P-51A through P-51D/K. In other words the radio behind the pilot didn't change - the fuse tank wasn't placed there in the P-51A and prototype B only because of the cg issue.

Do you know if that radio, while basically remaining the same unit, ever shrank (physically) at any point in time?
This is what I was getting at in my post.
I wasn't saying the radio got changed out, only that I've heard that it shrank in size, due to advances in electronics around that time.
It's been my understanding that the radio, originally, was quite large and that it shrank down a good deal, thus opening up the cavity that was later used to house the little 5th fuel tank ("5th", if you're using wing tanks).



Elvis
P.S. Re: "Don't shoot the messenger". I actually wasn't referring to you so much, but its cool. I was just sort of taken aback by the responses to my post. I probably shouldn't have posted that, to begin with.

 

[Milosh]

In Gruenhagen's Mustang book, he has the command radio as SCR-522, or SCR-274, or ARC-3.

 

[davparlr]

Dave,

Not sure where you got that idea from, but I was referring to the P-51 in that post, not the P-47.



Elvis

Okay, I see. Sorry for the misunderstanding. What did you mean by P-M engine?

 

[Colin1]

What did you mean by P-M engine?

I was wondering too
in context, I think it's Packard Merlin

 

[davparlr]

For what it's worth, The History Channel stated the P-51 used only half as much fuel as the P-47 when covering the same distance.

Perhaps the P-47 really was that much of a fuel hog.

This would tend to verify my analysis.

 

[renrich]

From USAAF table of combat radius at 25000 feet..... P47D with 670 gallons of fuel-600 miles
P51B,C,D with 419 gallons of fuel-700 miles.
This would include start up, warmup, takeoff, climb, cruise, combat, cruise back and reserve. That little 85 gallon tank behind the pilot would add 510 pounds to the P51, not including the weight of the tank. Was the tank self sealing?
The wing tanks in the F4U1 were not self sealing but had a CO2 purge system. A lot of F4U1s had the wing tanks which substantially increased the range of the Corsair over the Wildcat and was a big help in escort missions in the Solomons.

 

[drgondog]

Do you know if that radio, while basically remaining the same unit, ever shrank (physically) at any point in time?
This is what I was getting at in my post.
I wasn't saying the radio got changed out, only that I've heard that it shrank in size, due to advances in electronics around that time.
It's been my understanding that the radio, originally, was quite large and that it shrank down a good deal, thus opening up the cavity that was later used to house the little 5th fuel tank ("5th", if you're using wing tanks).



Elvis
P.S. Re: "Don't shoot the messenger". I actually wasn't referring to you so much, but its cool. I was just sort of taken aback by the responses to my post. I probably shouldn't have posted that, to begin with.

A change in electronics resulting in a change of 'frame' would be the same as a new model Command Radio. They were all the same or pretty much the same size

 

[davparlr]

I was wondering too
in context, I think it's Packard Merlin

I thought he had mistyped P-W.

 

[davparlr]

Which has lead me to another off subject thought of seeing some effieciency comparisons of the P-47 vs F4U vs F6F.

Based on drag analysis of max airspeed at SL, I would say the F4U had somewhat better cruise efficiency than the P-47, which, in-turn, was somewhat better than the F6F. All of these were considerably less efficient than the P-51. Comparisons were between the F4U-1, P-47B, and F6F-3, all which used similar engines with equal HP.

 

[drgondog]

In an earlier post where I was comparing escort performance of American aircraft, and using AF pilot performance charts, I had calculated that the fuel used at cruise for the P-47D-22 was about 260 gallons for 600 miles. For the P-51, the fuel used was 108 gallons for 600 miles. This seems much higher than the 35-40% higher. If I have time, I will go back and reevaluate my calculations to see if i committed some error.

Dave - I think you are pretty close for the 51 results. SOP was ~ 35" 2700 RPM for the loaded birds on the way to RV and also essing in escort to keep TAS at 260. That would have been ~ 52 gph average, including MP at take off, assembly and climb out at 55", then down to 35"/2700 in steady formation cruise. Higher figures than for single ship Ferry.

 

[Elvis]

I thought he had mistyped P-W.

Dave,

Yes, "P-M" = "Packard-Merlin".
I can see where someone might see "P-M" and think "P&W", but its cool.
...its also cool to use your reading glasses when reading these posts (I know, the printing at some of these web pages are absolutely miniscule).
If anyone laughs at you, just hold them down with your walker and beat 'em with your cane.
-------------------------------------------------------------------------------

DragonDog,

Thanks for the further confirmation.
Apparently, I've been misinformed all these years.


Elvis

 

[Elvis]

Re: Range.

According to the MustangsMustangs website, The P-51D/K had an internal fuel capacity of 269 gallons.
This increased to 489 gallons with drop tanks.
This gave the plane a range of 1155 miles on internal fuel (cruising @ 294mph and 20K feet) and 2055 miles if you include drop tanks (cruising @ 280mph and 20K feet).

How that compares to the P-47, as it existed at that time, I don't know.



Elvis

 

[drgondog]

Re: Range.

According to the MustangsMustangs website, The P-51D/K had an internal fuel capacity of 269 gallons.
This increased to 489 gallons with drop tanks.
This gave the plane a range of 1155 miles on internal fuel (cruising @ 294mph and 20K feet) and 2055 miles if you include drop tanks (cruising @ 280mph and 20K feet).

How that compares to the P-47, as it existed at that time, I don't know.

Elvis

Elvis the late B/C and all D/K had the 1000 pound racks so the options were 75 gallon, 110 gallon (actually 108) gallon and 150 gallon Ferry tanks (165 for P-51H). So the basic internal load is 269 as you said, then the 'pairs' are +150 gallons, + 216 gallons and +300 gallons for the 75, 108 and 160 respectively.

A really good pilot could get a lot more than 2100 miles (Ferry) if he managed his throttle/rpm and altitude as he shed weight. No winds aloft of course but the extra 80 gallons in the ferry tank would easily extend the range another 450-500 miles.

 

[Elvis]

Dr. Gondog,

Good info, thanks for posting that.
You should email that information to the guy at the MustangsMustangs website. I'm sure he'd want to know.


Elvis

 

[drgondog]

Dr. Gondog,

Good info, thanks for posting that.
You should email that information to the guy at the MustangsMustangs website. I'm sure he'd want to know.


Elvis

Which 'guy'. Charlie Neely for example is an absolute expert on the 51 in all its forms.