WW2 fighter fuel consumption

[AlbertD]

I watched a documentary about the P-51 Mustang on YouTube today and in the background information they mentioned that the P-47 went about 3 miles per gallon and the Mustang used about half that. I knew the Mustang had greater range but didn't realize it was that much better. The whole show was interesting but for some reason that fact hit me.

[JeepsGunsTanks]

13 minutes ago, AlbertD said:

I watched a documentary about the P-51 Mustang on YouTube today and in the background information they mentioned that the P-47 went about 3 miles per gallon and the Mustang used about half that. I knew the Mustang had greater range but didn't realize it was that much better. The whole show was interesting but for some reason that fact hit me.

 

You might find this video interesting. 

 

 

This whole channel is pretty great. 

[AlbertD]

37 minutes ago, JeepsGunsTanks said:

 

You might find this video interesting. 

 

 

This whole channel is pretty great. 

I'll watch it tomorrow morning with my coffee. Thank you.

[Jack]

A very interesting and "reveiling" documentary, thanks for sharing.

 

J.

[cbk57]

I think the channel is Gregg:s airplanes and automobiles or something.  He does really detailed engineering explanations of some of these subjects.  too me however it is kind of common sense that Mustang should get better gas mileage than P-47 just looking at the shape of the two planes and the mustangs very small frontal area.  I am oversimplifying but to understand this stuff I have to do that.  Maybe that means I don:t understand.  I have watched some of these, a lot goes into detail beyond what I really want to know but he justifies his conclusions with facts, which add to the credibility of his videos.  It just happens facts can be complicated.

[Joe Hegedus]

Consider also that the P-47's engine is almost twice as large, displacement-wise, and produces more horsepower -  larger fuel consumption should be expected.  

 

 

[Jack]

I guess he tried to explain the actual reason for not applying external tanks to either aircraft in the beginning, just because of indeed the attitude displayed by people with an agenda towards fighter aircraft versus bombers at that time, and i've heard/read this story also in the past when digging into this unexplainable political mumbo-jumbo and downright BS by the USAAF hotshots at that time.......The Schweinfurt raid was ofcourse a gigantic disaster, and probably fully unnessary if escort had been available.......

Edited October 22, 2020 by Jack

[JeepsGunsTanks]

Gregg's is a great channel, he even has stuff on Musclecars.  If you ever have like 4 hours to spare, the whole P-47 series is really good. 

[LSP_Matt]

2 hours ago, Jennings Heilig said:

What has always amazed me is that in WWII the art of maximum range extension wasn’t really well known.  Charles Lindbergh went to the SWPA to show them how it was done, and they got a lot more range out of their aircraft following his lessons in fuel management.  I guess we have him to thank for the fact that I was taught those techniques as a private pilot student decades later.

 

The Japanese pilots were taught this. They used to fiddle with the mixtures on zero's to extend their range. I recall Saburo Sakai talking about it.

Imagine if planes back then could shut down cylinders like modern V8's can nowadays.

[JeepsGunsTanks]

8 hours ago, LSP_Matt said:

The Japanese pilots were taught this. They used to fiddle with the mixtures on zero's to extend their range. I recall Saburo Sakai talking about it.

Imagine if planes back then could shut down cylinders like modern V8's can nowadays.

 

He had to prove it to Air Force Aviators they were worried about engine damage. So he flew missions with them and always landed with more fuel, and the engines were fine.  He ended up flying about 50 combat missions between flying with the Marines near Rabaul, and then later with the 475th Fighter group. He flew missions with Tommy McGuire, as his wingman. Not sure if he flew with Bong. He got at least one kill while flying a P-38. 

Edited October 23, 2020 by JeepsGunsTanks

[AlbertD]

I wonder if they ever considered midair refueling back then. It would have been a challenge with props but I bet it could be done. 

[Oldbaldguy]

Aerial refueling in one form or another dates back to at least the 1920s.  Although it never really caught on until the jet age was upon us, I'm sure someone somewhere was  seriously pondering it during WW2.  It was just easier at the time to build airplanes with bigger gas tanks if you wanted to fly farther, so that was what everybody did.  As far as props getting in the way, we routinely refuel C-130s and a variety of helicopters, and I think B-50s could be tanked as well, so what you'd think would be an issue turned out to be not so much.  On a side note:  I was raised to believe that liquid cooled engines burn less fuel than an aircooled engine of the same displacement because big radials have to vaporize some of their fuel to help cool the engine.  Real or not real?

[Dpgsbody55]

Air to air refueling goes back a long way, but was pioneered most successfully by the British.  The Lancaster was the stand in aircraft for the Hiroshima and Nagasaki atomic bomb drops as by that time the RAF could refuel while still in the air.  The B-29 could not initially take a bomb of the sizes used in these attacks while the Lancaster could.  Very hurried redesigning the B-29 saw it ready in time (just) and it was faster which made the operation safer.

 

There were also plans in 1942 to use air to air refueling for Spitfire escort operations, but they came to nothing thanks to the emergence of the Merlin engine Mustang.   The propeller is not really an issue as the refuelling probe can go on the wing, away from the propeller arc.

 

As to the specific fuel consumption of air cooled engines versus inline liquid cooled engines, air cooled engines have to run richer fuel mixtures as the increase in fuel/air ratio helps that engine run cooler.  There is a certain band of air/fuel ratios in which an internal combustion engine will run properly, without washing down cylinder walls from too much fuel, to burning valves from too little fuel.  Lean mixture settings are hotter than rich settings as air burns at a higher temperature than petrol or diesel. and this is the biggest reason why we no longer have air cooled Porsches, or anything else air cooled (except your lawn mower).  Heat from lean mixtures can be controlled by the coolant jacket and radiator, and leaner settings are more environmentally friendly.

 

 

Cheers,

Michael

Edited October 25, 2020 by Dpgsbody55

[LSP_Matt]

On 10/22/2020 at 3:53 PM, AlbertD said:

I watched a documentary about the P-51 Mustang on YouTube today and in the background information they mentioned that the P-47 went about 3 miles per gallon and the Mustang used about half that. I knew the Mustang had greater range but didn't realize it was that much better. The whole show was interesting but for some reason that fact hit me.

I really enjoy his channel. I'm an engine nerd so all the discussions about boost and intercoolers, octanes etc is really interesting.

P47 - Pratt & Whitney R-2800 Double Wasp - 46 Litres
P-51 - Merlin engine - 27 Litres.

It's going to take a lots more fuel to power an engine nearly double the displacement.

What's interesting is how, despite so much more engine power (nearly double in the P&W) the fighter planes weren't super different in performance.

Matty

[AlbertD]

9 hours ago, LSP_Matt said:

I really enjoy his channel. I'm an engine nerd so all the discussions about boost and intercoolers, octanes etc is really interesting.

P47 - Pratt & Whitney R-2800 Double Wasp - 46 Litres
P-51 - Merlin engine - 27 Litres.

It's going to take a lots more fuel to power an engine nearly double the displacement.

What's interesting is how, despite so much more engine power (nearly double in the P&W) the fighter planes weren't super different in performance.

Matty

Am I reading the weight difference between a P-47 at 10,000 pounds and a P-51 at 12,000 pounds? That just doesn't sound right to me. I'm not saying it's not so but really? That's pretty wild.