"P-47s don't really have exhaust stains..."

[Astro32]

The only Thunderbolts that never had exhaust stains were the few versions that were powered by small fusion reactors. I looked it up on the Internet.

[BiggTim]

The only Thunderbolts that never had exhaust stains were the few versions that were powered by small fusion reactors. I looked it up on the Internet.

I want one of those!!

[Out2gtcha]

 I looked it up on the Internet.

 

 

That tears it, its fact then.  

[DougN]

Hmmm..no exhaust stains. I beg to differ:

 

 

Cheers,

 

D.B.

 

Those look more like oil/fluid stains actually.  They seem to originate from the oil cooler shutter and wheelwell, lower fuselage area.

[LSP_K2]

Those look more like oil/fluid stains actually.  They seem to originate from the oil cooler shutter and wheelwell, lower fuselage area.

 

The photo says oil streaked.

[LSP_Matt]

Seeing as turbosuperchargers were mentioned a performance question comes to mind.

 

Why do the P47 and Corsair etc with ostensibly the same engine still make the same hp?

 

Boosting combustion on a car massively increases the hp.

 

Or is this all about 'maintaining performance at altitude' where there is lower O2 density? Maybe the Naval/Marine planes were less effective at height?

 

Thanks Matty

[Zero77]

Those look more like oil/fluid stains actually.  They seem to originate from the oil cooler shutter and wheelwell, lower fuselage area.

 

Look at the small exhausts vents, there are big smoke stains there. The belly is covered with oil stains, but it seems that there are definitely exhaust stains as well. It looks like smoke stains to me.

Edited July 29, 2016 by Zero77

[Bryan]

 

Or is this all about 'maintaining performance at altitude' where there is lower O2 density? Maybe the Naval/Marine planes were less effective at height?

 

Thanks Matty

 

That's my understanding.  The naval planes powered by the R2800 were used strictly at low to medium altitudes.  The P-47 served as an escort fighter so high altitude performance was designed into it from the beginning.

 

I am sure the P-47 system could be "tweeked" to provide a huge boost in power at low altitude also, but I imagine the engines in normally aspirated form were already within the range of what the designers thought would be max reliable power.

 

Sort of like today's pylon racers with Merlins and such.  They make far more power than originally but they are also far from reliable.

[D Bellis]

Or is this all about 'maintaining performance at altitude' where there is lower O2 density? Maybe the Naval/Marine planes were less effective at height?

Correct. Some HP rating numbers @ altitude:

 

R-2800-8 (F4U-1 & 2):                 2,000 HP @ 1,000',  1,800 HP @ 15,500'

R-2800-21 (P-47B though K):      2,000 HP @ 2,500',   2,000HP @ 25000'

 

Water injected specs deliberately left out.

 

All R-2800 engines were mechanically supercharged. Only the P-47 used an additional turbocharger because it was originally intended to excel at high altitude interception. As mechanical supercharger technology improved, the need for additional turbochargers declined. By war's end, there were multi-stage, multi-speed superchargers and even variable-speed superchargers able to provide constant power levels up to the high altitude limit of the airframes available. Just as it was getting really good, the jets came along to render them obsolete.

 

Guess where all that multi-speed & variable-speed supercharger gearing technology ended up? In the average automobile's automatic transmission. But, that's another discussion for another time...

 

D

[Juggernut]

D,

 

Is the 2800-21 the civilian equivalent of the 2800-59, which powered all the bubbletop D jugs?  I don't have my Graham White text available to me so I'm curious.  

[LSP_Matt]

 

 

Guess where all that multi-speed & variable-speed supercharger gearing technology ended up? In the average automobile's automatic transmission. But, that's another discussion for another time...

 

D

Ah ha. Very cool. Thanks Bryan and Darin.

 

Cheers Matty

[D Bellis]

D,

 

Is the 2800-21 the civilian equivalent of the 2800-59, which powered all the bubbletop D jugs?  I don't have my Graham White text available to me so I'm curious.  

The -21 and -59 shared identical output specs, and both were military engines. The -21 information was used above for comparison purposes only, and was not intended to be taken as a claim for being the sole powerplant installed in all P-47B through K subtypes. 

 

Cheers, 

D

[AdamR]

Those look more like oil/fluid stains actually.  They seem to originate from the oil cooler shutter and wheelwell, lower fuselage area.

That bird's crew chief had a lot to answer for.