What of the Republic P-47 Turbo-Supercharger

[Shortround6]

Unless you can get original documents or get the museum that has it on display to weigh their display I doubt you will find the weight for the "system".
Weight for component parts may be available but the weight of the exhaust pipes and air ducts may be much harder to come by. Ducting that will withstand air pressure with a difference between inside and outside pressures of over double is going to be heavier than the air ducts in a building

 

[IdahoRenegade]

If I may.
Both impellers on both supercharger stages were on the same shaft on 2-stage Merlin (and Griffon, as well as on many German 2-stage supercharged engines). When driving gear was in 1st speed, both impellers were rotating at same angular speed. Or, doing the same RPM if you will. For example, on the Packard Merlin V-1650-3, the impellers were rotating 6.391 times the crankshaft RPM - for 3000 rpm the crankshaft will be making, impellers were making 19173 rpm, providing the boost of 61 in Hg at the rated (low) altitude.
When driving gear was switched up to 2nd gear, again both impellers were rotating at same angular speed (or, on same RPM), this time the ratio was 8.095:1 vs. crankshaft - for 3000 rpm the crankshaft is making, impellers will be making 24285 rpm, again providing the boost of 61 in Hg at the (now much higher) rated altitude.
The faster the impellers rotate, the more compressing work they will do, but also suck up more power (we're talking about gear-driven supercharges, as used on ww2 aero engines,but not just on them).
Low impeller speed (= S/C drive is in low gear; British name is 'MS' - medium supercharge) means the S/C will be using less power to provide required boost, so there is more power left to the prop. It is okay, since at altitudes the low gear is used has thick air around, so there is less of need for the S/C to compress the air. High impeller speed (= S/C drive is in high gear; British name is 'FS' - full supercharge) means the S/C will be using more power, but again that's okay since it will be providing the required boost at high altitudes. More boost = more power; the trade-off favors the 2-speed superchargers.
Some engines were outfitted with 3-speed 2-stage superchargers - yes, the drive gear is outfitted with 3 sets of gears. Such engines were the Jumo 213E and F (late ww2), as well as RR Griffon 100 series (post war)
Widely produced were the 2-speed 1-stage supercharged engines - 2 sets of gears, one impeller.

Thanks for the detailed explanation. For some reason I always thought that it was only the 2nd stage that was "2-speed" and that the 1st stage was at one constant ratio to engine RPM. Good to learn the difference.

 

[don4331]

I've been trying to find the weight of just the turbocharger system myself.

This what you are looking for?

 

[don4331]

Thanks for the detailed explanation. For some reason I always thought that it was only the 2nd stage that was "2-speed" and that the 1st stage was at one constant ratio to engine RPM. Good to learn the difference.

For the RR and some (?most?) of the German 2 stage speeds, the 2 impellers are on the same shaft, so both turn the same speed.

But Pratt & Whitney R-1830 & 2800, the 1st stage is constant ratio, while the 2nd stage has 2 speeds. Although, I really think of it as 3 speeds - neutral, low & high. Which IMHO makes the P&W radials better carrier engines - the engine isn't "fighting" against a supercharger trying to maintain some level of boost at 10k' or more but rather freewheeling. So, minor throttle movements don't result in the major power changes that happen when both impellers are on the same shaft.

 

[MIflyer]

Of Possible Interest:

 

[GreenKnight121]

This what you are looking for?

That's the weights of just the turbosuperchargers, they don't include the ducting and all of the rest of the items that make up the P-47 turbocharger system.

 

[Tony Kambic]

That's the weights of just the turbosuperchargers, they don't include the ducting and all of the rest of the items that make up the P-47 turbocharger system.

In Francis Dean's 1997 book "America's Hundred-Thousand U.S. Fighter Production of WWII", P-47 Empty and Basic Weights: ENGINE 2283 lbs. ENGINE ACCESSORIES 977 lbs. Not clear what engine accessories exactly are, but gets a better idea. Could include oil coolers. Two other categories are ENGINE SECTION 383 lbs. and ENGINE CONTROLS 58 lbs. COOLING category is left blank as I interpret this as being part of the above categories.

 

[tonycat77]

Dumb question, could they make the P-47 without the turbo?
I don't mean a large redesign, just someone proposing to ditch the big and expensive thing since most missions were becoming lower altitude ground attack ones.
Maybe add more armor in place of it to balance the CG.

 

[tomo pauk]

Dumb question, could they make the P-47 without the turbo?
I don't mean a large redesign, just someone proposing to ditch the big and expensive thing since most missions were becoming lower altitude ground attack ones.
Maybe add more armor in place of it to balance the CG.

We still end up with big, heavy and expensive P-47, that has less power.

 

[wuzak]

We still end up with big, heavy and expensive P-47, that has less power.

Unless you make it into the XP-72 with the R-4360.

From what I understand, that didn't have a turbo, but an auxiliary stage supercharger in the rear fuselage driven by an extension shaft.

 

[tomo pauk]

Unless you make it into the XP-72 with the R-4360.

From what I understand, that didn't have a turbo, but an auxiliary stage supercharger in the rear fuselage driven by an extension shaft.

'Just delete turbo' is quite different thing than 'let's install a spanking new engine instead from what was used'

 

[Shortround6]

From an old thread showing the P-47 from the engine back.

The engine from the single single stage is going to have just a few thousands of altitude and a lot less power at even 10,000ft.

 

[SaparotRob]

That picture always impresses. I can see just one of the many reasons jet engines are superior. Could that set up (except with an Allison inline engine) be installed in a P-39?

 

[Thumpalumpacus]

That picture always impresses. I can see just one of the many reasons jet engines are superior. Could that set up (except with an Allison inline engine) be installed in a P-39?

Man, if you thought a -39 was tail-heavy before ...

 

[pbehn]

That picture always impresses. I can see just one of the many reasons jet engines are superior. Could that set up (except with an Allison inline engine) be installed in a P-39?

If you take away the stuff that gives away the scale it looks like some things you see on refineries around cooling towers

 

[tomo pauk]

Unless you can get original documents or get the museum that has it on display to weigh their display I doubt you will find the weight for the "system".
Weight for component parts may be available but the weight of the exhaust pipes and air ducts may be much harder to come by. Ducting that will withstand air pressure with a difference between inside and outside pressures of over double is going to be heavier than the air ducts in a building

We can always ask the Soviets to help out
They list total weight of turbocharger (107 kg) + weight of tubing + weight of intercooler (=273 kg) at 380/385 kg (with/without regulators?).

 

[Acheron]

Didn't the Corsair use the same engine as the P-47 but lacking a turbosupercharger?

 

[tomo pauk]

Didn't the Corsair use the same engine as the P-47 but lacking a turbosupercharger?

Corsair used the 2-stage supercharged R-2800. Impellers of both supercharger stages were driven by engine itself.
P-47 used the 1-stage supercharged version, the addition of turbocharger meant that number of compression stages was also two. After everything is said and done, engine on the P-47 made better power at altitude, while the engine on the Corsair required less volume to be devoted to it, so the resulting A/C was shorter and lighter.

 

[tonycat77]

View attachment 648927

From an old thread showing the P-47 from the engine back.

The engine from the single single stage is going to have just a few thousands of altitude and a lot less power at even 10,000ft.

How much damage could this take?
I'd assume any hits in the plumbing or the intercooler would cause a massive loss of boost or maybe even a turbine failure.
But the p-47 has a reputation as a tough prick (confirmed in IL-2, you can't take that plane down on anything smaller than 20mm)

 

[PAT303]

How much damage could this take?
I'd assume any hits in the plumbing or the intercooler would cause a massive loss of boost or maybe even a turbine failure.
But the p-47 has a reputation as a tough prick (confirmed in IL-2, you can't take that plane down on anything smaller than 20mm)

The plumbing is a large target, a few holes would seriously effect boost, the supercharger impeller would explode if a couple of 20mm AP rounds hit it, the P47 is a big target full of important stuff.