Warbirds - Turbo vs Supercharging

[Marvin-E34]

[Killratio]

(EDIT Sorry, didn't realise there was a video with this...I can't see a preview or a url here for some reason!)


They are Supercharged. (If that is the question)

The very basic difference is that a Turbocharger is driven by exhaust gas and a Supercharger is driven by gearing from the engine.

Therefore a supercharger's is much better at driving engines at altitude as it is not directly affected by outside pressure but by rpm achievable.

A single stage supercharger (Spitfire I/II) is optimised for a certain rpm/altitude. A duel stage (P-51) can be changed to a higher gearing at high altitude to still deliver a similar boost scale as lower down but at a lower engine RPM.

[Oracle427]

A complete turbo charging system that compensates for altitude is also more complex and more failure prone than a supercharger. I think it may also make more sense to use the mechanically simple system for reliability.

[AKar]

Very good and interesting video.

Many WWII aircraft were turbocharged, notably P-47 and B-17. Advantages and disadvantages of the turbocharging are well discussed in the video. Mechanical supercharging has significant disadvantage in that a large amount of power must be produced to turn the compressor, and while net effect is benefitial, the power used to drive the supercharger stresses and heats the engine like any other. Turbos on the other hand are far more efficient, though they do cause an increase in exhaust backpressure, in turn causing some power to be lost.

-Esa

[ClipperLuna]

Very informative and interesting, thank you for posting!

I've often wondered what exactly drove the thinking of military aircraft designers of the 1930s with respect to turbocharging or supercharging. Like the video says, the US Army Air Corps had a definite bias toward turbocharging but pretty much everyone else went with the supercharger. Brings up a couple questions:

1. The US Navy preferred supercharging because of its compactness and simplicity. Is this why British and German designers also seemed to prefer it? With the power advantages, I would have thought at least one of these countries would have tried it in a fighter, but neither seemed to put as much research and development time into it as the US Army Air Corps did.

2. I though I read somewhere that the P-47 was a good fighter, but not an especially great one because of its size, which was itself a result of its turbocharger ducting. Coming back to the first question, is this the main reason for the apparent British and German preference for superchargers?