Friday 2010-12-17 Dev. update and Discussion

[SlipBall]

(quote)
WW2 planes had only superchargers, not turbochargers.



They are the same, the difference being the power source

[T}{OR]

Originally Posted by SlipBall

They are the same, the difference being the power source

In basic terms, yes.

For a supercharger to work you have to use some of the energy produced on the crankshaft, while turbo uses energy off the exhaust gases which is "free".

The downside is that turbo works best on higher RPM ("turbo lag"), while superchargers can follow and adjust to engine RPM much more rapidly.


IIRC the development of turbochargers and the reason why they are so available todays happened after WW2. => See post 141.


EDIT: As a result, the latest developments led to a process called 'downsizing' where in todays engines you now have a supercharger for low RPM which disengages (usually via magnetic clutch) around 2500 RPM and then turbo takes over.

[SlipBall]

Originally Posted by T}{OR

In basic terms, yes.

For a supercharger to work you have to use some of the energy produced on the crankshaft, while turbo uses energy off the exhaust gases which is "free".

The downside is that turbo works best on higher RPM ("turbo lag"), while superchargers can follow and adjust to engine RPM much more rapidly.


IIRC the development of turbochargers and the reason why they are so available todays happened after WW2.

Yes, you are correct

[Sutts]

Originally Posted by T}{OR

Unless I am mistaken, WW2 planes had only superchargers, not turbochargers.

In basic terms, yes.

For a supercharger to work you have to use some of the energy produced on the crankshaft, while turbo uses energy off the exhaust gases which is "free".

The downside is that turbo works best on higher RPM ("turbo lag"), while superchargers can follow and adjust to engine RPM much more rapidly.


IIRC the development of turbochargers and the reason why they are so available todays happened after WW2.


EDIT: As a result, the latest developments led to a process called 'downsizing' where in todays engines you now have a supercharger for low RPM which disengages (usually via magnetic clutch) around 2500 RPM and then turbo takes over.

Not sure if I understand you correctly. Turbochargers were most definitely used during WWII but on aircraft such as the P-47 and P-38 and bombers such as B-17 and B-24. I don't think any BoB aircraft used them.

[T}{OR]

Originally Posted by Sutts

Not sure if I understand you correctly. Turbochargers were most definitely used during WWII but on aircraft such as the P-47 and P-38 and bombers such as B-17 and B-24. I don't think any BoB aircraft used them.

The function of both is the same - i.e. to compress the air before it enters a cylinder. Either to produce the same atmosphere as if you were flying on sea level or to increase engine power. The difference is how they are driven. Supercharger is linked to the crankshaft usually with a belt pulley or set of gears. Turbocharger is driven by exhaust gases and thus for it to operate efficiently requires certain speed out of those gases - i.e. works best when on mid or high RPM. Early turbochargers were massive in comparison what we have today.

Although they were available before WW2, rapid development of turbochargers started after WW2, IIRC when F1 started using them (they were banned in F1 shortly afterwards due to excessive power these engines produced).



EDIT: You are correct:

Aircraft such as the Fw 190D, B-17 Flying Fortress, and P-47 Thunderbolt all used turbochargers to increase high altitude engine power.

So says Wikipedia.

I presume that you could only mount them in larger (e.g. radial engines), because even in 70's they were massive compared to today. And it makes sense - especially with P-38 which has those long pylons behind engines.

[swiss]

edit: cleaned this thread and removed my OT posts

[T}{OR]

EDIT: same as swiss

[ElAurens]

The P38 was powered by a pair of V12 Allisons that were turbocharged.

[T}{OR]

Originally Posted by ElAurens

The P38 was powered by a pair of V12 Allisons that were turbocharged.

And that is why its exhaust is different than the one found on planes equipped with Merlin engines (single engined fighters).


Back to the flames etc. Here is a nice example of modification done to prevent visible exhaust flames during night fighting: