Bootstrapping, BoostRapping or BoostStrapping ?

[R1Tamer]

Any takers!

In an externally supercharged aviation(turbocharged) variable pressure piston engine (not many around now I know but it's still in the JAA ATPL's) what is the correct term for the phenomena which can occur at the inlet when the compressor output fluctuates due to temp/pressure anomolies?

I believe the phenomona is corrected by a pair of controller valves (diff pressure & density) but can't find anywhere a comprehensive explantion as to it's cause and correct name.

Anybody give me a steer on where I can find out more - preferably online?

Thanks,

[411A]

Yes, bootstrapping is the preferred term, and it indeed was a problem on some earlier types, especially at or above the critical altitude.

Have a look at www.enginehistory.org and you might find a discussion there.

Good luck!

[enicalyth]

indeed it is the bootstrap

Websearch on "bootstrap", "wastegate" "automatic wastegate" "differential pressure controller". eg
http://www.ec.erau.edu/cce/centers/e...esentation.htm


The phenomenon is that the engine cannot maintain the desired manifold pressure and is principally caused by the engine rpm being too low and the altitude too high.

[R1Tamer]

411A / Enicalith

Thanks to you both for the web links. Curious to know now though, why it's called 'bootstrapping'. The name doesn't seem to bear any relevance to the phenomona or am I missing an obvious connection here?

[Tinstaafl]

This goes back a long time ago in my training so is probably not exactly correct. However:

If you can increase the engine RPM then you will increase the supercharger RPM which will in turn increase the engine HP which will then increase the engine's ability to drive the supercharger and all the other things that need HP.

'Lifting itself up by its own bootstraps' comes to mind.

[R1Tamer]

tinstaafl,

now that makes a lot of sense.....thanks!