Running engines beyond published limits

gecko

gecko

Charter Member
Looking for some informed opinions, what effect (if any) would running an engine at a given setting for longer than the published time limit for that setting have on engine performance. For example, the Spitfire II pilot manual limits running at 3000 rpm to 20 minutes, or various warnings about overheating. What happens if these instructions are ignored?

Thanks,

Daniel
 
How soon? Hit 20 minutes and CONK! Or a gradual reduction in power leading to a seizure or erratic power surges etc. Or would she go on just fine for a while longer although irreversible damage was being done?
 
Apologies Gecko, for all above (late night
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).

Understand the Q.

Might suggest a letter to BBMF, RAF Engineering Branch, Rolls Royce as official operators [Rolls would keep their experience from the War, and saw their own flying aircaft on the net (had a gear failure!)

Some of 'the Few' still arround: some might recall the actual engine response. 'Shacks' are still fairly recent, some crews still around on Facebook: Avro Shackelton Trust. Rolls supports this Trust with data; they are returning to flight.

Also operators of the P-51 Pylon racers in Reno, etc, might get into this area.

The official route might help serious historical modellers as yourself, in CFS3. [As you know RAF endorsed JF BOB Version of CFS3].


Hope relevant. (Might take awhile to get).
Cheers.




[My 1/2 cent worth on your last is, you'd go for awhile and see Temps/Pressures go abnormal, with power eventually slowly reducing. I'd be worried about head gasket failure and coolant loss. Then Radiator Temp (and Cyl Head Temp, if fitted) would go up a lot with quicker power loss, and possible seizure imminent.

In short: would last a fair while initially, then gradually decline and end very badly, quite quickly.]
 
'A/L3' to above. On Facebook, 'Supermarine Spitfires' has shared a Duxford photo with CO BBMF Sqn Ldr Dunc Mason climbing out of his Spit from current display practice. He'd know.



['1/4 cent worth', for above: re 'go badly at the end' was just thinking about a bit of rough running before siezure; rather than 'blowing up'.
Wouldn't surprise if Rolls tested the engine to deliver useable power as long as possible then fail in a 'graceful mode' (ie: min damage), when over the limits.]

(Interesting DVD 'The Spitfire Story', tells of RJ Mitchell and the aircraft design; refers to the Scneider Racers and exposed longitudinal tubes along the aft fuselage for engine cooling. They knew all about the heat issue. You've probably seen all that anyway..)
Cheers.
 
Thanks, I'll look into it. Hadn't really considered facebook etc for research purposes as I'm not a particularly avid facebooker, despise twitter etc, but like you say its a good way to get in touch with people who have the experience I'm looking for.
 
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