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Engine Surge...
Ok, so this is engine related, but not exactly a Vauxhall/Fiat lump...
More something like this...:
Ten points for anyone who can name the aicraft..
Twenty for anyone who can name the engine..
And 100 for anyone who can name the airfield...
Anyway, as some of you know, I'm an aircraft engineer in the RAF (along with quite a few other people on here, who either are or were...) and I work on the engines and airframes side of it all. In RAF-Speak, this is known as being a 'Heavy'. For those who have met me, you'll appreciate the irony...
So today, a bunch of us are tasked with finishing off a set of checks post-birdstrike. In this case, the Oyster-Catcher decided to throw itself at the aircraft just below the engine intake, and got split in half. Most of it went under the wing, spreading itself over the engine nacelle and undercarriage, and one wing with part of the body stuck flat against the first stage of the LP rotor (unlike big passenger aircraft engines, the first stage doesn't move...) Because we can't be sure what has and hasn't gone down the engine, you do visual inspections, hand turn the engine, check the airflow control bits and bobs, and then finally start it and run a series of performance checks. I'm doing the driving, being monitored as I'm still under training for using the throttles, and things go fine till we get to the cleaning part.
Now, on youtube you'll see plenty of videos of aircraft engines being forcefully injected with water (Nutron take note...) and carrying on as though nothing is happening. ie http://uk.youtube.com/watch?v=faDWFw...eature=related
In order to clean the compressor at the front of the engine or bird remains, and on advice from the Engine Bay here on camp, we ran the engine at just above idle, and had a perosn outside chuck some water down it. Monitoring the gauges upstairs, I noticed a slight incvrease in the RPM, proving Nutron's thoery of water injection... It took a bucketful in two loads, and then took another 3/4 bucket of an oil used to water protection similar to WD40. When the final little bit was chucked in, something didn't go quite right...
There was an almighty bang, the engine surged, and flames leapt out of the front and back, narrowly avoiding the bloke standing at the front throwing the water in...
For anyone not familiar with aircraft engines, the basic principle of a surge is when the airflow inside the engine breaks down, for various reasons, and completely reverses itself. For an instant everything comes out the front of the engine instead of the back. Depending on the reasons for it, sometimes it can carry on regardless, and will run happily if there's no damage. Today, however, it killed it completely and the engine ran down to nothing by itself.
On board we had no fire warnings, just the huge bang and severe vibration when it happened. The looks we got from everywhere else though, including people standing several hundred metres away, the RAF policeman who came over to investigate, the fireman who got fired up ready to come out, and the Air Traffic Controllers in the tower who asked us if we'd made that noise, and if we were ok, said it all though. Apparently it was a very VERY large bang indeed...
So, back to square one then - carrying out all the same checks as had been carried out for the possible bird strike all over again (Post Shock Loading Checks) And what did we find?
Absolutely nothing...
Started her up again, ran her all the way up to a very loud maximum power, and not a thing...
Vauxhall could learn something from 1950's Rollys Royce technology...
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