cursorkeys
Veteran Member
Proper engines use the Brayton cycle
Joined: July 2012
Posts: 108
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Post by cursorkeys on May 29, 2013 11:41:35 GMT -5
I don't, but I promised Andy I'd send him some things (which I still haven't done) so I'll give him a call tonight  From Andy's description I think it failed in the 'inner' wall of the double skinned area. You can just about see the area is double-skinned on the below diagram and I've helpfully added a rubbish red line where I think the fault occurred:  |
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Post by turbochris on May 29, 2013 14:44:51 GMT -5
I'm w John. These motors surge really easily. I think you rattled it pretty hard. Again, as John said a few gauges are in order. I'm thinking about messing w the IGV's myself, rip the atmospheric referenced crap off and just make something w a piston and easily changeable spring. Proper design might get some shock waves! If John lived near me we would be on the homeland watch list...... along w a long time member Ernie |
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cursorkeys
Veteran Member
Proper engines use the Brayton cycle
Joined: July 2012
Posts: 108
|
Post by cursorkeys on Jul 9, 2013 13:13:52 GMT -5
Andy very kindly sent me a big pic. (Again, this is not my engine. I just took an interest in understanding the fault!) I misunderstood him before, the crack is around the bearing support struts where they meet the 'outer' case. He says that the metal was 'folded over' at the fault. Its hard to see that in the pic, but its a seriously impressive failure:  Any load from the rotating assembly shouldn't be on that metal? It's just effectively a aerodynamic cover for the actual bearing supports that run though the middle of it and load that thick webbing on the casing outer. Still can't see why a failure would happen there. I didn't want to bump the thread to ask before, but that sounds very interesting about manually controlling the IGVs Chris. Would that be to take advantage of some slack in the design to get a bit more mass flow at sea level without choking the compressor? Cheers, Jon |
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Post by turbochris on Jul 11, 2013 15:07:17 GMT -5
Just keep an eye on the tailpipe pressure and open the guide vanes as much as possible w/o surging.. Open up the thrust nozzle until it stops surging. Trying to put more mass flow through the compressor while things downstream are plugged up makes for more surging. it hammers the shit out of things
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