Wanted: RR Nimbus MK105 rear bearing casing

[pabloottawa]

Hey folks,
I've got a RR Nimbus MK105 that developed a crack on its rear bearing casing. I asked a "specialist" to weld it and he almost destroyed the piece - bottom line it won't fit any more so I'm looking at replacing it.

Does anybody happen to have a rear bearing casing hanging around, and willing to sell it?

Thanks all,

Pablo

[gidge348]

Hi Pablo,

When you mention the rear bearing casing, which one do you mean? Gas generator, gearbox, ancillaries, power output?

Can you load a photograph of drawings, I may be able to help.

Cheers
Ian...

[pabloottawa]

Hey Ian, thanks for your reply. The part in question is the rear bearing support casing for the gas generator. I've attached a couple of pictures of the part, as well as a diagram. Hope this helps! Thanks,

Pablo

[gidge348]

Hi Pablo, sorry that part I don't have, have you tried Everett Aero?

How bad is the part that was welded?

Ian...

[cursorkeys]

Hi Pablo, I do have a spare but just the one so I'm very sorry but I can't part with it.

I do know the Everett's don't have any more, my spare took months of sourcing and they seem to be like rocking-horse poo these days.

Was the crack at the struts? There are some acceptable limits for cracks there. I agree with Ian, a precision engineer should be able to repair what's been done to it even if the whole thing has been heat-distorted.
For welding it Hastalloy-X rod works fine as a filler if the repair can't be made to be autogenous.

Jon

Edit: For looking for engineers that can do this kind of work I found a local company that does ultra-high vacuum physics equipment, they seemed to have all the expertise necessary.

Edit2: LAS Aerospace still have all the fixings and o-rings necessary to rebuild the rear-bearing housing ex-stock. You can key in the part numbers straight from the manual on their website.

[jetric]

May 19, 2015 18:12:11 GMT -5 pabloottawa said:

[jetric]

  Hi Pablo,
   Get in touch with Harry at Jet Engine Trader.com he has some brand new RR Artouste rear bearing housings for sale these are very simular to the Nimbus rear bearing housing because i had to measure them up for a pal of mine Andy Plezsco for his RR Nimbus that has been converted to thrust that is fitted to his classic mini, I had to research for him some alteratives for the rear bearing housing because we were testing a few reheat designs for the engine and because the inner skin on the rear bearing housing is so thin we just kept on cracking the inner skin on them, the big problem was finding Nimbus rear bearing housings that were'nt cracked!! thats why i was looking for alternatives for him. The big problem with the inner skin cracking on the bearing housing is once this has happened it stops the circulation of cooling air for the rear bearing and starts blasting the rear bearing with hot 600oC gas from the exhaust stream ( Due to the exhaust gas stream being at a higher pressure than the ambient outside air used for cooling the bearing via the strutts ) this then overheats the rear bearing oil flow and makes the rear bearing housing smoke. I did do a modification on andys engine using the ( now redundant because of ground running ) anti-ice compressor bleed fed to the rear bearing housing to ensure that the rear bearing is always cooled regardless of how many cracks appear in the bearing housing inner skin.

  Rich.

May 19, 2015 18:12:11 GMT -5 pabloottawa said:

Hey folks,
I've got a RR Nimbus MK105 that developed a crack on its rear bearing casing. I asked a "specialist" to weld it and he almost destroyed the piece - bottom line it won't fit any more so I'm looking at replacing it.

Does anybody happen to have a rear bearing casing hanging around, and willing to sell it?

Thanks all,

Pablo

[turbochris]

ha ha ha those 2 pics you posted are of my nimbus! It's been around, like a slut!

[drswami]

Sorry no casing but if you decide to part yours out I need a starter generator [e-mail]