Gearbox Modification.

[gidge348]

Still not much to photo but the painting is complete and now I am putting the gas generator back together.

Finally after much fighting with the CNC computer the hemispherical undercut is done on the gear. Apparently if the CNC computer decides that a particular tool wont do a job it throws it hands up and wont do it.

The gear & Shaft are at the guy that will be doing the splining he has done a few test pieces and we have now decided to go for 36 spline 60 degree, 1.5mm deep. The original idea of 45 teeth did not leave enough material at the root or tip of the splines.

Ian...

[racket]

Hi Ian

LOL.......bloody machines , what would they know ;-)

Cheers
John

[gidge348]

Yep.... he was using a tool that the machine did not recognise.

In the good old days before "Confusers" you just measure it, bolt in the tool and off you go.... I some times wonder if we are going forwards or backwards.

Have just finished bolting 1 table full of parts and pipes on the engine.... 2 more to go.... looks pretty though.

Ian...

[gidge348]

Still not much to report at the moment, the gear & shaft are still down at the machine shop waiting completion.

Have been keeping myself busy cleaning & painting the gas generator.

This is what it looked like before:





Now





Also replaced all the 40 year old "O" rings and gaskets as well as cleaning out the dried crud in the fuel system.





Air craft stuff is so much nicer to work on than cars, everything is engineered to fit and be taken apart and put back together again, unlike cars that are just throw away items now.


I must admit though I am sick of being stabbed with lock wire though

[Johansson]

All looking very sweet!

[gidge348]

HELP>>>>>>>>>>>>>>

I am hoping someone with a nimbus can help me.

I am finishing off the re build of the gas generator and though I had all the pics I needed but am missing one.

On the right hand side of the engine about half way down there is a block aprox 1 inch square and 2 inches long with a serries of pipes going from it to the governor, fuel pump and hp tap.


My question is the 2 pipes that run forward from the block.... "does the top one go to the HP tap or the fuel pump???

Have been trying to load pictures for a few hours now but no luck will try and load them tomorrow.

Any replies much appreciated.

Ian...

[ozbooster]

Ian is that the heat exchanger or junction block
in the manual section 1 chapter 3 p4 and p5 may help
can forward pics if needed

[cursorkeys]

That engine is looking awesome with a new paint job, did you paint the interstage spacer and the rear bearing housing silver or is that a bead/soda blasted finish?

I think I know the bit you mean and that pipe goes to the HP Cock:

[gidge348]

Thanks for your help Jon & Greg,

The pipe I am looking for is the other side of the HP cock.


I can now get the pics uploaded.

This is the block I was talking about, it is on the lower right hand side. Note the 2 pipes (upper & lower) going to the right ie the front of the engine, and disappearing behind the fuel heat exchanger.



Once they come out from behind the fuel heat exchanger.


one goes to the HP cock




and one goes to the fuel pump.

[gidge348]

Jon

Yes I have painted the rear housings in PPG HI temp silver, the rear of the main casing was discoloured on my engine so I painted that and the exhaust/ngv in the same paint but in dark charcoal. Trying to paint as much as I can to help stop corrosion. The blue is just a quick dry industrial enamel

[gidge348]

Dec 7, 2013 5:15:40 GMT -5 ozbooster said:

Ian is that the heat exchanger or junction block
in the manual section 1 chapter 3 p4 and p5 may help
can forward pics if needed

Bingo thanks Greg I should have looked at this earlier.






Thanks Guys....

[cursorkeys]

Aha, I see. Sorry for the misinformation!

I don't have that bit fitted any more on my engine. It got removed when the gearbox was ditched and the HP cock is connected directly to the FCU port by a short pipe, I should have remembered that my engine is incomplete compared to yours on the fuel and oil systems.

I don't know if I mentioned it before but I do have the complete overhaul manuals for the Nimbus scanned if you ever need them.

[gidge348]

Hi Jon,

Thanks for that, I have a "Maintenance Manual" with several hundred pages in it that I scanned a few years ago.



Not sure if that is the same as yours but if not we could do a swap?

More information the better I always say

[cursorkeys]

Mines a series of 8 books each about 400-800 pages long. The title is just 'Nimbus Overhaul Manual' and it's split, effectively, into strip, check and rebuild and then sub-divided for each of the engine's various major sections.
It is a bit of a bugger to read as each operation has sections for each 'mod' level of that particular component and you have to work out which paragraph is applicable. Turned out my engine has nearly the latest mod levels for every component which is nice I guess.

It took me a month of evenings to scan and is about 10GB!

I'll acquire a suitable sized USB stick and put it in the post to you.

[turbochris]

I could use those manuals. I'll put up a drop box if you think you have enough upload bandwidth. Maybe we need to make a file area here. I have a copy of the engine change out manual- swap, tuning and maintenance mostly but still lots of info. 3 nimbus useres here so far? way cool! great turbine! kinda clunky n old but great!