Turbopump nightmare...

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TheGreenGoblin
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Turbopump nightmare...

#1 Post by TheGreenGoblin » Sat May 16, 2020 7:11 am

As is my wont I had a bizarre dream last night, you know the type, where you are sitting a final exam in something and haven't a clue about the subject although you should understand it perfectly and need to pass it. I dreamed about the lubrication of turbopump bearings and the question related to lubrication methods of rocket turbopumps (I know, either a shrink or getting out a bit more might help) and I woke up in a sweat and the fug of ignorance and couldn't help myself and got up at 04:00 hrs and devoured this interesting article...

History of Space Shuttle Main Engine Turbopump Bearing Testing at the Marshall Space Flight Center

Of course rocket turbopumps, and turbines generally, are very interesting but rocket turbopumps most particularly, not least because of the extremes they operate under, and the high RPM required contrasted with cryogenic conditions and alternate areas of extreme heat and pressure coupled with the need to interact with volatile, corrosive fuels and oxidizers, that would react spontaneously and explosively with hydrocarbon based lubricants within fine tolerances in a mechanical environment. Ally all these issues to vibrations, both short and long wave, plus fluid and gas dynamics and the need to operate in extremely low external pressure environments and you have a complicated operational environment indeed.



I really enjoy Scott Manley's style, intellect and ability to explain complex things clearly and very well and also admire the fact that he is clearly a vinyl lover... How is that that we have allowed this man from Troon to escape to America like we, here in the UK, do with any native with a modicum of science in his or her transom?

Scott Manley
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Re: Turbopump nightmare...

#2 Post by G-CPTN » Sat May 16, 2020 9:16 am

My dream last night involved servicing a Maxi in and around my first house that we bought new when I married.
Not a nightmare, but an exhausting experience.

Maybe I should point out that the Maxi involved was not mine (that I owned some 15 years later) but was my father's that he owned (one of the first).
Mine was one of the very last that was built with various parts swept up from the production line which meant that nothing was as expected.

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Re: Turbopump nightmare...

#3 Post by TheGreenGoblin » Sat May 16, 2020 9:47 am

G-CPTN wrote:
Sat May 16, 2020 9:16 am
My dream last night involved servicing a Maxi in and around my first house that we bought new when I married.
Not a nightmare, but an exhausting experience.

Maybe I should point out that the Maxi involved was not mine (that I owned some 15 years later) but was my father's that he owned (one of the first).
Mine was one of the very last that was built with various parts swept up from the production line which meant that nothing was as expected.
I often still dream of having to clean and reset the points on my old Triumph Herald which required some kind of fettling like this almost once a week in winter. Dream based upon recollection of a well rehearsed process in the past.
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Re: Turbopump nightmare...

#4 Post by k3k3 » Sat May 16, 2020 12:56 pm

My nightmare would be having to replace a collapsed knuckle joint on the rear suspension of a 1962 Mini with rubber springs, again.

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Re: Turbopump nightmare...

#5 Post by G-CPTN » Sat May 16, 2020 1:23 pm

My worst (non sleeping) experience with a vehicle was removing the gearbox of a Sunbeam Rapier.

I was lying underneath the vehicle and having withdrawn the gearbox, it fell onto my chest and prevented me from breathing properly or being able to move the gearbox's dead weight from my chest.

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Re: Turbopump nightmare...

#6 Post by ian16th » Sat May 16, 2020 2:03 pm

G-CPTN wrote:
Sat May 16, 2020 1:23 pm
My worst (non sleeping) experience with a vehicle was removing the gearbox of a Sunbeam Rapier.

I was lying underneath the vehicle and having withdrawn the gearbox, it fell onto my chest and prevented me from breathing properly or being able to move the gearbox's dead weight from my chest.
Did it have overdrive?
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Re: Turbopump nightmare...

#7 Post by G-CPTN » Sat May 16, 2020 2:11 pm

ian16th wrote:
Sat May 16, 2020 2:03 pm
G-CPTN wrote:
Sat May 16, 2020 1:23 pm
My worst (non sleeping) experience with a vehicle was removing the gearbox of a Sunbeam Rapier.

I was lying underneath the vehicle and having withdrawn the gearbox, it fell onto my chest and prevented me from breathing properly or being able to move the gearbox's dead weight from my chest.
Did it have overdrive?
Yes.

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Re: Turbopump nightmare...

#8 Post by ian16th » Sat May 16, 2020 2:39 pm

G-CPTN wrote:
Sat May 16, 2020 2:11 pm
ian16th wrote:
Sat May 16, 2020 2:03 pm
G-CPTN wrote:
Sat May 16, 2020 1:23 pm
My worst (non sleeping) experience with a vehicle was removing the gearbox of a Sunbeam Rapier.

I was lying underneath the vehicle and having withdrawn the gearbox, it fell onto my chest and prevented me from breathing properly or being able to move the gearbox's dead weight from my chest.
Did it have overdrive?
Yes.
So it was that much heavier!

A nice feature to have, I had it on my 2nd Hillman Hunter.
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Great balls of fire...

#9 Post by TheGreenGoblin » Sat May 16, 2020 7:04 pm

Of course rocket turbopumps, and turbines generally, are very interesting but rocket turbopumps most particularly, not least because of the extremes they operate under, and the high RPM required contrasted with cryogenic conditions and alternate areas of extreme heat and pressure coupled with the need to interact with volatile, corrosive fuels and oxidizers, that would react spontaneously and explosively with hydrocarbon based lubricants within fine tolerances in a mechanical environment. Ally all these issues to vibrations, both short and long wave, plus fluid and gas dynamics and the need to operate in extremely low external pressure environments and you have a complicated operational environment indeed.


With continuous operation at high temperatures, engines require a stronger type of bearing than other machinery.

This is where silver enters the picture. When steel ball bearings are electroplated with silver, they become stronger than any other type of bearing. Jet engines, for example, rely on silver bearings because they can function continuously and at very high temperatures. So do helicopter engines.

Not only is a silver-coated steel ball bearing strong, but the silver acts as a lubricant, reducing friction between the bearing and its housing. This increases the performance and longevity of the engine. Despite high internal temperatures, silver-coated bearings provide superior performance and a critical margin of safety for engines. Even in the event of an oil pump failure, for instance, silver-plated bearings provide enough lubrication to allow a safe engine shutdown before serious damage can occur.
Or
Silicon Nitride (Si3N4) Ceramic Balls are formed from a new material suitable for applications where high loads, high speeds and extreme temperatures are factors. Long life and the need for minimal lubrication make this material appropriate for extreme applications. Silicon Nitride is non-porous, non-magnetic, non corrosive, lighter than steel and, in ball form, is harder than steel. Because ceramic balls are non-porous they are virtually frictionless and are capable of spinning faster than steel balls.
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Re: Turbopump nightmare...

#10 Post by OFSO » Sun May 17, 2020 7:20 pm

We had a batch of sounding rockets down in Sardinia where the pyro-ejected multipoint exterior cable connector had become unreliable. It would have cost a fortune to replace on each vehicle. Some old guy from the village was found to stand on the tower next to each vehicle listening carefully. When he heard the turbopump spinning up he had to give the connector an almighty kick, then run down the steps and across the hardstanding as fast as he could and when it all turned bright and he could see his own shadow in front of him, fall to the ground and put his hands over his ears. This earned him a box of fags and bottle of whiskey per launch. Worked well until he broke his leg and nobody else from the village would do it.

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Re: Turbopump nightmare...

#11 Post by TheGreenGoblin » Sun May 17, 2020 8:01 pm

OFSO wrote:
Sun May 17, 2020 7:20 pm
We had a batch of sounding rockets down in Sardinia where the pyro-ejected multipoint exterior cable connector had become unreliable. It would have cost a fortune to replace on each vehicle. Some old guy from the village was found to stand on the tower next to each vehicle listening carefully. When he heard the turbopump spinning up he had to give the connector an almighty kick, then run down the steps and across the hardstanding as fast as he could and when it all turned bright and he could see his own shadow in front of him, fall to the ground and put his hands over his ears. This earned him a box of fags and bottle of whiskey per launch. Worked well until he broke his leg and nobody else from the village would do it.
That is a wonderful anecdote. Were you working for a meteorological or a space agency? I suspect there are a lot good stories here. Tell us more. :)

Turbo pumps have, actually, been a big part of my life, for reasons that are too tedious, and long winded to relate here but I miss them...
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Re: Turbopump nightmare...

#12 Post by Rwy in Sight » Sun May 17, 2020 8:28 pm

OFSO, great story made me laugh not because he fell down but the whole story

TGG, "reasons that are too tedious, and long winded to relate here" is the password to ask you to write them...

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Re: Turbopump nightmare...

#13 Post by TheGreenGoblin » Sun May 17, 2020 8:39 pm

Rwy in Sight wrote:
Sun May 17, 2020 8:28 pm
OFSO, great story made me laugh not because he fell down but the whole story

TGG, "reasons that are too tedious, and long winded to relate here" is the password to ask you to write them...
Not tonight, but maybe over a bottle of Grappa, with mutual friends. Rwy in Sight. I look forward to that. :)
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Re: Turbopump nightmare...

#14 Post by Rwy in Sight » Mon May 18, 2020 3:53 am

Definitely TheGreenGoblin an experience worth looking forward to.

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Re: Turbopump nightmare...

#15 Post by OFSO » Fri May 22, 2020 5:21 pm

Former staffer at the European Space Agency, 1968-1993. Lots of stories I sadly can't relate if I want to keep my pension.

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