Author Topic: starting the RD-0120  (Read 2798 times)

Offline se jones

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starting the RD-0120
« on: 05/30/2015 12:55 AM »
Does anyone know if the RD-0120 used the hydraulic head to spool-up the turbo pumps?

I would guess so, but I can't find that info anywhere.

Assuming it did use hydraulic head, would that have been a problem for the smaller Energia-M core?
By problem, I mean expensive re-design of the engine to start it on the pad. The Energia-M core was about in the same ballpark as the original Ares 1 upper stage, with its problematic air-startable RS-25.

Thanks,
-Steve

Offline Zero-G

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Re: starting the RD-0120
« Reply #1 on: 05/30/2015 10:36 AM »
Hi Steve,

Do you already know this website: http://www.lpre.de/kbkha/RD-0120/index.htm ? You may find answers to your questions there. The site is in Russian, but you can use Google Translate.

You can find quite a detailed description of the startup sequence in a paragraph titled as "Launch" by Google Translate ("Запуск" in Russian).
« Last Edit: 05/30/2015 10:45 AM by Zero-G »
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Offline se jones

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Re: starting the RD-0120
« Reply #2 on: 05/30/2015 10:37 PM »
No.
Thanks Zero-G, that's a big help.

"in the void" I like it.

thanks again,
-Steve

Offline fregate

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Re: starting the RD-0120
« Reply #3 on: 06/01/2015 02:17 AM »
After reading an article I believe that ignition procedure used pneumatic valves, not hydraulics :) 
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Offline se jones

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Re: starting the RD-0120
« Reply #4 on: 06/01/2015 07:06 AM »
Thanks, but that's not what I'm talking about, not how the valves are actuated, but how the engines are started.

Most stage one engines use some sort of gas generator or high-pressure gas supplied by ground support to start the engines, something has to get the turbo pumps spooled up so they can do their job.

The Shuttle SSME (RS-25) is unusual (maybe unique) in that it uses the hydraulic head (the fluid pressure) of all that fuel and oxidizer in the huge ET to force fuel/oxidizer through the turbo pumps and get everything going.

Elegant solution, but it lead to the death spiral of the Aris I (to air start an RS-25 Aris I would have used a split second of acceleration from the single SRB to force the liquids from the much smaller upper-stage tank into the single RS-25 engine...fire in the hole!).

I was just wondering if the Russians used the same hydraulic head pressure to start their Energia Buran RD-0120.
If they did, the the smaller Energia M would have required plan B to start the single RD-0120 engine.





   

Offline Jim

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Re: starting the RD-0120
« Reply #5 on: 06/01/2015 12:57 PM »

Elegant solution, but it lead to the death spiral of the Aris I (to air start an RS-25 Aris I would have used a split second of acceleration from the single SRB to force the liquids from the much smaller upper-stage tank into the single RS-25 engine...fire in the hole!).


A. It wasn't going to be fire in the hole.  It would have used ullage rockets for acceleration after stage separation
b.  The reason for the open or grid interstage was due to the massive of amount of He/H2 that would be dumped in preconditioning the engine for start. 


The Shuttle SSME (RS-25) is unusual (maybe unique) in that it uses the hydraulic head (the fluid pressure) of all that fuel and oxidizer in the huge ET to force fuel/oxidizer through the turbo pumps and get everything going.

RD-180  and RL-10 use head pressure.
« Last Edit: 06/01/2015 01:00 PM by Jim »