4 ms·

Musk says Merlin-1C has the highest thrust-to-weight ratio of any (liquid fuel) rocket today. Well: http://en.wikipedia.org/wiki/Merlin_(rocket_engine) http://e

by iwwr 14y ago

Musk says Merlin-1C has the highest thrust-to-weight ratio of any (liquid fuel) rocket today. Well: http://en.wikipedia.org/wiki/Merlin_(rocket_engine) http://en.wikipedia.org/wiki/Merlin_(rocket_engine) http://en.wikipedia.org/wiki/NK-33 http://en.wikipedia.org/wiki/NK-33 Merlin 1C is 96:1, while NK-33 is 133:1 Obviously Musk knows what he's talking about, so where's the discrepancy?

mbenjaminsmith 14y ago
Is the latter still in production? Maybe he meant among currently produced engines. [Edit] "About 150 engines survived, and in the mid-1990s, Russia sold 36 engines to Aerojet General for $1.1 million each. This company also acquired a license for the production of new engines. Aerojet has modified and renamed the updated NK-33 and NK-43 the AJ26-58 and AJ26-59, respectively." But that doesn't mean they are in production. I'd check but the Aerojet website doesn't seem to be working. "The oxygen-rich technology lives on in the RD-170/-171 engines, and their RD-180 and recently developed RD-191 derivatives." The engines produced after the NK-33/43, using a similar design, all have a power to weight ratio of under 90.
- Gravityloss 14y ago
  The Soviet NK-33 engines will be used for SpaceX's competitor's, Orbital Sciences' Antares rocket. If NASA doesn't kill that program. SpaceX has gotten so much publicity that killing commercial ISS supply is getting harder though. But they can still downselect. You should fight against this politically. SpaceX isn't doing very high performance rocketry if you look at their engines. It's a liquid oxygen - kerosene gas generator engine, similar to first big rocket engines everywhere in the fifties. The NK-33 for example is a much higher pressure staged combustion engine meaning it gets a much better exhaust velocity and you get more payload. So are the RD-170 and RD-180 used on Zenit and Atlas respectively. In gas generator engines, a small amount of fuel and oxidizer is burnt in the gas generator to drive a turbine which drives the pump for all propellants. After the turbine the gas generator gas is exhausted. In staged combustion, you put the gas generator gas into the chamber so it is not wasted and its volume can be much higher. There doesn't exist US technology for oxygen rich kerosene staged combustion engines, so that's why either you use gas generators like SpaceX, or use Russian engines like Lockheed Martin (Nowadays United Launch Alliance) or Orbital Sciences. Boeing (Now ULA too) used an odd hydrogen gas generator for the Delta IV first stage engine. The Space shuttle main engine (SSME) was a hydrogen staged combustion engine, a technological marvel with extreme performance but also complex and very expensive. It is a wonder of the world that they got it to work reliably. EDIT: Which makes me think - Some Russian companies like NPO Energomash http://www.npoenergomash.ru/eng/ http://www.npoenergomash.ru/eng/ can perhaps be considered the Foxconns of rocketry. You can also buy propellant tanks and structures from Russian and Ukrainian companies.
pawmar 14y ago
Maybe he was talking about Merlin 1D, which will be used (starting from 2013?) in Falcon 9 v1.1 and Falcon Heavy. Merlin 1D according to wiki has thrust-to-weight ratio 160:1
Symmetry 14y ago
Has anyone yet done a successful launch with a NK-33 based design? According to Wikipedia Antares will be doing test launch this August with a design based on the NK-33, though.
tjmc 14y ago
There's a documentary about the NK-33 called "The engine that came in from the cold". Pretty amazing story - the Russians had these engines hidden in a warehouse for over 20 years before the Americans found out about them and they were better than anything that had been developed in the meantime. It's on Google video here: http://video.google.com/videoplay?docid=-5787437371570928 http://video.google.com/videoplay?docid=-5787437371570928
- bane 14y ago
  Good find. "In 2010 stockpiled NK-33 engines were successfully tested for use by the Orbital Sciences Antares light-to-medium-lift launcher." If I'm not mistaken, isn't the Antares lifter the other lifter by Orbital that's currently in parallel production to SpaceX's (but not almost never talked about in the media)?

by iwwr 14y ago

mbenjaminsmith 14y ago

Is the latter still in production? Maybe he meant among currently produced engines. [Edit] "About 150 engines survived, and in the mid-1990s, Russia sold 36 engines to Aerojet General for $1.1 million each. This company also acquired a license for the production of new engines. Aerojet has modified and renamed the updated NK-33 and NK-43 the AJ26-58 and AJ26-59, respectively." But that doesn't mean they are in production. I'd check but the Aerojet website doesn't seem to be working. "The oxygen-rich technology lives on in the RD-170/-171 engines, and their RD-180 and recently developed RD-191 derivatives." The engines produced after the NK-33/43, using a similar design, all have a power to weight ratio of under 90.

Gravityloss 14y ago
The Soviet NK-33 engines will be used for SpaceX's competitor's, Orbital Sciences' Antares rocket. If NASA doesn't kill that program. SpaceX has gotten so much publicity that killing commercial ISS supply is getting harder though. But they can still downselect. You should fight against this politically. SpaceX isn't doing very high performance rocketry if you look at their engines. It's a liquid oxygen - kerosene gas generator engine, similar to first big rocket engines everywhere in the fifties. The NK-33 for example is a much higher pressure staged combustion engine meaning it gets a much better exhaust velocity and you get more payload. So are the RD-170 and RD-180 used on Zenit and Atlas respectively. In gas generator engines, a small amount of fuel and oxidizer is burnt in the gas generator to drive a turbine which drives the pump for all propellants. After the turbine the gas generator gas is exhausted. In staged combustion, you put the gas generator gas into the chamber so it is not wasted and its volume can be much higher. There doesn't exist US technology for oxygen rich kerosene staged combustion engines, so that's why either you use gas generators like SpaceX, or use Russian engines like Lockheed Martin (Nowadays United Launch Alliance) or Orbital Sciences. Boeing (Now ULA too) used an odd hydrogen gas generator for the Delta IV first stage engine. The Space shuttle main engine (SSME) was a hydrogen staged combustion engine, a technological marvel with extreme performance but also complex and very expensive. It is a wonder of the world that they got it to work reliably. EDIT: Which makes me think - Some Russian companies like NPO Energomash http://www.npoenergomash.ru/eng/ http://www.npoenergomash.ru/eng/ can perhaps be considered the Foxconns of rocketry. You can also buy propellant tanks and structures from Russian and Ukrainian companies.

pawmar 14y ago

Maybe he was talking about Merlin 1D, which will be used (starting from 2013?) in Falcon 9 v1.1 and Falcon Heavy. Merlin 1D according to wiki has thrust-to-weight ratio 160:1

Symmetry 14y ago

Has anyone yet done a successful launch with a NK-33 based design? According to Wikipedia Antares will be doing test launch this August with a design based on the NK-33, though.

tjmc 14y ago

There's a documentary about the NK-33 called "The engine that came in from the cold". Pretty amazing story - the Russians had these engines hidden in a warehouse for over 20 years before the Americans found out about them and they were better than anything that had been developed in the meantime. It's on Google video here: http://video.google.com/videoplay?docid=-5787437371570928 http://video.google.com/videoplay?docid=-5787437371570928

bane 14y ago
Good find. "In 2010 stockpiled NK-33 engines were successfully tested for use by the Orbital Sciences Antares light-to-medium-lift launcher." If I'm not mistaken, isn't the Antares lifter the other lifter by Orbital that's currently in parallel production to SpaceX's (but not almost never talked about in the media)?