The Zenit gets NK-33s instead of RD-171s

[fasquardon]

According to RussianSpaceWeb.com:

"However, the developers of the super-powerful engine of the first stage for Zenit run into considerable trouble. Between 1981 and 1983, the problems plagued the test firings of the RD-171 engine. One of solution proposed at the time called for the use of one-chamber engines from the first stage of the N-1 rocket. "

So what if the RD-171 is abandoned and the NK-33 becomes the engine of choice for the Zenit?

Does this also mean the RD-170 is never developed?

Could the NK-33 fill all the roles that the RD-170 and RD-171 were designed for, and for the roles that it could fill, would it be better or worse than the RD-170/171?

fasquardon

 

[Michel Van]

The problem is here Valentin Gluchko
He built the engine for Zenit and Energia rocket
Kuznetsov build Nk-33 what Gluchko consider as "rotten quality"

Zenit RD-170 had thrust of 7259 kN and the NK-33 give 1505 kN
that would need 5 NK-33 in first stage of Zenit
used on Energia rocket you would have in total 24 engine, Something Gluchko not wanted !

Before objection, hey the Energia got 24 combustions chamber that's not the same ?
Nope, it all about the POGO and Turbopumps
Pogo is a oscillation, produce by Turbopump and combustions chamber and fuel flow.
That can result in resonance with rocket structure and rip the rocket into pieces

With RD-170 has Energia only 8 turbo pumps compare to 24 turbo pumps with NK-33 and RD-0120.

 

[Archibald]

It seems that Orbital Sciences found the NK-33 to be flawed (after the October 2014 explosion of their NK-33 powered Antares rocket)
http://spacenews.com/nasa-orbital-differ-on-root-cause-of-antares-launch-failure/

One potential root cause was an “inadequate design robustness” of the engine. Investigators said the nature of the engine’s design made it susceptible to oxygen fires and failures similar to the one experienced on the Antares mission.

 

[fasquardon]

Nope, it all about the POGO and Turbopumps
Pogo is a oscillation, produce by Turbopump and combustions chamber and fuel flow.

Hmm. So POGO oscillation depends less upon the total power of the turbopumps? Or do larger turbopumps get away with being less powerful?

It seems that Orbital Sciences found the NK-33 to be flawed (after the October 2014 explosion of their NK-33 powered Antares rocket)
http://spacenews.com/nasa-orbital-differ-on-root-cause-of-antares-launch-failure/

Hmm, looks like manufacturing defect could also be a likely cause of the explosion.

Still, that would really pose difficulties to any "N1 succeeds" TLs if it were a design flaw!

I wonder if trying the NK-33 on the Zenit would stop the whole Energia/Buran program? Say they try the NK-33, it doesn't work, but shows enough promise for them to try and iron out the bugs in the engine for maybe 3 years, then switch back to developing the RD-170/171 but by the time that is ready to fly, the Soviet Union is in the middle of the 80s budget crunch and decides not to bother with a shuttle clone, but instead develops something like the Spiral capsule or the later Klipper capsule and has them being launched by a single Zenit?

fasquardon

 

[Michel Van]

Hmm. So POGO oscillation depends less upon the total power of the turbopumps? Or do larger turbopumps get away with being less powerful?

Hmm, looks like manufacturing defect could also be a likely cause of the explosion.

Still, that would really pose difficulties to any "N1 succeeds" TLs if it were a design flaw!

I wonder if trying the NK-33 on the Zenit would stop the whole Energia/Buran program? Say they try the NK-33, it doesn't work, but shows enough promise for them to try and iron out the bugs in the engine for maybe 3 years, then switch back to developing the RD-170/171 but by the time that is ready to fly, the Soviet Union is in the middle of the 80s budget crunch and decides not to bother with a shuttle clone, but instead develops something like the Spiral capsule or the later Klipper capsule and has them being launched by a single Zenit?

fasquardon

On POGO oscillation it depends how much turbo pumps are running in engine bay, special if you got central one in 5 engine configuration
here the central engine produce Pogo oscillation along the long axis of rocket, interacting with Pogo oscillation with four external engine.
the Saturn V had some issue with those Pogo oscillation.
Gluchko way to deal with this was, one large turbo pump that feed 4 combustion chambers. reducing pogo oscillation to one. not five.

on NK-33 in Antares
In 1974 Kuznetsov got from Gluchko the order to destroy ALL NK-33 engine
Kuznetsov hide 150 of them in a storage house were they found in 1992 by NASA engineers !
So that was a 41 YEAR OLD rocket engine that blow up in 2014 and that was modified by Aerojet Rocketdyne
(equipping the engines for gimballing, adding US electronics, and qualifying the engines to fire for twice as long as designed and to operate at 108% of their original thrust)