Rocket Engine Design...

[Firedtm]

Good Evening follow space nerds.

Thought You knew a lot about rockets think again, I would recommend watching "Cosmodrome" on netflix, it talks about the Russian Moon Program, and how just the Rocket Engines was ahead of their time, the rocket may of not worked but just the talk about the engines is fascinating

Gas-generator cycle (Open Cycle) this is what most rocket designs are based off of

Staged combustion cycle (Closed Cycle) this is what the Russians came up with and if used would of been the most powerful rockets of the 1970's to 1990's

Expander cycle (Can be Open or Closed Cycle) most engines was open cycler till the 1990's when the Closed Cycle system was found out

Combustion tap-off cycle (Open Cycle) the Turbine feeds off the Combustion Chamber, This is used in the Blue Origin(Amazon) space program

Pressure-fed engine (No Cycle) these are what Apollo used to get to the Moon with, on both the Apollo Command/Service Module for the RCS &  Service Propulsion System (SPS) engine, and Apollo Lunar Module for RCS, ascent and descent engines. These type of engines are used in most spacecraft as Reaction Control (RCS) and the Orbital Maneuvering (OMS) engines of the Space Shuttle Orbiter

 

 

[Red Iron Crown]

9 hours ago, Firedtm said:

Staged combustion cycle (Closed Cycle) this is what the Russians came up with and if used would of been the most powerful rockets of the 1970's to 1990's

Staged combustion has seen heavy use. Atlas III, Atlas V, Space Shuttle, Energia, Proton, Antares, Long March 6, GSLV and some of the Japanese H-series all use it, and it's planned for Vulcan.

Also, moving this over to Science & Spaceflight.

[Kryten]

10 hours ago, Firedtm said:

Expander cycle (Can be Open or Closed Cycle) most engines was open cycler till the 1990's when the Closed Cycle system was found out

 Almost all expander engines are closed-cycle, with the first being the RL-10 in the 60s. It was the open-cycle version (expander-bleed cycle) that was invented in the 90s, with the Japanese LE-5A, and the Japanese are still the only ones using this cycle. Closed-cycle expander has higher efficiency but a hard thrust limit of about 300kN (with hydrolox), which limits it to upper stages and very small vehicles, while expander-bleed allows enough thrust to be used in large booster stages.

[Scientia1423]

I think the reason the Soviet were (mostly?) ahead of it's time is because they had scientists from all over Russia competing with each other to see who could be the best. IDK why the N1 didn't fly well and it put the Soviets into debt  but it was a good idea.

[DerekL1963]

54 minutes ago, Scientia1423 said:

I think the reason the Soviet were (mostly?) ahead of it's time is because they had scientists from all over Russia competing with each other to see who could be the best. IDK why the N1 didn't fly well and it put the Soviets into debt  but it was a good idea.

Basically, the N-1 didn't fly well because it wasn't tested as a system until they tried to launch one.  Trying to fly a completely untested and un-debugged design is... madness at best.

And no, it wasn't a particularly good idea.  It had waaaaay too many too small engines, which significantly increases the chance of something going wrong.

[Scientia1423]

2 hours ago, DerekL1963 said:

It had waaaaay too many too small engines, which significantly increases the chance of something going wrong.

Wow lol. The British black arrow rocket also had small engines, I think. The R1 and R3 were the only successful and R2 only just as it's payload Orba was sent to measure the upper atmosphere density by monitoring the decay of its orbit.

[Kryten]

3 minutes ago, Scientia1423 said:

Wow lol. The British black arrow rocket also had small engines, I think. The R1 and R3 were the only successful and R2 only just as it's payload Orba was sent to measure the upper atmosphere density by monitoring the decay of its orbit.

Black Arrow had 11 engines, one of them a dependable solid. Nothing too bad with that with enough testing; Ariane 4 had many flights with a total of ten with very high reliability, and Falcon 9 also uses ten with reasonable reliability. N1 had 44, all liquid. To make it worse, most of the engines on N1 could only be fired once, meaning they couldn't test them before flight.

[Scientia1423]

1 minute ago, Kryten said:

Ariane 4 had many flights with a total of ten with very high reliability, and Falcon 9 also uses ten with reasonable reliability. N1 had 44, all liquid. To make it worse, most of the engines on N1 could only be fired once, meaning they couldn't test them before flight.

So 10 engines is the magic number lol. And N1's 44 non-restartable engines not only blew up physically, but also economically which led to the downfall of USSR.

I'm reading the wiki and it's quite hilarious. The rocket did the Antares thing then blew up apparently ranking it among one of the largest non-nuclear explosions in human history.

[DDE]

4 hours ago, Scientia1423 said:

I think the reason the Soviet were (mostly?) ahead of it's time is because they had scientists from all over Russia competing with each other to see who could be the best. IDK why the N1 didn't fly well and it put the Soviets into debt  but it was a good idea.

If you take a more detailed look, though, it's because the engine-eers behind N-1 had never built rocket engines. After Valentin Glushko told Korolev to either use the hypergolic RD-23x and RD-270 engines, or **** off; Korolev had to go to Nikolai Kuznetsov, a jet engine designer (not to be confused with Victor Kuznetsov, a telemetry expert), and have his people learn to make kerolox/Sintin-lOx motors from scratch; no surprise they went down the untrodden path and eventually produced the NK-33 with its unparalleled TWR. Glushko correctly predicted that he'd need twenty years of general R&D to create an equivalent to F-1s, which is the RD-170/171/180/190 family, based on Kuznetsov's work.

Edited September 18, 2016 by DDE

[A Fuzzy Velociraptor]

7 hours ago, DerekL1963 said:

Basically, the N-1 didn't fly well because it wasn't tested as a system until they tried to launch one.  Trying to fly a completely untested and un-debugged design is... madness at best.

And no, it wasn't a particularly good idea.  It had waaaaay too many too small engines, which significantly increases the chance of something going wrong.

They were also forced to use an engine Korolev didn't want to use for political reasons and Korolev was noted as saying it likely wouldn't be until the 10th launch that it would actually work. The flight testing was to debug the system.

It does increase the chances of something going wrong, though it also reduces the impact of a failure. The engines themselves were unreliable and had acoustic problems which caused the pogoing that would cause some of the N1 failures. Other vehicles such as Soyuz which starts with 20 nozzles (not including Vernier engines) did not have those issues. However proton, especially in its early life is well noted for suffering from extreme unreliability. As for Black Arrow, the engines were noted to be the most reliable at the time, if not particularly powerful or efficient. Should you design a rocket with as many engines as the N1, no probably not, you're going to make the plumbing and control systems hell and you're probably not going to save any money but having that many engines is not a guarantee for failure. 

[DerekL1963]

1 hour ago, A Fuzzy Velociraptor said:

It does increase the chances of something going wrong, though it also reduces the impact of a failure.

Having a truckload of engines only reduces the impact of a failure *if* you have a control system that can promptly and correctly introduce the appropriate corrections.  (And such a control system itself introduces additional complexity and chances for failure - as happened on AS-502.*)  The KORD system carried by the N1 was...  not the best in that department and would itself (IIRC) cause one flight failure.

* As a side note:  Something not generally known was that reactor control systems were a major point of focus for Rickover during the development of naval nuclear reactors.  They relentlessly lowered the number of parameters monitored so as to simplify the system to the maximum extent possible.

[A Fuzzy Velociraptor]

26 minutes ago, DerekL1963 said:

Having a truckload of engines only reduces the impact of a failure *if* you have a control system that can promptly and correctly introduce the appropriate corrections.  (And such a control system itself introduces additional complexity and chances for failure - as happened on AS-502.*)  The KORD system carried by the N1 was...  not the best in that department and would itself (IIRC) cause one flight failure.

I'm not disagreeing with you there.

I think I assumed you were just oversimplifying things.

Edited September 18, 2016 by A Fuzzy Velociraptor

[Rhomphaia]

7 hours ago, Kryten said:

Black Arrow had 11 engines, one of them a dependable solid. Nothing too bad with that with enough testing; Ariane 4 had many flights with a total of ten with very high reliability, and Falcon 9 also uses ten with reasonable reliability. N1 had 44, all liquid. To make it worse, most of the engines on N1 could only be fired once, meaning they couldn't test them before flight.

The Black Arrow had three engines, one per stage.

The first stage had 8 nozzles.

 

It is a different matter to have multiple engines.

[Kryten]

2 minutes ago, Rhomphaia said:

The Black Arrow had three engines, one per stage.

The first stage had 8 nozzles.

 

It is a different matter to have multiple engines.

Do you have a diagram showing this? I can't make out the gas generator/s in images of Gamma engines I can find, so I don't know if it really is one engine or multiple engines referred to as a single engine. The latter is quite common.

[magnemoe]

12 hours ago, Kryten said:

Do you have a diagram showing this? I can't make out the gas generator/s in images of Gamma engines I can find, so I don't know if it really is one engine or multiple engines referred to as a single engine. The latter is quite common.

My guess it had one turbopump feeding 8 chambers and nozzles. looked the rocket up and the individual gimball on two and two nozzles/ chambers. 
Russia has used this setup on many rockets. Benefit is fewer turbopumps without making an huge chamber. 
Black arrow is a bit special in that it uses gimbal on each part- 
 

[DDE]

13 hours ago, DerekL1963 said:

The KORD system carried by the N1 was...  not the best in that department and would itself (IIRC) cause one flight failure.

That's the price of Pilyugin setting out to use a digital computer in a rocket.