Typical fluid rocket engines to show in a presentation

[Elthy]

In my class "technical english" at university we have to do a presentation about a technical topic, it has to be 10-15min long. I want to present rocket engines, since they are the pinacle of engineering. While the first part of the presentation will be abuot rocket engines in general i also want to show examples which were/are important for rocketry. Since i have only limited time i want to present 3-4 engines in closer detail. Those engines are supposed to be important for rocketry and to have typical characteristics, also it should be easy to find information and good pictures about them. Also i would like to limit it to hardware that has realy been used. I have a few engines in mind, but thats just ideas:

SpaceX Merlin engine:
Shows the new approach of building cheap but powerfull engines which dont have supreme ISP, but excel in other things. Also they are reusable and its great to show the difference between a vacuum engine and a booster engine.

SSME:
Designed to be reusable and to be efficent at a range of altitudes, economicaly the opposite of the super cheap Merlin. Also neat cooling solution and redesign for the expendable SLS.

Vinci:
Optimised for extreme ISP and thus specialised for upper stages like no other engine, also sports an extendable nozzle. Sadly there are not many good pictures for it.

F1 engine:
Designed for extreme power, the F1-B shows the design difference with new technologys

 

Im also thinking about hypergolic or monopropellant engines, but i dont know to much about them. Also it seems that its way harder to find pictures for russian engines than for american ones...

[UmbralRaptor]

I'd personally be tempted to go with: RD-107 (kerolox lower stage), RL10 (hydrolox upper stage), AJ10 (hypergolic upper stage/post orbit maneuvers), and some monoprop RCS engine.

Edited June 12, 2016 by UmbralRaptor

[Robotengineer]

I would probably focus on technical aspects specific to most/all rockets (injectors, turbo pumps, nozzles, propellant(s)) and how those parts affect efficiency,  like why you want to have different shaped engine bells depending on atmospheric pressure, or why different propellants are better for different segments of a mission.

[Elthy]

2 hours ago, Robotengineer said:

I would probably focus on technical aspects specific to most/all rockets (injectors, turbo pumps, nozzles, propellant(s)) and how those parts affect efficiency,  like why you want to have different shaped engine bells depending on atmospheric pressure, or why different propellants are better for different segments of a mission.

Thats what i want to do first, but then give practical examples. E.g. how the special nozzle of the SSME makes it work on all altitudes and how the injector of the Merlin enables it to deep throttle...

[Streetwind]

If it was me giving that presentation, I would probably select my example engines based on representing the various combustion cycles, and pick one for each:

- Pressure-fed engine (turbineless):
Probably the most widely flown type of rocket engine. Monopropellant control thrusters and other smaller engines, such as the Apollo lunar module's descent engine, are pressure-fed.

- Gas generator cycle (open combusting turbine):
Probably the second most widely flown type of rocket engine. Almost everything built in the United States runs on this, for example the F-1 and the Merlin series. Since it's much less complicated than other turbine cycles, yet much more powerful than pressure-fed systems, it's also the cycle of choice for most other countries. For example the Vulcain-II on the Ariane 5, or even the YF-20 family that's been powering many different variants of China's Long March rockets.

- Staged combustion (closed combusting turbine):
This is really the domain of Russian engines, since the Russians invented this cycle. And they built a LOT of engines over the years. You have a huge range of interesting examples that tell great stories, from the NK-33 (which was supposed to send the Soviets to the Moon, then sat in a warehouse for decades, and then still managed to blow the minds of US rocket scientists when they were discovered after the fall of the USSR) to the RD-180 (powerful, reliable, and extremely likely to raise a US Congressman's blood pressure). On the US side, you can mention the RS-25 (SSME). Because you have limited time, you probably won't go into the difference between classic and full-flow staged combustion... but if you do, you can mention the RD-270 that pioneered the concept, and the Raptor that's going to be the first one to fly this cycle (but be careful with it, as that one's merely in subscale subcomponent development right now).

- Expander cycle (pressure-fed turbine):
Potentially the single most efficient cycle for chemical engines known to man, but sadly limited to small engine sizes by the laws of physics. Instead of the Vinci, though, I'd probably present the RL-10, which has huge flight history and had some variants that reached up to 470s of Isp.

- Electric turbine:
This is brand new technology, mainly because nobody thought it was even valid... there isn't even an established name for this cycle yet! The basic idea is pretty simple: if you had an electric motor driving the turbine, then you could essentially combine the extreme simplicity of a pressure-fed system - you really only have two pipes and a combustion chamber - with the extreme power afforded by a turbine. Unfortunately, the sheer power throughput of such a turbine, which a bipropellant rocket even has two of, was thought to be simply too much to supply with batteries. You'd have to mount so many batteries that the extra weight overrides any advantages. Only a single engine exists today that has an electric turbine: Rocket Lab's Rutherford engine, used in their new Electron rocket which is supposed to have its first test flight this fall. Rocket Lab cites that their batteries are good enough to let them get away with a performance advantage over a classic pressure-fed system, but we don't know the engine's exact specs just yet.

 

Edited June 13, 2016 by Streetwind

[DDE]

You can do a comparison between F-1 and RD-170, two heavy-lift Kerolox engines from the opposite sides of the Iron Curtain.

When it comes to other Soviet motors, if you want a quick overview, you could go through the RD-2xx series (hypergolic, including heavy lift), the RD-301 (a fluorine-ammonia upper stage motor) and RD-701 that goes from Kerolox to H2-lOx mid-flight. And that's just Valentin Glushko's Energomash.

[Elthy]

For pressure-fed ones the AJ-10 seems like a good option, since it flew on many rockets and for different purposes. Sadly i cant find any pictures of it being fired, which is kinda strange considering how often it was used. Its also supposed to power Orion, there should be recent tests, right?

 

It seems with those 4 engines i would have covered everything:
-Merlin
-RL-10
-AJ-10
-NK-33

Edited June 13, 2016 by Elthy