The Competition of the Methalox engines

[Tywin]

Which engines will be better in weight efficiency, ISP, reliability, power, etc....

In short, which will be the best Methalox engine in this decade?

JD-1

TQ-12

Raptor

BE-4

Aeon-R

Archimedes

Prometheus

Dhawan-1

RD-0169

[Tywin]

If we are lucky we will see 3 of these engines debut this year, the TQ-12, the Raptor, and the BE-4...

[Lemurion]

I don't know that this is a good question. Consider the BE-4, Raptor, and Archimedes. All three engines are designed to power reusable first stages, but they use different combustion cycles and have different ISPs. Each company has made different decisions due to their individual needs.

[DreamyPickle]

There is really not much of a point into a topic asking what is the "best" engine. These engines are being designed for different applications with different goals and don't particularly compete with each other.

There is a general industry trend where launch companies are developing their own engines which are not sold externally so comparing engines is getting less and less relevant. The success of engine development is entirely tied to their launcher.

[TrevorMonty]

As per others comments horses for courses.
Which is better a race car engine with excellent power to weight but short life or car engine which is lower powered, heavier but has more low down torque and is good for 200-400,000kms.

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[spacenut]

Ok, I'll bite, which is the best for booster engines, T/W ratio?

Then which is the best for upper stage engines, ISP? 

These are the two main choices I see.  I would think Raptor would have a better T/W ratio than BE-4 since BE-4 is a larger engine.  Don't know about the others.  Upper stages?  Don't know.  Anyone know more about this. 

[Yggdrasill]

T/W isn't very important for a booster engine, it's more important for an upper stage engine. The most important things for a booster engine would in my opinion be:

1. Price per kN
2. Reliability
3. Thrust to nozzle exit area. (Higher means you can make higher untapered rockets)
4. For reusable engines, little to no required refurbishment.

[Tywin]

T/W isn't very important for a booster engine, it's more important for an upper stage engine. The most important things for a booster engine would in my opinion be:

1. Price per kN
2. Reliability
3. Thrust to nozzle exit area. (Higher means you can make higher untapered rockets)
4. For reusable engines, little to no required refurbishment.

And what are your favorites in those categories?

[TrevorMonty]

T/W isn't very important for a booster engine, it's more important for an upper stage engine. The most important things for a booster engine would in my opinion be:

1. Price per kN
2. Reliability
3. Thrust to nozzle exit area. (Higher means you can make higher untapered rockets)
4. For reusable engines, little to no required refurbishment.

For a RLV booster engine life is more important than build cost . In case of expendable US low build cost is very important.

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[Yggdrasill]

T/W isn't very important for a booster engine, it's more important for an upper stage engine. The most important things for a booster engine would in my opinion be:

1. Price per kN
2. Reliability
3. Thrust to nozzle exit area. (Higher means you can make higher untapered rockets)
4. For reusable engines, little to no required refurbishment.

And what are your favorites in those categories?

I'm really liking Raptor across the board. I just think the volume SpaceX is planning will give extremely low cost per unit, while they at the same time get so much experience flying these engines which allows them to tweak away most of the minor flaws for reliability/reuse over the next couple of years. It's the engine that is furthest along in it's development and I don't see them losing ground.

For a RLV booster engine life is more important than build cost . In case of expendable US low build cost is very important.

I agree engine life is very important for the reusable engines. The number one metric could really be cost per kN per flight. In which case metric number 4 could really be eliminated.

[Yggdrasill]

For upper stage engines, the most important metrics in my book are:

1. Cost per kN per flight
2. Specific Impulse
3. Thrust to weight

I think Raptor comes out quite well on this too.

[Tywin]

For upper stage engines, the most important metrics in my book are:

1. Cost per kN per flight
2. Specific Impulse
3. Thrust to weight

I think Raptor comes out quite well on this too.

And what is your second choice for a first stage and second stage?

[Yggdrasill]

And what is your second choice for a first stage and second stage?

For the first stage I think I like the BE-4 the most for my second choice. For the second stage I'm thinking the Aeon-1 Vacuum.

Admittedly, I just don't know much about several of the options. And I prefer more mature designs. Getting to market quickly is important in getting the launch cadence up, and getting the launch cadence up is very important for cost and reliability.

[Lemurion]

After doing a bit more research, there really isn't a lot of information available on many of these engines. What there is seems to indicate that they have very little in common other than propellant choice. Some, such as the Aeon-R and Archimedes are very low TRL. Most of the engines that I could find information on are gas-generator, which is perfectly workable but hardly cutting edge. The only information I found on Dhawan 1 was that it was probably an expander cycle, while the JD-1 is pump-fed.

There is no war, and the only real competition at this point in my opinion is that between BE-4 and Raptor, and even that's more an artifact of circumstance. Both are staged combustion engines, of roughly similar performance, to be developed and used by companies competing for the same contracts, and set to enter service roughly simultaneously. The thing is, both engines would have been in a similar competition regardless of the propellant choice.

Archimedes may be in some competition with BE-4 in future as Neutron will theoretically have some competitive overlap with New Glenn, but even that's a bit too far out to bank on at this point.

[Tywin]

After doing a bit more research, there really isn't a lot of information available on many of these engines. What there is seems to indicate that they have very little in common other than propellant choice. Some, such as the Aeon-R and Archimedes are very low TRL. Most of the engines that I could find information on are gas-generator, which is perfectly workable but hardly cutting edge. The only information I found on Dhawan 1 was that it was probably an expander cycle, while the JD-1 is pump-fed.

There is no war, and the only real competition at this point in my opinion is that between BE-4 and Raptor, and even that's more an artifact of circumstance. Both are staged combustion engines, of roughly similar performance, to be developed and used by companies competing for the same contracts, and set to enter service roughly simultaneously. The thing is, both engines would have been in a similar competition regardless of the propellant choice.

Archimedes may be in some competition with BE-4 in future as Neutron will theoretically have some competitive overlap with New Glenn, but even that's a bit too far out to bank on at this point.

Which engine is better for you the Aeon-R or Archimedes?

[Lemurion]

After doing a bit more research, there really isn't a lot of information available on many of these engines. What there is seems to indicate that they have very little in common other than propellant choice. Some, such as the Aeon-R and Archimedes are very low TRL. Most of the engines that I could find information on are gas-generator, which is perfectly workable but hardly cutting edge. The only information I found on Dhawan 1 was that it was probably an expander cycle, while the JD-1 is pump-fed.

There is no war, and the only real competition at this point in my opinion is that between BE-4 and Raptor, and even that's more an artifact of circumstance. Both are staged combustion engines, of roughly similar performance, to be developed and used by companies competing for the same contracts, and set to enter service roughly simultaneously. The thing is, both engines would have been in a similar competition regardless of the propellant choice.

Archimedes may be in some competition with BE-4 in future as Neutron will theoretically have some competitive overlap with New Glenn, but even that's a bit too far out to bank on at this point.

Which engine is better for you the Aeon-R or Archimedes?

At this point I have no preference, and no reason to have one. It's too early to tell.

[Gliderflyer]

It's going to be hard to determine which engine is "best" as most engines are very custom and fitted to their specific roles. You aren't going to use a Raptor on a smallsat orbital tug, and you aren't going to use 2000 tiny RCS thrusters on a 100 ton lander. You will always be able to shift the "what is better" goalposts to make your favorite engine win, because most are already "winning" at their specific task.

That being said, I would cast my vote for the one I'm working on (which didn't make the list).

[Tywin]

It's going to be hard to determine which engine is "best" as most engines are very custom and fitted to their specific roles. You aren't going to use a Raptor on a smallsat orbital tug, and you aren't going to use 2000 tiny RCS thrusters on a 100 ton lander. You will always be able to shift the "what is better" goalposts to make your favorite engine win, because most are already "winning" at their specific task.

That being said, I would cast my vote for the one I'm working on (which didn't make the list).

Oh wow, can you say the name of the engine?

A new BE-5 or BE-6?

[Gliderflyer]

It's going to be hard to determine which engine is "best" as most engines are very custom and fitted to their specific roles. You aren't going to use a Raptor on a smallsat orbital tug, and you aren't going to use 2000 tiny RCS thrusters on a 100 ton lander. You will always be able to shift the "what is better" goalposts to make your favorite engine win, because most are already "winning" at their specific task.

That being said, I would cast my vote for the one I'm working on (which didn't make the list).

Oh wow, can you say the name of the engine?

A new BE-5 or BE-6?

ALPACA main engine.

[Tywin]

It's going to be hard to determine which engine is "best" as most engines are very custom and fitted to their specific roles. You aren't going to use a Raptor on a smallsat orbital tug, and you aren't going to use 2000 tiny RCS thrusters on a 100 ton lander. You will always be able to shift the "what is better" goalposts to make your favorite engine win, because most are already "winning" at their specific task.

That being said, I would cast my vote for the one I'm working on (which didn't make the list).

Oh wow, can you say the name of the engine?

A new BE-5 or BE-6?

ALPACA main engine.

Does the work continue in ALPACA?