IRL engine analogs

[Awsumerguy]

I'm still confused about the engine analogs in real life. If someone could explain to me that'd be great.

 

[Altaïr]

It really depends on the engines.

For the Titan, his analog in real life is clearly the F1, the engine that propelled the Saturn 5, and the most powerful engine that ever existed (apart from the russian RD-170, but that one had 4 nozzles).

The Frontier is the equivalent of the SSME (Space Shuttle Main Engine), that equipped the american shuttle, and will also equip the future SLS. A staged combustion engine, both powerful and efficient. The Ferrari of space engines (which also applies to its cost by the way ).

For the rest, it's not as clear.

The Valiant could be the american RL-10 engine. A small engine for upper stages, efficient, but its thrust is rather weak.

For the Hawk I have no idea. It's clearly a kerosene engine suited for first stage/boosters, but its equivalent in real life is not clear. A pair of Hawk would eventually be closed to the RD-180 russian engine, that propells the Atlas 5.

Finally, the small Kolibri is similar to those hypergolic engines that equip satellites... or the LEM engines.

 

[Zeeray13]

It really depends on the engines.

For the Titan, his analog in real life is clearly the F1, the engine that propelled the Saturn 5, and the most powerful engine that ever existed (apart from the russian RD-170, but that one had 4 nozzles).

The Frontier is the equivalent of the SSME (Space Shuttle Main Engine), that equipped the american shuttle, and will also equip the future SLS. A staged combustion engine, both powerful and efficient. The Ferrari of space engines (which also applies to its cost by the way ).

For the rest, it's not as clear.

The Valiant could be the american RL-10 engine. A small engine for upper stages, efficient, but its thrust is rather weak.

For the Hawk I have no idea. It's clearly a kerosene engine suited for first stage/boosters, but its equivalent in real life is not clear. A pair of Hawk would eventually be closed to the RD-180 russian engine, that propells the Atlas 5.

Finally, the small Kolibri is similar to those hypergolic engines that equip satellites... or the LEM engines.

I disagree on the frontier I believe it's based on the raptor. That's for a few reasons the .
Model design of the nozzle is too smooth to be an RS-25 which has those ribs to pump fuel to cool the nozzle. Also the engine exhaust is a bright blue rather then the orange blue that is put out by a hydrolox engine. And frontier is is 3.5 meters tall which is closer to raptors 3.1 meters tall than the RS-25's 4.3 meters tall.

 

[Altaïr]

I disagree on the frontier I believe it's based on the raptor. That's for a few reasons the .
Model design of the nozzle is too smooth to be an RS-25 which has those ribs to pump fuel to cool the nozzle. Also the engine exhaust is a bright blue rather then the orange blue that is put out by a hydrolox engine. And frontier is is 3.5 meters tall which is closer to raptors 3.1 meters tall than the RS-25's 4.3 meters tall.

It could be another staged combustion engine indeed. Maybe the Raptor, or the BE-4 as well. However, I have to disagree about the exhaust. The SSME's exhaust is of a very pale blue and by far the cleanest of all. Apart from the diamond shock, the flame is barely visible:

A Methane flame is way more visible and has some pink shades in its trail:

To me the Frontier exhaust is clearly an hydrogen flame.

About the dimensions I'm not sure it should be a criteria, the F1 engine doesn't correspond as well. And their dimensions changed with 1.5 by the way.

 

[Horus Lupercal]

About the dimensions I'm not sure it should be a criteria, the F1 engine doesn't correspond as well. And their dimensions changed with 1.5 by the way.

I thought the new titan moved away from pretending to be an F-1 engine with the shape change?

 

[Altaïr]

I thought the new titan moved away from pretending to be an F-1 engine with the shape change?

Ah, you're right. But that's what it was suppposed to be historically, or at least something similar.

 

[Horus Lupercal]

Ah, you're right. But that's what it was suppposed to be historically, or at least something similar.

Aye, historically its supposed to be the F1, frontier was RS-25 or J-2 etc.

I heard somewhere (probably wrongly) that he changed Titan from 'F-1' to a more open cycle engine so he could create another engine which was closer to the F-1 in looks and performance.

 

[Altaïr]

Aye, historically its supposed to be the F1, frontier was RS-25 or J-2 etc.

I heard somewhere (probably wrongly) that he changed Titan from 'F-1' to a more open cycle engine so he could create another engine which was closer to the F-1 in looks and performance.

There's probably a story like that, but I can't really remember. Well, I guess we'll see...

 

[Horus Lupercal]

Yeah, it'll likely not come before the SRB update.

I'm trying to remember the source. It was roughly during the tutorial competition last year, the 'winners' got free access to planned NASA skins. Can't remember if that included re-worked engines to include the F-1/J-2 properly.

 

[Awsumerguy]

Yeah, it'll likely not come before the SRB update.

I'm trying to remember the source. It was roughly during the tutorial competition last year, the 'winners' got free access to planned NASA skins. Can't remember if that included re-worked engines to include the F-1/J-2 properly.

Also just a sidenote, before the SRB update what engines would you use for them?

 

[Pink]

Also just a sidenote, before the SRB update what engines would you use for them?

Hawk or Titan, since Valiant and Frontier are efficient and have the wrong exhaust.
Maybe Kolibri for really small SRBs

 

[Horus Lupercal]

Also just a sidenote, before the SRB update what engines would you use for them?

The bigger and less efficient the better. The quicker you can get rid of boosters / SRBs, the better the rocket will be. Hawk is a better engine than titan in 1.5, so if you can fit multiple Hawks in, do so. If not, got for titan.

 

[Altaïr]

The bigger and less efficient the better. The quicker you can get rid of boosters / SRBs, the better the rocket will be. Hawk is a better engine than titan in 1.5, so if you can fit multiple Hawks in, do so. If not, got for titan.

Agreed about the SRBs, but why is the Hawk better than Titan? They have the same Isp, the Hawk has a slightly better TWR, but nothing really significant... To me the Titan is more like a bigger version of the Hawk right now.

The main difference is that "surface-wise" (I would rather say volume-wise, but we are in 2D) the Titan packs more power than the Hawk.

 

[Horus Lupercal]

but why is the Hawk better than Titan? They have the same Isp, the Hawk has a slightly better TWR, but nothing really significant... To me the Titan is more like a bigger version of the Hawk right now.

Because of that TWR. Pound for pound of thrust, it weighs less so you get more Dv for your trouble. It's not much more, but it's still something.

The main difference is that "surface-wise" (I would rather say volume-wise, but we are in 2D) the Titan packs more power than the Hawk.

That's what I mean. If you need the thrust but don't have much space under a fuel tank, then titan all the way. Otherwise, go for hawk.
I like to think it's intentionally done to keep hawk relevant after you get the DLC, in the same way broadsword/valiant is vs. frontier

 

[Altaïr]

Because of that TWR. Pound for pound of thrust, it weighs less so you get more Dv for your trouble. It's not much more, but it's still something.




That's what I mean. If you need the thrust but don't have much space under a fuel tank, then titan all the way. Otherwise, go for hawk.
I like to think it's intentionally done to keep hawk relevant after you get the DLC, in the same way broadsword/valiant is vs. frontier

Makes sense indeed.
Personally I would still have made them more different: more thrust and more TWR for the Titan but less Isp, to make it more booster-like. The Titan would be the ultimate gravity killer, but not suitable for anything else.
Same logic for efficient engines: I would have given less thrust/more Isp to the Valiant, to make it the ultimate engine in terms of efficiency. The Frontier would be slightly less efficient, but with a decent thrust and TWR in comparison. And that would be realistic, engines like the RL-10 or the european Vinci engines are more efficient than the SSME in the end.

The only problem then is that the Frontier can also do the Hawk's job, so this one becomes useless. In campaign mode this could be fixed by making the Frontier way more expensive (that's the Ferrari), but in sandbox I have no solution...

 

[Horus Lupercal]

more thrust and more TWR for the Titan but less Isp, to make it more booster-like

I think it's intentionally not like that, ready for the SRB update. He'll probably introduce 2 types, a small and large with an enormous thrust rating and probably 230 seconds of Isp. That way Titan will (unchanged) jump into the large, powerful core engine slot and the SRBs will do the heavy lifting from launch to about 5-10km up.

The only problem then is that the Frontier can also do the Hawk's job, so this one becomes useless.

Yeah well that's traditionally been the problem, 'how to keep Hawk and Frontier away from each other?'. The 1.4 solution was hitting frontier with a nerf bomb so the TWR was shocking and only really competitive in vacuum with large stages. They've made it much better in 1.5 (even though it's less powerful, it's much more useful), so they've had to alter Hawk as well to keep them apart.