Six part SSTO - R.A.P.I.E.R.

[Chozo Nomad]

So I made a teeny-tiny SSTO using the new engine. It was based off of Scott Manley's mini-space plane. This new engine is really cool and extremely versatile, but does anyone else think it might be a little over-powered? Maybe I'm just clinging to old ways. Oh well! :b

Craft file is in the description, for those who are interested.

[meve12]

It does make SSTOs absurdly easy.

[Hodo]

It is a bit overpowered, and this is coming from someone who uses B9.

[Chozo Nomad]

It is a bit overpowered, and this is coming from someone who uses B9.

So it's not just me, then. :l

[Hodo]

So it's not just me, then. :l

Actually it is heavier than the B9 SABRE S engine, by .25 tons.

And generates less power, 190/175 vs 215/185

But the engine response is faster in the RAPIER and heat generation is less.

Not to mention a far more compact design.

But for some reason it feels more over powered then the SABRE-S

Edited December 18, 2013 by Hodo

[Lohan2008]

Ditto: the RAPIER is too overpowered ^

[Wile E. Coyote]

I think jets in general just got a buff as my SSTO from .22 got into orbit on almost dry tanks and now the same craft gets there with about 3/4 fuel not even trying.

[iDan122]

I can make a 5 part ssto, without a rapier, beat that

[Rune]

Actually, it is pretty well balanced. The thing that is letting us all get to orbit with so much efficiency and makes our eyes go like balloons when we revise the fuel after orbit insertion, is that it makes the rocket takeover automatically. Meaning you milk every last bit out of them! Stats-wise, I can make clipped designs that work better, with more thrust in atmo and greater isp in orbit (I.E: my standard SABRE equivalent, a turbojet + LV-909 clipped inside).

In fact, I predict RAPIER SSTO's are going to be very easy to get to space, but no so easy to get really far. And that is great! KSP is already complicated enough without needing to learn all the tricks to survive flameouts, and the aerodynamic problems are all still there. You just don't have to clip so much to get a result that a few days ago was just in the hands of people with a lot of experience in teaching the building UI how to behave in ways it was never meant to.

Rune. All in all, much less OP than the 48-7S.

[Alguien]

without needing to learn all the tricks to survive flameouts

actually i am sure they make flameouts to be harder to happen now

[Rune]

actually i am sure they make flameouts to be harder to happen now

...which is what I say... :S

[mikeman7918]

Those engines are not over powered, they are less efficient then a turbojet in jet mode and less efficient then a normal rocket in rocket mode, they can't easily lift a payload vertically because of their low thrust in jet mode, and if you put them in clusters, they will overheat and explode if you do not apply thrust limiting. This does not mean that they are not in the ranks of best engines in the game (up there with Atomic Rockets and Ion Drives) and they are also quite far in the tech tree, I believe these engines are very balanced.

[barrenwaste]

I agree with Rune and Mikeman, the new engine isn't op. I get far more thrust in atmo, where it is most needed, and fuel efficiency with my clipped atomic/jet set up. It does allow you to achieve orbit with one engine, which is impressively easy to use, but as for op, I just don't see it.

[Wjolcz]

In my opinion the engine simply opens the space around Kerbin. You will get with it to orbit, but it won't let you go interplanetary/Mun/Minmus and back.

[Tankbuster32]

The RAPIER makes for very efficient LKO-capable planes, but going beyond that is going to be hampered by the low ISP of the engine, so you still want to lug an NTR around if you're going to Duna.

[Hodo]

The reason they feel overpowered to me is because of their ridiculously compact size. The SABRE which is what the RAPIER is modeled off of, is almost 6 times as long and when used as a complete unit with the nonfunctional precooler and intake you have a unit that is almost 7.5m long! The RAPIER I can slap a .5m long tank between it and the RAM intake and it total be about 1.5m in length and weigh less than the previously mentioned combo, and it has fuel as opposed to the SABRE which does not.

They do have some drawbacks but not many. They don't generate the power of the turbojet, but who cares when they keep producing power well past mach 5.5. Not only this but they also can operate at 100% throttle well after the air intake flow has dropped to 50% of the required air to keep it running on jet mode. In some applications that can be as much as 6km in altitude or 500m/s d/v.

When B9 gets fixed I will compare the two on one of my test craft (the X series). But I also never really liked using the SABRE, it just felt like a cheap way to get to space. I used them because they cut parts count down, and there is no large 2.5m jet engines.

[KissSh0t]

Could you imagine how long all of the engines would be if they realistically modeled them with all the internal workings of a normal Jet engine for instance.

These new engines are so great, as someone that does not use mods... it is just amazing to have something that can be both a jet engine and a rocket.. they are not "OP".. but they do make it easier to do what would have been done with more parts in the past.

[Hodo]

Could you imagine how long all of the engines would be if they realistically modeled them with all the internal workings of a normal Jet engine for instance.

These new engines are so great, as someone that does not use mods... it is just amazing to have something that can be both a jet engine and a rocket.. they are not "OP".. but they do make it easier to do what would have been done with more parts in the past.

In the past, like it was that long ago, if you wanted to make a SSTO space plane you could do it with a single turbojet engine, 3 RAM intakes, and a LV-909. And that was pushing it to get it to 70km x 70km. Now you can do it with a single RAPIER, 1 RAM intake, and no other engines.

Seeing the problem, it is the drop in air needed that bothers me. Every other jet engine flames out at around 90% airflow on the FAR readout, or .1 on the air intake in KSP. Now the RAPIER flames out or switches over at 49%, which is REAL low compared to any other airbreather out there.

[KissSh0t]

Ahh yes.. in that regard I see what you mean

[Hodo]

Ahh yes.. in that regard I see what you mean

Otherwise it is fine. Maybe Squad has a plan for it to start to use oxidizer as the airflow drops below 100% to boost the air intake for the airbreather before it gets below a certain pressure level. I think that is what the real SABRE does anyway.

[Guest]

In my opinion, the RAPIER is actually well balanced. Yes it makes SSTO's much simpler, but there are trade-offs.

Its not OP because...

-lower thrust than turbojets

-higher mass than dual engine designs

-lower efficiency (360 specific impulse)

But, its not underpowered because...

-simpler design, less parts and more compact

-automatic switching (flat spins avoided)

Also, an important thing to consider is the new way intake air and airbreathing engines work. The RAPIER may feel OP in part because airbreathers now flame out at much higher altitudes. The thrust will die out, but engines don't cut out until you have really low levels of intake air.