Toroidal Aerospike rocket engine

[Temstar]

Is it just me, or is that new aerospike engine a bit overpowered? I ran test on all my boosters from fast accelerating light lifters to lumbering heavy weights and in all cases replacing LV-T30 with aerospike noticeably improve rocket performance. That extra bit of weight is nothing when you look at its thrust and fuel efficiency.

Then I thought maybe this engine is suppose to be hard to place since it can\'t sit on top of decouplers, rendering it only useful for parallel stage side boosters or very cleverly engineered rockets, turns out my 12-tanks-to-LKO orbital tanker was perfectly happy sitting on the pad on top of 6 needle thin spikes.

It would seem possible also to setup aerospike engines for upper stages for giant rockets too by using decoupler only in the center stack and have the aerospike engines clustered around it and attached to the below stage with struts (might get a bit hairy during staging), so what\'s the point of LV-T30 now?

[RedDwarfIV]

The aerospike engine is intended for spaceplanes.

The LVT-30 still has the Rule Of Cool on its side. I mean, it\'s a sodding rocket. Not like those pansy toroids.

[ColdFire75]

Surely it only works in atmosphere?

Though I except it may well still be broken.

[Kosmo-not]

Right now, all the C7 engines are unbalanced. Currently, there is no use for the regular jet engine as the scram jet fills that role and more. The scram jet is very much overpowered. Try putting some on your rocket and you get to 10km with using very little fuel (also, the scram jet isn\'t supposed to function at low altitudes).

One thing that the regular rocket parts have over the C7 parts is the fuel tank. The propellant is lighter in our standard fuel tank.

[Temstar]

I was expecting the jet fuel to be different to liquid rocket fuel like how liquid rocket fuel is different from RCS monopropellant so I was very surprised to find out they\'re actually the same.

That makes no sense, jet engines need avgas or kerosene were as rockets use LOX/RP-1 or LOX/LH2 or some other more exotic mix of fuel and oxidizer. Even though RP-1 is very similar to kerosene the tanks for rockets will be very different to fuel tanks for jets and shouldn\'t be compatible.

[Rico88]

I was expecting the jet fuel to be different to liquid rocket fuel like how liquid rocket fuel is different from RCS monopropellant so I was very surprised to find out they\'re actually the same.

That makes no sense, jet engines need avgas or kerosene were as rockets use LOX/RP-1 or LOX/LH2 or some other more exotic mix of fuel and oxidizer. Even though RP-1 is very similar to kerosene the tanks for rockets will be very different to fuel tanks for jets and shouldn\'t be compatible.

C7 is working on jetfuel, but it didn\'t make it into this release. Everything is just a placeholder right now, they will change in future updates.

[avan]

The Aerospike does have the issue that you can\'t attach anything under it, unlike the LV-T30

[Salda007]

I was expecting the jet fuel to be different to liquid rocket fuel like how liquid rocket fuel is different from RCS monopropellant so I was very surprised to find out they\'re actually the same.

That makes no sense, jet engines need avgas or kerosene were as rockets use LOX/RP-1 or LOX/LH2 or some other more exotic mix of fuel and oxidizer. Even though RP-1 is very similar to kerosene the tanks for rockets will be very different to fuel tanks for jets and shouldn\'t be compatible.

Turbine engines can be tuned to run on damn near anything, and early rocket engines were certainly fueled with jet fuel. The reason for the divide between the two was that the US military\'s original JP-1 fuel standard was very broad to ensure a ready supply from refineries, but resulted in a wide range of fuel characteristics. RP-1 was developed as a more restricted standard for the much tighter tolerances required by rocket engines, which also didn\'t need nearly as secure a supply. It\'s basically a very refined kerosene, and could certainly be pumped through a jet turbine engine.

TL:DR - rocket fuel = jet fuel, for certain definitions of both.

[trbinsc]

But the Rocket fuel tanks also carry oxidizer, and I\'m sure a jet engine would have no use for that.

[Tosh]

Well, areospikes are believed to be more effective than 'regular' LFEs (although there\'s no one flew to space for this moment, they\'re only passing ground tests). And its current in-game implementation looks somewhat 'realistic' (by design, aerospikes should be a bit heavier than comparable LFEs \'cause of quite complicated cooling system).

But: I\'d rather have a lighter and less powerful areospike with an efficiency slightly greater that that of standard LFE.

[sal_vager]

The big thing about aerospikes was that they had better performance over the whole altitude range than a regular engine that was optimized for one altitude, aerospikes are actually less efficient at at the same point a regular engine is tuned for.

I looked these things up in detail back when I was excited about the Direct launcher, they are interesting but there are better ways to solve this problem.

Seeing as KSP doesn\'t simulate air pressure on engine bells (yet) aerospikes are just a novelty, I\'d have preferred Moach\'s Aerospike over C7\'s as well just for the looks.

[Nibb31]

Aerospikes are not really a type of engine. They are just a type of nozzle. You can have aerospike jet engines or aerospike rocket engines (or aerospile ramjets, scramjets, or whatever...)

The main advantage of an aerospike is efficiency over a larger range of altitudes than bell nozzles, which makes them practical for SSTO craft, but less optimal for any specific altitude. Bell nozzles have to be tuned for a specific operational air pressure, which is actually the best way to go when you are using staged rockets. Also, non-reusable bell nozzles are capable of ablation: part of the bell burns up, which changes the geometry of the bell with the altitude.

Linear aerospikes are also used to reduce the heat signature, like on the B2 or the F22.

[Tosh]

Aerospikes are not really a type of engine. They are just a type of nozzle. You can have aerospike jet engines or aerospike rocket engines (or aerospile ramjets, scramjets, or whatever...)

I\'ve never heard of air-breathing areospikes :.

Moreover, aerospikes have different combustion chamber configuration (and linear aerospikes generally have several of them). This, added to differences in cooling system, requires to consider an aerospike a different type of engine.

Linear aerospikes are also used to reduce the heat signature, like on the B2 or the F22.

More likely flat de Laval nozzles are used there.

The main advantage of an aerospike is efficiency over a larger range of altitudes than bell nozzles, which makes them practical for SSTO craft, but less optimal for any specific altitude.

Yep .

[LukeTim]

I don\'t get the Aerospike rocket...

It\'s a rocket, so it mustn\'t need an air inlet, and I presume it doesn\'t need the jet body part... so where does it go?

Also, I was under the impression that Turbo-Jet and Ram-Jet work in wildly different ways (with a turbo-jet using a series of fans to compress the air before burning and a ram-jet using the actual speed with which the air moves through the engine to compress it), so why have a ram inlet without a ram engine part?

[sal_vager]

The aerospike is a rocket engine, just like the ones we\'re used to from 0.14.4

[zpox357]

I thought it was a nozzle attachment at first so I attached it to my upper stage engines

I quickly realised it wasn\'t a nozzle when my decent engine failed to start on the way down from Minimus orbit =P

Nozzel attachments would be cool though