Demonstrator SSTO for the new KRABE engine

[sgt_flyer]

here i have a SSTO demonstrator for my brand new KRABE engine (Kerbal Rocket Air Breathing Engine) (yes, this is inspired by the SABRE engine ) - note : i did not need to use the debug menu to do the clipping.

the idea behind this engine pod was to have a self contained engine + air intakes (so we don't have to spam air intakes all over our designs, this one has it's air intakes placed where the compression would take place)

the SSTO with it's two KRABE engines (the LV-N is a plus, once the SSTO has a good apoapsis, the LV-N is all it need to maintain it until it has escaped atmosphere and circularize.

the SSTO make a smooth climbing on it's own after take off, and is a good reentry / glider plane.

the engine :

basically, the engine has 3 engines clipped in one spot : 1 basic jet engine, 1 turbojet engine and a Aerospike, mounted behind a structural fuselage. the radial engine body is here to hide the 8 circular air intakes.

the advantage of this self contained system, is to be able to easily use it with subassembly loader.

it gives this SSTO a good steady thrust (as height goes up, the turbojet thrust increases, while the basic jet thrust decrease).

.craft file : KRABE Demonstrator

Launch profile :

Keys :

1 - Turn on the jets and turbojets

2 - Turn off the jets

3 - Turn off the turbojets, close all air intakes, and activate the aerospikes and LV-N.

4 - Turn off the aerospikes

5 - Turn off the LV-N, open all air intakes, activate the jets.

Ascent profile :

hit '1', go full throttle. you can take off on your own or let the plane do it (don't use ASAS for automatic takeoff ) the plane will start climbing alone as it passes the end of the runway.

keep a 30° angle of attack over the horizon until you climb to 15000 meters (usually, you will have around 1.5 air in the intakes remaining at 15000m)

at 15000m, shut down the basic jet engines with '2' and keep a 15° angle of attack over the horizon until you get to 30000m.

at 30000m (or if you have 0.12 air remaining in the intakes, but that's the remaining air i got at 30000m) , hit '3' to shut down the turbojets and activate the 3 rockets engines, and go for a 30° angle of attack.

push your apoapsis to 100km, and hit '4' to disable the aerospikes. make some low throttle burns with the lv-n to keep your apoapsis to 100km until you cleared the atmosphere.

for the circularization burn, you will usually need a bit less than 1mn of burn with the LV-N, so start you circularization 30s before reaching apoapsis.

Reentry :

after deorbiting, simply keep the nose towards the prograde marker. the plane is able to stabilize itself alone during reentry (no need for ASAS during reentry)

it's a capable glider with the few remaining fuel left, but you should still have more than enough liquid fuel left to make a powered landing (hit '5' to disable the LV-N and reopen the air intakes).

Have fun

[Rune]

This "did not use the debug console to build this" business bugs me a bit, really. Pretty much every time someone says that, all they are doing is taking advantage of game bugs in the VAB (yes, putting something some place else, then moving it around is a way to do part-clipping without the debug console, due to a bug).

I mean, it's not that I am calling you cheat, because I actually open the debug console and turn off part clipping as a reflex whenever I start building something. It's that you give the impression you are calling me one for not doing what you do. And as it has been said a gazillion times... it's hard to cheat in a sandbox game.

As to the SSTO, looks good, it seems clipping engines into each other is all the rage.

Rune. I recommend doing it properly, you will save parts and time. It's an ALT+F12 away.

[sgt_flyer]

in fact, i sometimes encountered violent reactions to heavily cliped things (my fregat stage once completely shattered randomly ) that's why i try to not use the debug menu if it can't be clipped without the menu, i don't do it - plus, it's not that i'm calling you a cheater, it's just that there's several persons who call the people who use clipping cheaters - so i added this mention just to clarify for them don't feel targeted by it, it's was meant for all the contrary

- plus, more than just 'clipping' engines, i built it for ease of use - i just need to grab one part of it to copy the entire thing, so i'll be able to reuse it on other designs

Edited June 4, 2013 by sgt_flyer

[1096bimu]

Might as well just edit the part.cfg files to make them the way you wanted instead of clipping them together. That's what I would do if I felt that standard parts and rules could not get me as far as I like.

[sgt_flyer]

that would not be stock anymore after that