LittleBird SSTO

[Tada]

Ok, after year of playing KSP, visiting almost all bodies, doing great missions, hauling 350 ton payloads to Jool I finally built a SSTO!

It is 100% legit - no clipping and no air-hogging!

Easy to fly and very light! I plan to bring it as a lander to Laythe.

LittleBird SSTO

Tech data:

Weight: 8.49t

Parts: 37

Fuel: 150 units of jet fuel, 225 rocket fuel, 265 units of oxidizer, 80 units of monopropelant

Electricity: 1 thermo-nuclear generator, 50 units of electricity

Communication: Commutron 16 antena

Propulsion: 1x TurboJet, 2x LV-909 Liquid Fuel Engine

It is completely capable of reaching 1600m/s2 at height around 24.500m, then switching to liquid fuel and coasting to orbit. I´ve succesfully rendezvoused with space station in 100km orbit.

Launch profile:

1. Turn on the ASAS

2. Turn on TurboJet engine by pressing 1 and set throtle to 100%

3. Lift off just around 100m/s2

4. Start climbing at 45 degree angle

5. Watch you apopapsis, you dont want it get over 24.500m

6. Level the flight and gather speed in height of 24.500m

7. When reaching 1550-1600m/s2 turn on the LV-909s by pressing 2 and pitch up 45 degree again - watch turbojet engine and turn it of when it flames out (pressing 1) also press 3 to close air-intakes to reduce drag.

8. Let apoapsis hit desired height (85km x 85km guarantee given by manufacturer), shut down engine.

9. Circularize

10. Congrats you are in orbit!

Other intstructions:

- Flight characteristics with ASAS turned off have not been tested fully but plane seems to be mostly stable, just little bit nose heavy when fully loaded.

- Trying to land with full fuel tanks may lead to crash

- It is not advised to land as complete glider, hitting low speed at landing aproach may lead to catastrophical loose of lift - 1/4 throttle is advice when plane loaded with some fuel.

- Moderatley skilled pilot can bring plane safely to ground even as a glider.

- Don´t slam brakes on runway hard plane may tip over!

Download

Test it and let me know!

Edited November 14, 2013 by Tada

[Corona688]

That is absolutely superb. Beats my smallest landable ramjet by a long ways.

I can't test it yet, but will later.

In what direction does the plane tip when braking? You could set up an action group for only the front or rear brakes accordingly.

[Tada]

Little bit front, but only when landing and brakind from excesive speeds.

The design is not perfekt, but bunch of compromise has to be made, when you want to built thing like this without clipping etc.

Main purpose is to serve as a light Laythe lander or as a mean of evacuating spacestation in emergency with crossrange capability.

EDIT: I consider thise craft basicaly 2/3 scale down of the best small SSTO - Sparrow by Zombiphylax. It has 2/3 of its weight and 2/3 of its parts. But it comes with bit disadvantage in form of little less stability during landing maneuvre. I will see ho LittleBird perfoms on Laythe, but I´m kinda worried that it´s high landing speed when loaded with fuel will lead to some failures.

Edited November 14, 2013 by Tada

[Corona688]

Well it definitely works, and handles very well on the way up. I forgot to close the intakes but still made it. It handles less well on the way down -- don't let the velocity go below 140m/s until you're below a thousand feet! It actually went into a complete tumble but it's so SMALL that it was actually able to recover by throttling up. I was able to land it within sight of the center, first try.

I changed the radioisotope generator to a Z-1K battery pack because its both lighter and far more battery than its ever likely to need. Even the 200 would do, but I don't see a nice place to put one.

I'm not sure it truly needs RCS at all unless you included it as counterweight or deorbiting fuel. I wonder if the 48-7S engine here would work too -- slightly less thrust but a four-fifths less weight!

Lower gravity should mean lower stall speed. Whether you can find suitably flat landing sites is another question. It might be worth trying to make this into a VTOL -- something not efficient enough for Kerbal orbit can be plenty efficient anywhere smaller.

Oh -- and as you begin re-entry, be sure to transfer your remaining fuel into the inner tank or you'll be in for a nasty surprise when you turn the jet back on

Edited November 15, 2013 by Corona688

[Corona688]

I've confirmed that it still works SSTO with 48-7S engines instead of 909's -- which reduces weight nearly a ton.

[Virindi]

Nice small craft! It's good to see spaceplanes that don't have 100000 intakes clipped on to one attach node.

[tstehler1]

Nice small craft! It's good to see spaceplanes that don't have 100000 intakes clipped on to one attach node.

Story of every spaceplane that I [attempt to] build. The insane amount of intakes on my last one probably have a combined mass roughly equivalent to that of Gilly.

[Corona688]

You know, these could make decent space tugs too, with their high fuel capacity and SAS torque for a tiny orbiter. I'm gonna dock up and refuel, then see if I can shove around some space junk.

Edited November 15, 2013 by Corona688

[Corona688]

Maybe not... Docking it was real trouble. I had to IGNORE the horizon and eyeball everything. Somehow even with 'control from here' and targeting it was always pointing in the wrong direction.

[Tada]

I was thinking about trying those smaller engines also. Question is, if lower weight will make up for lower ISP - 350 for 48-7S vs. 390 of LV-909. I also care about aesthetics, sou I would have to put a plates on those tanks if I use small engines and that would add some parts + more weight, so I went with LV-909.

2 RCS tanks are total over-kill but: they act as counter weight. First versioun had 1 RCS tank located next to RTG generator, but center of gravity was too off-set from thrust vector, so it was bit unstable when performing full power burns in orbit. Also given the weight of the craft they give you pretty solid Dv reserve for emergency landings.

Behaviour of plane while landing is as is... It doesn´t have that much lift + center of gravity of such small craft shifts violently, when fuel is consumed. Pumping fuel into tank behind cockpit helps. With good piloting it is possible to land completely as a glider, but you don´t have much chances changing course.

As far as VTOL goes - I don´t consider them efficient for SSTO purposes. Another topic would be adding little landing legs, so SSTO spaceplane can land on low gravity worlds. But that would kinda brak concept of light and low part count SSTO which I wanted at first place

[pinolallo]

- It is 100% legit - no clipping and no air-hogging! -

Sure?

ram air intakes are clipped into wings

you are using 4 air intakes/engine ratio...

If "legit" or "weight" are the main specs for this single seat SSTO, you showed a very poor result.

[Corona688]

I was thinking about trying those smaller engines also. Question is, if lower weight will make up for lower ISP - 350 for 48-7S vs. 390 of LV-909.

The 48-7S works great for me whenever weight really matters... The 909 is fuel-efficient, but has a terrible thrust-to-weight ratio, which hurts small craft the worst. The 48-7S has the best in the game.

I think there was benefit, I was able to reach orbit with more fuel. But that could have just been practice.

Also remember, any craft you build to reach Kerbin orbit is massively overbuilt to reach Laythe orbit.

2 RCS tanks are total over-kill but: they act as counter weight. First versioun had 1 RCS tank located next to RTG generator, but center of gravity was too off-set from thrust vector, so it was bit unstable when performing full power burns in orbit. Also given the weight of the craft they give you pretty solid Dv reserve for emergency landings.

That is true. And SOME RCS is needed for docking in any case, I'd almost forgot.

Behaviour of plane while landing is as is... It doesn´t have that much lift + center of gravity of such small craft shifts violently, when fuel is consumed.

I see. Makes sense.

Another topic would be adding little landing legs, so SSTO spaceplane can land on low gravity worlds. But that would kinda brak concept of light and low part count SSTO which I wanted at first place

Heh. It kind of already has legs, if you stick the brakes on.

I don't think the nose-light is necessary when landing-gear has lights built in. A light by the docking coupler would be nice.

Edited November 15, 2013 by Corona688

[Corona688]

you are using 4 air intakes/engine ratio...

It only operates up to 24,000m, so what's wrong with that?

If "legit" or "weight" are the main specs for this single seat SSTO, you showed a very poor result.

Add 'functional' to the list, then -- I've seen smaller SSTO's but they can't land, dock, or even fly nonballistically. I'm sure the intakes can be fixed. Edited November 15, 2013 by Corona688

[Immashift]

I like it! I think you definitely beat out my smallest. I basically took the Aeris 3A and made it orbit capable.

It gets up to around 28km before the jet becomes useless, but at that point you're going ~1700m/s and can just breeze up into orbit.

Its fuel margins are relatively tight but I have docked it to a 100x100 station. I clipped the rockets so I guess that counts me out

Anyway wonderful little design. Definitely going to test it out.

[Tada]

Well, intakes are as they are because I like them like that, they can be turned no problem

I consider "clipping" when you turn your no-clip in cheat menu, I didn´t...

[zombiphylax]

Hah! Excellent work, Tada! I'll have to try this out this weekend.

[Tada]

I have 2 of them loaded on Laythe drive stage and I will test them, but I think landing them on thin atmosphere with little less lift will be deadly

But still it can be viable stuff on Kerbin.

[Corona688]

Laythe's atmosphere is thicker than Kerbin's.

[Tada]

Laythe's atmosphere is thicker than Kerbin's.

That may be, but surface is big unknown for me after last patch. Even in .21 it became very rough...

[barrenwaste]

Have to say, it's air hogged. You didn't use clipping on the airhogging, but you still piled 5 air intakes on to fuel one engine. That's air hogging. Other than that? Nice little economical build, I like it.

[Tada]

Just 4

If I remember correctly first version had only ram intakes and it was enough to get into orbit, but this proved bit easier and more forgiving on fuel margins.