The K Prize - 100% reusable spaceplane to orbit and back

[numerobis]

Would I be right in thinking that if ksp modelled decent aerodynamics, it would be immaterial, as the engine would be shielded by the body of the spaceplane, so, purely aerodynamically, there would be no difference?

Indeed; improved aerodynamics would require rebalancing the parts.

[WafflesToo]

How do you get it into orbit? All my planes shutdown completely and spin out of control at around 20,000m...

I usually go with two ram air intakes for every turbojet on-board. Even at that you really need to be cooking by the time you hit 20k (1.1kps at least). Even then I find it helps to throttle back to 70% or so to reduce the strain on the intakes. You've got to keep an eye on your intake air and listen to your engines. If they start to spool-down on thier own with intake air below 0.1 shut them down, throttle back up, and finish the insertion on the rocket motors.

Flying these is as much about technique as it is design. Scott Manley has some good videos on youtube on it and I know there's some others as well. Go check them out for some basics.

Good luck!

Edited July 13, 2013 by WafflesToo

[boolybooly]

Lazer Cut, nice ship, interesting use of aerospike NERVA combo, is giving me ideas. Thanks for your mission report, which is properly and mercifully linked in the gate crashers list

Thanks for sharing your ship coolpantskyle.

[Tarsus]

Seeing as how my name has been removed from the roll of honor after the new patch I figured I would enter a new design. Its nothing special just a more compact and stable version of a previous design. Called the X-13 it should win the Advanced pilot precision award, it also performs an orbital docking and transfers over some crew.

[Lazer Cut]

Lazer Cut, nice ship, interesting use of aerospike NERVA combo, is giving me ideas. Thanks for your mission report, which is properly and mercifully linked in the gate crashers list

Thanks I actually wanted to use 6xNERVA's, but the TWR of those is less than ideal to break into orbit :/ I'm currently experimenting with different ascent parameters that might give me more DeltaV to use once in orbit, current record is of 2000m/s with an ISP of 443(that's 3600m/s using NERVA's). If the tutorial on the wikia page is legit, I might actually be able to travel to Duna, and back with that amount! I'll update my post as soon as I've managed it, and then I hope I'll escape the gate crashers list ^^

[pa1983]

On that design you could get away with the two NERVA alone and no airospikes but it would require intake abuse. But it would make the craft lighter overall. You could also reduce the number of jets, probable to 3 at least sens they will give you more power at high altitude like 32km with lots off intakes due to the low drag.

But all this assumes you comfortable with having at least 7 intakes per engine that should give you at least 30-34km altitude on jets.

The trick here is to get above 32km in to the 3:e layer atmosphere there is where the jet realy kicks in.

This is just a friendly suggestion based on my experience.

[Tryptophan]

It's not perfect, but here's my attempt: The Oracle. Tends to get a bit jumpy at low fuel loads, but overall handles ok.

Pics: http://imgur.com/a/PuWcV

In orbit over Kerbin

Successful Landing! (though I missed the runway by a little bit)

[Tryptophan]

Edit: Removed due to redundancy

Edited July 16, 2013 by Tryptophan

[kahlzun]

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And here's me claiming the prize for a second time.

I entered 2 different SOI's (one of them 3 times) and landed safely on Minmus, and later the runway.

By my count, that's 3 (or 4) different awards:

Pilot Proficiency (landing at KSC) and/or Advanced Pilot Precision (Landing on KSC runway)

Kosmokerbal Commendation (Entered foreign SOI (Mun, Minmus) &

Astrokerbal Distinction (Landed on planetoid (Minmus))

I feel that I beat my previous attempt quite nicely!

Edited July 22, 2013 by kahlzun

[Rosarium]

......... FILE UNDER EXAMINATION

TAKE OFFTO ORBITTHE MUNLANDWAY BACKTO THE RUNWAY WTF!!!! HUSTON!JUST BEFORE THE IMPACT KSC CRASH DATAs (LOOK CAREFULLY) PILOT IS SAFE ( LUCE IS THE MOST SECURE CRAFT IN ASAAAA HANGAR)........

OK now can someone tell me please who put KeRBAl CoLa in the Water PiPE.... and WTF is a water PiPe?!?!??!

[pa1983]

......... FILE UNDER EXAMINATION

-Lots of pictures-

KSC CRASH DATAs (LOOK CAREFULLY) PILOT IS SAFE ( LUCE IS THE MOST SECURE CRAFT IN ASAAAA HANGAR)........

OK now can someone tell me please who put KeRBAl CoLa in the Water PiPE.... and WTF is a water PiPe?!?!??!

Its a bug. I know at least one more user that have reported it in this thread but he never wrote in the bug report I made, to bad because the more that reports the bug the better. It only seems to happen for missions leaving LKO. Happend to me 3 out of 4 times when going to Duna. I use the small airport on the island out side of KSC instead it seems to work.

http://forum.kerbalspaceprogram.com/showthread.php/25975-Hiting-Water-Pipe-on-the-runway-of-KSC-when-returning-from-Duna-or-Laythe

Edited July 24, 2013 by DYJ
Please don't quote large pictures.

[kahlzun]

So here's what a silly obviously-illegitimate infiniglide entry looks like.

You LANDED an infiniglider?? (SLOW CLAP)

[Lazer Cut]

On that design you could get away with the two NERVA alone and no airospikes but it would require intake abuse. But it would make the craft lighter overall. You could also reduce the number of jets, probable to 3 at least sens they will give you more power at high altitude like 32km with lots off intakes due to the low drag.

But all this assumes you comfortable with having at least 7 intakes per engine that should give you at least 30-34km altitude on jets.

The trick here is to get above 32km in to the 3:e layer atmosphere there is where the jet realy kicks in.

This is just a friendly suggestion based on my experience.

I'm personally against intake abuse even though I know that KSP doesn't use a model for it that's realistic. After a little experimenting I've come to the conclusion that my current engine configuration is the most optimal, and I'm pretty sure I got enough delta v to get to Duna and back. However, since I suck at intercepting Duna, I'm always forced to do a brake burn(I'm hoping to achieve a PE so low I can aerobrake directly from Kerbin), this burn ends up with using up to much fuel and voila, I can't get back

[tavert]

You LANDED an infiniglider?? (SLOW CLAP)

Heh, yep. I do love those landing gear. Wonder what I'll do if they stop being massless in 0.21...

[pa1983]

I'm personally against intake abuse even though I know that KSP doesn't use a model for it that's realistic. After a little experimenting I've come to the conclusion that my current engine configuration is the most optimal, and I'm pretty sure I got enough delta v to get to Duna and back. However, since I suck at intercepting Duna, I'm always forced to do a brake burn(I'm hoping to achieve a PE so low I can aerobrake directly from Kerbin), this burn ends up with using up to much fuel and voila, I can't get back

I never try to get a perfect interception from one planet to the other. Sure close but due to floating point precision being inaccurate not even the computer will be a 100% accurate for you so its just a wast of time and effort.

I make sure to get an interception first then I burn. After that I leave kerbins orbit and once I am 1/3 to 2/3 on the way to Duna I adjust my vector so I get close enough to Duna but also make sure I intercept at the equator. This usually dont cost more then 13-70m/s of delta V. Then when I intercept Duna I make final adjustment and it will cost very little to. Thats the way I do it with my Falcon X Jumbo or any other craft. Witha good intercept of Duna 11.5Km altitude works well most of the time for arobreaking.

Also Time warping slower especially when ever your about to intercept a planet will reduce the floating point errors and your Pe will end up closer to the predicted vector.

The thing that annoys me with the current engine and intake setup in KSP is that its even more unrealistic then intake abuse to some extent. First off a jet engine is not 1m long its at least 5-6 times as long. Second is the fact that you dont use ram air intakes for a jet engine. You use a nosecone or similar for high speed craft or a intact duct that will reduce the incoming air to subsonic speeds for it to work with the Jet engine. So raimair makes 0 sense because a jet has its own compressor and it requires subsonic speeds. Even sens they added intakes they used no known logic behind it at all. Also the fact that engines are limited to intake air with some bucket system rather then Temperature and altitude makes even less sens. Real jets at Mach 3 have problems with temperature first of all but also the fact that they need intakes that reduces the airspeed to a working subsonic speed so ramair makes no sens.

So what we actually need is proper intakes that are altitude limited first of all that would make intake abuse well not working at all. Sure if you had on intake for two engines you could get a less well preforming craft but once your at say 2x intakes per engine there is no more gain to be had. Could also differ from intakes to intakes. Would be smaller once where two equals one big etc.

Then we would need a precooler to even make efficient SSTO spaceplanes realistic. Thats whats needed IRL and thats whats being tested for the Skylon. Part exist in KSP as fare as I am concerned but it has 0 use atm.

I would like to see that jet engines overheat and either explodes or shuts down when exceeding mach 3 for longer periods. Going past this would require t his precooler part that would be 1m long at least and 1-2 tons sens its the heaviest part of a precooled jet engine.

When I use intake abuse I use it because KSP stock wont allow for efficient SSTO spaceplanes the way they the once under development IRL would work.

Intakes atm are unrealistic and counter productive.

At least when I stack 10 of them in a row with cubes and have a jet behind it I get a total size at least closer to a real jet engine and I have to make room for that.

So intake abuse might be more efficient but if you just dont stack intakes on the same intake giving the same volume as one it still requires some added engineering and the howl power plant requires more space.

I was also much against intake abuse before I gave it a closer examination but the fact that the way intakes works now is at least as unrealistic as intake abuse if not even more and I dont realy see why one should not use it if one can get more work done with less engines etc. Only real problem with intake abuse is the big part count that comes with it and the fact that engines dont overheat at high speeds due to the 1000C intake air on would have at mach 5.5.

But I have no problems with people not wanting to use intake abuse. I didn't either and I still dont like it but I dont like the stock idea of intakes either. Its like they say, its crap either way because both are just as unrealistic.

We can just hope for more realistic intakes and precoolers in the final stage of the game. If not Im probably going mods by then to solve that problem.

Edited July 20, 2013 by pa1983

[carazvan]

Presentation

3 stock SSTOs for your enjoyment all weighing in about 7t (weight on runway) with 3 different propulsions to complement the turbojet:

Flea (Ion), Fly (RCS), Mosquito (fuel)

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values presented refer to space deltaV left once in orbit after circularization and to surface TWR values (orbiting values are much higher)

Plane flight profile

All planes fly roughly the same with the only difference being the circularization burn/switchover moment:

- at 50-70 kph pull up and climb at 45* up to 10k

- at 10k lower the ascent angle to 30* up to 15k

- at 15k drop ascent angle to 10-15* and climb up to just over 30k

- hold at 30-33k while gaining speed.

- when you're at 2k+ surface speed pitch up slightly and bring up Ap as high as possible while lowering thrust to prevent flameout

- at 40-45k shut off jet engine and close air intakes

- at 50k/(or AP) switch over to circularization/travel propulsion

Depending on how well ascent is done fuel cost is between 70-100 of the 160 available and circularization can cost as little as 50deltaV

Example of a non-perfect ascent in my Flea SSTO presentation

Action Groups

Flea (Ion), Fly(RCS), Mosquito(Fuel)

1-toggle jet engine

3-toggle air intakes (all)

5-toggle ladders

Flea (Ion)

2-toggle ion engines

4-toggle solar panels (all)

Mosquito (Fuel)

2-toggle rocket engines

Download

SSTO Flea (Ion) <- with patience allot can be achieved with 3500deltaV budget

SSTO Fly (RCS) <- this is really a good plane to perfect jet SSTOs ascent (at least for my type of SSTOs)

SSTO Mosquito(Fuel) <- this is a fairly forgiving SSTO

Edited August 3, 2013 by carazvan
removing some links

[PotatoOverdose]

Here's my SSTO, the Gnat 7.

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60 Parts, 15 Tons, 6 air intakes, Stock (/w kerbal engineer), and can go all the way to Laythe from the runway without refueling. Requires some decent piloting, aerobraking, and orbital adjustments to get everything just right, but I've gone to laythe, flown around in the atmosphere, refueled on the surface, and returned 4 times with this craft so far.

The above album is an overview of my most recent flight.

Flight Plan to orbit:

Liftoff and gradual ascent to 45 degree inclination.

Maintain 45 degree inclination until 18km.

Level out at 18km keeping velocity vector slightly above horizon.

Run jets until your velocity is 1600m/s+ and you've spent 160 units of liquid fuel. Flight ceiling for jets is just over 28km. Best velocity I've gotten is 1850m/s under jets, but typically I get just over 1600m/s which is more than efficient enough to get to Laythe.

Once velocity and fuel amount is satisfactory, turn on the LV 909's, burn at 45 degrees until you reach desired apoapsis (70km+).

Once at apoapsis, prograde until you reach desired apoapsis (70km+).

Now use all that leftover delta V to go wherever you want.

Also: my first post on the forums.

[carazvan]

SSTO Ant Series

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Full description & download links in the Ant SSTO presentation

Edited August 3, 2013 by carazvan
updated link to v0.21

[PotatoOverdose]

Edit: Double Post

Edited July 22, 2013 by PotatoOverdose

[kahlzun]

Update: Made a tweak to my Swoop, making it the Swoop-Cargo, which carries 2 minimalist satellites into space!

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So, to tally up, that's:

4. Landing on KSC terrain. Pilot proficiency medal.

5. Landing on any KSC runway. Advanced pilot precision award.

6. Visiting other SOIs. Kosmokerbal Commendation.

7. Planetoid landings. Astrokerbal Distinction.

8. Payload to orbit. Utilitarial Commendation.

9. Payload to planet surface. Utilitarial Distinction.

It got a little dramatic in the end, I nearly ran out of fuel in space, and had to get a little lucky with Mun assists.

Edited July 22, 2013 by kahlzun

[pa1983]

This is my latest craft. People have been asking me for a video of how I build my crafts so I decided to make one sens I wanted to try some stuff out for future crafts. Its not my best craft so its more experimental.

I went with a low profile slim wing with closely mounted engine nacelles. This allows the wing to support it self with out the help of the fuselage or external struts and that was a must to accommodated the cargo hold or it would just collapse on it self from previous experience. The closely mounted engine nacelles allows fuel to be stored in them with out adding stress on the wings and the low profile wing in combination with the closely mounted engine nacelles allows for landing wheels to be placed optimally to take stress of the fuselage and wings. The Cockpit is mounted with a 10 degree down tilt to allow for IVA take of and landings and overall easier IVA flight. A probe core is mounted at the default angle to allow for a proper vector when doing burns in space.

It also has stock cargo bay doors that can open and close. Not my idea so I wont take credit for that. But they do help stiffening the fuselage when close.

The cargo bay is relatively long and can hold more jumbo tanks then the craft can carry but the intended cargo tends to be a lot longer VS weight then a few jumbo tanks so I wanted a long cargo bay, as long as posible. Benchmark payload was 63 tons and thats its max with out any further optimization to the craft. The craft is 99 ton dry weight so its not a light one due to a lot of I beams, many are cosmetic but most are structural. Further optimization with less esthetics's could reduce tonnage and increase payload capacity with 16 tons at least.

But I think its sufficient to lift my Explorer version 2 or a equally capable version of it sens it was about 58 tons. But a real mission has not been undertaken yet.

I call here the Falcon XII Skymaster Transport (didn't come up with anything better, names are not my thing)

Here is two videos, part 1 covers construction and part 2 is the test flight.

http://youtu.be/4epfP6F7AF8

http://youtu.be/NEKtKB76udA

Edited July 22, 2013 by pa1983

[Lazer Cut]

That's a slick looking transport. Holy damn, you gotta be the god of SSTO's!

Hope you don't mind if I try to incorporate some of your design elements into my own. I'll make sure to credit you with any uploads tough.

From a design perspective, I can easily see you tackle the situation very differently from me. Personally I just end up with a mk2 fuselage and tanks on the sides with engines behind, then cover it with wings and lift surfaces as well as making the wings themselves. Then I tweak it until I got an engine configuration that can take off, and provide enough delta-v to where I want to go. I guess this is the method most people do, and I would say it's a good method for small to mid sized SSTO's, but after that I'm not so sure anymore.

And regarding our discussion about intakes and jets, yes I do see your point, and my opinion on intake 'abuse' has been changed. I'm tired of trying to tweak with so much to avoid it, especially since it isn't even realistic. I hope that in the future versions of the game they will add in Ram and Scram jet types, since those are the only type of engines that would be suitable to use on SSTO's for high altitude supersonic speeds. The fact that most of those jet's can't function without air being 'rammed'(hence the name) into them, is an interesting challenge I would very much like to try out.

[pa1983]

If I recall, scram jets are pretty inefficient and requires high speed just to fire up. Those small once tested now are fired from a rocket stage so they fail as a ssto there already.

Simple reason why the saber engine for the skylon is a jet engine/rocket engine hybrid is because it has its own compressor and in effect is self sustaining once spooled up like any other jet engine, and its efficient despite its precooler.

Edited July 23, 2013 by pa1983

[Cinocal]

I appreciate you making the build video. How you build around the potential cargo weight to build it balanced and your fuel system setup are what I've been lacking when trying to efficiently build VTOL crafts.

No doubt this approach makes any build better from the get go, less trial and error. Also link to the stock hinge idea for the bay doors?

[pa1983]

I saw some pics on the forum. Show you awsome pictur thread I think it was. Or you could just dl my craft file, theres a link in the description of part 2. Usually I mount all the fuel tanks last and all in parallel with out stacking at the center of CG. That way cg is the same at all time.