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

[that1guy]

no, 4 turbo jets, 2 LV-T45s and 1LV-N Atomic Rocket. I mainly use the thing to do crew rotations from the surface to Gavia Station in LKO. But yeah, I could prlly have one go to minmus in the near future. Thanks for running this thread Booly

[boolybooly]

You're welcome that1guy, thanks.

Thanks also Col_Jessep for a new mission report, congratulations on taking the minimalist record for v0.22 and an Advanced Pilot Precision Award, not sure if you just missed out on the 1st Class due to reloading / replaying after docking difficulties or got it by carrying on after emergency undock? Let me know and I will update if necessary, currently left it out. Have you tried disabling SAS on both craft? I find this is often effective, though there are a few craft which oscillate even then, a quick timewarp to 5x and back usually settles it long enough to get stuff done. Allternatively disable some of the reaction wheels.

Edited November 8, 2013 by boolybooly

[barrenwaste]

Yay! I has done IT! Notice the capitals for it. That is because it is so amazing it must be spoken of with reverence and awe. It is the pinnacle of all space plane pilot achievements. It is really working hard to build itself up from being just a run to orbit and back. Nod nod nod.

Here is the craft in orbit.

Showing Periapsis.

Showing Apopsis. (I'm pretty good at circularizing. *dusts imaginary lint off shoulder*)

In Orbit!

Bill's hair is on fire! Quick, somebody get some jet fuel...wait...Water, get water!

And back planetside safe and sound..if with new nightmares.

Ok you lot, I did yer silly challenge, but I gots plenty of fuel left and lots of.....desert...to esplore, catch yalls later!

[Col_Jessep]

Thanks also Col_Jessep for a new mission report, congratulations on taking the minimalist record for v0.22 and an Advanced Pilot Precision Award, not sure if you just missed out on the 1st Class due to reloading / replaying after docking difficulties or got it by carrying on after emergency undock? Let me know and I will update if necessary, currently left it out. Have you tried disabling SAS on both craft? I find this is often effective, though there are a few craft which oscillate even then, a quick timewarp to 5x and back usually settles it long enough to get stuff done. Allternatively disable some of the reaction wheels.

I reloaded although I could probably have recovered the situation. Nothing was destroyed but I didn't want to start an race to EVA all 4 Kerbalnauts back to the Low Gravity Training Station. Frankly, I threw a little hissy fit. After I had put up that station as a target for my mission report, tweaked the rendezvous so close and went through all the (unnecessary) trouble to dock the damn thing starts to use my Kerbalnauts as bowling pins?!? I will fly a very large rocket with lots of fuel into that station one day...

Thanks for the tip with switching the SAS off, I only did that on the Ladybird. The station has reaction wheels in 3 of its 5 cans which might be the reason for the whole trouble. Hmmm...

[Rhomphaia]

I reloaded although I could probably have recovered the situation. Nothing was destroyed but I didn't want to start an race to EVA all 4 Kerbalnauts back to the Low Gravity Training Station. Frankly, I threw a little hissy fit. After I had put up that station as a target for my mission report, tweaked the rendezvous so close and went through all the (unnecessary) trouble to dock the damn thing starts to use my Kerbalnauts as bowling pins?!? I will fly a very large rocket with lots of fuel into that station one day...

Thanks for the tip with switching the SAS off, I only did that on the Ladybird. The station has reaction wheels in 3 of its 5 cans which might be the reason for the whole trouble. Hmmm...

The reason for the whole trouble is the docking port mounted on octagonal struts. That is Kraken bait right there. (cubic octagonals have the same problem)

[Col_Jessep]

Good to know, thanks!

[El wonso]

My entry with SSTO X1 Probe++ spaceplane.

Stock parts + mechjeb.

Achieved:

• Regular SSTO flight.
  
• Payload to orbit.
  
• Visiting other SOIs.
  
• Landing on any KSC runway.
  

Click for craft file.

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Edited November 9, 2013 by El wonso

[boolybooly]

Thanks for the clarification Col_Jessep, I will leave it as it is then.

Congratulations to barrenwaste for constructing a craft capable of completing the K-Prize challenge and landing safely, which is no mean feat btw! Thanks for participating and for your mission report with commentary. Your craft looks like it has an effectively high power to weight ratio and saves weight and complexity by using one tank for both engine types (twin aerojet with single aerospike clipped nuclear engine). Welcome to the K-Prize party guest list (aka roll of honour).

Congratulations also to El wonso for completing the K-Prize challenge with room to spare for an Advanced Pilot Precision Award for a safe landing at KSC runway, a Utilitarial Commendation for dropping 2 probes into Kerbin orbit and a Kosmokerbal Commendation for visiting the Münar SOI with SSTO X1 Probe++, a classic V wing design (which reminds me a little of the Vulcan), using the small radial rocket engines around a single central aeroengine. Thanks for your Imgur mission report and welcome to the K-Prize.

Edited November 10, 2013 by boolybooly

[barrenwaste]

Thanks Booly! That's not an aerospike, thought. That's an Atomic engine. I put three of the cubic struts inside the fuel tank so that it had just enough length to peek out the back without exploding on ignition. All told that plane has 28 parts, most as hidden supports or clipped parts. I didn't use the noclip cheat or devconsole or anything, it can all be done by somebody who just loaded up the game the first time.

[11Bravo49417]

This was a real challenge and a lot of fun. Took several tries and finally did it barely in a very lame craft that required much manual management. I really should have used action groups.

The plane uses a single turbojet for stability during flameout, and dual LV-909 for stability during boost.

Take-off and climb to 10k. Then reduce climb rate to build up speed and burn off excess jet fuel. Prepare the chinese fire drill called flameout.

Flameout. Turn on the rockets. Turn off the turbojet. Turn off the jet fuel. Pitch up. Keep control. Burn for Apo.

Establish Apoapsis. Turn off the electricity or you wont be able to maneuver for deorbiting.

Turn on the electricity. Orient the craft. Burn for Periapsis. Try not to vomit when the camera swings around wildly. Periapsis established. Turn off the electricity or you won't be coming down.

That's half the battle. Now for landing at KSC.

Wildly guess where you should start deorbit burn. Turn on electricity. Point at Retrograde. Turn off electricity.

Run out of liquid fuel at the precise moment you are happy with the deorbit burn. Try not to feel cocky.

Glide in like you did it a hundred times before. Debate whether to even use the turbojet. Come to your senses and turn it on.

Touchdown!

Success!

Thanks again.

[El wonso]

This was a real challenge and a lot of fun. Took several tries and finally did it barely in a very lame craft that required much manual management. I really should have used action groups.

The plane uses a single turbojet for stability during flameout, and dual LV-909 for stability during boost.

(...)

Try putting ram air intakes on these fuel tanks, that's going to give atmo engine a lot of air

[11Bravo49417]

That's worth a try. Currently using 6 of the scoops.

[sploden]

Here's my minimalist entry for .22. It should be the same weight as my previous version, except slightly lighter due to not having MechJeb onboard.

Minisistilikio 2

Parts: 12

Weight: 1.14

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[boolybooly]

11Bravo49417 thanks for your mission report and congratulations on completing the K-Prize mission with flying colours and an Advanced Pilot Precision Award for landing on the KSC runway with your classical and effective twin rocket single aerojet delta wing design. If you gave it a name I could edit the guest list btw as your description of your own craft was less than complimentary. I dont know if you noticed that you can keep the aerojet going longer by reducing throttle, thought it might be worth a mention.

sploden thanks for your mission report and congratulations on winning the K-Prize once again and acquiring the minimalist record in the process as well as an Advanced Pilot Precision Award with Minisistilikio 2. The orbit looked elliptical which suggests you had fuel to spare!

[11Bravo49417]

Thanks! The craft was named the Lame X for this run at the prize.

[numerobis]

The plane uses a single turbojet for stability during flameout, and dual LV-909 for stability during boost.

To not lose electricity, just turn off SAS.

Flight tips:

- Stay level at 25 km and build more speed; you should be able to hit about 1500 m/s there. Then pitch up about 30 degrees, and throttle back as you climb. With the intakes you have, you can maintain 1/3 throttle at 30 km. Go as high as you can, until your vertical velocity starts to get low; transition to rockets then. You can run both rockets and jets at the same time for a bit.

- Close the intakes when you transition to rockets. That will reduce drag quite significantly.

- On re-entry, you only need to get the periapsis down into the atmosphere, and let your orbit decay. In other words, you had extra fuel left. Pitch down as you reenter to have lift suck you further into the atmosphere.

Construction tips: the lower your mass (and drag), the faster and higher you can go off the jets. Also, the lower your mass, the less rocket fuel you need. Eventually, you can get so light that you can use lighter rocket engines, and save even more mass. It all snowballs.

Construction tips about your jet stage: when you transition to rockets, your airframe is currently 3540 kg not counting the rocket engines and rocket fuel tanks, and the cross-section area is 0.271 units not counting the wings or rocket bits. You can save 890 kg of that, and reduce the area to 0.106:

- Use the Mk2 cockpit rather than the Mk1 cockpit. Saves 250 kg, and has lower drag (despite the visual appearance). Unfortunately you lose the nice cockpit view.

- Use an Mk2 fuselage rather than the Mk1 fuselage. Your jet fuel at the transition to rockets had a mass of 350 kg dry mass + 380 kg fuel = 730 kg total. The same flight with an Mk2 would have 200 dry + 430 fuel = 630 total. Saves 100kg.

- In fact, given how much fuel you had left, you could use a "Mk2 to size 1 Adapter". You'll have 100 kg dry + 30 kg fuel = 130kg. Saves another 500 kg. This part of the advice conflicts with the flatter flight profile; it might not work out unless you save enough fuel from lightening up the airframe.

- A pair of ram intakes rather than 6 radials will save you a bit of mass, but get you just as much air. Saves 40 kg. Intakes have very high drag at speed, so while this looks like small potatoes, it significantly improves your top speed.

Rocket stage tips: your rocket bits currently are at 6,625 kg and provide 100 kN of thrust at Isp 390. This gives you a TWR of 1 at your 25km transition at 1 km/s.

- Use the 48-7S rather than the LV-909. Saves 800 kg, reduces thrust to 60 kN at Isp 350. Your TWR is now 0.72, but given the other changes you'll be much higher and faster: at least 30 km if not 35 km, and 1.5 km/s. So you should be fine.

- Bring much less fuel. Then you will get even higher and faster off the jets, and your rocket TWR will be higher.

[immelman]

Minmus and back to the KSC, far too exciting at the landing with a couple of minutes fuel left:

Takeoff:

Onwards and outwards:

Minmus:

Back at the KSC (just)

[boolybooly]

Thanks for your mission report immelman, glad you made it back and congratulations on your Advanced Pilot Precision Award and Astrokerbal Distinction for your Minmus landing with your twin aerojet with single aerospike design (does it have a name?) Welcome to the K-Prize guest list aka the honor roll.

[Cinocal]

One of my current favorite ships. The Gypsy Danger Mk4

Variable-sweep wings.

[boolybooly]

That is a very sleek and striking looking craft there Cinocal, a worthy gatecrasher if ever there was one! (My crashometer detected non stock lift, thrust and fuel parts. Nevertheless a well put together craft and effective on its own terms.) That is an interesting thruster arrangement, must have been quite difficult to get balanced working through the SPH. Thanks for your flight report and hope you dont mind being on the gatecrashers list.

[Cinocal]

Thanks.

Designed and flown using FAR, Pwings, B9 and Infernal Robotics.

[Cinocal]

Here is a stock entry.

Delta G2

[700NitroXpress]

I have 2 questions.

1. Can I refuel this craft in orbit at my orbital refueling station?

2. After the SSTO achieves orbit, can I fly it to another planet with an orbital tug, land on that other planet, take off from that other planet, use the same tug to get back to Kerban and land at the KSC?

[that1guy]

I have 2 questions.

1. Can I refuel this craft in orbit at my orbital refueling station?

2. After the SSTO achieves orbit, can I fly it to another planet with an orbital tug, land on that other planet, take off from that other planet, use the same tug to get back to Kerban and land at the KSC?

Short answer, no.

Longer answer, in order to achieve a K-Prize the rule of thumb -- besides being completely stock lifting body, fuel, and engines -- is that the craft brings everything that it needs for a mission with it. Or, put more simply, everything that goes up with the SSTO (except fuel used in flight) must come down with it too. However, looking back at your quote, you never mentioned that this was to be K-prize mission, so I suppose if you are looking for functionality of the craft, this could work. It just would disqualify the mission for a K-prize...

Hope this answered your question

[700NitroXpress]

Hope this answered your question

Yeah, that answers it.