SSTO Kerbin Orbital Shuttle - only 35 parts

[sturmstiger]

This is the SSTO orbital shuttle I use to send up to 3 kerbals to stations or interplanetary ships in Low Kerbin Orbit. As with my other designs, simplicity is a key feature - it's got only 35 parts and weighs less than 13 ton before takeoff. It's very easy to takeoff, controls smoothly in flight, and should have > 300m of delta V left after reaching 75km circular orbit - enough for LKO docking & deorbiting. It's got a probe core for uncrewed returned flights, 2xRTGs for electric power, a powerful headlight for docking & landing, and 40 units of monopropellent.

Craft file: https://www.dropbox.com/s/rgdiajx5ljm8c39/OrbitPlane.craft?v=0mcns

Hotkeys: 1. Toggle jet engine & intakes 2. Toggle the rocket engines

Flight instructions:

1. Apply break, turn on SAS, and start jet engine with full throttle. When jet engine power goes above 110KN release break. The plane should start moving when engine power gets ~112KN and will takeoff by itself before the end of runway.

2. Once it takes off, take gears up, release SAS and gently pitch up to ~30 degrees. You can then turn SAS back on, and it will ascent to around 20KM in ~10 minutes.

3. Pitch down to ~15 degress. At some point you may throttle down a bit to reduce air consumption. The 4x intakes allow it to fly to >28km & >1750m/s using jet power. Because it has only one jet engine, you don't need to worry about flameout, which are difficult to recover for planes with multiple jet engines.

4. When it reaches >28km and >1750 m/s, press 2 to start the rocket engines. The jet engine will flame out shortly, then you'll press 1 to turn it off. At this point you may want to pitch up a bit to get out of denser atomosphere quicker. When the apoapsis gets above your intended orbital altitude, stop the engines, and circalize when it reaches the apoapsis.

5. The plane usually have 30 ~ 50 units of extra jet fuel left which may used for landing. It should have a pitch of 5 ~ 6 degrees at the moment of touch down for main gears to touch down first but not scraping the engine nozzles.

Try it out and let me know what you think! Also take a look at my modular medium & heavy lift ELV family - up to 100ton to orbit with very few parts.

[Loocas]

Very nice! I'm struggling to even get an aircraft off the ground without spinning.

[sturmstiger]

Very nice! I'm struggling to even get an aircraft off the ground without spinning.

Thanks. And yeah building planes can be a more difficult than rockets in the beginning. Some tips to deal with your problem:

1. Turn on the CoG (center of gravity) and CoL (center of lift) indicator. Put the center of gravity a little bit in front of the center of lift makes the plane stable and prevents spinning when you pitch up.

2. Arrange you landing gears so that the plane would sit on the ground nose up - a 3 to 7 degree pitch is usually good. This will often allow your plane to takeoff "by itself" (without you pressing "s") before end of runway. Also when taking off, you may put the parking breaks on while you wait the jet engine to powerup - it will start moving once it gets to full power, and you'll then release the breaks.

3. If your plane is going sideways (left or right) during takeoff, even without any input from you, check if all parts are perfectly balanced & aligned along the center line. If they are then it's usually because of too much flex in the parts - consider removing parts (especially wings) too far from the body, or add struts to reduce the flex.

[Loocas]

Yeah, thanks. I already followed tips 2 and 3, but I will try number 1 now.

[longbyte1]

I like it. How long does it take to reach orbital velocity though?

[sturmstiger]

I like it. How long does it take to reach orbital velocity though?

About 15 to 17 minutes to reach flameout altitude (28.5km) and another maybe 2 to 3 minutes to reach stable orbit, depending on your ascent profile. However for most part of ascent you can leave it to fly by itself with SAS turned on.