My First SSTO spaceplane

[JonhyBee]

Hello guys,

I know you KSP old timers have seen them all probably a million times already, but ever since I have started KSP I have been obsessed with make a viable spaceplane.

Tonight I finally did it! This baby made it with just enough fuel for a clean re-entry and I will try a landing. I present the JonhyjetMk2

The take off is a little skechy tho. I need to jump off the run way and wait till I am going downhill near the sea... any advice?

Regards,

Jonhy

[rodion_herrera]

Congrats! I see you used the LV-N's, that's interesting. Good luck on re-entry and landing!

[rodion_herrera]

The take off is a little skechy tho. I need to jump off the run way and wait till I am going downhill near the sea... any advice?

Actually for me, that is a GOOD thing--it means it's a bit nose-heavy. Why is that good? Well if your fuel tank setup is one that lets most of the fuel flow back towards the rear of the craft, then it will eventually balance it out once fuel gets depleted, which is important after re-entry and setting up for landing, at least for my XRSTS-04E

[Scoundrel]

The take off is a little skechy tho. I need to jump off the run way and wait till I am going downhill near the sea... any advice?

Firstly, congratulations on getting your spaceplane into orbit! That's a great achievement, and it's very tricky to do. Secondly, post the craft file. For, uh, science reasons. And stuff.

Some design advice:

1) I would get rid of those big RCS tanks the nukes are attached to and use the little spherical tanks so you can balance your craft's center of mass better. It should only take 4 spherical radial tanks to balance that one by the nose. You're already a bit tailheavy with the nukes.

2) some people will suggest replacing the nukes with the little 50 thrust .5 ton engines - the 1m yellow and black landing-type engine whose name escapes me. you *might* find that if you do that, then you only need 1 of those jet engines, which means you can get rid of that ton or so worth of radial intakes and practically fly into orbit with that one jet engine alone. It will also help reduce the risk of losing your rocket engines on take-off or landing.

3) this is the big one: move your rear landing gear forward closer to the center of mass of your ship. You have enough wing for that mass that you should be able to rotate and get airborne long before you run off the runway. Also, hitting the brakes and waiting until the engines have spooled up to full throttle will cut your takeoff run by a fair chunk. If you find you have to really be "nose up" (pilots call it alpha, or angle of attack) before it lifts off, then you need to add a bit more wing. I like to use the intake nacelle under the aerodynamics tab to give my planes a little more length so I can do just that, since it also adds moar air.

That said, you should completely ignore all my advice and strap on a pair of SRBs (preferably the BACC) and a few lawn chairs so you can use it as a shuttle. Or a barbecue. Either works.

[Neotician]

The take off is a little skechy tho. I need to jump off the run way and wait till I am going downhill near the sea... any advice?

You could try changing the angle of the landing gear, so that the nose is pitched up a bit while you're on the ground.

Also, Jet engines increase in thrust slowly, you could try clambing the breaks until they're at full thrust and then release the breaks.

This should get you a higher velocity before leaving the runway

[Tripod27]

Firstly, congratulations on getting your spaceplane into orbit! That's a great achievement, and it's very tricky to do. Secondly, post the craft file. For, uh, science reasons. And stuff.

Some design advice:

1) I would get rid of those big RCS tanks the nukes are attached to and use the little spherical tanks so you can balance your craft's center of mass better. It should only take 4 spherical radial tanks to balance that one by the nose. You're already a bit tailheavy with the nukes.

2) some people will suggest replacing the nukes with the little 50 thrust .5 ton engines - the 1m yellow and black landing-type engine whose name escapes me. you *might* find that if you do that, then you only need 1 of those jet engines, which means you can get rid of that ton or so worth of radial intakes and practically fly into orbit with that one jet engine alone. It will also help reduce the risk of losing your rocket engines on take-off or landing.

3) this is the big one: move your rear landing gear forward closer to the center of mass of your ship. You have enough wing for that mass that you should be able to rotate and get airborne long before you run off the runway. Also, hitting the brakes and waiting until the engines have spooled up to full throttle will cut your takeoff run by a fair chunk. If you find you have to really be "nose up" (pilots call it alpha, or angle of attack) before it lifts off, then you need to add a bit more wing. I like to use the intake nacelle under the aerodynamics tab to give my planes a little more length so I can do just that, since it also adds moar air.

That said, you should completely ignore all my advice and strap on a pair of SRBs (preferably the BACC) and a few lawn chairs so you can use it as a shuttle. Or a barbecue. Either works.

Pretty much everything this guy said is good advice, although #2 is a bit conditional

Also this entire time I've been calling them SSAO (single stage atmosphere to orbit) so now I fell a little stupid >_>

[JonhyBee]

Wow thanks for all the great advices! The landing is... very tricky to say the least. I will have to improve on that design.

[JonhyBee]

3) this is the big one: move your rear landing gear forward closer to the center of mass of your ship. You have enough wing for that mass that you should be able to rotate and get airborne long before you run off the runway. Also, hitting the brakes and waiting until the engines have spooled up to full throttle will cut your takeoff run by a fair chunk. If you find you have to really be "nose up" (pilots call it alpha, or angle of attack) before it lifts off, then you need to add a bit more wing. I like to use the intake nacelle under the aerodynamics tab to give my planes a little more length so I can do just that, since it also adds moar air.

This really did the trick! I had put the back wheel on long struts cause I was worried about the LV-N hitting the pavement at rotation. Turns out there is a nice spot under thoses RCS fuel tanks to put wheel just under the CoM. Thanks for the advice it take off in less then 1/2 the runway now.