Nuclear engine on an SSTO?

[Raincloud Man]

Has anyone tried making an SSTO that uses just liquid fuel and the NERV yet? I did some trial runs but it seems that my test model can't get up to a high enough speed using its conventional engines to allow the puny 60kn NERVA to push it the last bit out of the atmosphere.

So is the solution to go bigger? I mean, I know the magic number lies somewhere in the 1.40-1.44 TWR inteval and just one nuclear engine won't get anywhere close to that, so I'd guess I need at least three engines to get the plane, and the NERVA to a high enough altitude for it to do anything useful.

[raydioactive]

you could make it a jet plane and then once your jets flame out, kick in the nuclear engines?
i've got a prototype, but it still needs some work:
https://drive.google.com/file/d/0B8eKM3yD8wl-X0VicHBWLUhRZnM/view?usp=sharing

[Surimi]

I've been struggling with this myself, and my feeling is it's going to be extremely hard without exploits. Plus, even if it works, you'll be spending so long trying to establish orbit with your nuclear engines that it's not necessarily going to be terribly efficient anyway, as you won't escape from drag or gravity as quickly as with conventional rockets.

I'm not sure going bigger will help much, as the bigger you go the more NERVAs you will need and those things are heavy. For this reason, I suspect the answer may actually be to go smaller, carry much less fuel than you normally would and hope that the efficiency gain from the NERVA compensates.

[Raincloud Man]

Originally posted by Deep Hurting:

I've been struggling with this myself, and my feeling is it's going to be extremely hard without exploits. Plus, even if it works, you'll be spending so long trying to establish orbit with your nuclear engines that it's not necessarily going to be terribly efficient anyway, as you won't escape from drag or gravity as quickly as with conventional rockets.

I'm not sure going bigger will help much, as the bigger you go the more NERVAs you will need and those things are heavy. For this reason, I suspect the answer may actually be to go smaller, carry much less fuel than you normally would and hope that the efficiency gain from the NERVA compensates.

I meant going bigger as in adding another rocket engine dedicated to takeoff, like an aerospike or something... Then again I guess you could also cheat by having the middle engine attached to a docking port, and then jettisoning it and attaching a nuclear engine in orbit!
Actually, with KAS and KIS that might actually be an idea, even though I'd have to extend my cargo bay a little to have one onboard. I could have a crew of two kerbals and then swap engines once I leave the atmosphere!

[El Rushbo]

Originally posted by Zagreus:

I meant going bigger as in adding another rocket engine dedicated to takeoff, like an aerospike or something... Then again I guess you could also cheat by having the middle engine attached to a docking port, and then jettisoning it and attaching a nuclear engine in orbit!
Actually, with KAS and KIS that might actually be an idea, even though I'd have to extend my cargo bay a little to have one onboard. I could have a crew of two kerbals and then swap engines once I leave the atmosphere!

I actually considered working something like that myself. My idea would revolve around the NERV being stored at an orbital facility which the SSTO would reach, then I simply detach the conventional rocket, attach the NERV and off I go. When returning to Kerbin I'd simply remove the NERV engine and put the rocket back in place.

[whatdoesthisbuttondo?]

There is a mod that has a couple of nice MK2 adapters, you could use a triple adapter and go with rapiers for establishing orbit, and use the NERV just for orbital maneuvering.

I really don't see it being terribly efficient any other way, and even if just for orbiting, that's another 3 tons you need to haul up, plus the more complex fuel considerations.