Alternative for Nerv rockets on SSTO's?

[PF45]

Hey everyone,

I'm sure the SSTO hype in the community has passed but I'm getting into a bit of an SSTO phase here. I've had success building several SSTO capable of Minmus missions (with mining) and returned to Kerbal. I find this challenge very rewarding and was wondering if there was a lighter alternative to the Nerv rocket. I've done some browsing and can't really seem to find anything as efficient but is lighter and produces more thrust. Of course, it's possible I've been over thinking things and the Nerv rocket is actually quite OP.  At any rate -- I'd like to play around with what ever is available. Any suggestions are greatly appreciated.

Cheers!

[Human Person]

Hmm. Your question is quickly answered: 

Terrier, Poodle, Aerospike.

also the Spark is pretty good because it's so lightweight.

 

But of course you won't get the delta V you would get with the LV-N. It's high specific impulse cannot be beaten, but it comes at the cost of a very low TWR.

Edited June 10, 2017 by Physics Student

[PF45]

Just now, Physics Student said:

Hmm. Your question is quickly answered: 

Terrier, Poodle, Aerospike.

also the Spark is pretty good because it's so lightweight.

Awesome, thank you for the quick reply! I'll give them a try! MFG!

[Wanderfound]

An addendum: while the Terriers/Poodles/etc are the most efficient space engines after the nukes, they aren't compulsory. Any motor you carry unused is dead weight; sometimes it's better to take the efficiency hit of a lower-isp rocket in order to avoid the mass penalty of an extra space-only engine.

For example:

OTOH, if I slapped a pair of nukes on that it could do Minmus and back on about half the fuel that this ship uses. It wouldn't have anywhere near the TWR, though.

[Spricigo]

1 hour ago, Physics Student said:

But of course you won't get the delta V you would get with the LV-N. It's high specific impulse cannot be beaten, but it comes at the cost of a very low TWR.

Well,  might be possible to get a higher deltaV with a considerable better fuel fraction. Problem is to get a reasonable fuel fraction carrying "useless"  jet engines,  fuel tanks and intakes around. 

[PF45]

23 hours ago, Wanderfound said:

An addendum: while the Terriers/Poodles/etc are the most efficient space engines after the nukes, they aren't compulsory. Any motor you carry unused is dead weight; sometimes it's better to take the efficiency hit of a lower-isp rocket in order to avoid the mass penalty of an extra space-only engine.

For example:

OTOH, if I slapped a pair of nukes on that it could do Minmus and back on about half the fuel that this ship uses. It wouldn't have anywhere near the TWR, though.

Cool, I'll experiment around with something like this -- thank you very much for the descriptive reply! 

[Aegolius13]

I'm sure there are exceptions, but I think most of the time, if you don't want nukes the best alternative is just to use the rocket mode on the Rapiers.  Sure,  the ISP is not the best,  but the mass and drag you have to add to include another chemical rocket engine is considerable.

If your plane was intended for really long range space stuff,  maybe a Dart or Poodle could close the gap.   But nukes are better for long range stuff anyway.   

[suicidejunkie]

The only thing with more Isp is the ion engine.  The only thing with better TWR is everything except the ion engine.

If you just want to get to orbit, Whiplash + Reliants will suffice.

 

IMO, the best part of using LV-Ns is that you can go pure LF, and never have unusable fuel types acting as dead weight, but the efficiency is a very close second.