Engines

[Lanley Kerman]

What is/are the best engines for transfer burns?

 

 

[AHHans]

Short answer: the ones that give you the best dV at an acceptable TWR.

Long(er) answer: It's complicated. a start would be to look at the discussion in this thread.

 

[jimmymcgoochie]

That depends on where you're transferring from and to.

For a short hop over to the Mun or Minmus, or back again, the Terrier is probably your best bet.

For transferring to other planets you can still get away with a Terrier if your rocket is small, but you'll probably need a Poodle for larger rockets. If you have the Making History DLC then the Wolfhound is also a good choice as it has the highest ISP of any stock engine- but it's also pretty heavy and so has a low TWR, making it better suited for rockets that are already heavy as the additional mass won't make as much of a difference.

The NERV engine has even higher ISP than any chemical rocket, but fairly low thrust and as it runs solely on liquid fuel you'll have to either use plane fuel tanks or (preferably) use a fuel switcher mod to make the regular tanks hold just liquid fuel- using the standard LF+Ox setup with no oxidiser is wasting over half the tank capacity.

If you're going really far and don't mind waiting, ion engines are the way to go- they're vastly more efficient than chemical engines and have stupendous range, but also have tiny thrust and require electric charge to operate. Best used on light probes, and due to their low thrust doing transfer burns can be a little bit dodgy as your trajectory can end up being markedly different than intended. If you're going anywhere beyond Duna, use RTGs for power as solar panels are much less effective further out (Gigantor orbiting Jool got me 2 power instead of the 24 it gets around Kerbin).

 

[Regor]

2 minutes ago, jimmymcgoochie said:

If you're going anywhere beyond Duna, use RTGs for power as solar panels are much less effective further out (Gigantor orbiting Jool got me 2 power instead of the 24 it gets around Kerbin).

 

That's odd; Solar power at Jool should be 25 times less, not 12?

[jimmymcgoochie]

1 minute ago, mabdi36 said:

That's odd; Solar power at Jool should be 25 times less, not 12?

Actually, now that you've said that, I do remember it being ~4% effective at Jool. 

[Regor]

Just now, jimmymcgoochie said:

Actually, now that you've said that, I do remember it being ~4% effective at Jool. 

Oh well, minor hiccups do happen!