Magnetoplasmodynamic thrusters

[Markush100]

I recently got the Near future propulsion mod, and i have to say its pretty good. but one thing that i found very strange were the magnetoplasmodynamic engines.

1. They use lithium, and the smallest tank is 1.25 meters, but the smallest engine is 0.635.
2. The EC drain. 400 for a 0.635 engine!? i get that this is a very EC heavy engine, but getting that much EC is crazy. I have to slap on a garnet fission generator, or tons of huge solar panels which will reduce my TWR to like 0.5
3. I find it far more efficient to use some VASMIR engines paired with a lot of batteries and capacitors.

I may not find the point but can someone please tell me a practical way to use these?

Edited March 24, 2016 by Markush100

[Streetwind]

Well, what kind of TWR did you expect out of an electric engine? 0.5 is huge for those. That's comparable to chemical rockets with 1/10th the Isp. You probably measured that without payload.

The thing with Near Future's engines is, they are not designed to always be vastly better than stock engines. There's a lot of engine options, with various different stats, which suit different kinds of vessels and playstyles to different degrees. But there exist cases where chemical or even NTR is a competitive or superior choice... while at other times, the electric engines win out. The times they win out usually involve dV as a metric of interest, not TWR. You then pay a markup in funds for the privilege. All this is by design.

Why 400 Ec/s in such a small form factor? Beause it's unusual and interesting, giving you a design challenge while avoiding to have a parts pack full of identical engines with different graphics. Also, all engines have the weight of a matching reactor and its required radiators factored in when deciding on a stat distribution. The MPDTs only have so much thrust precisely because pushing their own reactor around is factored in.

Why isn't it 1.25m? Because there's already a different, much stronger MPDT at 1.25m, and yet another one at 2.5m. Again, variety is the spice of life, and opens up additional construction options and clustering styles.

VASIMRs more efficient? Of course they are, they run at higher Isp, and they're one or two tech levels higher up the tree! But they do give you less TWR per Ec invested...

And finally: lithium fuel was only just introduced in the very latest update. The stats on the MPDTs were tentative. Turns out they were a little weak. They'll get buffed come 1.1. That update will also include a comfortable pre-packaged way to tweak all the electric engine thrust levels higher (or lower), if you like to play that way.
 

(As an aside: I'm pleased you like to build buffer setups with capaitors. Too few people realize the potential these things have. )

Edited March 24, 2016 by Streetwind

[Markush100]

11 hours ago, Streetwind said:

Well, what kind of TWR did you expect out of an electric engine? 0.5 is huge for those. That's comparable to chemical rockets with 1/10th the Isp. You probably measured that without payload.

The thing with Near Future's engines is, they are not designed to always be vastly better than stock engines. There's a lot of engine options, with various different stats, which suit different kinds of vessels and playstyles to different degrees. But there exist cases where chemical or even NTR is a competitive or superior choice... while at other times, the electric engines win out. The times they win out usually involve dV as a metric of interest, not TWR. You then pay a markup in funds for the privilege. All this is by design.

Why 400 Ec/s in such a small form factor? Beause it's unusual and interesting, giving you a design challenge while avoiding to have a parts pack full of identical engines with different graphics. Also, all engines have the weight of a matching reactor and its required radiators factored in when deciding on a stat distribution. The MPDTs only have so much thrust precisely because pushing their own reactor around is factored in.

Why isn't it 1.25m? Because there's already a different, much stronger MPDT at 1.25m, and yet another one at 2.5m. Again, variety is the spice of life, and opens up additional construction options and clustering styles.

VASIMRs more efficient? Of course they are, they run at higher Isp, and they're one or two tech levels higher up the tree! But they do give you less TWR per Ec invested...

And finally: lithium fuel was only just introduced in the very latest update. The stats on the MPDTs were tentative. Turns out they were a little weak. They'll get buffed come 1.1. That update will also include a comfortable pre-packaged way to tweak all the electric engine thrust levels higher (or lower), if you like to play that way.
 

(As an aside: I'm pleased you like to build buffer setups with capaitors. Too few people realize the potential these things have. )

That makes sense, i may try to make a MPD craft now, only with a ton of capacitors.

I know that dV is the point of the engine, but with a bad TWR, timing a burn is hell to me.