Keeping a mun rover on the ground

[Perotis]

Would it work if I put some RCS thrusters on the top of my rover pushing it down?  Would that give me the stability I need to be able to drive around on the moon at a decent speed?

[Brainlord Mesomorph]

You can try - I don't think it will help.

I've been working on a tutorial for high-speed rover driving, currently unfinished at 6 pages. If you 'd like I'll send you the rough draft as a private message.

[Foxster]

You could do that but the fuel won't last too long. An ion engine is better. 

There's quite a few little tweaks to make your Munar rover more stable but a slightly sneaky way is to mount an (unused) jet engine like this. It has the effect of lower the CoM because the CoM of a jet engine is outside its body...

You can really get some speed up with something like this...

Edited February 8, 2016 by Foxster

[JoeNapalm]

 

They're supposed to stay on the ground?!

-Jn-

[Foxster]

3 minutes ago, JoeNapalm said:

 

They're supposed to stay on the ground?!

-Jn-

Well, I suppose so, but once you get over 100m/s that get's kinda optional 

[jonrd463]

I use the single nozzle RCS thrusters pointed down on each corner. It works quite well, but as mentioned, fuel is a concern. My rovers are usually used in the vicinity of a refinery base, so refueling isn't an issue. Never considered ion before, though. Might have to give it a try.

[LordKael]

My Mun rover used a jet engine to offset the CoM to below the surface, which makes a literally unflippable rover. That, coupled with a suitably wide base and nerves of steel, allowed Jeb to achieve almost 55 m/s and still be completely stable.

[Fearless Son]

2 hours ago, Perotis said:

Would it work if I put some RCS thrusters on the top of my rover pushing it down?  Would that give me the stability I need to be able to drive around on the moon at a decent speed?

Yes, that is the way that I do rovers.  It functions by increasing the effective frictional force of the tires on the surface, resulting in greater acceleration.  But they key here is acceleration, you do not need them on constantly.  This is how I make the monopropellant last, I only turn on the RCS thrusters when I need some extra "oomph" in my acceleration.  This includes things like going up or down a steep slope or trying to break from a high cruising speed before I begin making a sharp turn.  If you leave them on all the time, you will (as has been mentioned) quickly run out of fuel.  

Foxter mentioned ion engines, and I can see how those would give a nice, constant, fuel-efficient thrust, but I think that a limitation of that design is getting your rover enough power to run both the wheels and the ion engines at the same time and in enough conditions to keep going.  You would need to get pretty far into the tech tree to unlock those RTGs and the ion engine, and even then their cost is a concern.  So it really depends on cost/benefit analysis and mission profile.  

[Foxster]

Ah, but it's good for Jeb's Top Gear audition video...

 

[Fearless Son]

7 minutes ago, Foxster said:

Ah, but it's good for Jeb's Top Gear audition video...

 

Right up until just before end there I was thinking that would be a great craft for a Munar Elcano challenge...