Flat areas like polar caps or Minmus seas.

[magnemoe]

I'm playing around with rocket powered drag racers, finding that 450m/s is pretty much maximum speed on Kerbin because of drag.

I tested Minmus but the low gravity is an problem so I wonder if its very flat areas on Duna or the airless worlds. I tested Eeloo and its not flat enough.

Duna would be pretty nice as it has some gravity but not enough to generate serious drag, Val, Tylo or Moho would also be nice.

[Xaiier]

There are some canyons on Duna that are fairly flat I think. Vall is fairly flat but only for very short distances, with mountains between, Tylo isn't smooth and neither is Moho.

[Tex_NL]

Tylo! Jool's moon Tylo is where you want to go.

Tylo has large, perfectly flat areas, no atmosphere and a surface gravity of 0.8g.

[PUNiSH3R]

I can confirm that Duna's south pole is exceptionally far from flat; there's half a dozen mountain ranges that converge at the pole:

I designed that plane as a CESTOL specifically for Duna, and I barely got it back in the air after landing on the ice cap; there was hardly any room for a proper run up.

[magnemoe]

Tylo! Jool's moon Tylo is where you want to go.

Tylo has large, perfectly flat areas, no atmosphere and a surface gravity of 0.8g.

Tried out Tylo with hyperedit, and yes it has some pretty flat areas, but did not found any flat enough for +400m/s driving.

This is the kind of car I use

Downside with Minmus is that you will liftoff at high speed even with an decent down-force.

Yes an upside with minmus is that the car is safe at higher speeds.

I might want to look into more downforce

[Vanamonde]

The bottom of Duna's analog of the Mariner Valley has a flat bottom, but the valley turns here and there and might not give you a straightaway long enough for a good speed run.

[Taki117]

you could always download Planet Factory and make your own bowling ball.

[m4rt14n]

How bout Eve? Nice gravity and atmosphere to keep your craft from flying away?

[Tex_NL]

How bout Eve? Nice gravity and atmosphere to keep your craft from flying away?

I don't think Eve will be an option as drag was magnemoe's limiting factor when going fast on Kerbins poles.

I haven't been to Tylo in quite a while, but I can clearly remember some pretty big perfectly flat area's.

[celem]

Yeah you wont be able to get much past your current 450ms on Kerbin. Even adding FAR wont change things too drastically as the terminal V at sea-level is still fairly low.

I did something similar to you, rocket-powered cars are awesome. I use the Minmus flats usually for drag-racing. As you pointed out, downforce is the tricky bit. Seems from your screenshot that you are using RCS for the downforce. Depending on the mass of your car you may have more luck with LFO burning engines for that aspect. I use ants (lv-1) or the little rockomax 48S quite often to stick the thing to the ground, just dont get carried away and add too much downward thrust as i snapped a number of wheel-bases before 0.23 brought us thrust limiters.

I've long suspected that the reason (or part of it) why minmus drag-cars liftoff is that the curvature of that world is so small. If you enable SAS before starting your run then the car will slowly increase it's 'Angle of Attack' as you burn across the flats. It's trying to hold the heading you began with, which is now above the horizon. Try with the SAS off

Of course the other fun part of drag races across the minmus flats is that when (not if) you fail to stop in time, the slope at the end of the flat is often enough to punt the car into minmus escape (think Harvey Wedstone in The Darwin Awards and his rocket-powered Chevy)

Edited March 5, 2014 by celem