Rover design

[Warzouz]

As 1.1 approaches, I'm starting to wonder on what to design in my next carreer game. On the previous one I sent a probe carrier around Eve with 8 dropable 2.5 science probes.

For my next career, I want to do better, I want to carry ROVERS, maybe 4 per trip.

I was wondering about their design and especially electricity. The most efficient wheels seems to use 0.7e/s. As I like standard build, I want to do a PB-Nuke rover not a solar one (I had bad experience landing solar probe on Eve pole and getting no direct sun because of surrounding hills..).

• Does wheels use 0.7e/s per wheel ?
• In that case should I build a 2 wheel rover helped by 2 additional landing gears ?
• If I understand, top speed is around 23m/s and tire blow if I go over 60m/s (means I fall ?)
• I was wondering about structural fuselage and sticking equipment on it. Stack probe up front and stack battery at the back.
• For vac bodies, I'll add a skycrane stage (and hope not to blow tires on landing)
• For atmo bodies, I'll go with the heat shield and small deorbiting engine.

Do you have some suggestions ? mistakes not to do ?

[Snark]

42 minutes ago, Warzouz said:

Do you have some suggestions ? mistakes not to do ?

Rovers eat a lot of electricity.  Are you planning on doing long cross-country journeys where you go halfway around the planet, or just pootling around a few kilometers?  If it's the former, you need to make sure that you have enough electricity to run continuously at full power.  If it's the latter, you don't need so much electricity generating capacity, as long as you have a reasonable amount of battery storage.

I usually power my rovers solar-only (unless I'm out beyond Duna where solar = teh sucks). PB-NUK is fine, but you'd need a lot of them to do continuous full-power rover exploring.

My usual rover designs for vac worlds have a few of the retractable 1x6 solar panels mounted in a V shape, tilted about 30 degrees above horizontal to keep them well clear of the ground for when I may tumble a bit.  For worlds with an atmosphere, I tend to use a fair number of OX-STAT panels on the back of the rover, so that I can keep generating some electricity even when in motion... but I still include a couple of the retractables, which I can extend when I stop in order to charge up more rapidly.

Your main concern with breaking wheels is not going too fast as in "I went over 60 m/s and they can't handle that much", but rather the bumpiness of terrain:  hitting a sudden speed bump can break your wheels even if you're going fairly slow.  It matters a lot how smooth the terrain is, which varies a lot from planet to planet.  If you're on the Minmus flats, knock yourself out.  :-)  Otherwise terrain is a concern.

Another wheel-breaking worry besides just how bumpy the terrain is, is how massive your rover is, i.e. how many tons per wheel.  More massive rover = more inertia = more strain on the wheels when you hit a bump = more likely to break.  If you have a very lightweight rover, wheel breakage is much less of an issue than with something massive.

The "ruggedized" wheels you get at tech 550 are a lot more breakage-resistant than the simple ones you get at tech 300, so use those if you possibly can.  The fragile ones are certainly usable, but you have to baby them a lot more. In particular, your effective max speed over terrain will be lower for the low-tech wheels, because you'll have to go slower to avoid breaking them.

When placing wheels, make sure you give yourself plenty of ground clearance-- your rover body will "sink" quite a bit when the suspention bottoms out as you go over rough terrain, and you don't want anything other than wheels to touch the terrain while you're zipping over it.  In other words, if you're using a cylindrical 1.25m rover body, don't mount the wheels directly on the left and right sides like a lizard's legs; you want them a bit underneath.  I usually mount my wheels radially about 45 degrees below the left and right sides, then use the rotator widget to adjust the wheels so that their axis is parallel to the ground.

Incidentally:  All of the above advice is based on 1.0.  From what Squad has said in their devnotes, apparently wheel physics will be getting a major overhaul in 1.1 due to the Unity engine change, and I have no idea what the experience will be like in 1.1-- about the same?  more breakage-prone? less breakage-prone?  No clue.  So take all this advice with a grain of salt until 1.1 is out and there's more data on what the experience is like.

One absolute must have for a rover:  put a headlight on it.  The long-range spotlight, not the short-range floodlight.  You need to be able to see where you're going, bumps can kill you.  Without a headlight, you basically have to sit around doing nothing any time the sun is lower than about 15 degrees above the horizon, 'coz you just can't see where you're going.

If you're roving on Eve, I suggest putting some stubby fixed wings on the left and right sides of the rover.  Doesn't need to be a lot.  You can glide suprisingly well-- enough to land with when descending from space, for example, and when you come to a steep downslope you can glide there, too.

 

42 minutes ago, Warzouz said:

I was wondering about structural fuselage and sticking equipment on it. Stack probe up front and stack battery at the back.

That should work pretty well.  I'm a big fan of the structural fuselage-- light, stiff, strong.  Gives you some wheelbase to make it less likely to tumble.

42 minutes ago, Warzouz said:

If I understand, top speed is around 23m/s and tire blow if I go over 60m/s (means I fall ?)

Top speed is about that, yes.  Tires will definitely blow over 60 m/s, even if you're on perfectly level ground.  But in practice, if you're going over anything but Minmus flats, you're going to have to go way slower than that.  Bumps in the terrain smack hard.  In practice, I find going faster than 18 m/s is very risky unless I'm watching the terrain like a hawk and ready to slow down any time there's an irregularity.  If you have heavy loading per wheel, the safe limit may be lower than that.

Also:  it takes forever to get anywhere in a rover, so you'll find yourself wanting to use physics warp to speed things up.  It does... but it also makes your rover more fragile and tires more likely to pop, so your safe speed limit will be somewhat lower in m/s if you're running with physics warp.

42 minutes ago, Warzouz said:

For vac bodies, I'll add a skycrane stage (and hope not to blow tires on landing)

That works.  Actually, for small science rovers, what I like to do is not bother with a skycrane, and just put a little engine (like a Spark) on the rear of the rover, with a small fuel tank like an Oscar.  The small amount of weight doesn't bother the rover much, when it's landed.  The rover just lands itself, coming down tail-first to a soft landing, then rotates down to the horizontal.  Simple, easy, lightweight.  It also can be handy when you get into a region with steep hills and can use a bit of a rocket boost to go up.  Or if you're running around at high speed on a low-grav world and accidentally go flying off a hill crest, and fall a long way, and are plummeting wheel-breakingly fast towards the surface; you can use a rocket assist to slow down.

(I actually like to put a taillight on my rovers like this, and then in the "Action" tab of the VAB, I deliberately take the taillight out of the "Light" group and put the light into the "Gear" group.  That way, the light serves as my "landing gear" to provide a visual reference when landing, extremely helpful in gauging my distance from surface when I'm on final approach.  And it toggles on/off separately from the headlight, which is in the Light group.)

 

[HebaruSan]

• If you intend to drive with WASD, remember to turn off any reaction wheels to avoid rotation while you're steering.
• The farther apart your wheels are, the more stable your rover is. An I-beam sticking off the side may look foolish, but you'll have the last laugh when you're able to go a kilometer without a quickload.
• You can toggle brakes per wheel. Disabling your forward brakes can prevent your rover from flipping when you try to stop it.
• Bring a high level Engineer to repair your wheels.
• Fuel cells and ISRU might be a viable alternative to solar or RTGs, if you're patient.
• The surface prograde vector is bugged pre-1.1 (and I think they said it'll be fixed in 1.1); it looks like your surface velocity is applied twice, so don't completely trust the navball.
• It really does take a very, very long time to get anywhere, and it doesn't help that you have to babysit your velocity with W, S, and B thanks to the lack of throttling for wheels.

Not quite rover specific, but I only tend to forget it with rovers:

• You need crew for optimum science collection (crew reports, EVA reports, and surface samples), and you can't get crew reports from a command chair; it has to be an enclosed pod.

If you're OK with "cheating":

• Minmus's solar occlusion model was a bit bugged at one point; if they haven't fixed it, consider solar panels on the bottom of the rover for nighttime operation on Minmus.
• Jet engines have a center of mass outside the actual model, which some people have exploited to give rovers a very low center of mass for added stability.

[Warzouz]

Thx for your answers.

I was also thinking about retrofitting my usual lander with wheels. I'll test that too.

I'll do some Kerbin testing.

And BTW : do you design rovers in VAB or SPH ?

Edited March 17, 2016 by Warzouz

[HebaruSan]

6 minutes ago, Warzouz said:

And BTW : do you design rovers in VAB or SPH ?

SPH is marginally easier since it gets you a horizontal orientation and mirror symmetry by default, but I transfer to VAB to build the launcher.

[Warzouz]

OK, here is my starting base.

• Front wheel : no motor, brake = 100, steering
• Rear wheel : motor, no steering, brake = 600

It's reasonably stable. To flip on braking. Only flips on hard turns, but I've time to correct. Autonomous.

[Warzouz]

Ok, that was easier than expected !

Here is the science rover "Doggy One" (every science equipment except Material Study), equipped with the Tylo-rated Skycrane (tested on Kerbin).

Rover is 875kg and 3660kg with Tylo Skycrane (2700m/s, TWR=1.25)

Atmospheric analyzers are useless, but look nice

Now I've to develop a variant for Eve and Laythe with a heatshield. I suppose this version will do for Duna. No need for chutes and heatshield.

Some more test :

• The rover can land by hitting the ground at 10m/s, not tire blast.
• Braking hard doesn't flip the rover. But it can if the skycrane is still attached.
• The rover can flip while jumping
• X4 physic warp is... dangerous

Edited March 17, 2016 by Warzouz

[Vim Razz]

Lots of good stuff in this thread.

If you plan to spend a lot of time rovering, it might be worth mapping a set of drive controls to something other than WASD.  I've got them on the arrow keys (with camera controls re-mapped to the number pad) with "roll" double-bound to left and right so that rovers with reaction wheels lean into the turn.

Also, you can use trim control on drive keys (ex: hold alt+forward to set in forward acceleration, alt-x to clear).  Using trim this way works the same as rotational trim (the longer you hold, the stronger the setting), but there are no UI indicators to tell you what your current drive trim settings are.

 

[Snark]

4 hours ago, HebaruSan said:

If you intend to drive with WASD, remember to turn off any reaction wheels to avoid rotation while you're steering.

Actually, that brings up an excellent point I forgot to mention.

First, opinions vary on this, but for me:  I like to put some powerful reaction wheels on my rovers, especially if they're on a low-gravity world (meaning pretty much anywhere but Eve).  Rovers tumble easily in low grav, and the best defense against this is strong SAS.  However, doing this means I definitely need to remap the keys.  I like to remap the rover controls (forward, reverse, turn left, turn right) to the numpad, so that I can drive and steer with both the torque controls WASD as per usual, in concert with the rover controls on the numpad.

On Eve it doesn't matter much, the gravity's so string that your rover stays pretty much glued to the ground.

3 hours ago, Warzouz said:

OK, here is my starting base.

Nice start!    Making it a bit longer front-to-back would help a lot with resting a flip when braking hard.

1 hour ago, Warzouz said:

Here is the science rover "Doggy One"

Nice!  Like the skycrane. 

Suggestion, put a reaction wheel on the rover itself-- will help with stability, as long as you map the rover steering controls away from the WASD torque controls.

[Warzouz]

I'll add a small reaction wheel upfront and a material lab at the back. The rover will be around 1 ton. Crane will be OK, but Tylo crane may qualify as low TWR.

I'll test it on Minmus.

I have a idea for a 4 rover carrier. The carrier will be equipped with science to do high and low non reusable science + a survey scanner. The carrier is designed to be deployed into polar orbit.

Total carrier weight should be around 20 tons (Tylo crane version). I'll be able to send it easily anywhere.

 

Do you have any idea for a design with heat shield (I think I could stick it on top of the crane with a decoupler so it would reenter up front and the crane would still be usable with the shield to maneuver and deorbit. Further more, that would still fit in my carrier. Chutes could be added on the crane.

But as I increase the size of the rover, wheels may be out of the shield.

 

EDIT : Hopefully wheels behave strangely. As the rover flip while braking, I was doing a classic thing : rdecung brake force on front wheel. That mainly solved the forward flipping on Kerbin. But as I added the crane, I tested the brakes again. and it flipped. That make basically no sense as forward wheel don't brake. Braking could have been less effective and may result in lateral control loss but not flipping forward.

I hope 1.1 will improve wheels.

 

Edited March 18, 2016 by Warzouz

[Geschosskopf]

19 hours ago, Warzouz said:

I was wondering about their design and especially electricity. The most efficient wheels seems to use 0.7e/s. As I like standard build, I want to do a PB-Nuke rover not a solar one (I had bad experience landing solar probe on Eve pole and getting no direct sun because of surrounding hills..).

• Does wheels use 0.7e/s per wheel ?
• In that case should I build a 2 wheel rover helped by 2 additional landing gears ?
• If I understand, top speed is around 23m/s and tire blow if I go over 60m/s (means I fall ?)
• I was wondering about structural fuselage and sticking equipment on it. Stack probe up front and stack battery at the back.
• For vac bodies, I'll add a skycrane stage (and hope not to blow tires on landing)
• For atmo bodies, I'll go with the heat shield and small deorbiting engine.

Do you have some suggestions ? mistakes not to do ?

1.  Yup, the ruggedized rover wheels currently use 0.7 EC/sec at full, continuous power.  This might change in 1.1 in the wheel overhaul but I don't know.  An RTG makes 0.75 EC/sec, enough to run the wheel and have some left over (especially due to the excess from the RTGs running the other wheels) for the probe core, SAS, and lights.  HOWEVER, RTGs cost $23K each or so, meaning even a small probe rover weighing less than a ton will cost about $100K.  Of course, RTGs are at the end of the tech tree so by then you can afford such extravagance.

HOWEVER, you normally only run the wheels continuously when going up long hills on relatively high-gravity planets.  If you're going to a low-gravity place, and/or avoid climbing mountains, and/or have a big battery capacity, you can usually get by with fewer RTGs.

2.  It's generally better to have all the wheels the same type, for stability reasons.

3.  Yup on the speeds.

4.  I tend to put the important guts of probe rovers in the middle and keep the ends as light as possible.  First, this protects the important bits from ground impacts.  Second, it makes the rover easier to get back rightside up if it flips.

5.  Skycranes don't work well with carrying multiple rovers per ship.  I find it a lot easier to use radially mounted tanks/engines.  These are attached to the main rover body by the Hardpoints, the only radial decouplers that leave no residue.  This enables stacking several rovers atop each other, all neatly nested and enclosed by the same fairing.  Such as this:

Also note that each rover has 2 probe cores.  It has a 1.25m core amidships  (between the SAS and battery), and it has a 0.625m probe core mounted horizontally on top.  The 1.25m core is for driving, the 0.625m is for landing.  You switch from 1 to the other as needed so the navball is aligned correctly when what you're doing.  When adding the landing probe core, it appears in the SPH on edge.  Hit the S key 1 time to level it.  This puts it facing the correct direction for navball purposes.

The landing core is also the point of attachment between stacked rovers.  Each rover also has a 2nd cubic octagonal strut on the belly.  Put a 0.625m stack separator (the blue ring) on top of the landing probe core, then set the next rover's belly strut on top of that.  Thus, no residue from separating the rovers, either.

5.  Another way to land rovers in atmospheres is to mount them vertically atop a normal lander.  Once on the ground, the lander tips itself over thanks to a clever arrangment of legs so the rover is more or less horizontal and just above the ground.  Then release the rover.  This way, the rover only needs a driving probe core, but the lander needs its own stack core for flight.  However, this method only really works for 1 rover at a time.

[radonek]

My 2c to lots of good stuff here:

• stick things down to have CoM low. Especially those heavy PB-Nuks.
• so you pushed everything down and have CoM almost touching ground? Great, now move camera to forward view and move things back up a bit to have more ground clearance.
• while having landing light is good, having more is better. You see big splotch of light first which then separate to distinct beams. If you angle them correctly, it give good perception of height even in complete darkness.
• weight is a factor too. if your wheels get often broken by small bumps, add more wheels to distribute weight more.
• have some  spare torque. If I see rover is going to flip, I just bash F key and only then I start thinking how to recover. Minums rover definitely should be able to turn itself over.
• think about what will be softest part on each side of your rover. Especially lower front can get into contact with terrain when breaking hard. Also bottom of four-wheelers can get hit while going over sharp edges.
• not sure about wings on Eve. If they have enough lift to be useful, they will just the same make you more flip-prone. Never tried that though.

[Kerbal101]

I hate stock wheels... They do only 10-20 m/s and can unexpectedly break

Thats why my rollers are made of girders, empty RCS fuel tanks and joints from Infernal Robotics. These come earlier in carrier mode and can easily carry over 80 tons at 30 m/s, without risk of braking.

[Warzouz]

Thx

BTW I've changed the wheels to reduce flip

• Front wheels : steering and motion
• Rear wheels : braking

As I use only 2WD and not 4WD, I only need 2 PBNuke and not 4. And mixing wheels and landing gear didn't do well. I started on the runway with the wheel IN the ground and I could get out of it. When I used 4 wheel, not problem.

As for the unflip device, I tried the landing gear on top, but that hit the crane and blew everything. I'll do some testing to see if the rover is usable. I was also considering RCS thrusters.

I'm not sure about stacking the rover on top of each other. As I intend to increase it's length, that may not fit. I'll try a carrier design this evening. 4 rover may fit around a central axis, I may have to offset 2 by 2. I'll dig into it.

Objectives for this evening :

• Add reaction wheel control to Doggy One
• Increase length by adding a small lab
• Test on Kerbin
• Test in Minmus
• Design the carrier for 4 doggy rovers (should be quite light but very bulky)

And BTW, here is the name of my rover design

• Doggy : the actual rover
• Leash : the sky crane (which comes in 4 variations)
• Pack Master : the carrier probe in low polar orbit

[juanml82]

There is another issue with rovers in Eve. Due the strong gravity, if you're driving downhill, the rover can speed up very fast and, once it's above 50 m/s, the wheels will break

[Snark]

4 hours ago, Geschosskopf said:

These are attached to the main rover body by the Hardpoints, the only radial decouplers that leave no residue.

It's true they leave no residue... but residue doesn't matter much (at least, not to me), because it's ephemeral.  The moment you save and reload, or switch back to KSC or some other ship and come back, the residue evaporates.  So, if I can eliminate the residue in a few seconds with two keystrokes, I tend not to worry about it much. 

4 hours ago, Geschosskopf said:

4.  I tend to put the important guts of probe rovers in the middle and keep the ends as light as possible.  First, this protects the important bits from ground impacts.  Second, it makes the rover easier to get back rightside up if it flips.

Agreed with this.  Plus, there's a third benefit you didn't mention:  putting most of the mass in the center means the rover has a lower moment of inertia, which in turn means it requires less torque to turn, which in turn means that when you hit a bump with your front wheels, the wheel suspension takes less of a "shock" and you're therefore a little less likely to bust a wheel.

 

2 hours ago, radonek said:

not sure about wings on Eve. If they have enough lift to be useful, they will just the same make you more flip-prone.

No flipping problem at all.  I've used 'em on Eve, they worked great.  Stubby wings, is the thing.  Mount them on left and right, putting the CoL just slightly behind the CoM.  No problem at all.  It only takes a tiny amount of wing to be able to glide on Eve.

11 minutes ago, juanml82 said:

There is another issue with rovers in Eve. Due the strong gravity, if you're driving downhill, the rover can speed up very fast and, once it's above 50 m/s, the wheels will break

This is one reason I like to put stubby wings on Eve rovers.  If you start to go too fast, just pull up and glide gently and slowly until you get down to where the slope levels out.

[Foxster]

23 hours ago, Warzouz said:

As 1.1 approaches...

Sorry, matey. Would like to help but I just can't read a thread with your profile picture in it. I'm sure this is a problem with me but it just makes me feel nauseas. 

[Geschosskopf]

3 hours ago, Warzouz said:

BTW I've changed the wheels to reduce flip

• Front wheels : steering and motion
• Rear wheels : braking

As I use only 2WD and not 4WD, I only need 2 PBNuke and not 4. And mixing wheels and landing gear didn't do well. I started on the runway with the wheel IN the ground and I could get out of it. When I used 4 wheel, not problem.

These things are not hard-and-fast rules or even best practices, but are things you can use or not depending on circumstances.  Lots of folks seem to treat them as dogma but they're really not.  For example, steering.  4-wheel steering is essential for maneuvering in tight places or where you need precise positioning (like docking to a base).  And it causes no problems at any other times if you know how to drive.  Trying to turn hard at high speed will flip you even with 2-wheel steering so I count this one as a myth.

It's largely the same with 2-wheel vs. 4-wheel braking.  The only reason to have no front brakes is if you routinely stomp the brakes at high speed.  If you just tap them, and do a lot of your slowing with reverse drive instead of brakes, you don't need to worry about flipping when stopping very much.  HOWEVER, this depends a lot on the type of wheel you're using.  Some wheels are much more grabby than others so do some test drives.  And remember, there's a right-click adjustment for brake torque you can use.

As to 2-wheel vs. 4-wheel drive, the viability of this varies with the weight of the rover, the steepness of the terrain, and the gravity of the planet.  If the rover is light enough, and the hills aren't too steep, you can get away with it.  But in other cases, you'll need more oomph to go where you want to.  Also, the best braking comes from applying reverse drive while moving forward and the more powered wheels you have, the better braking you have.

3 hours ago, Warzouz said:

As for the unflip device, I tried the landing gear on top, but that hit the crane and blew everything. I'll do some testing to see if the rover is usable. I was also considering RCS thrusters.

There's no point in having a mechanical un-flip device.  They don't work on any place with high gravity and on places with low gravity, they work too well.  It's best just not to flip over to begin with, which is mostly a matter of not driving like a drunken, texting teenager.  But if you flip on a low-gravity place, if torque alone won't flip you back, you can just use a little RCS.

 

59 minutes ago, Snark said:

It's true they leave no residue... but residue doesn't matter much (at least, not to me), because it's ephemeral.  The moment you save and reload, or switch back to KSC or some other ship and come back, the residue evaporates.  So, if I can eliminate the residue in a few seconds with two keystrokes, I tend not to worry about it much. 

But the Hardpoints have other advantages over other radial decouplers.  First is their shape, which is VERY convenient for positioning the tanks where you want them.  Second is that you can remove them from the staging menu so you don't accidentally fire them before you're ready.

20 hours ago, Vim Razz said:

If you plan to spend a lot of time rovering, it might be worth mapping a set of drive controls to something other than WASD.  I've got them on the arrow keys (with camera controls re-mapped to the number pad) with "roll" double-bound to left and right so that rovers with reaction wheels lean into the turn.

Yes, remapping the driving keys is very useful and important.  It tends to minimize adverse roll and yaw when turning, it allows you to do pitch and roll corrections easily mid-jump to land flat aftwards, and you can use both torque and steering as needed to turn, or 1 or the other.

 

 

[Warzouz]

Minmus test : that was much less fun than I expected. I don't understand why, the the rear of the rover is lifting when I accelerate. Torque partially compensate. Rover is 1.1T.

EDIT : Remapping steering solve this issue : it's VERY important to remap the keys

Brake works fine, no flipping. But on stop, with brake on, the river starts to jiggle.

EDITs : well, that mountain was very far....

 

[Snark]

1 hour ago, Warzouz said:

Minmus test : that was much less fun than I expected. I don't understand why, the the rear of the rover is lifting when I accelerate.

EDIT : Remapping steering solve this issue : it's VERY important to remap the keys

Ding ding ding! 

If you don't remap the keys, then "W" is telling your rover "Use the wheels to accelerate forward, AND use the reaction torque to try to pitch down."

[seaces]

There is my roover on the Moon. It has almost every science experiment except those that require atmosphere and materials bay was too big for me. I have used Infernal robotics parts to make it more compact for crane, on the bottom I have 4 small airbags also from one mod and it had 4 retrorockets also fro mone mod. I included all these to guarantee a safe landing and good error margin. Oh and Infernal robotics has a drill ( see the fron of the rover it is lowered) with that I took surface samples. Some batteries got destroyed becouse I fliped this 2 times but got it under control since i put reaction wheels. What I sugest is to play with infernal robtics and rovers it can be made more comapct maybe and add some itneresting option. For example is have used it also to rotate around my panels and also stow the in safe place when I drive, only when I am use the electricity I deploy like this this is to save the panels. Oh and palce on some good postions those 1x1 solar panels they can act like emrgency charing if you destry your big panels or something. that is the only mistake that I made with this design. this one proved really good one and I can go fast too. Autonomy on batteries is like 20 minutes but I destroyed some as I have said so now it is like 11-15min then I have to charge.

Hope this gives you some ideas. Oh and test test test while on kerbin. I drived this one a lot around rocket launch pad becosue you have some steep hils there so you can see how it can climb, stability etc.

[Warzouz]

Roving on the Mun at 25m/s and jumping into craters is very fun... but dangerous.

I added action groups :

• 6 : toggle 4WD to climb hills
• 8 : Full science activation
• 10 : Antenna deploy (cosmetic - it's a dog after all)

[Warzouz]

Well everything is going nicely

Here is my Eve skycrane

Rolling down a 30° hill on Eve at 30m/s.

Edited March 19, 2016 by Warzouz

[ryan234abc]

Nice job with the Eve rover!

As you've probably gathered, centre of mass needs to be very low down. I tend to base my rovers on a turtle as that helps to stick to the low COM model. This is a rover I slapped together quickly and it flipped very quickly.

Now, it works, but when going faster than 3m/s in low G or once a tire is broken, it just flips and there is NO chance of getting it back. Believe me dude, getting a rover down to Eve surface is 1 up from anything I've ever done. Quick question though - Are you ever going to get it back again? *HINT HINT CHALLENGE HINT HINT*

Edited March 19, 2016 by ryan234abc

[Warzouz]

Yes.I've figure that the rover, at high speed (>15m/s) can bump, even on flat terrain. This result in loss of control. In that case, the rover don't blow immediately. That leave the time to control with the reaction wheel. It's the same when Jumping from cliffs. If you've time to set the wheels parallel to to arriving terrain, you don't bounce and your rover is fine. If you hit one or 2 wheels before the other, you can start a heavy roll. It's recoverable, but hazardous.

And BTW, The rover performs very well. I was rolling on a 22% slope at 55m/s on Laythe and I could brake to 0 quite fast without even loosing control.

Edited March 19, 2016 by Warzouz