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Rover Endurance on 100 EC


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Posted (edited)

Rover Endurance on 100 EC (Electric Charge)

How far can you drive a rover with only 100 units of Electric Charge to work with?  Let's find out!

The basic idea:

  • Build and launch a rover on the KSC runway.
  • Plant a flag on the runway next to the rover.
  • Drive as far as you can from the flag.  How far did you get?

Rover Construction Rules:

  • Stock parts only. 
  • Rover must have at least 2 Kerbals.  They may be in external seats (lawn chairs..) or in pods.
  • Rover must have no more than 100 EC at launch.  
  • Rover must not have ANY means of recharging the batteries.  No solar panels, no fuel cells, no engines with alternators.  Also, no RTGs ( @Mars-Bound Hokie )
  • No flying vehicles or boats.  (That might be a separate challenge..)
  • No propulsion from any source other than rover wheels.  No rocket engines, no propellers, no jet engines.  

General Challenge Rules:

  • No, you can not 'get out and push' with the Kerbals.  That's prohibited.
  • However, you may use a Kerbal to flip a rover back up if it flips over.  Just don't use Kerbals to add distance. ( @OJT )
  • You may use a combination of powered and unpowered wheels.  Aircraft landing gear are allowed.  At least one wheel must be a powered rover wheel though.
  • Mods that add or alter the functionality of parts, or which alter game physics are not allowed.  Other mods are fine.
  • You must start at the KSC runway.  You can go any direction you want though.
  • Entries should ideally have a few screenshots:  One showing the rover on the runway with no more that 100 EC, and another showing your distance from the runway (flag) when you run out of juice.
  • If you are posting more than 3 or 4 screenshots, please put them inside a spoiler window.

I managed to get a rover with 2 Kerbals 7.1 km from the flag, but I think you can go much farther than I did!

Leaderboard:

9.9 km  @OJT  12 May 2022  - A couple of rollovers, and a Kraken attack to end the run.  Lots of EC remaining when the rover unglued itself.

10.0 km @camacju  12 MAY 2022  -  A classic camacju entry, with parts attached by no visible means!  Also classic by carefully evaluating the limitations and characteristics of the elements involved.  I think camacju already has some ideas for improving his distance..

13.5 km  @swjr-swis  15 May 2022  -  A stylish blue and green chassis, how did he do that?  Kerbals reclined for lower drag, and more comfort while sleeping and driving.

14.7 km  @camacju  12 MAY 2022  -  Investigating some aero tweaks.  End distance is more than double my original test run.  Terrain is becoming a bigger factor as it becomes less flat.  Confirms @OJT's observation that small wheelbase tricycle rovers might occasionally tip over.

26.7 km  @swjr-swis  16 May 2022  -  Focusing more on drag reductions than weight, nearly doubling the previous record!  I just realized I’m ordering these from lowest to highest distances, not sure why I ordered them that way.

Edited by 18Watt
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3 hours ago, 18Watt said:

7.1 km

Wow that is far more than I would have guessed was possible.

This is an interesting challenge, I might try it...

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Posted (edited)
1 hour ago, Mars-Bound Hokie said:

I guess that means RTGs are out of the question, then.

Correct.  I'll adjust the rules section, forgot about RTGs (my favorite rover power source!).  But yeah, the point here is to see how far you can get on 100 EC, anything that gives you additional EC is outside the bounds of this challenge.

Think of it as an exercise for when things break on other CBs.  For example, I lost all my solar panels and RTGs and ALL OTHER means of recharging my batteries.  But the rover and crew are X number of km from the ship.  Can I get the crew back to the ship on, say, 100 EC?

Good question!  Funny how when you make a challenge you like to think you have covered all the rules.  If there was a prize for first person to find a possible loophole in the rules of this challenge, you'd win!  (There isn't..)

Edit:  Curious what a 'Hokie' is?

Edited by 18Watt
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Posted (edited)
3 hours ago, 18Watt said:

Edit:  Curious what a 'Hokie' is?

I am.

Spoiler

For those who honestly don't know, it's the name of Virginia Tech's mascot. AOE Class of '21, baby.

 

12 hours ago, 18Watt said:

I managed to get a rover with 2 Kerbals 7.1 km from the flag

Let's see pictures of it, then.

Edited by Mars-Bound Hokie
Asking for proof that the challenge is doable.
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8 hours ago, Mars-Bound Hokie said:

Let's see pictures of it, then.

Here ya go!

Spoiler

It's basically 4 wheels and a small battery.  Two lawn chair seats.  I started out with all 4 wheels powered, but after a few km I de-powered the front wheels.  Otherwise I didn't even change any wheel settings.

eEnKqjH.png

I went south.  KSC sits slightly above sea-level, so if you head towards the ocean, that's downhill.  That only works until you reach the ocean though- after that it's all uphill..  After depleting my battery I allowed the rover to gradually coast closer to the ocean.  I think I rolled nearly a kilometer after the batteries ran out, just by creeping downhill towards the sea.

lRdL1zP.png

Planting a flag on the runway lets you target the flag, to see how far away from it you managed to get.

I'm not sure what configurations will give the best range, but my rover certainly is not optimized for range.  Disabling the power on the front wheels improved things for me, but I forgot to do that until I was at about 50 EC.  Other rover wheels might be more efficient.  I suspect the aircraft wheels are also fairly efficient, but you'd need at least one rover wheel to make it move.

There are a lot of settings you can adjust in the wheel's PAW (Part Action Window, aka right-click window).  I didn't touch any of them, but surely they also have an effect on efficiency too.

 

 

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I hate building rovers in KSP. They're too slow, handling model is way too simplistic and lacks basic stuff that even arcade racers have, let alone racing sims (and I know what I am talking about). And the fact that they can't reliably drive even on x2 physical timewarp makes the whole experience truly dreadful. I genuinely don't understand how some people have the patience to complete Elcano challenges

This right here seemed interesting though. Relatively short (compared to Elcano) distances, room for optimizing and creativity... So I decided to give it a quick crack

KFNcXcP.jpg

iheHkh5.jpg

I basically picked up the lightest parts that I could gather up and stitched them up together. Tricycle configuration, with powered Rover wheel at the back and offset to center. I initially wanted to do this with only octogonal strut piece, but the rover was too susceptible to rollovers due to narrow wheelbase, so I added two small cubic strut pieces at the front to make the front track wider. 188kg dry, 376kg with 2 kerbals

Planting the flag and showing that rover is fully charged and has 100 charge units

Spoiler

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I decided to also go south like you to utilize the flats around KSC. After that I proceeded along the shore. I also took off the helmets on both kerbals: we are driving on Kerbin after all, might aswell enjoy the fresh air

Spoiler

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Breaking your record, and I still have charge to spare

Spoiler

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And soon after that. what I feared most happened: the rover flipped

Spoiler

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You clearly stated in the rules that I am not allowed to push the rover as a kerbal. However, I wasn't sure if it was forbidden to push the rover at all or if I was allowed to get out and try to flip it back on its wheels to continue further: I did have more than half of battery charge left. I didn't make any saves, so I decided to take the liberty and flip the rover with Jebediah

Spoiler

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Back on track! I continued and passed the 9km mark. 10km was so close...

Spoiler

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And then the damn rover flipped again :mad:

Spoiler

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I tried to fix the situation again like the first time, but Kraken decided to finess me and started to spin the rover by itself violently. Valentina was knocked off her seat in the process. The rover could not be saved

Spoiler

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And to put salt on the wounds, I flipped the rover at 9.9km... But eh, what can I do. There still is a realistic chance that this milestone will be annulled anyway

Spoiler

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pt8x3Vo.jpg

So here it is: 7.7 km without any pushes, 9.9 km with a push to flip the rover back onto its wheels. I will leave it up to you to decide which milestone to take

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10 minutes ago, OJT said:

Relatively short (compared to Elcano) distances

Yeah, that is why I chose 100 EC, the smallest battery in the stock game- An average attempt probably won't take more than 10 minutes.

12 minutes ago, OJT said:

Breaking your record, and I still have charge to spare

I figured that wouldn't take long!  Your rover is similar to what I pictured would do well, with a single powered drive wheel.  And boy, you do have a lot of charge to spare!

15 minutes ago, OJT said:

You clearly stated in the rules that I am not allowed to push the rover as a kerbal. However, I wasn't sure if it was forbidden to push the rover at all or if I was allowed to get out and try to flip it back on its wheels to continue further:

This is fine, I didn't think about that.  I know you didn't push the rover to gain additional distance.  Normally I put a lot of reaction wheels on my rovers to get them back upright.  That is wasting electricity though!  Anyway, this is within the spirit of the challenge, and does not invalidate your run.

18 minutes ago, OJT said:

And then the damn rover flipped again :mad:

Oh man that's funny.  Rovers can be frustrating.  Adding ya to the leaderboard!

 

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3 hours ago, 18Watt said:

An average attempt probably won't take more than 10 minutes

Oh boy, I'd better get faster then!

My attempt was motivated by an electric motor power curve:

Electric Motor Power (Really Simple) and HP Ratings | The Electric  Chronicles: Power in Flux

I aim to be operating near the far right end of the graph - basically as fast as possible.

Spoiler

For those who know more about electric motors, it's not efficiency that matters as much as power consumption and speed, so I really want to be operating at a point to the right of the efficiency peak. But it's close enough for a simple explanation.

Also, this doesn't take air drag into account, which scales as the square of velocity. So a reduction by half of speed is worth up to 4 times less efficiency. I'll try to address this in my next run.

2lggMWZ.png

Planting a flag

Spoiler

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Journeying out at full speed

vEnzKuI.png

Reaching the edge of the flats

cjpmD87.png

Out of battery!

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Scavenging the last of our kinetic energy

Jny8JI0.png

Stopped, 10 km from KSC

cs2pYZ3.png

F3 screen says I've covered almost 17 km of ground distance. This actually makes a good deal of sense - I took a very wiggly path in an attempt to stay as level as possible and this probably hurt me.

I have a couple ideas for further optimization:

-KSP has very little rolling friction, so my primary source of energy loss is drag. About 80-85% of my drag comes from the two Kerbals. I suspect that I'll actually get better results by putting the kerbals in a fairing and eating the mass penalty.

-Looking at the electric motor curve, I may get a better outcome from using only one motor, which reduces mass and drag. I feel like KSP's motor curve is not exactly like an ideal electric motor, and it's different in a way that would benefit a single motor even more - but I'm not sure.

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20 minutes ago, camacju said:

My attempt was motivated by an electric motor power curve:

You're putting a lot of faith in KSP modeling electric motors after real-world examples.  Probably not a ridiculous assumption, now that I think of it..

22 minutes ago, camacju said:

Also, this doesn't take air drag into account, which scales as the square of velocity. So a reduction by half of speed is worth up to 4 times less efficiency.

Yeah, one thing I've been wondering is if the added weight of aero devices would offset the penalty to moving (actually just accelerating) that extra mass.  I know you have achieved some insane results with fairings on aircraft..

25 minutes ago, camacju said:

Scavenging the last of our kinetic energy

Yep.  Probably doesn't make a huge difference, but then again, why wouldn't you?   

26 minutes ago, camacju said:

F3 screen says I've covered almost 17 km of ground distance.

Although your ground distance value looks somewhat reasonable, I would take that value with a grain of salt.  At the end of my test run, the F3 screen showed a ground distance that was impossibly large.  And also said I'd reached a fairly high altitude, as well as groundspeed of over 200 m/s!  Not sure if I just found a really random bug, or if there are some oddities that occur regularly with the F3 screen.  Anyway, sticking with the 'distance from planted flag' seems like the best way to measure this challenge.

30 minutes ago, camacju said:

Looking at the electric motor curve, I may get a better outcome from using only one motor, which reduces mass and drag. I feel like KSP's motor curve is not exactly like an ideal electric motor, and it's different in a way that would benefit a single motor even more

@OJT used a single driven motor, with what I would call stellar results.  I personally improved performance by (belatedly) turning off the motors on the front wheels.

32 minutes ago, camacju said:

but I'm not sure.

Me neither!  Hoping for a bunch of entries to see what improves performance, and what doesn't.  Adding you to the leaderboard!

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Well, I was indeed able to get a good deal further.

K30YSAQ.png

Craft in VAB. I used the heavier fixed wheels instead of the steerable wheels because I was getting some bad fishtailing behavior that no amount of traction settings would correct. I also added a cosmetic strut piece just so everything's connected together (:

Note that I'm not doing any funny aero stuff on the service bay - both of its nodes are bare. This leaves significant room for drag improvement.

Spoiler

hPSIatv.png

Flag planting

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Power usage is much lower

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I used the other rover as a marker, this way I could look ahead and try to keep to a contour line as much as possible.

GWTfh0Q.png

Reached 10 km with a bunch of fuel left.

ysEDOxL.png

The rover actually flipped over here because I took a sharp turn on a steep incline. Somehow it managed to land on its wheels, but I lost a lot of electric charge getting it back up to speed.

lmUwJl3.png

Right after 10 km the shores become a lot steeper. It becomes a lot harder to manage vertical velocity and I bleed off a lot more electric charge in this part.

hxl85It.png

Out of power, coasting down to sea level

Z0WckaV.png

I accidentally hit the water too early here - probably could have gone another few hundred meters for that 15 km mark.

Drag tended to be around 60-70 Newtons rather than the ~120 I had before, which is an improvement. Again, almost all the drag came from the service bay, and I'm assuming most of it comes from the exposed front node. I wonder if a nose cone will help range even further.

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51 minutes ago, camacju said:

I also added a cosmetic strut piece just so everything's connected together (:

Ha!  That's not required for this challenge, just have to use stock parts.  I do like to give you a little joking for your designs, I know some challenges frown on using extreme offsetting.  For this challenge, that doesn't matter, just gotta use stock parts and physics.  But the strut does add something to the design.  For me it's aesthetics.  For you, it probably just adds weight and drag.

55 minutes ago, camacju said:

Note that I'm not doing any funny aero stuff on the service bay

I'm still curious if there is a net gain with optimizing drag at these speeds.  Your evaluation of efficiency charts of electric motors seemed to indicate higher speeds would yield better electric motor efficiency, so perhaps?

59 minutes ago, camacju said:

I used the other rover as a marker, this way I could look ahead and try to keep to a contour line as much as possible.

At some point the best gains might be found in finding the most level terrain.  Following the shoreline might be one way to keep elevation fairly constant.  On the other hand, losses due to not driving a straight path might outweigh the benefits.

Another addition to the leaderboard!

 

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10 hours ago, 18Watt said:

An average attempt probably won't take more than 10 minutes.

My attempt was almost 50 minutes lmao

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On 5/13/2022 at 1:23 AM, OJT said:

My attempt was almost 50 minutes lmao

Well, to be honest, you (and @camacju) went a lot farther than I did!  Still, it's a way less time-consuming challenge than the Elcano.  Plus, I hear the guy who runs the Elcano challenge is a real doofus!

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Posted (edited)

Is this a private party, or can my R100EC-1 rover enter too? :D

5qHldeR.png

Seats lying down to lower drag. I needed a Jr dock for correct control orientation, so I used cones and a 0.625 battery limited to 100 EC. Trying my luck with the DLC rover wheels. Using a flag to visually connect everything with zero extra drag.

PzDT8z0.png

On the KSC runway, flag planted. Resource panels shows 100 EC (battery at half capacity).

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Ran almost out of juice just as a pretty steep hill got in my way of following the coastline - even the bit of climb killed the rest. I may have to retry a different path to get a bit further.

13.5 km as the crow flies.

 

 

Edited by swjr-swis
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44 minutes ago, swjr-swis said:

Is this a private party, or can my R100EC-1 rover enter too? :D

Still open!  Straight off the bat, I gotta ask, how did you get the green and blue flat frame?  That's neat!  

46 minutes ago, swjr-swis said:

I needed a Jr dock for correct control orientation

Or the Kerbals could try to steer using a mirror?  Yeah, using the docking port was probably a good call..

48 minutes ago, swjr-swis said:

I may have to retry a different path to get a bit further.

I couldn't tell if you went south or north- I think everyone so far has gone south.  I don't think it's any smoother to the north, but who knows?

49 minutes ago, swjr-swis said:

13.5 km as the crow flies.

Adding ya to the board!  Good to hear from you @swjr-swis!!

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40 minutes ago, 18Watt said:

Straight off the bat, I gotta ask, how did you get the green and blue flat frame?  That's neat!

RFP-F Flag Flat. One of the stock parts added since... 1.11 I think? In the utility section. It adds no drag or even collision; that way I can have all parts visually connected and still spread my wheel base.

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Ok another entry, this time to (temporarily, I expect) take the top spot. The R100EC-2, making it 26.7 km away from the planted flag on the KSC Runway spawn point.

R0C9Sqn.png

This one was a test to see if maybe drag was more of an impact than weight. There's still one more thing I can do to make it better drag-wise, but posting this one since it got me a top entry already.

Fx9256q.png

On the KSC Runway with flag planted.

2NclllS.png

Battery empty; spent more than half the time maneuvering slowly down slopes to keep free-wheel momentum. Then I literally ran myself into a corner where it was either roll back towards the flag, or climb a steep hill with no juice left to do so. So I just stepped on the brakes and measured here.

Compared to my previous entry it *seems* like it pays to optimize for drag instead of weight. But the cave at is that the path one takes seems to be the even more important factor. I took a completely differnt path, trying to keep to low slopes, climbing at first and then trying to use the potential energy by following the slopes down in a generally away-from-the-flag direction. So I'm not sure this offers conclusive evidence of drag vs weight as much as it shows it really pays to watch where you're going.

 

Suggestion: why not move the starting point for the challenge to the Dessert Runway? It may be possible to get longer runs from there, purely because on average it looks flatter for longer distances away from the span point. Just a thought.

 

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3 hours ago, swjr-swis said:

did my last entry not meet the criteria?

Yes, it did!  And thank you for reminding me!  

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