The Elcano Challenge: Ground-Based Circumnavigation (5th)

[damerell]

On 12/11/2023 at 3:55 AM, Icky said:

 

• On atmospheric worlds your vehicle design must not provide significant aerodynamic lift.

how much lift is too much? im looking at the rules discussions over the last few months since i looked here last and im thinking my kerbin run wouldnt fly (heh) anymore. my rover was prop powered and would sort of glide. just enough to keep the descent from destroying the rover on landing, it was incapable of flying level even if you wanted to. im just curious what direction i should take my build when we inevitably start doing these in ksp2.

That's a tricky one (and I'm afraid it's almost impossible to quantify "significant", but RoninFrog is onto something with downwards-angled fins being better than upwards, and your design looks fine to me lift-wise).

18Watt wrote "Thrust devices (rockets, jets, props, RCS) are acceptable, as long as they are only used while in contact with the surface.  Using thrust of any sort to control or change the trajectory of your rover while above the surface is not allowed" (where I just say you can't use them to speed up), you clearly said "my rover DOES use control surfaces and prop power in the air"... and 18Watt approved it, which I don't understand. (My rules are intended to be laxer than 18Watt's...)

This whole rule is a bit of a mess anyway because who, going across a bumpy surface at speed, is going to be able to have the engines shut off the second the wheels leave the ground? kOS could wiggle the throttle, but a jet engine _can't_ even drop thrust instantly.

It's only really a problem on atmospheric worlds, not least because of the magic BG props. No-one is going to charge around Tylo burning a Mainsail the whole way.

It's hard to know what to do about this without giving a rule that's objective and impossible to follow (shut off props the instant you leave the ground) or even more subjective than "significant aerodynamic lift".

If the longest jumps are "about 10 seconds", though, as you say, that seems like a lot; if you were doing that in Kerbin's gravity but with no atmospheric effects or in-flight thrust you'd have to leave the ground with a vertical velocity of 50 m/s (assuming you've not just driven off a cliff, yes) and would hit a peak height of 125m. That's a lot more than the Dukes of Hazzard ever managed, and on the face of it makes that rover look like too much of a glider. (But on the other hand maybe the time estimate is off...)

FWIW, I am not even going to consider disqualifying already-approved entries for one moment.

[Kimera Industries]

Trying to quantitate subjective rules sure is hard, huh? It's one of those things where you can look at an attempt and say, "Oh, yeah, it's using aerodynamics to cheat and go farther" but it's nearly impossible to write down. Obeying the spirit of the law here is what's important. 

[18Watt]

5 hours ago, damerell said:

That's a lot more than the Dukes of Hazzard ever managed

Any chance I get to make a reference to the greatest TV show ever made, I take it!  Yee Haw!!

In the previous version of this challenge, I allowed @Icky's entry, although I struggled with the decision.  I think even Icky will agree that machine is borderline, but at the time I felt the entry still was keeping the spirit of the Elcano challenge.

Ideally, I think Icky is hoping to get an advance ruling on his rover, which is understandable considering the time and effort that goes into an Elcano run.  Unfortunately, for entries that skirt the edges of the rules and spirit of the challenge, it's difficult to state in advance what the ruling will be.  The 'close calls' are difficult to judge, and it's sometimes terrifying being a referee.  One of the best parts of (previously) acting as Elcano caretaker is the players were extremely polite, and always respected my decisions, even though they may not have agreed with them.  Good luck!

[RoninFrog]

8 hours ago, 18Watt said:

In the previous version of this challenge, I allowed @Icky's entry, although I struggled with the decision.  I think even Icky will agree that machine is borderline, but at the time I felt the entry still was keeping the spirit of the Elcano challenge.

I think the more quantitative rules are there more to prevent someone from spending hours and hours doing an Elcano that breaks the spirit of the challenge, only to be denied entry.  As long as the rover is within the spirit of the challenge, it's probably fine.  A green-light given by the Elcano caretaker overrules any fiddly rule breakages.

[damerell]

4 hours ago, RoninFrog said:

I think the more quantitative rules are there more to prevent someone from spending hours and hours doing an Elcano that breaks the spirit of the challenge, only to be denied entry.  As long as the rover is within the spirit of the challenge, it's probably fine.  A green-light given by the Elcano caretaker overrules any fiddly rule breakages.

Yes, I think that's a useful way of putting it, and perhaps suggests a rewrite more in terms of what is definitely OK. (For example, I might say, on high gravity worlds, if your rover is driven only by ground contact, you can make the jumps as big as you like because there's no way to stay off the ground indefinitely [1]).

[1] I await now someone coming up with a gossamer-winged construction which zooms up the first hill West of the KSC at 300 m/s and touches down three hours later...

[king of nowhere]

On 12/14/2023 at 10:34 AM, RoninFrog said:

I think the more quantitative rules are there more to prevent someone from spending hours and hours doing an Elcano that breaks the spirit of the challenge, only to be denied entry.  As long as the rover is within the spirit of the challenge, it's probably fine.  A green-light given by the Elcano caretaker overrules any fiddly rule breakages.

Indeed, a few months ago I asked permission to do an elcano on a plane, just going slow enough to not take off. And @18Watt approved the intention, provided I'd cut off thrust if I made a jump longer than a couple seconds, and I'd try to get down to ground when airborne. the spirit of the challenge is to drive the plane on the ground, and there's also quite some reason to use that plane - related to one of my grand tours where I would have liked to stay longer on Tekto, but I couldn't because of a bug. Anyway, there was enough of a case.

Incidentally, I got to around one sixth of the way before becoming engrossed with other projects and I haven't progressed in months, but I may come back to it eventually.

Now, one may question if I would actually abide by those limitations, or if I would obey the rules a couple of times while taking screenshots, and then fly gleefully the rest of the way. But then, if one wanted to cheat, one could just as easily alt-f12 his rover in a dozen places spaced around the planet and take screenshots, and pretend he circumnavigated the thing. At some point, you have to trust people. After all, what's the worst that could happen? Someone makes an entry in an internet challenge related to a 10-years-old game without fully earning it? Earns some underserved bragging points with the couple dozen people who actually bother looking at the scoreboard?

if people have a cool idea and want to try it, i wouldn't worry too much about the technicality of the rules or the prospect of cheating

[RoninFrog]

I tried to replicate Batman's bat-bike (bat-pod?) from The Dark Knight, and ended up making a super-durable, super-fast rover that I'm absolutely gonna do some Elcano's with.

Also note the nav-ball stability. 

 

[Kimera Industries]

1 hour ago, RoninFrog said:

I tried to replicate Batman's bat-bike (bat-pod?) from The Dark Knight, and ended up making a super-durable, super-fast rover that I'm absolutely gonna do some Elcano's with.

How'd you get the suspension to bounce like that? No autostrut on the wheels? Very awesome motorcycle.  

[RoninFrog]

34 minutes ago, Kimera Industries said:

How'd you get the suspension to bounce like that? No autostrut on the wheels? Very awesome motorcycle.  

If you strut a wheel to two separate BG hinge systems it gets super elastic and wierd.  Here's a thread with some other suspended craft:

Spoiler

...and if you really like suspension:

[Kimera Industries]

Ooh, nice! I can imagine that being a very good feature for an Elcano rover.

[RoninFrog]

Here's a Mun elcano with the motorcycle.  I've got a Stock Craft entry for Mun but this one is pure stock.

Spoiler

The bike pictured is actually the third one I sent as the first two had some issues that I didn't want to deal with for six hours.

Here's a video of the first few minutes of the run.  It's a super versatile bike, although there might be some reusability issues later on.

Anyone else seen red dirt on the Mun?  The dirt in this picture looks distinctly reddish, and there seems to be some sort of pattern with other colors too.  I know that one of the Tylo craters has intentionally colored terrain, could this be something similar??

I am 95% certain that it's in a distinct shape.  Could it be an easter egg or something?  I can't really tell if there's much else, and if I zoom out any further the terrain loads to a higher altitude and it disappears.

The red patch is super visible here, with maybe a sort of slight brownish patch in the foreground?  I swear it's not just my eyes playing tricks on me.

So I finished, but one of the downsides of this suspension system is that the wheel positioning tends to distort more and more with each hit as the elcano progresses.  By the end, the wheels had visibly shifted from their original positions and angles, leading to uneven load distribution and "bucking" as the back wheels caught the terrain at the wrong angle.

Edited December 17, 2023 by RoninFrog

[18Watt]

36 minutes ago, RoninFrog said:

So I finished, but one of the downsides of this suspension system is that the wheel positioning tends to distort more and more with each hit as the elcano progresses.  By the end, the wheels had visibly shifted from their original positions and angles, leading to uneven load distribution and "bucking" as the back wheels caught the terrain at the wrong angle.

That's a known issue, mainly affecting robotics parts, or items attached to robotics parts.  I really never found a good way to mitigate that, ended up accepting that eventually my rovers would end up distorted if they used robotics parts.  Eve was especially harsh on robotics parts.

[RoninFrog]

31 minutes ago, 18Watt said:

That's a known issue, mainly affecting robotics parts, or items attached to robotics parts.  I really never found a good way to mitigate that, ended up accepting that eventually my rovers would end up distorted if they used robotics parts.  Eve was especially harsh on robotics parts.

Yeah I definitely won't be doing any single-rover grand tours with this design.  It seems to last long enough to survive a single elcano without any major issues though.

I've started on Vall with a new motorcycle (same design).  It's such a useful vehicle for Elcano's, it rarely pops tires and I have the control point gyro-stabilized so it basically steers itself, allowing me to watch movies or patrol the forums while it runs in the background.

Edited December 17, 2023 by RoninFrog

[RoninFrog]

Ok so I noticed one issue a lot of people have when they are doing Elcano's is their tires keep popping.  So I thought I'd make a rover whose tires physically cannot pop.  And your tires cannot pop if you don't have tires.

It's gonna be a real real long Elcano.    But it's a decent mech suit that is actually capable of moving somewhat quickly and doesn't explode after ten steps.  I decided to send it to Eeloo since Eeloo has very smooth terrain and it will be a decently short Elcano.  So here goes!  The nice thing is I can leave it walking in the background without having to hold down the "wheel forward" keybind.

Trip details:

Spoiler

Well I guess I brought an Engineer instead of a Pilot.  Who needs maneuver nodes anyway.

[damerell]

I've added RoninFrog's stock Mun. Not many motorcycles. I looked at my Mun circumnavigation photos (asking myself once again why, with adequate life support, I did half of it in the dark) - not a trace of red, but then it was in 1.0.4.

Here's a redraft of the surface rule, intended to take account of comments above and the way it's difficult to write a strict set of rules. (And, I admit, the realisation that 18Watt was not quite so strict as I thought...)

 

• Try to stay on the ground or on/below the surface of any water.  Jumps over dunes and such are permitted. It can be hard to stay on the surface on low-gravity worlds, but if your trip around Gilly is turning into three suborbital trajectories, consider reducing speed or using upwards-firing engines (also a good way to get some traction to let you get moving on low-g worlds without it taking all week to accelerate). On land trips on atmospheric bodies (Kerbin or mods), don't design a glider that speeds off the top of a hill and comes gently to the ground a kilometre further on - if your craft has wings, that's a bad sign. If you have thrust devices (rockets, jets, props, RCS), it's fine to use them off the ground to slow down or avoid a crash (eg into a terrain scatter) but try to avoid prolonged thrust up or forwards. If you're in any doubt, show us your proposed craft.

[Kimera Industries]

Well, I've started my Elcano mission, at least:

I also documented my ice cream base, The Brain Freeze (TBF). I doubt I'll get around to doing the Elcano itself by the end of the year, though, because my attention will be focused on my Jool 5.

[Icky]

just throwing ideas out, what about a lift to weight ratio? lets say, provided the rover even has control in the air, whether it be reaction wheels or elevator/rudder, then the amount of total lift created at top speed cant be more than X percentage of the rover weight when its at its lightest during operation (low on fuel). so if it weighs 1000kg, it cant ever make more than 500kg of lift or 300kg or whatever ratio. unfortunately, as far as im aware, youd need a mod to tell you that so thats slightly off-putting, but id say if youre doing an atmospheric elcano, its not a big deal in the grand scheme. basically, it should probably be a ratio that ultimately discourages taking jumps at full speed and yeeting it as far as possible without consequence. 

[damerell]

It's been a little while - although I have a design for the Hangarmoth II - but I wanted to say that while I see what you mean, I think intent is the best way to express it; it's unavoidably subjective, so give as much guidance as I can in the OP.

[king of nowhere]

As I approached Ammenon, my latest target in the whirligig world grand tour, I was struck by its beauty and couldn't help circumnavigating it

EDIT: by the way, I looked at the written entries for modded planets, and they always mistake diameter for radius. the number given is radius, not diameter.

For the record, Ammenon is 95 km of radius.

Jifgif has a nominal radius of 6 km, but the lobes extend 10 km more on each side. Its actual size is roughly 35x18 (long and short axis)

Thresomin has a 2 km radius, so 4 km diameter is actually accurate there.

Wolda has a nominal radius of 9 km, but the lobes extend 15 km on each direction - and even the "neck" rarely goes below 5 km of altitude, so 50x30 (long and short axis) is a more accurate count

Edited January 30 by king of nowhere

[damerell]

Oh, damn. I'm not sure what went wrong there (or where I even got the sizes from). In future it'd be most helpful if you continued to just tell me the dimensions. I'll fix this up and review the most recent when I get a chance.

Edited January 30 by damerell

[damerell]

Update for the corrections to the planet sizes and to give @king of nowhere credit for Ammenon.

[king of nowhere]

I've done another circumnavigation in the whirligig world pack

This time it was an inanely tiny rock, a submoon of only 400 meters of radius. I normally wouldn't bother, except that I saw a unique opportunity: to make a "planetary circumnavigation" without wheel, or any other mean of surface propulsion - except using the reaction wheels to push the body of the spaceship against the ground, trying to crawl forward.

Indeed, I decided to take the extra step and eschew the use of rockets entirely while within Didd's sphere of influence. Escape speed is only 1.7 m/s, so I could safely lithobrake from interplanetary intercept, and launch back in space by pushing with reaction wheels extra strong.

[king of nowhere]

As part of my latest Jool 5, I run a circumnavigation of Pol

for once, it's a stock moon.

P.S. I see Didd hasn't been added to the scoreboard yet

Edited February 22 by king of nowhere

[damerell]

Done Didd. The curse of the Elcano challenge hasn't quite claimed me yet. I'll do Pol too when I have time to review it.

Another thing I've noticed is that the comments from earlier organisers seem to have got lost somewhere over the years. I think this is a pity and I'll see about replacing them. Also, some of the links are bust after the forum apocalypse and it would be useful to indicate to the reader which of them actually work.

[damerell]

Done @king of nowherearound Pol, a report I particularly enjoyed. It strikes me that technically an Elcano around a modded planet is "modded", but I think it should be classified as stock if the only mod was the planet mod.