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The Elcano Challenge: Ground-Based Circumnavigation (4th)


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After a break to do other stuff, I've started a circumnavigation of Vall.

I'm still driving Rover 1. So far this rover has seen a 150 km expedition to the Mun Canyon (and several attempts to jump off the rim), and a successful circumnavigation of Minmus. I gave her a new lander, with a bit more delta vee and more thrust for bigger moons, and flew her from her berth at Mun Station to Vall, with a stop at Laythe station for refueling on the way. I made a few minor modifications using EVA construction  -  a couple of RTGs under the cockpit, a command chair on the roof so Valentina can come along (what is Vall without Val?), and a snazzy bumper sticker commemorating my Minmus circumnavigation.

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Funny first day on Vall. We landed 10 km from Vallhenge and started looking for it. Roamed around for an hour searching with no luck. I figured it had to be around there somewhere. Decided to try uninstalling Parallax. Logged back in to this -

Fortunately no damage!

Edited by Sp1f
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Dozens of tests to get close to 120m/s on the water, and dozens more to exceed 140m/s. But this time we are slowly approaching Kerbin's sidereal rotation speed:

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Circumnavigation of Kerbin in less than 7 hours. Entry by sea valid this time ;)

Spoiler

Start from KSC at midday

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1 hour

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Cross the straits west of KSC in 2h25

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land !

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On land it's quite stable but you have to avoid jumps

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4 h

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5h

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1 Day (6h)

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Last marker

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6h50 ! I didn't see any sunrise or sunset ^^

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Specs : 4 rotors (medium) powered by 30 rtg at 460rpm. 16 blades by rotor. Top speed near 172,5m/s on water and 265m/s on land. Average speed on water near 169m/s.

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I leave you the hand to cross the sub-1-day mark! :cool:

Edited by Pouicpouic
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18 hours ago, Sp1f said:

After a break to do other stuff, I've started a circumnavigation of Vall.

I'm still driving Rover 1. So far this rover has seen a 150 km expedition to the Mun Canyon (and several attempts to jump off the rim), and a successful circumnavigation of Minmus. I gave her a new lander, with a bit more delta vee and more thrust for bigger moons, and flew her from her berth at Mun Station to Vall, with a stop at Laythe station for refueling on the way. I made a few minor modifications using EVA construction  -  a couple of RTGs under the cockpit, a command chair on the roof so Valentina can come along (what is Vall without Val?), and a snazzy bumper sticker commemorating my Minmus circumnavigation.

efo0afhop0e91.png

 

Funny first day on Vall. We landed 10 km from Vallhenge and started looking for it. Roamed around for an hour searching with no luck. I figured it had to be around there somewhere. Decided to try uninstalling Parallax. Logged back in to this -

Fortunately no damage!

I can’t see the image for some reason, but I’m assuming what happened is that after you disabled parallax, the structural spawned right on top of/right next to you?


Are you planning on doing a polar circumnavigation of Vall? If you are, given that you’re starting at vallhenge, I think you’ll be taking pretty much the exact same route I did. Beware the poles is all I’ll say.

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4 hours ago, Jack Joseph Kerman said:

I can’t see the image for some reason, but I’m assuming what happened is that after you disabled parallax, the structural spawned right on top of/right next to you?

Here's the link if you want to check it out.

https://www.reddit.com/r/KerbalSpaceProgram/comments/w926gk/found_vallhenge/

I spawned about 100m directly above the Vallhenge. Rover 1 is strong though, no biggie. (Hopefully the lander is ok, I should check that out). Yeah I think I'm going to go for the polar route. I was debating some kind of diagonal route to try and hit most of the biomes but I've decided I don't really need the science.

 

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On 7/26/2022 at 10:08 PM, Sp1f said:

and a snazzy bumper sticker commemorating my Minmus circumnavigation.

Nice!

14 hours ago, Pouicpouic said:

I leave you the hand to cross the sub-1-day mark!

Nice run!  I’ll get you entered soon.

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@Pouicpouic, I finally got the leaderboard updated with your latest Kerbin circumnavigation, which also added you to the list of Master Mariners.  Sorry it took so long, I’m away from reliable internet right now, on vacation.  While adding your entry, I made a couple of interesting observations.

  • The next entry for Kerbin ( @RexKramer ) did the same thing you did-  Completed a run intended to be a Sea circumnavigation, but cut across a chunk of land which disqualified the Sea entry.  And then re-did the run to complete a Sea entry.
  • All of the Grand Master Navigators, Master Mariners, and Planetary Navigators are Stock entries.  I have no explanation for this, aside from the fact that we are obviously very stubborn people!
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1 hour ago, 18Watt said:

All of the Grand Master Navigators, Master Mariners, and Planetary Navigators are Stock entries.  I have no explanation for this, aside from the fact that we are obviously very stubborn people!

All the Planetary Navigators won't be as soon as I work out a way to deal with the way my start flag on Eve is at the top of a sodding mountain.

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I'm done. https://forum.kerbalspaceprogram.com/index.php?/topic/146923-elcano-iv-circumnavigate-all-the-things/&do=findComment&comment=4155200 is where Eve starts. Gilly next but I've an idea that might not take quite so long.

And ofc that's the big one out the way. I've done Kerbin. Tylo I gather can be a slog but it's surely got to be less of one than driving up purple mountains in 1.6g.

Edited by damerell
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On 8/3/2022 at 5:53 PM, damerell said:

I'm done.

Leaderboard updated, congratulations!!  Indeed, now there is a modded entry for the Planetary Navigator category!

 

On 8/7/2022 at 8:15 AM, damerell said:

Quite a lot of jumps some of which were not brief

No way around the fact-  if you are moving on Gilly you are going to get airborne.  Makes it very difficult to gain any speed.  And even more difficult to bring your rover to a stop once you get moving.  In my opinion Gilly is the hardest CB to make a ground rover function at all, let alone good enough to do a circumnavigation.  But that's the challenge!

Nice job!

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1 hour ago, 18Watt said:

No way around the fact-  if you are moving on Gilly you are going to get airborne.  Makes it very difficult to gain any speed.  And even more difficult to bring your rover to a stop once you get moving.  In my opinion Gilly is the hardest CB to make a ground rover function at all, let alone good enough to do a circumnavigation.  But that's the challenge!

Now I've sorted out my KIS/KAS issues I have an idea for a rover propelled by having a kerbal (with suit RCS) repeatedly plant ground pylons ahead of the rover which would then use a KAS winch to pull itself up to the pylon, which I think would more or less keep it on or near the surface... but it would take circa one thousand pylon-plantings given the maximum winch extension is about 80m.

Oh! Or, much more feasibly, two parts with USI Ground Tethers connected by an extremely long beam they can DockRotate. One end tethers itself, the other end untethers, the whole thing majestically rotates the untethered end until it hits the ground again.

Edited by damerell
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15 minutes ago, damerell said:

Oh! Or, much more feasibly, two parts with USI Ground Tethers connected by an extremely long beam they can DockRotate.

Those both sound like interesting ideas!

Also, in your mission log it looked like you attempted downward facing thrusters?  I’ve never actually tried that approach- I’m curious how well you felt that worked?

That approach (vertical ion engines) has been suggested, but I don’t actually recall anyone actually doing it- successfully at least.

Gilly requires some creative solutions. 

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2 hours ago, 18Watt said:

Also, in your mission log it looked like you attempted downward facing thrusters?  I’ve never actually tried that approach- I’m curious how well you felt that worked?

I did it with downward facing LFO engines (in a realistic view of ElectricCharge world, which is how I try to play, ion thrusters would not amount to a gnat's fart, even on Gilly) - but this only worked with a kOS script to control them to apply a tiny amount of thrust when on the ground but increased thrust when off it to bring me back into contact with the ground in a sensible fashion. I do think if I had designed a Gilly-specific rover I could more or less have just had Minmus-ish gravity all the way around, but it would have needed more work in kOS.

I fear part of the problem is that in fact the safe way around Gilly - the way I would do it if killing or stranding kerbonauts would be unacceptable but I was required to stay near the ground - is to crawl around it at about 2 m/s.

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@18Watt Congratulations on your newly achieved status of forum overlord, we hope you will use your power sparingly and not fall into the many pits of unnamed things that some others have found themselves sliding into.

I humbly bow.

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On 8/9/2022 at 5:34 PM, 18Watt said:

 

That approach (vertical ion engines) has been suggested, but I don’t actually recall anyone actually doing it- successfully at least.

I was actually able to use vertical ion engines to great success during my Gilly run- in fact, I completed the entire thing in about half an hour. Even after breaking a wheel somehow, I was still able to drive semi-decently.
Personally, I thought Gilly was by far the easiest CB to circumnavigate, especially given its tiny circumference. In retrospect, I probably should have done the same thing on other low-G worlds such as Pol and Bop.

FFVHGpa.jpg
PAxm4Mq.jpg
 

Also on an unrelated side note, I just noticed that I wasn’t ever added to the Master Mariners list. @18Wattdo you mind taking the time to fix that?

Edited by Jack Joseph Kerman
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On 8/9/2022 at 10:11 PM, damerell said:

Oh! Or, much more feasibly, two parts with USI Ground Tethers connected by an extremely long beam they can DockRotate. One end tethers itself, the other end untethers, the whole thing majestically rotates the untethered end until it hits the ground again.

This doesn't work for three reasons, one annoying, one serious, and one apparently impossible to overcome.

Firstly AFAIK all the ground tethers on a vehicle turn on or off together. This is normally what you wanted but is no help here. That can be worked around by using Hangar Ground Hangars, whose anchors operate individually.

Furthermore the minimum DockRotate incremental rotation is 1 degree, with the port trying to turn at at least 1 deg/sec. With a 500m beam, this means the other end is moving in roughly 9m increments and - if torque can overcome gravity - getting slapped into the ground at 9 m/s. This could perhaps be worked around by a very flexible beam and the feet having landing legs to cushion the resulting impact.

The fundamental problem is that even under Gilly's gravity, to lift one "foot" into the air by applying torque at the other end of a very long beam needs a very large amount of torque and what happens in practice is the port gets twisted clean off the foot. Bigger heavier ports attached to bigger heavier parts just means you have bigger heavier feet.

One idea is for the foot/beam joint to rotate freely and for the rearward foot to propel itself upwards with some kind of piston fast enough that it will pass over the foot that's anchored to the ground, then use reaction wheels to control the descent speed so it doesn't just smack into the ground at the same speed.

Another idea is to make the whole thing much smaller and try to operate it faster to get an acceptable ground speed.

A third idea is to have the feet have wheels and to have the vehicle move by anchoring the front foot then contracting like a caterpillar, then anchor the rear foot and stretch out again.

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23 hours ago, Jack Joseph Kerman said:

I just noticed that I wasn’t ever added to the Master Mariners list.

I think you may have done the same thing @Pouicpouic did- cut across the peninsula east of KSC.  I know it seems minor, but Pouicpouic redid his sea run because of that too.  (Well, also to set a crazy fast speed record).  

Folks have been doing that since the first version of this challenge, I noticed the player right after Pouicpouic ( @RexKramer ) did that as well way back in version 1.

Edit:  So with 3 players all doing the same thing, it's becoming clear that the rules for Sea circumnavigations are poorly worded. I need to fix that..

 

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1 hour ago, 18Watt said:

I think you may have done the same thing @Pouicpouic did- cut across the peninsula east of KSC.  I know it seems minor, but Pouicpouic redid his sea run because of that too.  (Well, also to set a crazy fast speed record).  

Folks have been doing that since the first version of this challenge, I noticed the player right after Pouicpouic ( @RexKramer ) did that as well way back in version 1.

Edit:  So with 3 players all doing the same thing, it's becoming clear that the rules for Sea circumnavigations are poorly worded. I need to fix that..

 

Ah, I completely forgot that I even did that. I guess that's the excuse I've been looking for to try and set my own speed record. Maybe I can use some sort of hydrofoil setup to get the time under the 1-day mark.

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1 minute ago, Jack Joseph Kerman said:

Maybe I can use some sort of hydrofoil setup to get the time under the 1-day mark.

I think under 1 day should be possible.  I was never able to make a hydrofoil design work.  

Limiting the number of 'hulls' seemed to help keep water drag to a minimum.  I found a single MK2 or MK3 hull would float upright.  The MK3 hull surprised me, it looks like it would tip over, but doesn't.  I haven't tried a single MK1 hull, but I assume those would tip over.

At the speeds needed for a 6-hour circumnavigation air drag becomes a real issue too.

7 minutes ago, Jack Joseph Kerman said:

Ah, I completely forgot that I even did that.

I just looked at the rules.  It's in there, but it's buried.  The description of 'SEA' navigations is buried in a spoiler within a spoiler, and the part about not crossing any land is in the middle of a poorly-worded paragraph.  So it's not very visible.

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11 hours ago, 18Watt said:

 

Limiting the number of 'hulls' seemed to help keep water drag to a minimum.  I found a single MK2 or MK3 hull would float upright.  The MK3 hull surprised me, it looks like it would tip over, but doesn't.  I haven't tried a single MK1 hull, but I assume those would tip over.

At the speeds needed for a 6-hour circumnavigation air drag becomes a real issue too.

 

So essentially what you’re saying is that I could replace the structural fuselage pontoons on the KELP with an empty Kickback SRB and it would go faster? I always just kind of assumed it was the surface area in contact with the water than determined drag- I’ll have to try that out. I’m also wondering whether or not the fairing drag exploit also applies to water- given that fairings remove the buoyancy of the parts they contain, I think it might work for drag too.

According to some math, I’ll need to go at least 175m/s on average to have a chance of making it around Kerbin in under 6 hours. So yeah, I’ll definitely have to remove everything draggy, which I have on what I’m calling the “K.E.L.P Lightning”.

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Actually @Pouicpouic and I both used MK1 pontoons for our most recent runs.  I have no idea how KSP models water drag, or which parts are most efficient.   Just saying I’ve been surprised at how well different parts work.  If you get stuck using one type of fuselage, don’t hesitate to try something different.   I was very surprised at how well I was able to do with MK2 and MK3 hulls.

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2 hours ago, 18Watt said:

I was very surprised at how well I was able to do with MK2 and MK3 hulls.

My info on this is years old at this point but I remember hearing somewhere that water drag was essentially calculated the same way as air drag, so Kerbin's oceans are little more than ultra dense atmosphere with buoyancy added. MK2/3 hulls are made to be aerodynamic and in my opinion it translates well so long as you keep the craft steady.

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On 8/12/2022 at 4:01 AM, 18Watt said:

Well, also to set a crazy fast speed record

I almost lost my mind trying to keep up with your amazing speed on the water. :confused:
I've tried dozens of setups without success. And especially with the length adjustable hulls (the grooved ones) --> these have an absurd behaviour on the water: banish them.
I don't know why but I had problems with unaligned rotors at this speed, so I went for a 1 block configuration, all centered and aligned.
16 blades seemed better than 8, but I don't have a regular comparison to be sure.

15 hours ago, Jack Joseph Kerman said:

According to some math, I’ll need to go at least 175m/s on average

The theoretical maximum speed achievable with propellers should be close to 200m/s on the water. It is therefore necessary to be able to reach >300m/s on the ground: this will not be easy. ;)

To be honest, my attempt was very average: I lost at least 15 minutes, so with the same craft it would be easy to beat me.

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10 hours ago, Pouicpouic said:

The theoretical maximum speed achievable with propellers should be close to 200m/s on the water. It is therefore necessary to be able to reach >300m/s on the ground: this will not be easy. ;)

To be honest, my attempt was very average: I lost at least 15 minutes, so with the same craft it would be easy to beat me.

I’ve gotten my craft to go over 250 m/s on land so far, but I still need to optimize the CoM so that the extremely powerful blades don’t touch the water or just send the nose straight into the ocean.

So far all I’ve been able to do successfully is test the durability of the runway lights.

Z8M38LB.jpg

Edited by Jack Joseph Kerman
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