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

[18Watt]

Trying to see how fast I can get a boat to go.  Currently using 4 medium rotors with 16 blades each- which I noticed also worked well for @Pouicpouic.  Where did you put the 30 RTGs?  Are they hidden inside the fuel tanks?  I'm curious because I put a bunch of RTGs inside a fairing for a different challenge, and they eventually overheated.  Trying to figure out where to stash my RTGs safely.

I'm able to get 260+ on the runway, and briefly managed to hit 160 on the water before nose-diving into the sea.  I'm currently using MK1 pontoons, but might give a MK2 hull another try.

Edit- just managed to hit 182 on water with a MK2 hull.  No wheels on it yet though..

[damerell]

Out of interest I uninstalled FAR for a bit and got a heavily modified Laytheboat with an improvised hydrofoil and nuclear thermal jets up to 100 m/s. Briefly. I may leave this one to you. :-)

[Pouicpouic]

2 hours ago, 18Watt said:

Where did you put the 30 RTGs?

They are all positioned between the 1k battery and the 1st rotor. 30 was really borderline with the SAS: 31 would have been better.

3 hours ago, 18Watt said:

just managed to hit 182 on water with a MK2 hull.

can't wait to see a screenshot !

[18Watt]

1 hour ago, Pouicpouic said:

can't wait to see a screenshot !

Here ya go..

There are 32 RTGs inside.  I've found that eventually they will start to overheat inside cargo bays, but opening the bay doors for a few seconds will cool them off.  Better to place them exposed to outside air though.

This version doesn't have wheels, but I've since added wheels, and can still get 180+ m/s.  The horizontal fins are used to trim the boat.  With most boats, I usually get the best speed with the boat as near horizontal as I can get.  With this boat, I get better speed angled up slightly.  I suspect the MK2 fuselage is generating some lift, which is causing the boat to sit higher in the water- which is in turn reducing drag, and allowing better speed.  Just a theory.

I have also added fan ducts, and found they did not affect performance in any way.

I'm having issues with the front nose-cone getting destroyed.  Parts which stay in the water are OK at 180 m/s, but parts which bob above the water get destroyed when they return to the water at that speed.

Another problem with this design is it is not as stable on land as a wider twin pontoon boat would be.

I have another question for you-  I'm also doing 16 blades per rotor, but am having difficulty getting the second set of 8 blades spaced evenly.  How did you do that?  Do you turn off angle snap?  The uneven spacing doesn't affect performance, just looks odd.

 

 

[MythicalHeFF]

 

Just managed to ever-so-slightly exceed @Pouicpouic's top speed of 169 m/s with a design that can reliably operate at 170-171. Still not the 175-180 that I need for a circumnavigation in under 6 hours, but it's getting there. I went for a design similar to @18Watt's previous design with Mk1 pontoons spaced out over great distance, but with the Kerbal inside a service bay to reduce drag and using grip strips instead of girder segments to reduce mass. Overall this is my 11th iteration of the KELP Lightning.

Previous iterations were capable of anything from 75 to 157 m/s.

Spoiler

The boat is powered by four standard rotors, each of which have 24 blades on them. Instead of using RTGs, I decided to go for an entirely solar-powered build, seeing as solar panels are considerably lighter and, in addition, if I'm already moving near to Kerbin's rotation speed, I should be able to make the whole journey during the day, so long as I start by going west instead of east from the KSC. Another thing I did is I used the 1.25m Tail Connector nose cones instead of standard nosecones, as these produced significantly less drag.

1 hour ago, 18Watt said:

 

I have another question for you-  I'm also doing 16 blades per rotor, but am having difficulty getting the second set of 8 blades spaced evenly.  How did you do that?  Do you turn off angle snap?  The uneven spacing doesn't affect performance, just looks odd.

 

You can actually get pretty much any symmetry you want by multiplying symmetries together- this video explains it better than I could without screenshots.

 

 

 

[18Watt]

Ok, I'll stop after this.  Pontoon boat using twin MK2 hulls.  4 rotors, with 16 blades each.  goes about 179 m/s on water.

Spoiler

Not really sure how fast it goes on land.  Faster than I'd ever want to go, that's for sure.

A little over 180 on water, but I don't have enough solar panels to keep up..

Enough solar panels to keep up with the load, I'm getting about 179 m/s.  Pretty stable, and can even be turned while going that fast.  It does slow down a bit when turning.

 

The biggest remaining problem is that if I slow down suddenly the front nose cones are destroyed.  If I slow down carefully I'm ok though.  To slow down I first lower the nose a little, by reducing the angle on the horizontal fins.  Then I back off on the torque until I'm down to 120 or less.  Under 120 I can maneuver freely, without worrying about the nose cones disappearing.

[Pouicpouic]

7 hours ago, 18Watt said:

I suspect the MK2 fuselage is generating some lift, which is causing the boat to sit higher in the water- which is in turn reducing drag, and allowing better speed.  Just a theory.

I quite agree with this theory. I'm always afraid of the stability with the mk2, but your craft seems ready for a sub 6h trip !

7 hours ago, 18Watt said:

I'm having issues with the front nose-cone getting destroyed.

so remove them ? (if they dont affect performances)

2 hours ago, 18Watt said:

 Then I back off on the torque until I'm down to 120 or less.  Under 120 I can maneuver freely

With my model I also had to slow down around 130 to take turns

7 hours ago, 18Watt said:

I'm also doing 16 blades per rotor, but am having difficulty getting the second set of 8 blades spaced evenly.  How did you do that?  Do you turn off angle snap?  The uneven spacing doesn't affect performance,

Thanks @Jack Joseph Kerman, I would have struggled to explain the symmetry trick without this video.

5 hours ago, Jack Joseph Kerman said:

each of which have 24 blades on them

Do you think its better than 16 ?

5 hours ago, Jack Joseph Kerman said:

Another thing I did is I used the 1.25m Tail Connector nose cones instead of standard nosecones

I'm quite confused with this drag thing, I need some clarifications. KSP wiki shows drag values that do not match the text description:
Aerodynamic Nose Cone: drag 0,1
Advanced Nose Cone: drag 0,1 but the description text says: "It has 2.5× the mass but 55% the drag of the Aerodynamic Nose Cone" ?
Tail Connector : drag 0,2

I don't know how to think at this point ? plz help

5 hours ago, Jack Joseph Kerman said:

Instead of using RTGs, I decided to go for an entirely solar-powered build

Yes, in the end it seems a wise choice!

[Pouicpouic]

5 minutes ago, Pouicpouic said:

5 hours ago, Jack Joseph Kerman said:

Instead of using RTGs, I decided to go for an entirely solar-powered build

Yes, in the end it seems a wise choice!

Check that at 45° North you still have enough solar power (I'm thinking about this suddenly)

[18Watt]

7 hours ago, Pouicpouic said:

KSP wiki shows drag values

I would not trust drag info in the wiki.  KSP’s atmospheric and drag models have changed dramatically in several versions.  The wiki has not kept up with the changes.  Unfortunately I’m not sure where to point you for accurate atmospheric and drag information.

Edit:  I added a copy of my latest MK2 pontoon boat to another challenge:

 

[damerell]

Could one of you rotor-powered types estimate the thrust to mass ratio of your craft? I'm trying to work out if my nuclear thermal jet idea is at all feasible.

[18Watt]

22 minutes ago, damerell said:

Could one of you rotor-powered types estimate the thrust to mass ratio of your craft?

Near sea level I was able to climb vertically at over 170 m/s.  I’d roughly estimate thrust to mass at 1.5.

I’d add that for the Elcano challenge, there are no bonus points for speed.  Your name goes on the list wether you complete it in 1 day or 1,000 days.

Edit-  You don’t need anywhere near that thrust to make a very capable rover/boat.  We’ve been having a bit of fun, curious how fast you can get a boat to go with stock parts.  On land, speed is not really your friend- as you already know!  

[Pouicpouic]

11 hours ago, 18Watt said:

I’d roughly estimate thrust to mass at 1.5

You don't think it's much more than 1,5 in the first sec of flight? otherwise it would take longer to reach max speed. I'd say TWR > 4, but then it quickly decreases near 1 when reaching 90% of max speed. Here the mass does not change but the thrust varies enormously according to the speed.

[damerell]

16 hours ago, 18Watt said:

Edit-  You don’t need anywhere near that thrust to make a very capable rover/boat.  We’ve been having a bit of fun, curious how fast you can get a boat to go with stock parts.  On land, speed is not really your friend- as you already know!  

Oh, I know - I'm just wondering how fast I can get a boat to go with modded parts (which are no more magic than stock solar / rotors ;-)

ETA: as far as I can see the answer is "not very" - these NTJs are heavy and unlike electrically powered propulsion the entire added mass is in one place which has to be above the waterline (I'm aware KSP will let the engine run quite happily while immersed but I might roll an eye at that); the resulting boat wants to nose into the waves about 70 km/h, and while I've experimented a bit with hydrofoil configurations my understanding of stock drag is nonexistent.

Edited August 15, 2022 by damerell

[Pouicpouic]

19 hours ago, 18Watt said:

I’d roughly estimate thrust to mass at 1.5

G force approaching red zone ! far more than 1.5

About 8G here being far from max power (pressing 3 keys in less than 1s), so I would say a TWR close to 9 or 10 with best settings in the first seconds.

[Pouicpouic]

Nice, i have a consistent 184-185m/s with no risk of flying away at any moment but it feels like it's borderline.

[Pouicpouic]

What an improvement ! (This is not the total history, only since the beginning of 2021 --> there may have been better attempts before that, I'll have to go back up the forums for an update) // @Poppa Wheelie with mods //

Who will be next? (Not me, I'm currently on a shipment to Laythe and Eve)

[MythicalHeFF]

3 hours ago, Pouicpouic said:

Nice, i have a consistent 184-185m/s with no risk of flying away at any moment but it feels like it's borderline.

That tactical flag use is pure genius. Bravo!

[Pouicpouic]

8 hours ago, Jack Joseph Kerman said:

That tactical flag use is pure genius.

Not my genius, I stole @QF9E's one, seen in the 100EC challenge

Edited August 16, 2022 by Pouicpouic

[Pouicpouic]

Mission to Laythe with "The Kraken's Breath"

This is the penultimate missing circumnavigation for me (Laythe by sea)

KSC - Laythe :

Spoiler

First stage dropped

Leaving Kerbin...

...for the joolian system. Tylo assist as usual

dropped last stage in suborbital traj, no more fuel now

so beautiful

11m/s a bit fast, need to activate the propellers

ready

Circumnavigation

Spoiler

Starting D235 03h34 at 2°09 S / 19°19 W

Let's start gently

+200m/s but im not at max power, just didn't want to reload because of my greed for speed. At this speed, i guess the frontal nose cones won't last long

Almost 1h - back in the northern hemisphere (My journey is going to be mostly south, so if I cross the equator twice to the north on each side of the planet, I would be sure to have covered a distance greater than the perimeter)

Lost Kerbnet access (as usual ) - but only 20 minutes

First stop, i close the game for tonight.

Let's go, frontal nose cones are still alive... it's time to push now

let's see what you're made of "Kraken's Breath" !

1h30 (oh yeah 222m/s ! - It shakes on all sides! So much so that it makes me nauseous )

2h10 (half the journey is over)

3h - approaching my second break

Break next to one of my masterpieces. It reminds me of the good old days, when I allowed myself to play at less than 10FPS.

Here is "Laythe Triforce". So majestic, I loved this project !

Triforce because there is the helicopter and a submarine hidden in a cargo bay.

launch of this monster in video : https://www.twitch.tv/videos/1199631729

Ok guys, the break is over, let's cross the great ocean of laythe and go back to northern hemisphere.

3h30

almost 4h

only some km left (need to cross 19°19W)

line crossed Day236 - 1h48

Circumnavigation done in 4h14 min ! Raw average speed : 206m/s

The Kraken's Breath :

6 medium rotors, 24 blades each, 48 RTG... And the most important : tentacles

Now let's see if this craft can survive Eve or if I need to make some changes.

[damerell]

Coo, your Laytheboat is more aerodynamic than mine. Launching it from Kerbin posed considerable difficulties. Mind you, it is built to sail in Scatterer waves.

[Piatzin]

Well while you guys are here doing fancy things with rotors and pontoons and 100+ m/s speeds, I have gone ahead and launched some overweight aggregations of fuel tanks, jet engines and weaponry. There are three ships in this convoy, all military and unmanned. They are not a formal attempt at the challenge, but rather a first foray to see what works and what doesn't, how well the ships handle stress, the distances, mining and land-traversing, etc. The members of the expedition are...

A Fjellborg-class ship in the noodle-platform configuration (as opposed to the medium-platform configuration, these are very official and technical names, you understand). Fjellborg is not fitted for ISRU or terrestrial operations; it's only real role is eye-candy and to lug around the VTOL on its back, which I'll use to scout out low-incline beaches.

Then we have Renegade, a slightly older version of a ship class that currently goes by Vindjeger. Renegade has all the equipment that is expected to be necessary for the real deal - ore processors, drills, action-keyed rocket engines for moving left and right and backwards (or braking fast) and steel beams at the front to protect the fuel tanks when climbing up onto land.

Then there's Paladin, the original prototype for the modern Fjellborg class. Paladin is essentially a fatter, slower renegade. I added vectors at the back for fear that its engine block would be insufficient to push it up onto land.

An overhead comparison shot for the curious:

Spoiler

I'm probably only going to take these three to the southern tip of the KSC continent and perform a trial landing there.

All this being said though, big ships like these are dreadfully slow and for the real attempt I think I will use smaller and faster craft (also note that this formal attempt will not use military ships).

In the meantime...

Spoiler

...the convoy departs from the KSC waters...

Edited August 18, 2022 by Piatzin

[MythicalHeFF]

Just did a Kerbin sea circumnavigation in a rather disappointing 6h 7m. Although I still managed to improve upon  @Pouicpouic's previous record by about 45 minutes, what I was really aiming for was to finish in less than 6 hours. I'm almost sure that this was due to my route not being 100% optimal, with me having just followed the same route I took when I did my first Kerbin circumnavigation a few months ago (without cutting across the peninsula east of the KSC this time). Ah well, guess I'll have to try again.

Average speed: 170.8 m/s

I present to you the KELP-182 "Lightning", called this because its top speed in testing was about 182 m/s. I finally decided to just do away with solar panels entirely, as I realized that they simply weren't going to cut it for power generation at higher latitudes. Instead, I've crammed about 28 RTGs into the back service bay behind Jeb's seat.

Screenshots:

Spoiler

10 or so minutes after departure, 100 km covered already!

T + 18m, 4s, first KerbNet marker from original KELP mission reached

Going around the peninsula this time

Heading northeast to the land crossing

Nightfall

Losing a little bit of speed due to the increased density of the air, thanks to the lower temperatures. Normally, denser air would mean that I could go faster, but because the rotors aren't operating at full RPM to begin with, they gradually lose RPM as I go further north. Not exactly ideal.

Only got worse from there

T + 2:00:00, approaching the land crossing

Land crossing. Another design flaw with the KELP-182 is that its nose cones are very long, and thus hit the ground easily. Their abysmal impact tolerance of 8 m/s sure didn't help, either. I must have reloaded the game at least 30 times during this land crossing.

Crossed the lake in about 5 minutes

After yet more annoying climbing and several more reloads, I was finally on flat-ish ground, and could really crank up the speed to regain some of the lost time.

Once I re-entered the water, I was suddenly able to go much faster- over 200 m/s. I have no idea why, as the blades were still pumping out about the same RPM. Maybe the way I had the landing gear affected the buoyancy of the back pontoons somehow? Regardless, I'll take it.

3 hours in

Topped out at 210 m/s near the equator

Passing below the southern island chain southwest of the KSC. This turned out to be a big mistake, and is what probably cost me the sub-6 hour run. If I had gone north of them instead, I would have a) been able to go faster because of the higher temperature, and b) probably not have had to travel as far in the first place.

Final mad dash to the KSC- no- we aren't going to make it...

Finish

 

The disappointment in Jeb's face is unreal.

Edit: I'm planning on making a YouTube video about this adventure and its hopefully more successful successor, as well as the development and design process of the vehicle and the sort of "competition" that's been going on here lately.

Edited August 19, 2022 by Jack Joseph Kerman

[18Watt]

6 hours ago, Jack Joseph Kerman said:

I finally decided to just do away with solar panels entirely, as I realized that they simply weren't going to cut it for power generation at higher latitudes.

Yeah, I was wondering about that.  The weight savings is very useful, but I wondered how they would work at 45N or so.

6 hours ago, Jack Joseph Kerman said:

Going around the peninsula this time

Sorry about that..

6 hours ago, Jack Joseph Kerman said:

I was suddenly able to go much faster- over 200 m/s. I have no idea why,

I have also struggled to explain changes in indicated speed at different latitudes.

Awesome run!  

[Pouicpouic]

On 8/19/2022 at 11:11 PM, Jack Joseph Kerman said:

KELP-182 "Lightning"

Beautiful craft ! Awesome run ! In the footsteps of "Spirit of Australia", the speed record holder on the water (IRL, 142m/s official, with a peak speed of 555 km/h - 154m/s - 345 mph - 300 kn) !

On 8/19/2022 at 11:11 PM, Jack Joseph Kerman said:

I was really aiming for was to finish in less than 6 hours. I'm almost sure that this was due to my route not being 100% optimal

No doubt that by following a perfect route the sub-6 hour mark was a reality!

On 8/19/2022 at 11:11 PM, Jack Joseph Kerman said:

Average speed: 170.8 m/s

Raw average 3770km : 174.5m/s

On 8/19/2022 at 11:11 PM, Jack Joseph Kerman said:

I'm planning on making a YouTube video about this adventure and its hopefully more successful successor, as well as the development and design process of the vehicle and the sort of "competition" that's been going on here lately

That would be really great! If you need help with anything, don't hesitate to ask.

Edited August 26, 2022 by Pouicpouic

[king of nowhere]

I accidentally made an Ovok circumnavigation here

Basically, I was going to Polta for a circumnagivation there, I stopped for refueling on Ovok, and I thought, since I'm there I may as well.

 

I propose, since adding a new leaderboard for all modded planets would be highly impractical, to simply add another category, like "modded planet circumnavigators", or maybe "hexoplanet circumnavigators". My OPM submissions could go there.

 

My Wal circumnavigation is still halfway. Wal is harsh, unforgiving, and -worst of all - monotonous and boring.