Juno water speed record

[Pds314]

 

You have a single J-20 Juno engine. Your goal is to make a seaworthy boat and reach the fastest speed you can.

Rules
Your boat must be able to survive at this top speed and slow down afterward. It's okay if it takes minor damage, but it must be usable afterward.

This is a challenge for aquatic vehicles only. No seaplanes. Or at least, no taking off. And while we're at it, the vehicle must contain a Kerbal. They can be in a pod, in a seat, in a cargo bay, on a ladder, sitting on the bow of the ship hanging on for dear life. Anything goes.

Please notify me of what mods you're using on your craft and world. Especially if you use mods that alter air or water physics.
 

Scoreboard - FAR

1.  Pds314 in the Jet canoe v1.4: 290.0 m/s
2. ...
3. ...

Scoreboard - Stock

1. crashsolo36 in the Super "B": 155.7 m/s
2. GDJ in the ???: 124.7 m/s
3. swjr-swis in the TinyBoat2c: 90.4 m/s
4. Pds314 in the Hydrosegway: 77.4 m/s
5. Geschosskopf in ???: 73.9 m/s
6. Grenartia in the Sea missile: 63.6 m/s
7. ...

 

 

My entry

209.4 m/s!

Slowing down.

Passing close to the Island. 250.9 m/s! Above ~215 it starts to lean. It actually chopped off one of the airbrakes here.

Slowing down again, sans a brake. Still perfectly functional.

 

EDIT:

Optimized the control logic. Goes to 290.0 now without rolling.

 

Slowing down from it's airliner-like speeds.

Edited January 27, 2016 by Pds314

[swjr-swis]

Nice boat. Near-Mach speeds over water actually got me interested, so I tried your design. Alas, FAR must change water physics as well as aero these days, cause in pure stock I can't get it past 35m/s or so. Tried several variations to lift it more off the water, but as long as any part of the hull touches the surface it appears I'm stuck at 'submerged' speeds.

So unless there some trick to this, this challenge won't be much fun for stock installs.

 

[Foxster]

You can do anything with mods <shrugs and moves on...>

[Grenartia]

First attempt, didn't even get to 17m/s in water (though I did get airborne getting to the water). Using Quiztech's intake air RCS, alongside MechJeb (just for information). Stock aero.

[Pds314]

3 hours ago, swjr-swis said:

Nice boat. Near-Mach speeds over water actually got me interested, so I tried your design. Alas, FAR must change water physics as well as aero these days, cause in pure stock I can't get it past 35m/s or so. Tried several variations to lift it more off the water, but as long as any part of the hull touches the surface it appears I'm stuck at 'submerged' speeds.

So unless there some trick to this, this challenge won't be much fun for stock installs.

 

Did you empty it of oxidizer? There's no way it will get high enough on the water if it's full of oxidizer.

EDIT: nevermind. You're right. I couldn't get it past 39.1 m/s. I suspect this is related to stock water physics naively assuming everything is roughly a cylindrical or ball shape in the water. Due to this, I shall make FAR and stock leaderboards seperate.

 

Managed 77.4 m/s in stock via a segway hydrofoil craft. Dang stock hydro is annoying.

Edited January 2, 2016 by Pds314

[Grenartia]

Btw, my design is the ever so creatively named "Hydroplane 1". I've made a stripped down version called "Sea Missile 1". No control surfaces whatsoever, and aside from the Intake RCS, MJ, and Buffalo MSEV parts (the latter used to get it from the runway to the water), entirely stock. About to make my run now, will post screenies in a few.

[Grenartia]

I got it as high as 38.9m/s. Within spitting distance of the previous 39m/s claim.

 

The Sea Missile 1 with carriage:

 

Edited January 2, 2016 by Grenartia

[Grenartia]

Hold on, I just broke 39.3m/s. I left it running while posting. I'm going to wait until it runs out of fuel to post further screenshots.

[Grenartia]

Ultimate final speed: 41.2m/s.

As you can see, Sea Missile 1 is perfectly safe and sound, with the obvious exception of lack of fuel:

And proof of the speed record:



Once I reached 39.7m/s, it started slowing down a bit, and I thought that would be my record, but then I readjusted my pitch a bit (it wasn't super weird or anything, just making sure it was dead on the horizon), and that got it up to 40m/s. After a few minutes, I reached top speed.

[Pds314]

I've been trying to make some form of hydroplane boat that looks more conventional, and failing miserably. I got a hydroplane unicycle thing up to ~65 m/s, but it's totally unstable.

[Grenartia]

39 minutes ago, Pds314 said:

I've been trying to make some form of hydroplane boat that looks more conventional, and failing miserably. I got a hydroplane unicycle thing up to ~65 m/s, but it's totally unstable.

Got pics?

Also, by removing the reaction wheels, probe core, battery, intake RCS, and airbrakes (and reconfiguring the design so that I'm not left with that structural mount after detachment, I've gotten my Sea Missile 1 up to 58m/s (excuse me, spoke too soon) 63.6m/s. And its still very stable.

Edited January 2, 2016 by Grenartia

[Geschosskopf]

I tinkered with this a bit.  Using stock air.  I went for lightness, not sleekness.

This was absolutely the fastest I ever got ON THE WATER., 73.9m/s  And it actually slowed down and stopped safely from this speed.  However, the boat starts getting unstable at about 68m/s, pitching up and down with the speed going +/- 2-3m/s on either side of 70m/s.  If I don't throttle down quickly at this point, the boat will become airborne.  In the AIR, this thing will reach about 150m/s and over 500m altitude before I lose control and it tumbles to a fatal splashdown

So I'm thinking stock air has an on-water speed limit of under 100m/s.

[Grenartia]

4 minutes ago, Geschosskopf said:

I tinkered with this a bit.  Using stock air.  I went for lightness, not sleekness.

This was absolutely the fastest I ever got ON THE WATER., 73.9m/s  And it actually slowed down and stopped safely from this speed.  However, the boat starts getting unstable at about 68m/s, pitching up and down with the speed going +/- 2-3m/s on either side of 70m/s.  If I don't throttle down quickly at this point, the boat will become airborne.  In the AIR, this thing will reach about 150m/s and over 500m altitude before I lose control and it tumbles to a fatal splashdown

So I'm thinking stock air has an on-water speed limit of under 100m/s.

I see we were separately thinking the same thing as far as pontoons go.

[jwbrase]

6 hours ago, Pds314 said:

Managed 77.4 m/s in stock via a segway hydrofoil craft. Dang stock hydro is annoying.

The fastest any practical watercraft has travelled IRL is around 35 m/s. Vessels specifically designed to break records have reached up to around 150 m/s, but since about the 60 m/s point, 85% of would-be record breakers have died in the attempt. So maximum speeds in stock seem to be broadly commensurate with reality, even if the dynamics aren't quite.
 

[Grenartia]

My idea of strapping pontoons onto my Sea Missile made it highly unstable (like, it'd go 10 meters, dip the nose into the water, then go back, and repeat). So I'm abandoning that approach. I believe the key is minimizing hydrodynamic drag. AFAIK, the key to this is minimizing the number of parts in the water.

In pursuit of that, I tried this:

 

Yeah, that's top speed.

Edited January 2, 2016 by Grenartia

[crashsolo36]

Posted 2 hours ago · Report post

3 hours ago, Geschosskopf said:

I tinkered with this a bit.  Using stock air.  I went for lightness, not sleekness.

This was absolutely the fastest I ever got ON THE WATER., 73.9m/s  And it actually slowed down and stopped safely from this speed.  However, the boat starts getting unstable at about 68m/s, pitching up and down with the speed going +/- 2-3m/s on either side of 70m/s.  If I don't throttle down quickly at this point, the boat will become airborne.  In the AIR, this thing will reach about 150m/s and over 500m altitude before I lose control and it tumbles to a fatal splashdown

So I'm thinking stock air has an on-water speed limit of under 100m/s.

ok so i''m here to be crowned the fastest!!!!! My Entry is called the Super "B" (Stock) top speed is 155.7 ms and traveling at an altitude of 0m. I didn't use any mods like FAR or parts mods its all stock....

just sittin there waitin.... Jeb not even knowing whats gonna hit him..Oops First attempt didn't go well.. it rolled then everything went wrong..

did a few tweaks and second attempt went well top speed 155.7. I didn't add airbrakes cause they add drag plus weight. so instead I use the spoiler in the back to slow down when deployed.. check it out here too.. plus any other crafts...

http://www.ksp-players.com/en/logbook/crashsolo36/crafts/368

http://www.ksp-players.com/en/logbook/crashsolo36

 

Edited January 2, 2016 by crashsolo36

[Grenartia]

50 minutes ago, crashsolo36 said:

Posted 2 hours ago · Report post

ok so i''m here to be crowned the fastest!!!!! My Entry is called the Super "B" (Stock) top speed is 155.7 ms and traveling at an altitude of 0m. I didn't use any mods like FAR or parts mods its all stock....

just sittin there waitin.... Jeb not even knowing whats gonna hit him..Oops First attempt didn't go well.. it rolled then everything went wrong..

did a few tweaks and second attempt went well top speed 155.7. I didn't add airbrakes cause they add drag plus weight. so instead I use the spoiler in the back to slow down when deployed.. check it out here too.. plus any other crafts...

http://www.ksp-players.com/en/logbook/crashsolo36/crafts/368

http://www.ksp-players.com/en/logbook/crashsolo36

 

Interesting design, I must say.

On the other hand, I tried building a 0.625m version of my Sea Missile, only to instead, find out I'd built an underwater rover.

[Geschosskopf]

7 hours ago, jwbrase said:

The fastest any practical watercraft has travelled IRL is around 35 m/s. Vessels specifically designed to break records have reached up to around 150 m/s, but since about the 60 m/s point, 85% of would-be record breakers have died in the attempt. So maximum speeds in stock seem to be broadly commensurate with reality, even if the dynamics aren't quite.\

Well, in this particular case, stock air/water isn't the limiting factor, it's the low power of the specified Juno engine.  In the "unlimited / outlaw" class of racing boats, a 100% stock boat in 100% stock air can actually reach Mach 1, although losing at least the tip of the bow when slowing down again is almost unavoidable.

6 hours ago, crashsolo36 said:

Posted 2 hours ago · Report post

ok so i''m here to be crowned the fastest!!!!! My Entry is called the Super "B" (Stock) top speed is 155.7 ms and traveling at an altitude of 0m. I didn't use any mods like FAR or parts mods its all stock....

Hey, that's pretty cool.  Congrats

 

[Pds314]

10 hours ago, crashsolo36 said:

Posted 2 hours ago · Report post

ok so i''m here to be crowned the fastest!!!!! My Entry is called the Super "B" (Stock) top speed is 155.7 ms and traveling at an altitude of 0m. I didn't use any mods like FAR or parts mods its all stock....

Wow. 155.7 m/s. And here I was thinking that the practical limit in stock was ~90 m/s.

[Pds314]

I think the reason FAR allows for extremely optimistic boating is that, first of all, the shape you see is the shape you get, so you can make realistically sleek craft.

And second, is that it assumes that the craft rides up on compressible water that can all be shoved out of the way, rather than assuming it generates an incompressible rolling wake that makes it dramatically less efficient.

 

Stock makes the same errors as FAR, but it also makes an additional simplification in determining the shape of objects. So stock is like throwing bricks through super-optimistic water, whilst FAR is like throwing real boats through super-optimistic water.

So FAR allows submarines to be nearly realistic, except they become faster when they surface. Since the late 40s, real submarines actually generate less drag underwater, because at or near the surface, the wake ruins their ~0.1 drag coefficient.

Edited January 2, 2016 by Pds314

[swjr-swis]

On 1/2/2016 at 9:53 AM, crashsolo36 said:

Posted 2 hours ago · Report post

ok so i''m here to be crowned the fastest!!!!! My Entry is called the Super "B" (Stock) top speed is 155.7 ms and traveling at an altitude of 0m. I didn't use any mods like FAR or parts mods its all stock....

just sittin there waitin.... Jeb not even knowing whats gonna hit him..Oops First attempt didn't go well.. it rolled then everything went wrong..

did a few tweaks and second attempt went well top speed 155.7. I didn't add airbrakes cause they add drag plus weight. so instead I use the spoiler in the back to slow down when deployed.. check it out here too.. plus any other crafts...

http://www.ksp-players.com/en/logbook/crashsolo36/crafts/368

http://www.ksp-players.com/en/logbook/crashsolo36

 

@crashsolo36 First of all, I like your design. Out of principle. A hydrofoil, in anywhere near realistic water and air physics, should be at the very top of any water speed attempt. So out of principle you deserve to be on the top spot of the stock list. Now for the but (yes, there is a but).

I wasn't able to download your craft file (registration wall), so I eyeballed your design and tested it after doing a few more or less scientific attempts myself with other designs to absolutely minimize air drag and part count touching the water. I've come to the conclusion that aside from the expected components of total part count, weight and air drag, water speed seems most affected by how many parts actually touch the water, more than anything else. So I tried to make stuff work with minimal total parts, weight and drag, but mostly with just three, two, or even just one part touching the water.

I was unable to get a one-part design stable enough to hit a top speed, but even with perfectly stable two-part designs, I couldn't push anything beyond slightly over 90m/s. My copy of your 'three-part' design (or 4/5 part, cause the vertical fins seem to dip their tips into the water too) stayed well under that speed... that is, as long as it did not actually lift off and fly.

I have to ask: are you absolutely sure your craft was not off the water at the time you hit that speed, just under 1m of altitude? I need to ask because 150-160m/s is about the max airspeed I got out of my copy of your craft in level flight at near sea level a few meters over the water.

To compare: the boat I post after this, essentially a flying wing with an engine strapped to it, which I cranked up to 90.4m/s while still actually (barely!) touching the water with the two wing tips, can rapidly speed up to 190-195m/s in level flight just above the water. I tried a couple times to take a screenshot at the exact moment it shows 0m altitude to prove the point, but I'm a lousy pilot and can't maintain straight-and-level flight, I finally gave up trying. Just legitimately wondering if your craft might've actually been flying instead of on the water, since max airspeed of it seems to be very close to your reported water speed.

That, or I miserably failed at reproducing your craft precisely, which I admit could easily be the case. But with three (or up to 5) parts touching the water, in my experimental theory anyway, I'd expect it to be maxed at about 60 maybe 70 at most (I didn't get my copy up to that even).

[swjr-swis]

On 1/1/2016 at 9:38 AM, Pds314 said:

You have a single J-20 Juno engine. Your goal is to make a seaworthy boat and reach the fastest speed you can.

@Pds314 A serious attempt at a spot on the stock leaderboard:

Pure stock 1.0.5 install. Recorded top speed while still on the water: 90.4m/s, 2nd picture.

Took a lot of retries and patience to get that one, missed recording a >91m/s speed another run by a split second before it ran out of fuel. Absolute top speeds are not sustainable for more than a few seconds, it invariably destabilizes just enough to gain more water resistance and slow to 65-75m/s before slowly speeding up again. But it hits 80-85m/s consistently with a minimum of fuel - empty the wings, leave 25 units in the center Mk0 tank, throttle to max and let it run.

It is balanced to not lift off even when full throttle at top speed. You will know if you lift off because air speed hits 180-190m/s in mere seconds and it will pitch up quickly. But unless you force it to by manually pitching up, it will not leave the water surface.

Craft file for independent verification and/or anyone interested in the boat or undercarriage: TinyBoat2c

Edited January 11, 2016 by swjr-swis
added craft file

[Pds314]

On 1/11/2016 at 10:37 AM, swjr-swis said:

@Pds314 A serious attempt at a spot on the stock leaderboard:

-Snipped-

Pure stock 1.0.5 install. Recorded top speed while still on the water: 90.4m/s, 2nd picture.

-Snipped-

Craft file for independent verification and/or anyone interested in the boat or undercarriage: TinyBoat2c

I really like this one. Very fast-looking. I suspect you may be right on crashsolo's design. It might be flying. I think I should give them the benefit of the doubt until it's shown that it is indeed flying though.

Edited January 24, 2016 by Pds314

[Lego8_bit]

OOOH A MICRO-BOAT CHALLENGE  Count me in on this on this one >:D

[Lego8_bit]

Say is it OK if I use b9 adjustable landing gear and tweak scale?