Supersonic Boat on Kerbin

[DigitalDread]

The water-speed challenge has been made before, but lets take it up a notch for 2020 before KSP2 gets here.

MISSION: 

Your mission is simple. Build a watercraft of any size, and use any propulsion method you prefer, as long as you are using only 100% vanilla KSP parts (yes, expansion included). With the exception of tweakscale, no other mods are allowed in this build. 

 

CONDITIONS:

1- Your watercraft must get to the water by land under its own power, or towed there by another vehicle of your construction. Its your choice, but it must get there by land (no flying, or teleportation to the water)

2-  Supersonic (343m/s) is the minimum entrance posting, with hypersonic (1715m/s) being the holy grail of Kerbal aquatic dreams. Imagine moving snacks across water at those speeds, yummy.

3- Whats the point of a watercraft if there are no passengers, so your watercraft must be able to transport a minimum of 20 Kerbals. 

4- Finally, to truly claim the supersonic trophy, your watercraft must stay at or above its max supersonic speed for a minimum of 20 seconds so Bill Kerman has enough time to eat his cookies as supersonic

5- Post a link to your video to show evidence of your mad science in action...

 

SCORING:

Speed: Mach 1 = 100 points, Mach 2 = 200 points, Mach 3 = 400 points, Mach 4 = 800 points, Mach 5 = 1600 points, Mach 6 = have you lost your snacks... thats not possible

Seating: 20 Kerbals = 100 points, 24 Kerbals = 200 points, 28 Kerbals = 300 points, 32 Kerbals = 400 points, 40 kerbals = 500

[Mopoii]

I doubt this is possible, do you have any results of your own ?

[sturmhauke]

Supersonic might be possible, but as far as I'm aware no one has ever done it, at least not publicly. I'm going to go ahead and say that it's not remotely possible to get a boat moving at 1700 m/s, considering that aircraft are already in danger of melting at that speed.

[Bej Kerman]

10 hours ago, DigitalDread said:

With the exception of tweakscale, no other mods are allowed in this build.

Why?

[Mikenike]

1 hour ago, Bej Kerman said:

Why?

Prolly cause he gonna make MK3 parts into 0.625m size.

[Bej Kerman]

I don't think TweakScale should be allowed. You can abuse it pretty bad, and the rules already say stock parts only, so I'm not sure what makes scaled parts "stock".

[sturmhauke]

3 minutes ago, Bej Kerman said:

I don't think TweakScale should be allowed. You can abuse it pretty bad, and the rules already say stock parts only, so I'm not sure what makes scaled parts "stock".

True, but Tweakscale isn't gonna help you get around the thermal or stress tolerances.

[vyznev]

Given Kerbin's treacle-like water, I suspect that the best way to do this — if it's possible at all — is to have as little of the boat in the water as possible. So basically make a supersonic plane that will fly straight and almost level at 0 meters ASL, and then dip a couple of small "hydrofoils" in the water to provide a tiny bit of extra lift. And make those hydrofoils as sturdy as possible.

…which I suspect may be the showstopper here. I'm not sure exactly how KSP models objects interacting with water, but I have a hunch that any part hitting water at any speed higher than its "maximum impact tolerance" is just going to shatter. And I don't think there are any stock parts with impact tolerances higher than 300 m/s.

[sturmhauke]

19 minutes ago, vyznev said:

I'm not sure exactly how KSP models objects interacting with water, but I have a hunch that any part hitting water at any speed higher than its "maximum impact tolerance" is just going to shatter. And I don't think there are any stock parts with impact tolerances higher than 300 m/s.

Given my experience (crash) landing in water, and making hydrofoils, that sounds about right. My personal water speed record is about 115 m/s, although there certainly have been faster times from other people.

[Bej Kerman]

50 minutes ago, sturmhauke said:

True, but Tweakscale isn't gonna help you get around the thermal or stress tolerances.

Still, no point in a challenge if you can just attach a 5m jet to a cockpit with some fuel tanks and watch it go.

[Mikenike]

14 hours ago, Bej Kerman said:

Still, no point in a challenge if you can just attach a 5m jet to a cockpit with some fuel tanks and watch it go.

Or making a massive fuel stack with Rhino, and shrinking it.

[DigitalDread]

Supersonic on water is definitely possible, I have made supersonics watercrafts before. As for the Tweakscale questions, for those who have been playing KSP for awhile now will remember that the early versions of the game included different sizes of all the parts. Tweakscale just allows us to make larger parts with the vanilla game. I have tried a few versions of supersonic watercrafts before and larger isn't always better. 5M with a jet presents a few problems of its own. The weight, the balance, the simple act of getting to the water in one piece. When it comes to KSP builds, I will be the first to admit that I'm a rookie. But with my limited skill, I can get to mach 3 with 20 Kerbs onboard, then one of you more experienced and highly skilled builders can surely obliterate my score.  

 

 

[Mikenike]

3 hours ago, DigitalDread said:

Supersonic on water is definitely possible, I have made supersonics watercrafts before. As for the Tweakscale questions, for those who have been playing KSP for awhile now will remember that the early versions of the game included different sizes of all the parts. Tweakscale just allows us to make larger parts with the vanilla game. I have tried a few versions of supersonic watercrafts before and larger isn't always better. 5M with a jet presents a few problems of its own. The weight, the balance, the simple act of getting to the water in one piece. When it comes to KSP builds, I will be the first to admit that I'm a rookie. But with my limited skill, I can get to mach 3 with 20 Kerbs onboard, then one of you more experienced and highly skilled builders can surely obliterate my score.  

 

 

Well, proof it can be done, now somebody needs to kick it away, hmph, maybe I’ll give it a shot.

[Bej Kerman]

8 hours ago, DigitalDread said:

Supersonic on water is definitely possible, I have made supersonics watercrafts before. As for the Tweakscale questions, for those who have been playing KSP for awhile now will remember that the early versions of the game included different sizes of all the parts. Tweakscale just allows us to make larger parts with the vanilla game. I have tried a few versions of supersonic watercrafts before and larger isn't always better. 5M with a jet presents a few problems of its own. The weight, the balance, the simple act of getting to the water in one piece. When it comes to KSP builds, I will be the first to admit that I'm a rookie. But with my limited skill, I can get to mach 3 with 20 Kerbs onboard, then one of you more experienced and highly skilled builders can surely obliterate my score.  

 

 

Still, doesn't make sense if this is a supposedly 'stock' challenge. Quite unbalanced too. I mean, scaling up a 1.125m part or scaling down a 2.5m part makes them perform unrealistically given that they were made specifically for their sizes. Imagine how much more OP the Vector would be if you could scale it up to 5m rather than having to use engine clusters. At least it would be better if you had to say if your boat was stock or not.

Edited March 10, 2020 by Bej Kerman

[mystifeid]

2 hours ago, Bej Kerman said:

Still, doesn't make sense if this is a supposedly 'stock' challenge. Quite unbalanced too. I mean, scaling up a 1.125m part or scaling down a 2.5m part makes them perform unrealistically given that they were made specifically for their sizes. Imagine how much more OP the Vector would be if you could scale it up to 5m rather than having to use engine clusters. At least it would be better if you had to say if your boat was stock or not.

I don't get it. He's playing the game his way and inviting you to do the same. If you don't want to do that then that's fine but when half the game doesn't make sense, arguing about semantics seems like a bizarre and futile exercise. It is no wonder that the OP has chosen the name "DigitalDread".

Welcome to the forums btw @DigitalDread - I think your boat is pretty cool.

[Pds314]

Hmm... My problem seems to be that aquatic stability anywhere close to mach 1 is difficult. That being said, I don't think this challenge is impossible.

Edited March 11, 2020 by Pds314

[Pds314]

I must acquire MOAR BOOSTERS!

[Pds314]

Regarding the possibility of mach-6.... My suspicion is you could do it with an OP fuel-less propulsion system like drain valve overclocking, but I'm not 100% sure how water in KSP deals the the Eotvos. Also aero-thermal problems would quickly make all of that irrelevant as your craft melts.

[Pds314]

Mach 2.74 reached with 33 Kerbals. It stayed above mach 2 for 22 seconds. Total score = 600. Let the games begin.

At launch, the vehicle is heavier than a Saturn V and could actually fit one inside of it.

Edited March 11, 2020 by Pds314

[Pds314]

Just gonna boost my score to 700 by increasing Kerbals to 49. So far I can't break Mach 3, let alone break it and hold it above mach 3 for 20 s. So this is still a Mach 2 run (Mach 2.85 top speed).

Looking at the scoring system, you're gonna need to break Mach 3 for 20 seconds with >=32 Kerbals to beat me. Or break Mach 4 for 20 seconds.

Edited March 11, 2020 by Pds314

[Pds314]

As to the tweakscale question, I personally will not count your entry if you tweakscale a critical component. That being said I'm not the OP.

[XLjedi]

There is a max speed that any one part is capable of maintaining contact with water before it fails in spectacular fashion.  In my own hydrofoil testing the Vne speed seems to be around 125 m/s.  Granted, I have not tested EVERY part, but I have set 125 as my limit when in contact with water.

I s'pose it coulda been stress on my foils that caused the fail though...  It was a pretty big ship (400 tons) and built for sustained long distance runs, as opposed to a 20 second sprint.

Spoiler

 

 

Edited March 11, 2020 by XLjedi

[Pds314]

2 hours ago, XLjedi said:

There is a max speed that any one part is capable of maintaining contact with water before it fails in spectacular fashion.  In my own hydrofoil testing the Vne speed seems to be around 125 m/s.  Granted, I have not tested EVERY part, but I have set 125 as my limit when in contact with water.

I s'pose it coulda been stress on my foils that caused the fail though...  It was a pretty big ship (400 tons) and built for sustained long distance runs, as opposed to a 20 second sprint.

  Hide contents

 

 

Fairings can survive contact with the water at absurd speeds, and can even survive splashing at absurd speeds. I almost always use a fairing for any boat hull of any significant size.

Edited March 11, 2020 by Pds314

[Bej Kerman]

20 hours ago, mystifeid said:

22 hours ago, Bej Kerman said:

Still, doesn't make sense if this is a supposedly 'stock' challenge. Quite unbalanced too. I mean, scaling up a 1.125m part or scaling down a 2.5m part makes them perform unrealistically given that they were made specifically for their sizes. Imagine how much more OP the Vector would be if you could scale it up to 5m rather than having to use engine clusters. At least it would be better if you had to say if your boat was stock or not.

I don't get it. He's playing the game his way and inviting you to do the same. If you don't want to do that then that's fine but when half the game doesn't make sense, arguing about semantics seems like a bizarre and futile exercise. It is no wonder that the OP has chosen the name "DigitalDread".

Welcome to the forums btw @DigitalDread - I think your boat is pretty cool.

Christ on a bike, I was just saying that perhaps tweakscale on a public challenge may not be ideal given that it might be difficult to tell apart from stock parts.

[Lisias]

3 hours ago, Bej Kerman said:

Christ on a bike, I was just saying that perhaps tweakscale on a public challenge may not be ideal given that it might be difficult to tell apart from stock parts.

Except that the guy explicitly allowed TweakScale, so it's not a pure stock challenge.  So the argument itself is bogus.

On your original post, you complained about how unrealistically TweakScale scales parts. Well, I can say for sure: it depends. The scaling is doing using linear, quadratic or cubic exponents depending on how you configure the receipts.

From my experiments, engines are tricky to scale because in the real life the trust don't scale on a linear curve as the current configs is set, but instead tends to scale on a logarithm or exponential curve - what's theoretically possible if someone rewrites the patches (the scale is not limited to 2 or 3, you can use rational numbers as 0.123 or 2.444 too!). It only happens that nobody did it to this day.

So I agree that scaled jet engines can be shady on a contest. However, it can be very handy for propelled engines used on Firespitter and KAX.

Control surfaces and wings behave very well on scaling by the way, this allow you to do some very nice looking crafts. Way more realistic than clipping lots of parts in order to get something near what you indented to do - clipping two wings parts to look as one 50% bigger (150% of the original size) will give you twice the drag and twice the lift, while a scaled part to 150% will give exactly what you intend.

And the wheels on the Beta too (to be released soon™), with the sturdiness and strength correctly scaled with the sizing.

(and.. by the way.... How realistic is a "space simulator" with green guys poofing around on a planet with a soup as atmosphere and one third the size of the Earth but with the same gravity? Had I missed something? )