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V4 & V8 Diesel Catamarans

Azimech

By Azimech
in KSP1 The Spacecraft Exchange

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Azimech

Azimech

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Posted (edited)

Are these Detroit Diesels?

 

Stock V4 and V8 two-stroke with overhead camshafts

VNdrgQr.png

 

x9smixr.png

 

V4 specs:

Cylinder bank angle: 90°.
Piston drivers: 4x Panther in dry mode.
Stroke: 90cm.
Bore: We don't have compression so it doesn't matter.
Conrods: fork/blade type, this way the cylinder banks are evenly placed.
Main crankshaft bearings: 3x6 RCS balls.
Crank bearings: 4x20 RCS balls.
Max engine speed: 12.5 rad/s (120 rpm).
Economy cruise: throttle at 50%.
Top speed: ~12 m/s.
Propeller: 7 blades, fully adjustable.
Total part count with intake/exhaust stacks: 452.
Part count with the intake/exhaust stacks removed: 374.

V8 specs:

Cylinder bank angle: 90°.
Piston drivers: 8x Panther in dry mode.
Stroke: 90cm.
Bore: We don't have compression so it doesn't matter.
Crankshaft: Standard crossplane.
Camshafts: 2.
Conrods: fork/blade type, this way the cylinder banks are evenly placed.
Main crankshaft bearings: 5x6 RCS balls.
Crank bearings: 8x20 RCS balls.
Max engine speed: 10 rad/s (95 rpm).
Economy cruise: throttle at 50%.
Top speed: ~18 m/s.
Propeller: 9 blades, fully adjustable.
Part count: 568.
Output: 775kW @ 95 rpm.

The Goliath is just the air intake, it receives no fuel.

 

Instructions:

  1. Consider the removal of the intake/exhaust stacks (V4). Sure, they look nice but are as useful as Rick's butter passing robot. Top speed will increase. Also FPS.
  2. Also, the three Stack Tri-Adapters on the rear of the engine are just as useful. I think they look cool. You won't need them.
  3. Starting: just press stage. It will start turning. Lower throttle to 40% to be on the safe side.
  4. Change focus (left, once) and select a propeller blade. Pin it to the screen.
  5. Return focus to main. Now change the control authority towards 0. The boat starts to drive on the runway. Go wherever you like. Just remember, it can't climb hills.
  6. Increase throttle gradually while changing the propeller pitch towards higher values. Throttle at 75% is good, above it weird stuff might happen.
  7. If you overrev it, it will fail. I recommend to install V.O.I.D. to have a proper readout of the engine speed, in rad/s.
  8. Parking it: cut throttle. Set parking brake, adjust the braking power slider on the rover wheel to 200. When the boat is 100% dead in the water, you can save the game or leave.
 
 
 
While these machines are no real diesels, I use the mod Rover Wheel Sounds with my own sample to relax. Yes, I've recorded a Detroit Diesel :-P

You can download it in the link below, it’s the complete original mod but with added sounds and a changed configuration file. License is included. Just install manually like you would any other mod.
https://www.dropbox.com/s/xqq5x654t44d1z5/AzimechVehicleSounds_v10.zip?dl=0

 

Download V4 from KerbalX.

Download V8 from KerbalX.

Edited by Azimech
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Azimech

Azimech

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True. It's thanks to multiple people making discoveries and the combined knowledge. The big breakthrough is the discovery that you can make pretty sturdy bearings with RCS balls. This means the old landing gears bearings have fallen out of grace.

For your enjoyment, this was my first running piston engine, made almost three years ago. Made with mods and modded mods. I had to fire the pistons myself. Note the weird transmission. Warning, loud!

The big problem with piston engines was/is: how to make sure there's no force acting on the piston while it's moving "up" (correct expression: from BDC to TDC). While I was convinced at the time and was looking for a way to solve it electronically (which I eventually did, but not stock), both@klond and I invented ways to interrupt the stream of rocket/jet engines with mechanical solutions. His engine was a more pure piston engine in the classical sense, mine was an interpretation of the axial/swashplate engine.

https://kerbalx.com/klond/mechanical-valve-demo

https://kerbalx.com/Azimech/Axial--Swashplate-Piston-Engine-3

After that not a lot was happening for a long time until I discovered I could use that RCS ball for a huge number of things. So my next engine used gears made out of RCS balls to drive a camshaft, opening & closing valves.

https://kerbalx.com/Azimech/77I--Piston-Engine-Prototype-2L6

While this was nice, the construction was heavy, limiting engine speed and robbing a lot of power from the crankshaft. So last week I decided  I could use the cams as valves at the same time, and because the jets push the cams/valves down while the pistons go up, this actually adds power to the crankshaft.

It will be interesting to see how piston engine development will go from here. The current engines are way too large and heavy to be useful for anything else but marine vessels.
 

 

Edited by Azimech
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klond

klond

Posted
Posted
12 hours ago, Azimech said:

It will be interesting to see how piston engine development will go from here.

 Upwards and onwards thanks to your nice gears and working cams.  Thanks for the mention too.  That spinning crankshaft gif really does it for me.

 The exhaust looks very proportional to the size of the whole engine.  And the heads/cam covers have a very realistic shape.

 

12 hours ago, Azimech said:

The big problem with piston engines was/is: how to make sure there's no force acting on the piston while it's moving "up

 Tru dat.  Good challenge.

 

 

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Castille7

Castille7

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Took this one for a ride to the Island and almost back. This was about a 2 hour trip, ran at near full throttle and full authority on the blades then on the return I set throttle to full then tried 100% and as fuel reduced speed increase a little to a new Top Speed of 14 m/s. 

4CG30Vw.png

More pics of the trip

Spoiler

mGmQVQp.png

Hy2uPtW.png

Tj8zjIE.png

 

Edited by Castille7
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Azimech

Azimech

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9 minutes ago, Deddly said:

A very intersting and inspiring project, @Azimech!

It got me thinking: I wonder if it would be possible to fuel it by dropping parts into the combustion chamber that get destroyed by the compression cycle.

Not yet ... I can design a system that would work on paper. I think we can develop a form of pseudo- fluid dynamics: some of the basic properties but without the computational requirement of the full one.

If I could become part of the development team, I would shine a light in that direction for something like that in the future, could be used for rocket engines as well.

3 hours ago, qzgy said:

Sweet! Is it possible to see the internals in slow-mo or something? Just to get a better understanding of how it works.

Yes, download it and you can see the internals in every slo-mo cam available to the human eye :-P

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Azimech

Azimech

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1 minute ago, Galane said:

What about with FAR?

That's an interesting idea. I will test it in the future. But ... the way my mind works this idea might get buried under my large pile of projects (I'm never bored). So if it takes too long, please remind me.

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Azimech

Azimech

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Testing the V8 version.

CuzDcwP.png

WdsMcOf.png

That goliath is just the air intake. It receives no fuel.

Current top speed: 17m/s with tanks half full. That was to be expected with the extra mass and all. Maybe I can tune it some more, add 8 Juno's for example.

Edited by Azimech
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Azimech

Azimech

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Okay I hope I'm doing it right, if not I hope someone can help me out. I've never done this before.

The V8 is running ~95 rpm, I'm applying a force of 51500N at 1 meter from the center of the crankshaft. So the torque should be the same.

Torque x rpm / 9,5488 = 512kW at 66% throttle.

 

Edited by Azimech
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