Kerbal MonoRail [ IT WORKS ! ]

[Nazalassa]

Log 23.8 - Rail coupling technology

It's time to start thinking about rail coupling. Of course this MonoRail is going to travel for a longer distance than double KSP's physics loading range - 4.5 km. So the track must consist of several independent ships.
But if they are independent, there must be gaps between them, right?

It's time to play with KSP's physics. First of all, if you are further than 200m of the root part of a ship (NOT the center of mass), the ship will be unloaded: physics will not apply to it and it will be "on-rails", so impossible to move. If it's landed then it will not move when the vehicle passes on it.
However, in KSP, if a ship is landed on another ship that is "landed", then this ship will be "landed". So theorically I just need one rail element that is "landed", and then the second will be "landed" on the first, and so on. They will not move.

(more info about all that in @Stratzenblitz75's Dres Bridge video: https://www.youtube.com/watch?v=D_Ec3K7lx_4)

So, to add a rail element to a currently exisiting rail:
    1. we'll need a way to ensure that the rail can be "landed" on the already-placed rail element,
    2. we'll need a way to make the gap between two rail elements as small and inexistent as possible.

The second point is pretty straightforward: the use of enough engines will probably be enough. But for the first?
Well, I have a solution.

I made a special part, the "end rail module". It has as you can see, four flat surfaces. Two of them are fixed, the other two (in this case they're both under) can go up and down (I actually made the animation First Try^TM!)
The goal is for the flat slab-like things of the two parts (one at the end of each ship) to fit in such a way that the two parts are "fixed" together.
 

Here you can see the two moving slabs moving upwards. Do you see how they will fit?
 

And done! Due to the way it is designed, it prevents both vertical and horizontal movement. So if the two rails are slightly misaligned, they will be perfectly aligned after the module fixes itself. If there is a gap, it will be very small.
You may say that the moving slabs should slam into the fixed slabs of the other module... But no, It's pretty smooth, as long as the horizontal misalignment isn't too big. I think it can bend a tiny bit if needed...
 

Alas! The ship I fixed to the other is considered by the game as "flying". So when I timewarp, it sinks into the ground.
 

I tried a second time, and this time I drove the rover away. Once the ship unloads, it doesn't sink, good thing. I'll send another rover to check...

Spoiler

Memo to self: do not, ever, open a paraglider-like parachute while you're in a rover and you're going up a slope.

Yes it works! Next I tried to timewarp and well, it didn't move or crash or anything! That's very, very good. And that's one less problem to worry about.

So, in conclusion: we now have a way to fix rail segments together.
Next thing to worry about is heavy vehicles: I'll try putting some sturdier wheels to our fuel wagon, so that we can finally have five of them (or so)and not crash.

 

Oh wait...

Another New Page

Edited March 6 by Nazalassa

[Nazalassa]

Log 23.9 - Fairings theory

OK, my prototypes may be great, they may have potential (energy, which is converted into cinetic energy when derailing), but they have a problem: they're not stock. The only not-stock part of them, actually, is the 30m square-sectionned parts for the rail. To make it stock - which I want - I therefore need to get rid of them, and replace them by some stock thing.

Problem: to keep part count / lag relatively low, these parts need to be long. To avoid flipping over - a problem I had a lot with the Mk3 rail - these parts have to have a not-round cross-section (Mk3 does count as "round"). But there's no stock part that satisfies both conditions.

Solution: use two stacks of whatever part I use, so that the rail is wider than high (or vice-versa) and the train won't flip over easily.

Since I can use round-sectionned parts, let's use the longest available... Fairings.
As they can reach absurdly long lengths (well over 200m for example), there won't be much and lag will be kept low.

I then realized there are several ways of placing the train on over near the rail: either above, below, between (the two stacks of fairings) or around them. I think we can forget the "around" method since it would be way too difficult to add supports to the rail, or it would look quite unrealistic. So, here are the five ways of placing the train I could think of: Hmmm... The first one looks good. I should probably try with this configuration.

(some tests later)
Well, looks like I'll have to do some craft file editing to suppress the automatic autostrut on the fairings, it makes stuff buggy.

[Nazalassa]

Log 23.9b - Fairings theory "but it's not theory"

I've made a small test, with two supports on each side of each 250m long section, with two 250m long sections (in one craft), to see if there would be kraken attacks (like last try with two 250m long sections).

Turns out it's stable! Here's a photo of Bill at the point where the two fairings join

and here's one half of the whole thing, taken before I added the other half

Now to make a train to run on it.

[Nazalassa]

Log 23.9c - Fairing-compatible wheels

I've made a prototype of "wheel unit" - there will be at least two per vehicle. I used the big wheels, as they are more resistant that the smaller ones, which tend to break easily (see previous logs). Here's what it looks like:

I'll test it "soon".

 

EDIT:

Tested first test vehicle. Catastrophic failure. Both vehicle and rail were destroyed. Needs more struts.

 

EDIT #2:

Second test was a bit more successful - if you consider the car "crawling" (I don't have a better word to describe it) on the rails and eventually falling off the end of the track, after knocking its pilot off, to be a bit more successful.

Oh, I think I found the problem: this happens on decoupling.

 

EDIT #3:

I managed to make a less shaky version, that can reach 50 m/s without any issues.

Edited July 2, 2023 by Nazalassa