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[morfa]

EDIT: A friend just noticed I put a picture with 2 engines my Clyde and an M2B (was thinking about swapping them and looking at the size difference) - sorry for the confusion. Asking about PSI for the boiler with the Clyde..

Hi, I have a new StirlingKit Steam Plant (sure looks like Jin's Microcosm) -
The total height of the boiler is 260mm, the diameter is 85mm, the length is 120mm, the valve pressure is 0.5MPA, and the boiler capacity is 230ML.

I have a MSM Clyde engine. What is the proper or best PSI to run it at?
Or is there just slow speed or high speed and wait 'till steam ends.
Thanks,
Derek

[rhavrane]

Bonjour Derek,

Personally, I like operating around 2 bar / 30 PSI because at that pressure, I save steam, it is wet and so a little bit autolubricating.

Furthermore, this pressure allows a variation of the speed and prevents a possible take off of the pistons from their bases.

And I agree with you, especially because Stirlingkit is just a dealer, your boiler looks like a Jin's one.

Ypu will have to look after your autonomy because 230 ml is nothing for a machine I presume +/- 4 cm3.

[SteamboatPhil]

Just an observation but you will be losing a lot of power because of amount of universal joints you have. You should be able to remount the steam plant, with a slight angle on the engine (not the boiler), this will help your steam consumption.

[Circlip]

Looks like the mounting plate is very high. It could be 'slotted' to allow the engine only to be mounted lower and more in line with the prop shaft. Bet the crankshaft is taking a real hammering. Pity suppliers don't emphasise the importance of alignment, but suppose there would be less sales of horrorcue couplings.


  Regards  Ian.

[KBIO]

Hello !
I agree with Phil & Circlip. Let's try to explain the principle ! Interesting device that this universal joint, knuckle joint or whatever we call it.!
The "cardan joint", invented in 1545 by an Italian who tinkered with marine compasses: Gerolamo Cardano
What you need to know about this universal joint is that the angle formed by the "forks" causes a non-linearity in the angular velocity of one shaft relative to the other. It is not homokinetic.
In other words, they don't spin at the same speed. Funny, isn’t it ?
To overcome this problem, it is necessary to insert another cardan joint, wedged at 90° in relation to the first.
The speed lost on one will be caught up on the other and thus allow both to turn at the same speed.
The universal joint becomes homokinetic.

A friend of mine did this set up to help understand.
The first photo shows us the initial state, the small crosses allow to visualize the starting point,




Second photo: the leading shaft has turned 30° to the left, we can clearly see that the driven shaft has taken a few degrees advance


Third photo: the driveshaft has turned 90° to the left, the driven shaft has slowed down and is aligned on the driveshaft




Fourth photo: the drive shaft has now rotated 120° to the left, surprise: the driven shaft has now lagged,




Fifth photo: the two shafts are readjusted relative to each other,

The last drawing shows the good way to line up  the « knuckle joint"  from your engine to the propeller shaft.
Also as Phil and Circlip say, do not hesitate to give the required inclination to the engine. A steam engine can run upside down or on the side if necessary.
Sorry, I don't know how to set the pics along with the description. 
I hope that you find it OK.
Best regards.




You have it all there: https://modelismenavalvapeur.forumactif.com/t472-un-petit-point-sur-les-transmissions-a-cardans

[morfa]

Thank you so much - I enjoy learning more about the physics of the hobby, as my brain spent many years in communications with a start in film and advertising where they didn't talk a lot about homokinetics.
The mistake I made with the angle is all mine. I was told to add an angle to the engine (around 8 degrees). When I took out the M2B engine (had throttle problems now resolved) it had an angle to it and the u-joint was not as severe. My bad, when I put in the Clyde, I did not add the angle. Will be modifying it with that in mind, maybe moving in forward a little and if possible down.


Really thankful for the advice. Even with all the mistakes, she is so much fun to sail (and build...). Here is a short clip of her in my pool during the "trials" https://www.morfa.ca/mayhem.mp4
Derek

[DBS88]

KBIO thank you for that wonderful explanation, its a fantastic demonstration, well done.