Flash steam powerplant

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Basil

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This build is going to be a complete flash steam powerplant for a boat. Its been a project that's been rattling around inside my head for a while now and I need to do something about it so here goes.
Rather than pull something completely out of fresh air I have decided to start the project design around the powerplant for the Pisces tethered hydroplane.
The engine for a flash steamer I think I can build.
After reading lots of literature it seems the real challenge will come with the boiler. This in my mind is going to take lots more R &D to get it to the end result I am looking for.
For that reason I have decided to attack this item first.
First part...................
Locating the tubing;
I have found something close to what Pisces ran.
At this point I would like to say a massive thank you to Tom Clements for outlining his build in the magazine Model Engineer. Flash steam is a bit of a black art and this article has helped to answer some of my many questions.
The tubing I have located is as follows
6.35 OD. 0.91mm wall. 316/316L seamless stainless steel. I can get this in 6 meter lengths or a bundle roll of 60 meters!!
It is heavier wall than the type I was hoping to get @0.71mm (As used by Tom)
**Could anyone advise me if this might be an issue going forward. **
I have filled the 1 meter sample with water (I realize a good portion of this will be steam) and come up with a weight of 1.45KG for 10 meters, this length being pretty close to what was ran in Pisces.
I think I am going to need a lot of help from the forum on this one! lol
 

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Hi Basil, may pay to have a word with George on the Modelboatmayhem forum as he built a version of Bob Kirtleys engine in a radio controlled speed boat. He goes by the name Ooyha from memory.
On this forum I think it may have been a gentleman Windrush? did a wee write up and like Bob Kirtley he has some Utube videos
George also did a wee write up on the RC Groups forum in the steam boat section about the flash steam plant.
Sorry I dont pass this way very often now but I still look into the model boat mayhem site so can be contact more easily
http://www.modelboatmayhem.co.uk/forum/index.php
https://www.rcgroups.com/forums/showthread.php?2851104-A-Flashsteam-boatkeep well
frazer
 
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Basil, I guess you have already seen this?
http://www.flysteam.co.uk/steaming....tube theory and practice What is Flash Steam?
Here's some posts by Windy:
https://www.model-engineer.co.uk/forums/postings.asp?th=34163&p=1
Another thread:
https://onthewire.co.uk/flash.htm
Met this guy at Harrogate Model Engineering show some years ago, where he demonstrated his boat. What a great guy to talk to. And when I researched him later, he has done loads of stuff!
https://www.yorkpress.co.uk/news/10...eam-powered-model-boat-sets-new-speed-record/K2
 
Thanks everyone for the info. I have been following Paul’s escapades for a while. Very talented guy!
I’m busy on other projects this week but have located some 316 of the wall thickness I need.
Next is machining a flaring tool.
 
I have tried converting the video to MP4 - which will upload - but my computer (MS!) has disabled the software I previously used to play these... so can someone check and tell me if this works? All I can get is 11Mb of black screen! (Thankyou MS!). Even my Video editing software and other stuff has been junked by the helpful people at MS...(Hmmmm!).
K2
 

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Maybe this one?
K2

Note how after the first attempt stalled, he wound the screw - directly coupled to the engine - to wind the starter cord back on to the flywheel for the next start attempt.
The priming pump is pre-pressurising to paraffin tank - possibly? - or priming the water feed to the engine? (not sure) = Both paraffin feeds and water feeds come from separate pumps directly coupled to the engine, so as speed varies, so does the fuel and water supply, hence steam production. A great balancing act took ages to get right, so I understand from his brief talk, and a couple of different designs of engine before he settled on the single with cylinder ported exhaust. (rather like a 2-stroke engine?).
He had previously had engines explode with the pressure and stresses of running the steam generated. To get the maximum flames in the boiler, he has 3 paraffin jets from individual pre-heater coils. (I think?). That way he gets enough air with the fuel.
Hope this is as much fun for you as for him! He said after it was less than 50:50 that he would be so successful with his demo!
What a great knowledgeable guy to meet and have a chat with. - A true genius!
K2
 
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👍 Thank you so much for the video. I have ordered the Stainless tube for the Paraffin evap. coils and have also managed to get the Boiler tube. Looks like he vents the steam on the cockpit side to stop the engine and acts as a blowdown. It disconnects quickly so maybe a bayonet type fitting?
Could also be a vent from the boiler input side which blows back through the coils? I will wait until I acquire a little more in materials before I bother Paul.
 
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Basil, thank Windy.
Just a thought about your comments to stop the system... The boiler inlet is water from the feed pump.
I am not sure why you would spray that into the boiler? I would have thought that a relief valve on the fultimate line returning the vented fuel beck to the tank would cause a flame out due to loss of fuel pressure, but not sure if the water pumped through the boiler could develop an hydraulic lock before the engine stops spinning? An interesting problem?
K2
 
If you are going to use Tig welding be sure to either know wat you are doing over someone who can do the welding and understands how to use a back purge system on this . Stainless welds nice but the weld on the inside has to be good too . That is the hard part. If back purge is not done right the inside welds will get “ sugary and eventually fail . I’ve welded inside and outside tank trucks not a fun job at all .
In your case. Smaller pressure vessel with probably wildly varying temps and pressures .
Hi Basil, may pay to have a word with George on the Modelboatmayhem forum as he built a version of Bob Kirtleys engine in a radio controlled speed boat. He goes by the name Ooyha from memory.
On this forum I think it may have been a gentleman Windrush? did a wee write up and like Bob Kirtley he has some Utube videos
George also did a wee write up on the RC Groups forum in the steam boat section about the flash steam plant.
Sorry I dont pass this way very often now but I still look into the model boat mayhem site so can be contact more easily
http://www.modelboatmayhem.co.uk/forum/index.php
https://www.rcgroups.com/forums/showthread.php?2851104-A-Flashsteam-boatkeep well
frazer
 
Thank you Frazer. Very good information to know. I will speak to my welder. I am undecided whether to weld tube for the required length or make a stainless union and run this joint to a cooler place in the combustion chamber.
 
You could get different alloys of stainless steel from online metals or mc master carr

One thing that many TIG welders don’t watch is getting the stainless too hot. Stainless does not get rid of heat well the welds should be near natural color if stainless not blacken or heavily beaded use rod at least one alloy number higher than the project
Thank you Frazer. Very good information to know. I will speak to my welder. I am undecided whether to weld tube for the required length or make a stainless union and run this joint to a cooler place in the combustion chamber. On Amazon there is a booklet called steam tables. This shows temps and pressures of steam . Also you might want to look the thread I have been in a couple guys really helped get me started. My project is in temp hold. As the lathe is still not repaired.
 

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