PM Research Engine

[Peter Webster]

Hi All,
        Sorry I haven't been on for a while, another story, I have just finally run the engine for the P.S. Pevensey. 1/2in bore, 3/4in stroke, and was quite surprised . It ran from the first go, only on compressed air at present 15-20p.s.i. I will fire up the boiler inthe next few weeks and let you know how it goes. It's a Saito bolier 3in. diameter and 5in. long. 
If anyone builds this engine make sure you Loctite all parts recommended as per instructions, I forgot one of the nuts on top of one of the piston with the expected result. Fortunately no damage as I was turning it by hand when it locked up due to the nut coming off and sitting between the piston crown and cylinder top. You live and learn.
Peter W 

[kiwimodeller]

Peter, I am presuming you are using the P & M V Twin? I have sold several of these and everyone who has one is happy with it but now I am thinking of taking two of the single cylinder versions and bolting them to a common base to give me a twin cylinder horizontal. By coupling the shafts at 90 degrees it/they should still self start. I just have to get around to building a throttle and reversing valve before I give the idea a go. I have a design for one from the Peter Arnott series "Getting started in Steam" but it is very tiny and so I am just looking around for more ideas. Will post pictures once it is sorted. Look forward to seeing some pictures of your set up. Cheers, Ian.

[Underpressure]

Ian, there are a number of similar design throttle valves in the download section. The H Quad has a design similar to one I came up with independently about 1992. The only difference being that I milled curved transfer ports and the H Quad uses straight ports. Have a look at the download and hopefully it will make sense.

Neil

[kiwimodeller]

Thanks for that, I would not have thought to look there. I have downloaded the H - Quad. Not sure that I understand how to make the valve but I can probably get a mate to help me. I take it that this is just Fwd/Rev, not a throttle? Is there any way to preview the downloads to see which engines have throttle and reverse valves included? Cheers, Ian.

[Brooks]

The H-quad valve looks similar to that on my Krick Patricia. The Patricia's valve works as both reverse and throttle. The reverse comes from swapping steam and exhaust lines leading to the engine ports; the throttle comes from the gradual opening of steam ports (and exhaust ports) as the throttle disk is rotated. I get both functions from 1 servo, making a convenient setup. So, my guess is that this design does both, also.