Reading back over the early days of this thread, which started out as discussion of the Q3B engine from Jin, I see not only did we discuss the Q3B, but the TVR1A gets a mention as well as our experiences with the M29. I'd like to back up a little and ask about experiences with the TVR1A and the smaller Microcosm engines Jin calls the M2B and the M36. My real question is whether anyone has run either these and what working pressure they might require to power a 1m, 14.5lb boat. Or perhaps I should say, would they work for such an application using a 2" dia. boiler??
I assembled a TVR1A and thought it would be OK to run such a boat using a Miniature Steam Models (MSM) 2" vertical boiler. I had very modest expectation for the runtime (autonomy) of the steam plant at 10 minutes. But the boiler was able to keep a sustained WP of only 8 or 9 psi, and while the boat moves along ok as you see in the video, the performance in my opinion is very marginal and I intend to switch out the 2" boiler for a 3" boiler and be able to have a wide speed range and possibly a steam whistle. The boat has a 2.4" 4-blade prop, and looks like this in her partially completed form
Here is my launch RIVAL on her maiden run in a small pond. Run time about 8 minutes. I had only RC rudder control, so speed and reverse are not included yet. I will say this certainly appears to be a scale-like speed.
https://www.youtube.com/watch?v=SxfB2gCK8ngSo this leads me to wondering the best thing and boat to utilize the 2" boiler? It looks like a smaller oscillating engine is the best candidate. I find 6 possibilities, as you can see on the attached comparison table. I like the MSM Clyde but MSM won't commit to saying it will run adequately on the 2" boiler. If I have to use oe of the smallest 8 x 11 engines, I'll have to build a much smaller boat!
I'm interested in experiences with any of these small engines knowing they are to be steamed from a 2" boiler.
I hope the photos are in the right order...if they appear at all (they are not appearing in Preview)
Thanks for any comments
-Carl