If you have a relief valve after your pumps and no valve or check valve between them and the economizer, that relief will protect the economizer in case someone closes the boiler feed valve or the economizer overheats. The bypass can be a piece of replacement tubing that is ready to be fitted; I've ...

The third floor of the Science Museum in London has a large collection of steam engine builder's models.... well worth a (free!) stop in. Plus lots of full scale stuff: http://www.sciencemuseum.org.uk/visitmuseum/galleries/energy_hall.aspx I'll be in London on business just after Thanksgiving... ho...

Otter's stack is a piece of 7" surplus titanium aircraft APU exhaust tubing, single wall perhaps .020 thick. It's blued in one spot due to a stack fire with a vaporizing burner.

- Bart

For a uniflow, it seems that minimizing the clearance, using 750 F steam, jacketed heads, poppet valves with variable timing is the right approach. The superheat seems like a lot, but at 15 or 20 expansions little but the cylinder head will reach that temperature. I'm designing an engine along these...

We didn't manage nearly enough - perhaps 25 hours of steaming. I'm trying to get out more next year... we're going to bring Otter to the Pacific Northwest and participate in the NW Steam Society meets there next summer. I should have her in the water in the San Juans for six weeks or so; despite tel...

I of course have a drain on the bottom of the reflex gage; this allows me to blow the gage albeit w/o closing off one of the ports. But it's clear that the British are concerned with possible plugging of the gage connections, given the requirement for "rodding" capability. Right now the bottom of my...

I built a conversion of a refrigeration compressor that I ran for 20 years on our launch Otter. I think I spent about $50 for scrap bits for the conversion by the end. Here are some details: http://smaalders.net/bart/engine.html I find boilers more difficult to construct than engines, but I've got a...

metal conductivity is a very small part of the overall thermal resistance; you'll find the film coefficient predominates. Note that it takes a while to learn how to fire a new boiler effectively; excess air is a common problem, and robs much efficiency. The reason to heat a hotwell is that it lowers...

If steam production is inadequate, your engine is taking too much or your boiler isn't producing enough. Weighing the condensate will give you a quick way of estimating the BTU that are being transferred; the fuel consumption will let you know how many BTU are being generated. A 3x4 will likely need...

Otter's safety valve is connected to the boiler via a (non-isolated!) manifold; the same 1/2" boiler connection provides the top connection for the reflex gage and the pressure gage. I am at a loss to figure out how this affects safety. Yes, the boiler level as shown in the gage will be unreliable w...