Stuart Score - second test

jamespetts · Stuart Score - second test

I test-ran my Stuart Score again yesterday to see whether the recent improvements assisted the steam production. (Alas, they did not: see thread here for details).

Here is a video of the second run, which shows some of the improvements, and also gives an idea of the steam usage rate:

(Here is a link in case the embedding does not work).

I have also uploaded some new stills. Here is the improved boiler cladding (the outside shell is copper, and, sandwiched between teh outside shell and the boiler, are two layers of insulating kaowool):

Here is the engine running:

Les Marsh

What size is the steam pipe from the boiler to the engine??

jamespetts

Bogstandard

Have you removed the ceramic from the burner at all?

It is still not burning correctly, and looks like gas is leaking all around the edge of the burner.

If you have removed the ceramic, it needs resealing with very fine fire cement. There should be no leakage at all, and no flames higher than about 1/4" to 3/8". The gas should only come out of the small holes in the ceramic.

The ceramic isn't glowing, what you have there is just a red colour. If you have ever seen a mobile gas heater, where the elements glow a very bright red, that is what should be happening.

You are losing efficiency by using such large pipes, 5/32" should be ample from the boiler, all the way thru to the cylinders. By putting such large pipes on, you are effectively increasing the volume of the boiler above the water, and the steam is struggling to keep the pipes filled, plus you have a larger surface area effectively cooling the steam.

Also noticed a few leaks still, even a very small weepage is enough to prevent steam build up.

When you run the engine towards the end, that is the correct speed, not running as fast as possible.

Get all that lot fixed, and you might stand a chance.

John

Les Marsh

jamespetts

John,

I have not removed the ceramic from the burner, although it has become very slightly chipped in the corners in one or two places. The flame only does the dropping down the sides thing when the gas is turned up high. (I wonder whether the chips account for the flame spilling).

As I wrote on another thread, I am wondering whether gas is leaking around the joint between the jet holder and the ring: when the fire blew back in the wind on one occasion, a small flame persisted at the join until I blew it out. I shall try sealing it with PTFE tape and see whether that helps to achieve the mythical red glow.

As to the pipes, I chose that size because that was the size of both the valve connexion from the boiler and the pipes installed into the engine by the person who built it. I did plan to clad the pipes (which I am hoping will improve efficiency), although that can only be part of the problem, since the boiler takes much time to build up steam even when the main steam valve is closed. As to the leaks, the one on the displacement lubricator I fixed yesterday, and the one on the steam pipe into the engine I plan to fix before the next run.

Les, I am not sure that I quite follow - if too much steam is getting to the engine, then simply closing the valve partly would cure it - I find that, even when running at slow speeds, the boiler pressure is depleted.