The loco cylinders have a bore of 24 mm and 30mm stroke. Under the setup of of full pressure for all cylinders the boiler was not able to come over 4 bar during permanent driving. The coal consumption was extraordinary high, compared to a ruby . All people who saw my tests said oh very good ,but in real world it was bad. The same experts say you can never have a compound action in such a small loco.

After i saw this coal consumtion i tried the compound setup. The start procedure was more difficult to get the water out of the cylinder, but the driving and coal consumption was much better. After all steps in optimization my son and i drove my ruby and the mallet and we have both the subjectiv feeling that the mallet have less coal and water consumption as the ruby.

I had talks to the locomotive driver of the original and both say , the mallet is very difficult to drive and what they say was similar to my experience. The bigest problem is the start procedure. The start have to be in full pressure setup and then after some wheel turns switched to compound action. If the loco is cold it last much longer.

One of the importants step was to understand how the blast nozzle and the front setup was to be tunned.

Another step was to understand how it is possible to bring the high pressure steam to the low pressure cylinders.

will be continued

Edited By Werner Schleidt on 02/01/2022 17:19:25

On my test ride I had another issue after assembling all again I found that my fire burns not so good as I had it in mind. A few years ago I bought the book "The Fire Burns Much Better" and in the last pages there were for models a multi jet nozzle with the words " that have a better performance".

I decided to measure the different steps in the development of a new front end configuration. At first i build a simple u shape low pressure gauge from wood and clear plastic hose. This was filled with water. One end is open the other end is running trough the fire hole and the smoke pipe into the smpke chamber. The smoke chamber had a clamped in rubber sealing for the smoke pipes. Only the measuring hose came in. The test run with air pressure in my basement. So I was able to compare the different nozzle and had readings at the scale of the U Pipe gauge. And I made electronic measurements too.

This is an exampel reading under test with 1.5 bar air pressure. I made several tests, helping blower alone, then with the running engine and both.

So it was easy to compare the different nozzle setups. Without the test both water parts in the gauge have the same height. In the shown picture there is a low pressure from about 4.5 mbar.

this was the initial setup with a nozzle of 2.5 mm bore hole

new setup with the multijet nozzle.

The initial nozzle had an area of 4.9 mm² the new one 6.64 mm² . I made several tests and I playing with the optimal height setup and so on. The first step was 7 * 1.1 mm bore straigth. this had a better low pressure reading as before. Then i made nozzle where the outside jets have inclination 2° and 5° to the outside.

The last one was in my tests the best one , so I made test rides under steam with this setup. This nozzle have 35 % more area for steam in the nozzle and therefore less back pressure for the steam engine.

The test at my garden track was very good so we decide to go to another club track.

Werner

Edited By Werner Schleidt on 03/01/2022 08:08:20