LIONSMEET at CHELMSFORD SOCIETY OF MODEL ENGINEERS 30th JULY 2011

Report by Alan Bibby

This year's event was held at the Chelmsford Society of Model Engineers track adjoining Central Park Chelmsford on 30th July. We were blessed once again with excellent weather and it seemed that the entire membership of the club was there bright and early to prepare the site and to see what the day would bring. Sadly, many of our northern regulars did not feel able for one reason or another to make the journey south, and our host's efforts to draw in support from local clubs also seemed to have fallen on stony ground. This was disappointing, given that members from as far away as Guildford, Bristol and even Tiverton have regularly attended northern venues for Lionsmeet, but there it is.

Having said that, we can honestly say that those who did trouble to make the trip enjoyed an excellent day out with a number of unexpected treats, often a feature of Lionsmeet gatherings. The highlight of the day was undoubtedly the exhibit table, the best seen for many years, and truly as feast for the eyes. We also saw David Neish's new dynamometer device in action for the first time, and Andy Haresnape's beautifully restored red 1965 Jaguar 'E' type, and the meal afterwards at the Horse and Groom was the usual convivial affair, with many things put to rights!.

The picture captions tell the story of this year's event, but just to recap, Lionsmeet is a 'work done' competition, not an 'efficiency' competition. The morning is given over to practice, of which there was little this year except for checking out the dynamometers, and the competition proper starts at one o'clock. Each competitor makes up to two 'free' laps to assess the conditions and choose his load, following which there is a timed run of exactly ten minutes supervised by our onboard 'dynamometrix' Jan Ford with her stopwatch and results pad. Jan also ensures that the speed limit is observed, on this occasion 8 mph. At the end of the ten minutes Jan says 'Stop now!' and the driver stops immediately, wherever on the track he may be. The dynamometer display is read, and the train returns to the start point for the next run. At the end of the day the person with the most 'work done' in foot-pounds is the winner. It's as simple as that! 

A short discourse on dynamometers may be of interest. They measure the work done by the locomotive in hauling the train, and often give additional information such as distance run, average speed and horsepower. OLCO has had to borrow a dynamometer car for each Lionsmeet and, while we are grateful for the loan, one or two have occasionally revealed some lack of TLC on the part of their owners, or difficulty with the particular modus operandii, as well as variations in the quality of calibration and therefore accuracy of results. OLCO has long felt the need for a dynamometer of its own, which would remove the latter two problems, and with appropriate design and care perhaps the first also. David Neish was the first to come up with a viable solution and we were able to test David's prototype at today's event by running it in series with the host club's own dynamometer designed some years ago by the club's chairman who, like David, is a professional electronics engineer. David's device is described below. It measures only work done, not distance run, though this facility could be added. The electronic cyclometer on David's driving truck was used in the morning trials for the distance run figures for comparison purposes.

With the exception of the first run, probably as a result of operating error, the results were consistent though not identical, revealing a reading 26% higher on the Chelmsford dynamometer than on David's. It is anyone's guess which device is nearer the truth! The distance run figures given by the Chelmsford car and by David's cyclometer were the same, within the vagaries of experimental error. This is reassuring, suggesting that so far as the concept is concerned the only thing needing further work is the calibration of the drawbar pull measurement. Without the resources of an accredited laboratory, this is rather hard to do with any certainty, but model engineers are a resourceful lot and by making covert use of some device of known and calibrated accuracy, such as the scales in the local post office, one can get a fair level of confidence in the outcome! 

Next year's Lionsmeet will be held at Newport in south Wales, hopefully, on the 11th August, a couple of weeks later than our usual date of recent years. Our contact there, Philip Pritchard, is aready working out the details. There is another excellent club just down the road from Newport, at Cardiff, home of the first true scale 7¼" gauge Lion built to John Hawley's drawings, by Harrye Frowen. That has to be a pretty good reason for taking a short break in South Wales about the middle of next August!

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