dec 2015

http://www.maritimedays.com/#!titanic-exhibit/c1563

Nick Jonkman talked about saw sets: Apparently he has ~112 in his collection but a huge number of different types must have been made because there are something like 1400 early American patents on the subject. (It is hard to believe there are so many ways of slightly bending the teeth on a saw.)

Continuing our frequent theme of miscellaneous trivia; somewhere Bruce had seen that singer Rod Stewart is very much into model trains. (If you "Google" "Rod Stewart Model Trains" several items pop up.)

Brian Lawson talked about RM Restorations who claim to be the leading restorer of classic cars in N. America. They have one place in Lakemoor, IL and another in the Blenheim/Chatham area. What they do is really amazing and Brian talked about one person who specializes in making/restoring dials for classic cars – you know, the ones everyone had before LCD and touch screen displays came along.

Steering chain shaft

Kasseys model drill press

stationary and mobile applications. Maybe there was "fashion" aspect as well because back then true diesel was regarded as the way to go so the semi-diesel approach was regarded as old technology and just allowed to die.

How about modelling hot bulb engines? Making model engines using fuel injection invariably means pumping or in some way metering tiny amounts of fuel for each cycle. Taking a 40 cc displacement engine (the size of my Wyvern,) when you do the calculations, this theoretically requires an injection pump with ~ 1/16" bore x 1/16" stroke to provide the fuel needed at maximum power. Fortunately, the early type of hot bulb engine does not require the oil to be finely atomized the way a diesel does so injection pressures can be lower and injector design is less critical. On this basis, modelling a hot bulb engine should be less difficult than a true diesel. Looking on the web there is one person in Denmark, Find Hansen, who has managed to construct engines of this kind (a lot of them in fact) and get them to work.

Since starting to collect information out of general interest and to write up something ready to give a seminar at NAMES next year, I have unearthed more and more interesting stuff (at least to me.) Putting all of this in the newsletter would take several more issues and this does not seem appropriate. Therefore I will just cover a few additional points then finish:

Why did hot bulb and semi-diesel engines stop being produced? Clearly the early types with their low efficiency, low power output and the need to use a blowlamp to heat up the bulb for starting were never going to survive very long when more efficient, easier to operate engines became available. However, when the engines had evolved to the semi-diesel stage with glow plugs to provide the initial heated surface for ignition and an electric or air system for starting, many of the drawbacks associated with the earlier engines went away. There was maybe some advantage in efficiency going from the 10:1 compression ratio of a semi diesel to the ~15:1 ratio of a true diesel but the reasons for the eventual transition are likely more subtle. The semi diesel requires a combustion chamber that is not cooled and this significantly complicates the design, particularly on a 4 stroke or valved 2 stroke where the valves have to be accommodated in the head as well as a rather special combustion chamber. Post WW2 there was also enough expertise around to build engines that would stand up to the pressures existing in true diesels and fuel injection/combustion chamber technology had reached a stage where the engines could be used satisfactorily in a wide range of

There was one organization in the UK the Alyn Foundry that did supply castings for a ¼ scale Hornsby Akroyd engine, however the company no longer appears to be in business (pity.) There have been some indications that it will be resurrected (we can but hope.)

I thought that it would be worth starting this section so that members can pass on useful pieces of information and hopefully someone can contribute an item each month.

To start the ball rolling, this is mine: After finishing some machining operations on a component, particularly when using soluble oil as a cutting fluid, it becomes covered with a rather disgusting mess of chips and oily liquid. You can clean it off with Varsol but that stinks in the workshop. What works well is to get a suitable container with very hot water and some dish soap then dunk the component in that and use an old toothbrush etc. to clean off the chips. Follow this with a hot water rinse and blow dry with compressed air. (The latter is particularly important with materials that rust.)

I have discussed how we can exchange newsletters with Geoff Kingma at TSME and since (like ours) their newsletters are available on their website, the easiest approach therefore is for me to just give the link:

https://sites.google.com/site/tsmeweb/the-modeller