Is it really sensible to consider full size practice on something that is so considerably smaller? I wonder?
I certainly bow to Derek's full size working experiences as I simply have none to base my thinking on. But - I have made several model engines now over many years and all fitted as described above. To me I offer the advice based on personal experience from a model making point of view - if it's not seen as such by all means dismiss it.
One of the factors that I believe consideration is paramount in building any engine is that of friction and particularly so the smaller it gets - if it is desired for display only and potential slow running then that is a factor that needs to be given particular credence to. If, on the other hand, it's intended to running it at higher pressure and in a working environment perhaps less so.
Like most things it's 'horses for courses' but to me the focus should be on making the model as efficient as possible rather than basing it on what would have been required in full size practice. Easing friction goes a long way to making for an efficient engine and is certainly something I shall keep firmly in mind on my latest marine compound build
Like most things - 'Yer pays yer Money' - 'Yer pays yer choice' - it's always up to the individual
You may recall this build Derek .....
...... and the pistons fitted
Just some further thoughts from a model makers perspective
Tug
