Have I forgotten anything?
I’m sure you’ll let me know. Please feel free to ask questions.
As with all my previous builds the engine is assembled bit by bit. The conrod length was found by inserting the piston into the bore just touching the end and then relieving it. This turned out to be way too much compression so a second rod was made to leave 13 mm space. In all cases the fitting of parts is found by offering one up against the next. I then leave it up to the draughtsman to finalise the measurements. Unlike some engines the Robinson is fairly simple in construction and a testament to its inventor.
As stated previously the first run saw the engine trying to fire at around 120 degrees before TDC. Only by the use of a power drill was it able to run. A call to the museum saw the cylinder head being removed to find that the combustion space happened to be 1500.00” not 0.010” like I had got! Hence the shortening of the conrod. The second thing that became apparent was the connection between cylinder and head was also larger than imagined. More remedial work was required, also mentioned earlier.
The next test run was amazing, I could use a single pull on the flywheel and away she went.
So I’m now at a point where the model is a good runner leaving me with the rather fiddly bits left to do. The governor….
At this time I literally have no idea whether this is going to work using liquid fuel. With gas I don’t see a problem but the liquid fuel will keep dripping into the valve seat and we could end up flooding during the “ miss “ cycles. Only time will tell.
Another problem to solve is the permanent lamp. It would be really neat to have a fully functional Paraffin blowlamp but I fear the scale might be a little too small. I’m toying with the idea of a small Paraffin wick lamp but instead of Glass a metal chimney to pull sufficient air to create a clean combustion ( Blue flame ) just like the Aladdin mantle over wick lamps. The exhaust would then be funnelled directly under the ignition tube.
As I close this chapter I would like to thank Jason Ballamy for his help with some of the more complicated patterns and look forward to seeing his Robinson HA engine emerge from his workshop.
Pictures of the “ pendulum “ governor assembly as fitted to the original engine.
Graham.