Hi guys - thanks for looking in
Zee - we all struggle - at all levels - so don't despair when things go wrong. It's the ability to overcome the mistakes we make that makes it worth the struggle
Dave - I think I may have mentioned it in passing but nothing specific as I recall. I'd be happy to pop something a bit more detailed up later as/if you think it's worth doing
Jason - I'm afraid AS is off track here. The Hunter was first introduced to the aeromodelling fraternity in 1949 as very much a new aero engine. It would appear as a marine version a year or so later. I don't recall any specific advertising feature with regard to that long prop driver but would hazard a guess that it was influenced by several Italian diesels of that time that featured long front ends and well described as you surmise by being able to be fitted well back in a cowl in order to help streamlining. As I said at the beginning my original suffered from that long shaft exerting enough leverage to break the crankcase. I don't know if that was a common occurrence but the engine was produced much later as a 'short shaft' version. It has a venerable history as an engine produced for many years, indeed it is still manufactured as a marine version (under the Hunter name) by Weston engines. Another British engine that exhibited a long shaft (but shorter prop driver length) was the Amco 3.5 PB (plain bearing) Another very powerful 3.5 it did have a reputation for breaking crankshafts ! Incidentally 'long' prop drivers were available as an accessory for many engines for just this reason of getting the engine further back.
Here's a short video for Per - turn the sound up
Whilst finishing these parts of I've also done a bit more on the 14cc spark ignition JLE engine - 'Jefs Engine' as featured on MEM a while back.
The major parts have been finish machined - just the ancillary pieces to do
Now, just to show we really
do all struggle Zee
This first liner on the left is a bin job - I miscounted the holes on the dividing device and these holes are some 36 degrees out of phase to the second version on the right:
Something good came out of it though as looking at it as drawn after machining I felt the exhaust was potentially rather wide for a ring to pass without catching so the second liner was done with a smaller cutter and the exhaust and inlet barred to prevent that
And - when making the 'Tufnol' rotors for the Hunters one had the blind holes drilled right through
so yep ''it happens to all of us
Y'all have a good time now - I'm off to tha ol shid
Ol Tug