Monday, June 27, 2016

In my minds eye

I can see how it's supposed to go in my minds eye. You spend years looking at technical drawings, photo's of how others have done it etc. But until it's your turn to actually do it everything you think you knew all seems to fade away into the ether! *sigh*

Such was the case with the placement of the Python Drive and associated hardware. I know how it's supposed to look (in profile) but once you're actually working in 3D in the real world that extra dimension appears at first to throw a wrench into the whole scenario.
Setting up shaft log support frame
The Python CV joints have to have at least 1.5 deg of angle in order to ensure proper lubrication of the joints. Minimum 3 degs total for both CV joints. I have designed the shaft log support frame to allow adjustments to the shaft angle (during mock-up) and will eventually have to lock in the angle. I was having problems visualizing how the Python drive jack shaft would fit between the engine and thrust bearing. The only way out of it was to haul it all out to the shed and lay it up!
Full length shaft log at 8 degs pointed dead nuts at engine output.
I was shooting for a prop shaft angle of 6 degs. This would give me, in theory, 3 degs on each CV joint. I got pretty close first time.
L to R: Prop shaft, thrust bearing, jack shaft w/CV joints
I will have to fabricate another bulkhead support for the thrust bearing. Easy enough, it's angle in relation to the prop shaft will be the same degree off vertical as the prop shaft is off horizontal.
Thrust bearing & prop shaft
The way it's sitting right now the prop shaft is at 7 degs and the jack shaft is at 2 degs so each CV joint should get about 2-1/2 degs of angle well within specs. Nothings glued in yet so I'll be able to optimize the angles as I go.

I'll double check my work and start gluing in the prop shaft support frame and then make up one for the Python Drive thrust bearing. I'll dry fit the stern bearing carrier and then figure out the total shaft length. I bought an 8' shaft so it'll have to be cut down to size. The one that's in there now is too short but used for mocking up the drive line.

My buddy Andrew came over yesterday afternoon and fixed up the shed roof so we should be nice & dry for another 6 months or so. Thank you Andrew.  :-)