As i start to lay the 3 major components (rear axle, engine/gearbox, front-end headstock) out onto my jig, I'm starting to wonder about centerlines. Up until now i'd assumed that everything is symmetrical - that is, the differential is in the middle of the rear axle, and the crankshaft is in line with the prop-shaft.
On closer inspection it seems like they are pretty well all designed to be on line down the center line of the vehicle - but how would i know? Does the engine have an off-center center of gravity? is it shifted in the original Reliant Robin to give more leg clearance for the driver? Does the long prop-shaft accommodate this in a way that my soon to be shortened prop-shaft couldn't? and would an offset, off-weight engine have a significant effect on the handling of my trike?
So many questions, and so few absolute answers?
I return to my mission statement (i should have it laminated and hung on the wall really) - "to create a trike of beauty" - The fog lifts and all is clear.... mount the engine so it LOOKS right - which in this case is on centerline of crankshaft. It will mean that the radiator will have to be shoved over (to be back on centerline of the vehicle) so it wont be getting the most direct benefit of the fan, but i guess it will generally keep cool enough if i drive fast enough!
And then there is the rake angle of the front-end. If i lean it back as far as i would like, will it make the handling dangerous. Check out wiki to make your own decision - http://en.wikipedia.org/wiki/Bicycle_and_motorcycle_geometry
1 comment:
Regarding the centre line you may remember that when I built the TF I got confused with the back axle crown wheel axis. I fitted the axle in the chassis and couldn't understand why the propshaft fouled the tunnel on "bump" conditions. It was only when I measured the crown wheel axis relative to the wheels that I descovered that it was offset! I guess the reason why the designers did this is lost in the mists of time, possibley it was required for one car and it was perpetuated for ever. Design reviews do serve a purpose.
Thinking of your radiator offset, I am assuming you want it on the centre line but the fan is offset. Could you fit an electrical fan? An alternative would be to fit and idler wheel on the centre line on which you fitted the fan?
I loved the reference to the fork angle,what fun. I thought it was all to do with how it looked and caster angle/weight of steering. How wrong can you get. Congratulations by the way on finding the site, you must show me how you do it some time.
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