we've designed a wand linkage system incorporating a cam on the wand axle (just a quick screen shot, parts to come) and also built a vang that sits inside the boom with just one dyneema rope coming out of the bottom to the king post. more pictures to come.
aahhh, I've been holding that in for awhile...whether those two items work or not is another matter, time will tell...it may all just be ill-conceived tinkering...
well, that was a secret fail
Very good timing (pun unintended), I was just thinking about a cam but with a tension system, i.e. string wrapped around the outside. Any thoughts on the cam shape that you want to share?
ReplyDeleteKirk
heaps of thoughts, the most useful one is to make the cam easily removable so you can try lots of shapes easily...trial and error method will likely be the best to find a good cam or cams for different conditions
ReplyDeletewe're still planning on getting the conventional conrod system working first (something to fall back on if required), then onto the cam system development
also considered the tension system but my opinion is that it may not allow as much variability in the ratio of wand to flap angles. this may not be a problem though. the linkage geometry on PM doesn't really allow it either, axle is too close to the conduit.
let us know how you go with your system, share the development love.
One idea is to put the cam and follower inside the boat, that is just in front of the CB. Then the cam can be driven by a pull-pull tension system from the wand. Similar to overhead cam vs cam and long pushrod.
ReplyDeleteIt might give you more room to get the cam and follower in the right relation.
Tension system is more urgent since I wiped out the bowden cable today....
Kirk
Hey guys.... how does this "cam" work? if that pink bit is just pinned to the "cam", then the cam does nothing.!! may as well be a direct rocker link. Am i missing something?
ReplyDeleteyes, you're missing something
ReplyDeletepink bit (pushrod) with bearing on end of it only moves in and out. it is the cam follower.
the red bit is the cam which rotates with the axle connected to the wand. It has a profile that determines the desired flap response.
there are details missing, some of which have been worked out, some haven't.
(which of the qld skiffies are you?)