bow is to the right in all renders.
the pushrod input is the pair of rod ends in olive colour on the right hand side. the pushrod is not perpendicular to the centreline, hence the rod ends.
this goes into the first rocker (pinkish). it has the same ratio and phase as the wand lever so the rotation of the bolt at the bow is exactly telegraphed (not sure if this is important, but may help with future development).
phase can be adjusted on this rocker by spinning (nigga) the on board bolt, draging the right hand side of the green linkage around that arc track. this is set up for adjustment on the land only. i may add a nob (ur) to the top to make it adjustable from the cockpit.
green linkage is a turnbuckle that is needed to use the extreme range of the phase adjustment. for minor adjustments to phase, it shouldn't be required, the brown rocker just won't stand up straight.
brown rocker is the gearing. spinning the bolt drags the input pin up it's track. going up amplifies the signal. it has a rope guide on one side only that moves with the rocker, however i expect it will be able to be adjusted from both sides of the boat, it will just need to remain rather tight, and i may need to make some sort of lead for it.
next is a blue linkage made from a turnbuckle. this acts as a dial. just before it exits the machine there are two nuts on either side of a plate. these are limit screws that mean no matter what you do upstream, it will bottom out on this plate before damaging the centreboard pushrod. will also be a convenient way to see what the flap is doing.
bearings are to be pressed in, then retained with worm screws. i have just bought some shock aborbers to add into there somewhere (probably on the pink one, with a screw to adjust lever to for dampening). wand length, bungie and wand stopper will also be run to the tramp, seperate to this machine but equally complicated.
all plate parts are watercut 4mm aluminium hard coat anodized. bolted to the boat with 5x M5 countersunk fasteners into a carbon channel bonded to the deck.
I've been thinking about revisiting shock absorbers (had one on my boat in 2006!) but came to the conclusion that you need something in the pushrod system itself with a positive and negative spring so you have some 'float' in the system to iron out the small bumps. Not sure such a thing exists at this scale!
ReplyDeleteAren't the flexibility of the wand and the size of the wand paddle the most simple shock absorbers? I presume that the original bare stick was a "soft" shock absorber and an enormous paddle on a stiff wand would produce a "hard" setup.
ReplyDeleteThe slots for the purple dial aren't needed, just a single hole on each side, one forward and one aft.
ReplyDeleteWhat's holding your purple dial in column when compressed?
cookie,
ReplyDeletei don't think the spring is necessary. i just want the dampener to slow the wand responses down. there is enough spring from the bungie and wand flex (as LC suggests)
i have come across two kinds of shock absorbers that should work. the first i will try is model car ones. I have picked up a pair for $15 which have 16mm of travel. the spring can be adjusted with packers, dampener can be adjusted with oil viscosity. second option is industrial ones:
http://australia.rs-online.com/web/c/?searchTerm=shock+absorber&sra=oss
bit expensive to start experimenting with.
i am also considering building one of my own if the model car one doesn't work. just need to sort out the oil seals.
LC,
I think wand flex is only part of the story. i am planning on a shock absorber to dampen the motions without storing any force. the shock absorber is easy to move slowly, but hard to move fast - and when it stops moving it doesn't spring back, just sits where it is left.
Anonymous Coward,
yes, quite right, i made them slots because i didn't have the confidence where the rope would run onto the winch. i should get more sack and commit to it to save any addiitonal fairleads.
keeping it in column... shouldn't the track do that? The track's arc is different to the pivot for its dial. there will probably be one place where it is sloppy but i would think it is mostly going to be fine. well i'll find out soon enough.
You might want to talk to Giovanni about dampers in that case as he had an experimental setup on his mach 2 a couple of years back.
ReplyDeleteAll the control improvements in the last few years have been about making the wand do it's job better and while I suspect there might be wave states where damping is a good idea I doubt they happen very often!
Another thing, damping the input going into the foil should be a better solution than damping the wand itself. Slowing it on the surface of the water will only add drag, whereas a floating spring arrangement between the two would iron out the peaks without slowing the wand...
ReplyDeleteDon't forget that there is an inbuilt damping and spring system in the whole control system right down to the foil. There is springiness in the control system and the foil itself provides damping.
ReplyDeleteWhat frequency of movement are you trying to filter out?