Archive for pavedwave longboarding distance longboarding, flatland pumping, cross-country adventuring, boardwalk cruising, and all things skateboarding and good times
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dustm
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slippery skates wheels!OK, I lied. Its not a wheel! But it goes on a board where the wheel goes, so poo on you! Some of you may have seen my old thread in the longboard hybrids section on silverfish for my ice blade design. I have done quite a bit on the mechanics of the tilt mechanism and blade assembly since then, and thought i'd share some of what I have here!
The whole idea here is to create a slick, efficient ice LDP board for generating serious speed on a rink. This mandates tilting blades with radiussed edges to ensure grip while minimizing scrub. I am still trying to crunch how exactly to get everything in tune (edge radius : blade tilt : board tilt : turning radius) but in lieu of actually figuring all that out before I even try it I'm just going to try to make the stuff adjustable and start there.
So, here is my prototype to check the fit of all my parts... I hope to complete the set soon but as time proves over and over things always take longer than you want. Money, time, blah, blah...
What you see here is the waterjet-cut 1/16 spring steel blade, 1/4" steel uprights, and 1/8" steel retainer. There is still a lot you don't see but that too shal be revealed as it comes together. The parts fit well, so I'm going to try the portion that goes from the truck axle to the blade assembly next. BTW the rusty area on the blade is just a spot where the jet rooster tail blasted the blue coating off the steel.
Bryan
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Belegnole
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Ok, we got ICE! so even if it takes until next winter I would have an interest in how these develop. in fact I suddenly have thoughts of getting a kite out as well.......hmm, mountain board deck with maybe Seismic trucks (no freeze factor) one Quad Kite and vooooom!
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dustm
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hehe, just reading your post made me shiver! Wind and ice! Sounds like a blast though. How rough is lake ice?
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Belegnole
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Lake ice depends on a number of things. Some places it is rough, real rough and others it may be as smooth as a skating rink. It's been awhile since I have been out on a lake but all I would have to do is find where the Ice boats go and find a smooth section....Or I could do laps at a outdoor rink. Either way it would be better than waiting for the roads to clear...
Oh,and as far as getting cold. I think I would wear a one piece winter carhardt outfit with thermals under it, Sorels, a full face mask, goggles and maybe pads.....and mittens.
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northcoast
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i'm curious as to how those would fit on a truck
and if you need any help testing, i work at an ice rink!
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dustm
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Sounds good guys! Its going to take a bit of testing to work out what works best given all the variables... After I get this first proto running I'd be happy to send out a couple sets with various blade geometries to play with. The blades are 2-sided allowing 2 different rocker radiusses/blade lengths per blade (or symmetrical and when it gets dull just flip it).
The proto there has a 96" rocker radius on one side and flat on the other. Its not sharpened yet but a radius hollow for more grip or 90 degree flat for better glide are the options. I'm getting excited just typing about it. I'm going to unnofficially say that the proto (just one complete corner) will be done next week sometime.
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northcoast
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i'm really excited about this, lol...got thinking about having a board on the ice as i was skating at work the other day...hard part about that would be finding a rink that, first off, has very few people and second off, would allow the board on the ice...i know the rink i work at ONLY allows skates on the ice, because anything else is an insurance liability.
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Crake
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VERY interesting to see this. I was just looking at the Iceboats we have locally on a ride I did past a lake. They have the lake racetrack all smooth and clean for the boats and I kept looking at the ice blades and my trucks and wondering if this was a possibility. This could be a sort of salvation for the ice and snow bound.
Brilliant stuff!
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dustm
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A little update for you guys. Still tweaking in the design stage and I'm still not completely satisfied with the linkage geometry. At full turn I'm ending up with the opposite of ideal difference in angles on the inside and outside blades. In other words the outside leans over more than the inside, and of course the inside is the one that needs to track a smaller radius.
I have some screen captures from the solidworks model attached (pat pend). I think I may suck it up and try it with the funky angles... I could also set center with the blades tilted out slightly, but then instead of fighting at full turn they will fight anywhere but full turn. It will most likely take some experimentation and brute force trial and error on the ice and in 3d cad land  I'm shooting in the dark somewhat anyway and I'd probably know exactly what not to do if I went ahead and built it. If anybody here knows how to design a multi-element, very complex 3d linkage the right way, please let me know! I'm sure it involves lots of advanced calculus and colorful language! Even if you don't I'm open to suggestions on linkage placement. Its rather difficult to mess with the Bennett although what you see is leaps and strides from the first configuration I tried. I have not set up the rear yet in the model but I anticipate it will be much easier with less turn angle and axle offset of the randal vs. the bennett.
Do the lean and turn angles for the full turn position look about right? Its hard to see how far the truck is turned/deck is leaned while pumping. I have the bennett mated as if it had a spherical bearing in the hangar... So it does not account for bushing squirm. Thats a whole other variable there too. And there are many more where that came from that I don't care to get into.
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jat.
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Wow. Pretty impressive looking stuff!
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stridey
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Wow. Thats cutting edge stuff....
er.....literally!
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pavedwave
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| dustm wrote: |
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Such an insanely cool design Bryan. Must come from a tortured creative mind that lives through months of frozen streets -- necessity's the mother of invention!!
Are you thinking of any springs or elastic inside the arms, that help pull the "outside" blade back to center? Or try to rely strictly on the bushings for rebound? Simple's always compelling and less prone to breakage, so I'm not really advocating springs and the fasteners they'd probably require, just spitballin...
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dustm
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Thanks you guys! Its not torture most of the time... I get a kick out of seeing it move on the screen.
Re: springs- Thats a good question, and good idea. I don't know if making the length of the linkage springy would help because that would allow motion that I'm trying to constrain. Instead, linking the springs from the deck to the blade assembly may reduce the force that the little ball links have to transfer to tilt the blades and of course improve rebound/return to center. I'm not sure exactry how the blade mechanism will affect the truck feel but it makes sense that some more rebound could be good. It would definitely be a good idea to at least include somewhere for springs to link before its built so I could experiment freely.
I don't know if all this is correct, its just how I think about it... Resolution of forces is very important and this is just an observational guess an what is going on. I could very well be missing something, or totally wrong altogether, so: Centrifugal force pushing sideways on the contact patch of your wheels in a turn adds leaning / turning force to the hangar if the axle has positive rake, like a bennett. Think how flipping the hangar on a Randal makes it more stable (more resistant to changing direction)... The rake goes from + to -. Wheels on a Bennett move towards the inside of the deck in a turn, however, the blades edge will move the opposite direction as the blade tilts in the same turn. That side force will also feed back up to the deck and fight the turn by torquing the blade axis and loading the linkages, the inside with buckling force and the outside with tension. It may turn out that to get the same bennett feel a more extreme + rake is needed. Who knows!
We don't get too much ice around here, but I don't like skating too much in the cold so I laze out for a few weeks in the winter. More time to build and draw! Ironically my motivation is to skate in the summer when we have all those nice 90F, 90% days. I have an aquaintance at a local rink who thought there would be enough empty ice time to help me out. I suppose I could make some friends at a regular roller rink but then I wouldn't have an excuse to make neat tilty ice blades...
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kayakr
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what about not leaning the blades?Ice boats don't need to tip the blades do they? Seems a lot simpler just to have vertical blades.
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