- Rule of cool
- Packaging the front suspension linkages looked kind of ridiculous on this build with a steering tube, no matter how I turned it around. Using a steering tube shortened the distance available to work with for the linkage
- I already have experience molding the carbon parts for the 4 bar linkage
- A steering mech with forward rake like mine will flop all the way over to the side at low speed when you lean the board, wish I presume is one of the reasons that @2swiftmo use reverse rake. That whole setup makes their board super easy to ride a low speed. A four bar linkage has a limited range of motion, which functions as a soft stop at the end of steering travel, which IMO makes for more comfortable low speed maneuvers (with forward rake).
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Yea the caster style approach allowed for the low speed handling as Flyboy mentioned. The manufacturing was also easier to go with that route based on the specs for this model. With that said, we should see about a collab project on the pro model we want to get into 
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This looks fun.
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Looks cool forsure. Do you think there is a chance the suspension linkages and the steering arms might bind, maybe when turning/leaning?
For caster style you could keep the suspension linkages in relatively the same spot and extend the steering tube out to the front. I think the leverage on the suspension would be similar because the tire contact point wouldn’t change. Makes me think of this bike.
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That’s the exact type of layout the “steering tube version” of my design had, except without the bars and their associated follower links. My parallelogram linkage was super short because it was limited by the steerer tube up front, and my front foot placement on its aft end. So, the axle path was awkward and it didn’t work well with off the shelf MTB coil-overs.
The current design has a parallelogram link nested into each side of the 4bar link. I don’t believe it will bind under torsion because I’m using ball bearings at all the pivots.
I thought there would be enough space for suspension linkages above your feet. Making room for your feet is definitely one of the tricky parts of suspension on boards… Your current design looks promising though, the axle path looks good. That was one thing I got wrong on my first attempt. And it’s kind of funny all electric scooters with front swing arms I’ve seen have it wrong also.
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There absolutely is, but i consider that a safety issue. I don’t want anything snagging my feet during an unplanned ejection, so clear space is a must for me. I also need to mount my front foot on and off the board anytime i come to a stop.
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Holy shit i made a part for the steering / suspension linkage and the bearings actually fit correctly with a hand pressure friction fit and no slop. What are the odds that ever happens again without sanding? I’m going to be riding this high all week.
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Ooof… that sucks it.
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This hurt my soul
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The previous tenants installed the shelf brackets with the blue anchors, so I’m replacing them with the corkscrews. Such a simple f@*&cking thing.
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The frame is patched up, plus it has black dyed panels now for 
the aesthetic
The heatsinks for @Skyart s solos are mounted at the rear with screws and epoxy
As is traditional, the engines are a stressed member in the chassis 
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Exciting build! Give me 2 weeks and I’ll have a really cool concept to share
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The cores for the rear swingarm are ready for vacuum bagging. The tail end of the cores use 3mm plywood to save on thickness, since I’ll be sandwiching a chain tensioner mechanism around the rear axle.
These forgings go at the front of the swingarm and hold the bearings. Eventually I’ll figure out how to remove the last bits of the mold from the bearing bores without damaging the diameter lol.
The core piece for the deck plate is also done, with a plywood recess to allow for the pivoting rear footpad. Most of the mounting screws will go straight down through the perimeter like normal, but some will go sideways through thinner flanges that I mocked up with craft paper.
The footpad will pivot on a carbon shaft that runs through this pass-through tunnel, which i printed with fuzzy walls to get better grab into epoxy.
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The final balsa cores are done, for the fork and the rear footpad
I started vacuum bagging the deck plate with just the lower ply, so I can trim the whole thing to size in preparation for wrapping the top plies over the edges
The top surface gets 2 550gsm plies (and all of these are laid on bias for torsional stiffness), then laid into the frame itself so that everything gets formed to a more exact fit.
Final product!
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Double, double, toil and trouble…
Vac bag suck out all the bubbles…
Now i have all the parts for the rear swingarm skinned in dyed black flax!
I made the rear footpad with a little concave, and some small flanges to help my foot locate blind. This part goes between the rear chassis walls, and i don’t wanna mess up my steering by standing on them by accident.
The torsion shaft that the footpad rides on starts off as a 9mm FG tube, glued to the edge of a +/- 45deg carbon fiber sheet.
I almost ended up scrapping the part, since rolling it up by pushing from the top kept introducing voids between the layers. I eventually glued dowels into each end of the mandrel so I could torque it backwards from the inside as i rolled, which kept it in tension. Each end got a little messed up, but most of it got to the target dimension of 20mm without going over.
I gave the parts for the front fork some nice facets. All hail the oscillator tool.
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Sexy parts! Your whole thread is making me miss doing composites work. Vacuum bagging composite laminated plywood is such a satisfying process. What’re you using for a vacuum?
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