ORBITAL | Bikeboard | Remoteless | 80100 | 20s7p

[credit to voice actors @jack.luis and @poastoast]

I’M BACK, BABY
200w
and even more fabulous!

This build sets out to correct several of the problems encountered with the TÜÜB. The control system will consist of a hall effect ebike throttle plugged right into a VESC ADC. This hopefully eliminates:

  • the reliability issue of the strain gauge system by replacing it with a proven component and reducing failure point count
  • the stability issue of a force based feedback loop by replacing it with position sensing

I’m also doing that thing everybody does where their builds gravitate towards big pnummies and big batteries EXCEPT I’M NOT HALF ASSING IT LIKE THE REST OF YOU CHUMPS. I found that I was often stopped from doing what I wanted with the TÜÜB by range and road conditions, so this build will have:

  • 20 inch road bike wheels/mudguards to handle rough and wet ground without giving up rolling resistance
  • foot hooks and a medium flexy deck so I can unweight and hop over stuff without being ejected
  • 2.5kWh of 20s goodness

But hold up, bicycle?
Deck?
Did I mention that this is a speedboard?


zoom zoom, mutherfukker

Well, that’s a trademark, and it’s a little bit dumb. We have that, the Dirt Surfer, and @frame.b022 's term, but no definitive name for the category of 2-wheel inline skateboards. I am therefore, by no power vested in me whatsoever, unilaterally declaring this vehicle type to be a “Bikeboard”.

NUFF YAKKIN MORE HACKIN here’s way too many pictures of an esk8 build:

Specs
  • Geometry: 25deg rake, 100mm trail, 1550mm wheelbase, 160mm ride height, 40deg available lean

  • Wheels: 406 disc wheels, Schwable Marathon+ 500x35mm (20x1.35") tires

  • Brakes: 203mm disc front, regen rear

  • Weight: 28kg

  • Battery: 20s7p BAK N21700CG, 2.5kWh, set +60A/-40A

  • Motor: APS 80100 130Kv, set +130A/-130A

  • ESC: Maker-X HV200

  • Gearing: 12:140

  • Speed: 65kph @ half charge

  • Range: 120km @ 35kph

  • Efficiency: 18Wh/km @ 35kph (upright), 26Wh/km @65kph (full tuck)

  • Cost: $2500USD (projected), $3800USD (actual)


ORBITAL (adjective) - possessing sufficient velocity to remain in orbit of an object. ex: “mission control, the vehicle has gone orbital”

45 Likes
CHASSIS

Started off with the deck. 5 layers of 3mm baltic birch ply, glued up in a vacuum press with an inch of camber:

getting it in the bag with wet glue everywhere was a total birch

Cut to size with the jigsaw:

this girthy deck is 36 inches schlong

Had a minor panic attack here and started checking myself for injuries. Luckily I found the real culprit and it turned out I was being dumb in a different way than usual

turns out I was dyeing instead of dying, I’m so disappointed

A quick jump test before proceeding:
20220122_085147_1not sure yet if it’s a trampaline or an MBSline

I could have gotten the 13" I need from a continuous plywood sheet but I would have needed to buy 2 packs of 15" instead of one 12", so I decided to make like I was a ~fancy furniture boy~ and put hardwood edges on it:

the ‘hardwood’ joke for this caption is left as an exercise for the reader

In and out of the vac bag again for a 400gsm layer of +/-45deg carbon fiber
20220123_184231_1this part of the process really a-peels to me

This wasn’t supposed to change the flex very much since the fibers are on the bias, it’s more for torsional stiffness and waterproofing. The deck is flat when I stand on it, which means my math was correct for once.
20220124_213354_1jumping carbon and carboff

I made some 4 layer plywood by the same process as before, cut them with a jigsaw, and used the duct tape method to hold them in the zigzag shape needed for the rear arms during glue-up. There’s a platform made from a cereal box under the high side, to keep it parallel to the table and at the correct offset.

did you this plywood contains 87000% of your daily recommended fiber intake?

Then I cut a slot through the middle section to increase vertical compliance, and rounded all the edges over. The inside corners also got a big fillet with thixo so that the joints are hopefully not the weakest link in the system.

the bare slot is not pictured here for the sake of decency

The carbonized versions, fresh off the vacuum presses. The stray fibers will get cleaned up with sanding before installation, and they’ll be varnished after the chassis is put together.

Same procedure for the front arms, except these need to articulate to create a 4 bar linkage. I’ll need some heavy duty hinges for that. But where can I get extremely strong hinges with next to no friction?

same old jigsaw-ng and dance

OH SHIT @jack.luis GAVE ME A 3D PRINTER FOR THE BOTY CONTEST, THAT’S WHERE. I’ll just set Cura to vase mode and let it rip.
For real though these are PETG compression molds for making forged carbon parts, with 4 walls and 70% infill. The layup direction that gave the right fiber orientation was perpendicular to the direction the parts needed to de-mold from, so the molds have 4 parts. 5 if you count the dowel.

and you should, that dowel is trying its best

The molds get thoroughly waxed up and bolted into pairs, then packed with chopped carbon tow. Like 20% overfilled seems to work alright because air gets squeezed out, the excess just needs to be tucked in before closing the molds.

acheiving this EXACT level of messiness is CRITICAL

Step 27(b): Imprison the molds in THE FORTRESS OF MANY CLAMPS. If it oozes a bit you’re doing it right.

you fuckers will take that sentence out of context, won’t you

The chamfers in the mold blocks let me pry it apart with a putty knife and some pliers.

fresh and crispy

After deburring, I made a foam jig to keep the pivot lines parallel and correctly spaced during glue-up.

it was legally required that I cut the slots out with a jigsaw, smh

THIXO is a high strength filler epoxy that lets me create bevels to back up the hinge blocks. It also lets me get up, and get down with the thickness
20220424_141159_1OOH AH AH AH AH

The hinge blocks get an overwrap of carbon tow around their lower halves, so that tension doesn’t rip them off the wood, while the middle section gets more of the same to reinforce the flex cutouts.

TO SHOW YOU THE POWER OF DECK FLEX, I SAWED THIS CRITICAL STRUCTURAL MEMBER IN HALF

With tension/compression handled by the UD, the arms get 45deg biax cloth vacuumed on to handle shear loads. Yes, the middle links are wrinkly, it was crazy hard to get the vac bag to sit right.

that’ll buff out

With the hinge blocks reamed out to seat the bushings, the linkages can be clamped to the front wheel and aligned to the deck.

that’s not wood glue bonding the parts together, that’s pure elbow grease

And now the front wheel is floppy: :+1: :+1: :+1:
20220515_084154_11 leaning can’t turn the wheel past the point where the outside linkage straightens out, which is a useful and totally intentional feature to avoid steering lock at high lean angles

A flat fiberglass plate acts as a compression spring here to provide some centering force for the front wheel. An analog test ride showed that this noticeably helps controllability at low speeds.

the test ride was an analog for how the board rides when it’s acoustic

These dowels prevent the arms from flexing outward under load, and as a good place to pick up the board from. The arms also get big fillets of chopped fiberglass/carbon between them and the deck, and the whole structure gets a nice shiny clear coat :kissing_smiling_eyes: :ok_hand:

b3p1a09en1h21

Fillets and 3DP edge protectors on the outside too, and this shit’s DONE.

even my fillets have fillets over them

Ok well i changed out the threaded inserts for M8 steel hex, because the brass ones from Lowe’s were BS. But NOW it’s done.

wherein I make both bicycles and skateboards harder to ride

32 Likes
BATTERY

We begin, as all good things must, with a totally reasonable number of high capacity 2170 cells:

Fig. 32: Prudence

They’re glued up so that they can fit mostly under my feet, which trades away ~15mm of ground clearance to achieve a better sprung mass ratio for the “suspension”. If the pack avoids the center of the deck, where all the movement during flex occurs, the pack will avoid most of the vibration and provide less resistance to the wheels trying to move over bumps.

hide yer daughters, hide yer vibes

Fishhhhhhhhhhh. You know the drill.

Why isn’t there a fishpaper+rings store called Fish n Chips?

@Evwan lent me his kweld for a couple weeks and I managed to get everything hooked up with 0.2mm nickel after an embarrassing number of test welds. The 4 center groups are conventional double stack, but the 8 groups at each end are more like a brick pack, with current zigzagging up and down (from the perspective of the brick on the left in the pic). You can see the nickel fold showing between the top and bottom halves.

don’t even talk to me unless you buy 100mm wide nickel

Onto the enclosure. For the mold I stacked up different thicknesses of foam and wood to get the right height for the each section, and put drafts all around by carving and sanding.

those are acid brush bristles, get your minds out of the gutter

After covering the deck with packing tape and a plastic bag, I glued the blocks into position and started adding layers of 3 mm foam around them for flanges and wire routing space. This stuff got a layer of fiberglass, more sanding, and five layers of mold release wax.

Not Cocaine™ is the world’s leading fine white powdered substance that’s very bad for your health when inhaled

Fiberglass mat in a bag, not much to say.


i did think of a joke but it was pretty vacuous

Out of the bag and trimmed with some snips while the epoxy was still soft, but still needs sanding around the edges. Bedliner will hide the rest of my sins.

most of those markings are sharpie for aligning my fiberglass patterns, but one of them is my actual blood! I’m not telling you which! Hail Skatan, blood for the blood god!

With the sins hidden under a glorious, rubberized coating, the battery and BMS get wired up.

like and follow to find out what conditioner I use on my balance wires to get these beautiful curls

wherein I don’t burn down my apartment

27 Likes
POWERTRAIN

The control stick needs to rotate in all directions freely at the point it attaches to my leg, as well as extend freely to accommodate the fact that the throttle is not physically located inside my ankle bones. I glued a carbon rod inside of a ball end joint and used it (plus a paper spacer wrapped around the rod) to mold a fiberglass tube. They won’t be fastened to each other in any way, so that my shit doesn’t get ripped apart in an ejection.

you thought I wasn’t going to work a DIY composite tube into this build? You FOOL

The leg attachment pad is 6mm of EVA foam under a couple layers of fiberglass, using my leg as a mold surface cuz why the hell not?

[gratutious_leg_hair.png]

All of that gets glued together with a PETG hinge for following my lean angle. The ebike throttle sits on a 7/8" dowel (standard handlebar diameter) and has another PETG block to capture the trigger. The idea is that it should only capture forward/back motions with the sensor, and move freely for everything else.
20220522_185408_11proud to say I have the floppiest stick on this forum

All that gets mounted to the rear heelside deck, with a little JST plug loopkey to cut power to the throttle for when I step off the board or get ejected. Paired with a pulldown resistor on the ADC, this hits the brakes as soon as I leave the board.

theoretically, of course. It’s not like I’ve needed to test it out before. Yet. Obviously.

But enough about my stick, get a load of my BASS (big ass sprocket system). 140T #25 aluminum, with an adapter from sendcutsend to change bike disc brake mounting to scooter sprocket mounting.

did you know that if you fuck up your first set of mounting holes, you can just drill new ones and cut out a giant Cloverleaf pattern to hide the old ones?

This crime against engineerjng exists because I had to shave down a 4mm key to fit in a 4mm keyway on the sprocket but 3mm on the motor.

this isn’t a key, it’s a cry for help

I mounted the motor using another sendcutsend piece and a couple blocks with fun shapes and colors.

only the latest from Fisher-Price Motorsport

The battery is mounted with socket head screws, rubber washers, and butyl tape.

and swearing, don’t forget swearing

That’s the HV200 sticking out the back, running a custom firmware version from @jaykup, who improved the thermals of the motor slightly and also helped me work around an ADC failure because he’s just such a swell guy. The loop key, pre-charge circuit, fused charge port, and fused lighting loop key also live in this box.

I always start off with such high hopes for my electronics enclosures, but they always end up like….

3D printed lid and hold down clamps.

I’m all out of clever things to say about simple parts of the build, so if you want more of those please check out the “Bits and Bobs” section

wherein I train my power

22 Likes
BITS & BOBS

3DP blocks hold these 12V LED bars facing rearwards, and dyed epoxy diffuses the light and waterproofs them. 7 in series means they can jusy run on Vbatt.


brighter? I hardly know 'er!

My boots turned out to be the perfect mold for making fiberglass hooks over my boots. Who’da thunk it?

I’m a cobbler? I hardly know 'er!

Like a glove.

fits better? I hardly know 'er!

Initial testing revealed that the motor was running a bit hot, so I designed a cooling fan to bolt onto it.

Impeller? I hardly know 'er!

I thought it would be cool to see what a motorcycle steering damper did to the handling of the board, but initial testing revealed that this sucked.

Damper? I hardly know 'er!

Bike pump.

bike pump!

wherein I give up on trying to categorize my activities

19 Likes
CHASSIS PART 2: THE UNFUCKENING

Yeah so I rode up a curb and this shit cracked wide open. It’s a clean break along the parting line, so my efforts to try and interlace the fibers from each side of the mold probably didn’t work. These need a rebuild, and I’ll stiffen the deck while I’m at it since I don’t have enough lean angle clearance.

Are you suffering from a bent shaft? It may be a treatable medical condition, ask your doctor about–

LET THE UNFUCKENING BEGIN

The strategy for the new hinge design is to make the outside concave instead of convex, so that carbon tows can be overwrapped after the blocks are installed to create a continuous piece of material around the perimeter.

RETURN OF THE CLAMPS

I also tried to make a simpler mold design instead of the conventional piston type, did not go well.

move along, nothing to see here

Here the new blocks are jigged up, and you can see I have also elected to strengthen them by making them LONGER and GIRTHIER.

I could make a second joke in this caption, but I’m concerned I would be laying it on too thicc

Here you can see the concave sections filled up with carbon strands, I also dremelled out a small concave in the forward hinge blocks to retrofit the same reinforcement for them.

well, that’s a wrap

As much as I hate to cover up my pretty biax skin, it’s for a good cause. I at least took the unidirectional tape and tried to match the curvature of the board, as well as shape each bundle into a little bit of a concave pad.

the bottom of the deck is the same story, but just like my jokes, the tape is flat

wherein some parts of the build were so nice, I did them twice

21 Likes
FINISHED BUILD PR0N





wherein you marvel at my lack of photography skills

29 Likes

image

22 Likes

Dude… This is one best build threads I’ve ever seen on here. There’s a fuck ton of questions and comments I have about this, I just don’t have the time to put it all into text right now. But holy crap color me impressed. Makes me regret moving away. I’ll back back soon and I hope to see you and this beautiful device in person

19 Likes

Wouldn’t it be more accurate to call it a handlebar-less scooter?

It does look both cool and like a potential death trap though. Only thing you are missing is more LEDs

ok hear me out, what if in the v2 of this magicboard, u use fat (wider) bike tires?

3 Likes

Yeah, that would be great. More lean clearance and easier balancing in turns

Blasphemy.

y tho? This thing feels rock solid at speed, and I have yet to be knocked off balance by road conditions. Those were the main sources of danger on my last board.

Many thanks! I hope to ride with you again as well

8 Likes

some fat knobby tire might also enable u to go little bit offroad if u need to, might be sketchy af, but i figure its probably “doable”

Fucking madman. I wish I could see this before I leave.

7 Likes

If you have some kinda opening where you can ride, hmu :+1: I have no life

@longhairedboy can this be my title plz

8 Likes

granted

edit: also holy fuck, I just scrolled up. what is even happening this thing is insane, how do you even.

16 Likes

To be fair, I’ve said that my own board could be considered a death trap to the mountain board people on here due to its height. So long it is for personal use only it doesn’t matter if it is safe or not

The tire doesn’t matter that much for temporary off-roading. Biggest issue is if it has enough torque or not. My street board with thane wheels can go off road but it is very slow and uncomfortable. Works well enough for small stretches where the road is dangerous but there is no sidewalk but I’ll never take dirt paths with it if there is an alternate route.

2 Likes

Yeah, riding grass with it is manageable at low speed, but not comfortable due to the high pressure tires. Torque is plenty though.

Understandable, the deck height on this is like six or seven inches. But above 15 kph, it feels very much self-balancing. You don’t feel like you’re on stilts while riding it, if that’s what you’re worried about.

2 Likes

Thanks :+1:

The process is simple. You look at Speedboard™ and be overcome with equal parts awe and one-upmanship.

9 Likes

you have earned your title, sir. Well done.

5 Likes