A Motorized Mountainboard That Works

[Gomer]

Yah, It's not a scooter.

I'm confused on this point. Are you saying that the handle in the back is not used to steer the board? I couldn't understand, from your description of the center wheel drive effect on balance, if you included the rear handle as a method to steady the rider or as a way to control steering or both.

Control functions could happen through a teathered brake and throttle cable like on current gas powered mountainboards.

From the videos, it looks like the steering could be lean controled. That is why I wondered why you had the handle.

I thought you had said previously (although I can't find where I thought you said it) that the steering had to be controled with the rear handle because of the long throw and minimal resistance of the shocks. That is, like a four wheeled scooter, the steering resistance was too loose to be controled by lean steering.

If your board could be controled by lean steer only, I (as a personal preference) would have to eliminate the handle. Of course I would have to have some kind of bindings too but then that's just me.

[Gomer]

One major issue with powered boarding is acceleration. When the board accelerates independently of the rider (unlike gravity) there is a huge force applied at the rider’s feet that must cause the rider to anticipate in order to stay vertical.

Are you saying that the handle is for balance only and has no affect on steering? I totaly misunderstood. Can you control the board just by lean steering? Couldn't you take the handle and throw it to one side or the other and turn the back truck?

The only reason I say it is a scooter is because I thought the handle had some steering control function. A scooter's steering is controled (partially or exclusively) by using a handle.

If the handle is not needed to steer, I would have to get rid it. I can't see any acceleration speed that couldn't be controled by the rider adjusting his stance. I'd also add some bindings to help the rider stay on the board in the rough and provide some control in the air. Maybe I would add a grab handle to the "T" on the trucks to hold onto in a squat.

Also, the pendulum effect you describe is more pronounced on electric boards because of their high rate of acceleration, constant torgue electric motors and lack of a clutch. I agree that your low center-of-gravity is more stable although I'm not sure that the center wheel has anything to do with the rider being more stable in a quick acceleration.

I would guess that you could take any kind of board and accelarate it from the front, middle or rear and feel the same effect on balance. I think it is more the rate of acceleration that affects balance.

You have a cetrifugal clutch that allows the board to start at a more controled rate. An electric motor can apply all of its brake horsepower all at once. A clutchless electric motor also can take away all of it's torgue as soon as the power is cut. That makes for a very jerky ride requiring sensitive throttle feedback and control.

Your board has a clutch and a brake. You can better control your rate of acceleration and deceleration than can a glutchless electric powered board. I'm sure it is fun to gun your board and take off fast but, as a personal preference, I'd exchange squatting down for the handle bar to achieve the freedom of movement.

I notice in the recent video that the rider was forced to jump off the leading side of the board in a quick power slide stop. I don't think that would have been as prone to happen if the rider had been able to fully reduce his center-of-gravity and counter balance the force of the board direction by leaning further out.

Just curious about your rate of acceleration and braking. Exkate's specs say they can go from 0mph to 19mph in three seconds and brake from 19mph to 0mph in 40 feet.

Please don't take my observations and questions as criticism of your design. I know you have put a lot of thought, time and effort into your board. I'm sure you know better than me. I'm just trying to think it through for myself.

Thanks for discussing this board with us.

[Eric Briner]

These are great questions! The handle aids mostly on the roll axis of the board which helps with bump steer. The trails I like to ride are ungroomed and some impacts are severe. I'm not saying you need the handle, most of the time you don't use it except for speed control, but we need a place to mount controls anyway plus it comes in handy when things get rough.

As far as electric motors go, there are controllers available that allow you to set rates of accell and decell in forward and reverse that give precise control. I used a scooter controller and it was great... for 10 minutes.
All I will say about deck tilt is shat there is a different feel than a flat board. I will get those specs for you. Sounds like a cool project. I just finished a video.

[sk8norcal]

YouTube - PowerXBoard Promo

[Gomer]

The handle aids mostly on the roll axis of the board which helps with bump steer.

By "roll axis" do you mean when the board rolls from one side to the other of the drive wheel? I could see that. Having that leverage from that height must be easier to control than the quick roll you would get leaning it over from side to side with your weight.

I used a scooter controller and it was great... for 10 minutes.

Ha, yeah. Gotcha. Electrical power wouldn't mix well with water either. I saw the other "Splash" video. That was a pretty steep drop. I'm guessing you coast into a drop like that and acelerate to speed at the bottom. The ability to coast and hand brake is a good thing.

I'm sure the tilted deck is more stable than acelerating on a flat deck. Probably the single wheel balanced with the two wheels in back help too. You probably very quickly get up to a speed where the drive wheel takes over most of the balance. After that is looks like you are applying pressure side-to-side and fore and aft for steering control on the outside wheels.

There are so many more degrees of steering angle because of the "rocker" of your board. Do you experience much speed wobble at your top speeds?

There are a lot of self-balancing, single-wheeled boards out there (and a motorcycle too) and the technology is going to advance quickly. Sony wouldn't be in on it there wasn't something happening.

I think your board, for really rough and high speed off-road, is better than a self balancing single-wheeled board. You are able to take advantage of the differences in surface levels and ride all of it rather than a little skinny patch.

What do you mean by "bump steer"? Is that where you rebound off one suface to the other to steer around tall objects?

I can see where the control handle would be useful. Although you could mount controls on some kind of whip like the old Police radios used. Is there a twist throttle and one brake handle? It looked like there were two brake handles in the last picture featuring the attractive young ladies.

The loose brake cable on MBS mountainboards didn't work well. The brake cable itself was too lightweight and would cause the brake to become maladjusted if you held onto it in a bail to keep the board from running away. It always got tangled up in the wheels when you crouched low and you often crouched low.

It is good to have something to teather the board with though.

I wondered what kinds of boards you had ridden before the MotoX. In your video I see a Freebord and a skateboard, a skim board and a wake skateboard and two snowboards on the wall. Is that a wake surfboard on the top rack?

No mountainboard?

[Gomer]

PowerXBoard

I had forgotten about that board. Now that is a scooter. What did I tell you about front steer scooters. As fun as those look it still looks like they are holding their "poles" and "driving" the board rather than riding it. It is pretty much a stand up go-cart.

I'd have one if you it had rear wheel steering and you could stand on it sideways. I tried to call the number on the banner last year. It was disconnected and the web site is abandoned.

[Eric Briner]

The handle also makes it legal for street use in California. This is the shop mountain board. (old school)

101_0150.jpgI really like the wacky board site. It's cool to see the MXB on there. My favorite was the break dance board.

Bump steer is where your body goes one way and the board goes another. The real reason Jim jumped off the board is 'cause the chain came off. You can hear it in the audio.

I re-made our new video. Different shots and music (same band). I think it's better.

YouTube - motoxboard110 8

[dmgcat]

Seems like that center 5th wheel causes the board to pivot which looks like it will dig in a turn which made it chain fly off. I think this design can be fixed by putting that 5th wheel on a set of shocks so that most of the weight will be on the outer wheels and not in the center. What might even be better is to have it on shocks and have it lean into a turn along with the other trucks. The idea seems simple to fix but then comes the problem of having a flexible wheel connected to an anchored down motor. So would a shaft driven 5th wheel be the answer in order to allow for the flexibility without losing any torque? Another benefit of this change would be that whether you used battery motor or IC engine you could lift the 5th wheel up and skate it in case you ran out of gas or batteries. Anyways, great concept, thanks for the vid.

YouTube - motoXboard 110.5

i know what ur saying,
i ridden exkate powerboard,
acceleration is annoying cuz you have to counter it by leaning forward...

a handlebar/stick in the rear or front (or rope in front) helps this out...

you monowheel drawing reminds me of all the
segway like monowheel skateboards out there...

wackyboards: }self balancing

[Eric Briner]

We use a multi-link mono-shock design. An adjustable link rod allows deck height adjustment. A low deck is stable but sluggish, while, a high deck is very quick and less stable. A weight bearing center wheel is necessary for quick accelleration.center whl.jpg I appreciate the input.

[Eric Briner]

Wow. That's the best compliment I could receive.I put together some still sequences from the chain incident. The chain is adjustable via the jack shaft but it's more fun to ride than do maintenance.

The first photo shows a backside turn initiated under hard throttle. Three of the four satellite wheels are off the ground.

Photo two shows dirt displaced by the rear inner wheel which is almost collapsed by the various forces encountered.

Two frames later shows dirt displaced, now, by the drive wheel. You can see the extension of the center wheel below the deck, allowing for traction provided by the multi-link turn seq. 10.jpg.turn seq. 11.jpg

turn seq. 12.jpg

[Eric Briner]

Clips cont.

Clip four shows the camera (and me) getting pelted by the rooster tail from the center wheel.

Five; The board comes to a stop. Sequences 2 thru 5 happen in about a half a second.

Clip six shows Jim casually stepping off the board.

I hope you find this interesting. If your'e in the Sacramento area, Drop a line and we'll arrange a demo ride.turn seq. 13.jpg.turn seq. 14.jpg

turn seq. 15.jpg

Eric.