I know this has been done in the past, but almost always with gyro stabilisers and stuff like that. I still have a chainsaw engine lying about unused, several go-kart sprockets, a fair few feet of square metal tubing, and two unused learner unicycle’s. And my hands are beginning to itch as I havn’t done anything mechanically of late. Now, the building shouldn’t be a problem, I’m a good welder and I can design the frame (with the mathematical know-how to back it up), but it won’t be at least three weeks before I can get some real work into it, and I was wondering which skill would help me most, learning to ride a contraption like this? I intend to mount the footrests below the wheelaxle for maximum stability, so maybe gliding/coasting isn’t the best idea?
Ive never riden one but it sounds like a good idea
dude that will go so fast you might want handlebars or something
It will have handlebars, and am currently contemplating three designs. The first is a recumbent design, but that might not be the best for stability and agility. The second is a more conventional design, and is basically a triangle shape, with the seat just slightly behind the wheel axle (horizontally speaking) to act as a counterweight for the engine, but this might not be the best for stability, agility shouldn’t be a major problem here. The best design, I think, is something kind of like a motorised BC, and should approach something like riding seat out front. I’m going to use a standard 20" wheel, something I think I’ll be the first to use, all the other ones I’ve seen use very small, wide tires. But I want a unicycle, not a Segway. I’ve planned on a month to build it, and two months on learning how to ride it, as it’ll undoubtably be a major bitch to learn this… You need to translate the corrections you make with your feet to keep you upright into corrections you make with your hands (throttle and brake) to keep you upright…
Have you seen this page? http://www.jackiechabanais.com/the_monocycle.htm
In particular (re-translated)
“He practiced on average three hours a day everyday for 3 months before he could ride 200 metres one time in five”
Looks like you;ve got your work cut out.
I’ve been planning on making a motor uni as well, but I don’t have money for the scooter I’m using for parts.
I was originaly going to use a chainsay, and was thinking of putting it under the seat. I really don’t know how possible this is though. anyway, I thought the easiest control method would be to have a foot thing so when your foot leans forward it accererates the uni.
well I gotta go.
Wow that page (and the rest of his site) is amazing! There are videos for download too. Jackie can do so much cool stuff - crazy bikes, STC, monocycling. He can ride a penny farthing backwards and has performed for the crowds at the Tour de France. Very cool.
I don’t recommend a foot control. Remember, when you press the gas, it will make the cycle tilt. In other words, it will make your foot press the gas more. Put the control somewhere else. Not to be boring, but the hand controls that have been used on several other motorized unis seem to work.
First thing you’ll have to do is figure out how you’re going to supply power to the wheel in more than one direction. Or were you planning to accelerate indefinitely? 
You could try using a brake to counteract the power of the motor, but that would be pretty crude, like riding a motorcycle on the back wheel (but without the counterbalancing effect of the front of the motorcycle).
From the Jackie C. web site, you can see that he’s not a beginner when it comes to balancing on motorized vehicles. He’s pretty dang amazing and his site is worth spending some time on. If it took him 3 months to start getting success on his uni, this is probably for three reasons:
- The big wheel makes it heavy, which probably doesn’t help.
- He might be operating with no resistance; in other words it only accelerates so he had to learn to keep from speeding up too much.
- The web site is intended to market him, so the 3-month story is probably exaggerated.
Re: Motorised unicycle
On Mon, 30 May 2005 23:12:21 -0500, “johnfoss” wrote:
>I don’t recommend a foot control. Remember, when you press the gas, it
>will make the cycle tilt. In other words, it will make your foot press
>the gas more.
I thought that the foot control was a clever idea making the control
mechanism somewhat akin to a regular unicycle. I.e., you press
something on the front if you tend to fall forward. But I guess you’re
right about the positive feedback (tilting makes you press the gas
more) although you have to keep in mind that the person will largely
“rotate” backwards WITH the unicycle.
Klaas Bil - Newsgroup Addict
wouldnt you be grumpy if somone just said you had PMS? - jagur
Re: Motorised unicycle
On Mon, 30 May 2005 03:53:54 -0500, “Erant” wrote:
>The best design, I think, is something kind of like
>a motorised BC, and should approach something like riding seat out
>front.
I can’t quite visualise that. If it’s a BC, where do the reaction
forces of the engine go? And how can riding a BC be like riding SOF? A
BC definitely doesn’t have a seat at all.
(The previous sentence started with A B C D E F.)
Klaas Bil - Newsgroup Addict
wouldnt you be grumpy if somone just said you had PMS? - jagur
The motor will make it handle like a BC, the footrests will be just slightly below the wheel. And it’s going to be like riding seat out front, where the seat is just slightly higher, and has made a magic transformation into a handlebar 
Hmm, how weird, I can’t edit my message anymore… Ah well. I just took a look at that guy’s website, and I noticed several things. One, he controls it using some remote thingy, with only one hand. Two, the tire is extremely short, stubby, and fat. Three, he has no handlebars. Four, he doesn’t seem like an altogether too good unicyclist. Five, he’s a lot older then I am. These five points make it really hard for someone to control such a monster. Especially the fact that I don’t think he can ride a unicycle makes a big difference.
Also, as far as the control question goes, I’m going to make it without a clutch. I have one here I could mount in case this doesn’t work, but it basically comes down to releasing the throttle will make the unicycle ‘brake’. This is very close to what you’re actually doing when you’re pedaling.
If you’re not having a clutch then how on earth will you start the thing? Either you start it then try and jump on as it’s moving, or try and pull it over (i presume it’s pull start) while your sitting on it and the drive is engaged. Incidently, he may be older than you but he’s also a professional ‘acrobat’ not (quite the right word) with decades of experience at balancing on moving motorised objects, although i agree about the exaggeration point.
Yeah, his engine controls might be better, but I’ve been unicycling for over 6 months now (Ok, that doesn’t seem like a lot, but my brain has adapted by now), doing some trials and stuff, a brain learns to cope with that. Also, I was a speedskater for roughly 10 years, and I’ve done snowboarding. These might all seem fairly non-related, but every one of those things needs balance. As to the starting bit, first I’m going to try and get on while the engine’s idling. The engine’s idle is at about 1000RPM, and with the gear ratio and wheel size I have, that comes down to roughly 3km/h. If that doesn’t work, I’m going to get on (engine off), and get someone to push me (Thus turning the wheel, and the engine, making it fire). If THAT doesn’t work, I’m going to make a manual clutch, using a drive belt. This might all seem to be horrendously difficult, but I think the upsides outweigh the downsides. Because this way, there’ll be no ‘freewheel’, just like on a unicycle. (You’re either pedaling, or you’re standing still).
You have a 10-minute edit window.
Klaas Bil
Re: Motorised unicycle
“johnfoss” <johnfoss@NoEmail.Message.Poster.at.Unicyclist.com> writes:
> I don’t recommend a foot control. Remember, when you press the gas, it
> will make the cycle tilt. In other words, it will make your foot press
> the gas more. Put the control somewhere else. Not to be boring, but the
> hand controls that have been used on several other motorized unis seem
> to work.
Actually, foot control could work reasonably well. Imagine a pedal
controlling the throttle, but connected backwards. If you lower your
heel to accelerate, then when the wheel surges forward your foot will
tend to straighten out. Negative feedback is a good thing.
I wonder about throttle lag, which could make control especially
difficult.
> 2. He might be operating with no resistance; in other words it only
> accelerates so he had to learn to keep from speeding up too much.
According to the site, Jackie C. has a brake controlled by his right
foot. That makes sense to me. Brakes don’t suffer from throttle lag,
and normal (press forward to brake) action provides negative control
feedback.
Ken
Keep looking around his site. Check out the videos. He is ultra-skilled at balancing motorized vehicles on one wheel! Maybe the best I’ve seen anywhere. This does not necessarily make him a unicyclist, but I’m sure he’s better equipped to ride his fat, heavy uni than most of us.
No it isn’t. You can believe us or find out for yourself. Releasing the throttle in a clutchless design will be like freewheeling, not braking. Especially if you have a 1000rpm idle. Every ride will end in uncontrollable speed, unless you can balance things out with a brake.
Re: Re: Motorised unicycle
That would be better than a regular gas pedal, but I still wouldn’t recommend it on such an unstable vehicle. Learning to control it will be hard enough without the cycle’s feedback working the controls independent of your muscles!
Yes Klas, Ken is correct about the wheel surging forward when you apply throttle. Try it on a motorcycle!
Re: Motorised unicycle
On Tue, 31 May 2005 19:31:14 -0500, “johnfoss” wrote:
>Yes Klas, Ken is correct about the wheel surging forward when you apply
>throttle. Try it on a motorcycle!
Both you and Ken (who posted after me) were right. My wording may not
have been very clear but I didn’t say otherwise.
Klaas Bil - Newsgroup Addict
wouldnt you be grumpy if somone just said you had PMS? - jagur
You read me wrong. By braking I ment that some of the wheel’s energy will go not into propelling me forward, but into moving the pistons in the engine. That’s an engine’s natural braking. I will ofcourse install a normal brake, but that’s less easy to control. I never said that releasing the throttle would be an insta stop, but that it’d come closer to what you’re doing when balancing on a unicycle. You’re either putting extra energy in the wheel (pushing the pedals the same way as the wheel is going) , or taking it out (providing slight pressure the other way).