CojoTruk Quick Tour

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  • Опубліковано 29 січ 2025

КОМЕНТАРІ • 11

  • @DavidJohnson-xr2rz
    @DavidJohnson-xr2rz 4 роки тому +1

    UPDATE 11 JUNE 2020
    CojoTruk #2 is finished and has been ridden several times. We don't have much data on it yet and no photos or video posted to the Internet yet. Here's just a little info:
    DIMENSIONS
    8 inch front wheel with internal expanding brake
    20 inch BMX "mag" wheels on the rear.
    Rear cargo compartment is detachable, so that the remaining frame assembly will be shorter to help get it into a car.
    The front end is not detachable (a mistake, should have used a Hudora head tube so front end could be detachable like #1.)
    Wheelbase is 31 inches.
    Width 26 inches
    Total length 44 inches
    Seat height 20 inches
    Handlebar height: variable, 32 inches as tested.
    WEIGHT including tool kit and a 1.2 pound carry bag in the rear cargo compartment, but no flag or headlight:
    front wheel 9.8 lbs
    right rear wheel 13.3 lbs
    left rear wheel 13.6 lbs Note: left wheel has a freewheel installed which however is not used.
    total weight 36.7 lbs.
    NOTE: the reason it's so heavy is because of the fat sturdy BMX wheels and because I used .185" FR4 for the seat platform. Frame is fiberglass, no carbon fiber. If the objective had been light weight, it could have been gotten well under 30 pounds.
    CARGO CAPACITY
    6 HU (= 32 lbs). NOTE: an "HU" is a Hopperdilly Unit, comprising a 6-pack carton of 12 ounce cans of Karbach Brewing Co. Hopadillo IPA weighing 5.3 pounds.
    This is flat on the floor of the cargo compartments, no stacking, no filling in gaps with other stuff, no creativity. With a bit of creativity could have put a lot more in there.
    But remember, this is manual power. Lemmee tellya, with a 6 HU load, you really notice the weight.
    Cargo capacity is much greater than #1 despite the smaller size because of a better cargo compartment design.
    HANDLING
    In comparison to #1, it's more stable outdoors on irregular surfaces and much easier to steer, despite its much shorter wheelbase and smaller front wheel. However it does have a pronounced "flop" when turning, because of the product of steering angle and trail. Although flop is usually regarded as a defect in handling, nearly all vehicles do it. One gets used to it fairly quickly. Only way to get rid of flop if you have trail (and you gotta have trail) is to have a vertical steering axis and that puts the steering head 'way too far forward (as you can see on CojoTruk #1 ). ......Cojotruk #2 when you're on it going forward, everything's fine. When it's sitting there and you're trying to move it around, everything is counter-intuitive. I'll eventually get it figured out. ........ Going down a 4 inch curb, don't even have to slow down. Going up a 4 inch curb, it's a matter of knowing how. I haven't learned it yet, but when I accidentally get it right it's easy.

  • @DavidJohnson-xr2rz
    @DavidJohnson-xr2rz 5 років тому +1

    UPDATE 6 JAN 2020
    The pneumatic tires on mag BMX wheels were a HUGE improvement. They're threaded for freewheel. Getting ready to install an MY1016 250 watt motor left side drive.
    A lot has happened in the last couple weeks relating to the design of COJOTRUK #2. The tentative plan is as follows: Razor Pro RDS fork & downtube. L-Faster 8 inch pneumatic front wheel with integral drum brake. Stem & handlebar assembly possibly adapted from Hudora kick scooter. Mongoose Mode 270 mag wheels, machined for standard hub thread and half inch axles. 24 volt MY1016 drive for each wheel: primary use is as a go-anywhere mobility scooter but can be used manually with a little effort. Aluminum frame. Telescoping horizontal tube allows shorting the wheelbase so it can go on the public bus. ...... For low speed work as mobility scooter and steep hills , the motors are wired in series giving inherent differential action without the need for any mechanical differential stuff, not even dual freewheels. For high speed work, the motors are wired in parallel but with about total 6 ampere current limiting to reduce mechanical stresses on the drivetrain and to improve battery life. Since it doesn't use freewheels, it can also go in reverse. Note that in the parallel configuration there is still differential action, but it prefers to go straight, helping with steering stability.
    This design, if it works, is even more versatile and more unlike anything else on the market. At the flip of a switch, it is either a legal mobility device, or a legal electric bicycle. It can go in the dirt, can negotiate 4 inch curbs, and can negotiate tight spaces including board the public bus like a wheelchair or SmartScoot. And of course can carry groceries. The telescoping mechanism that allows shortening the wheelbase for really tight spaces, is also the means by which the thing breaks down for loading into a car. Of course the wheels are also detachable-- not QD axles, but axles pinned with an easily pulled clevis.

    • @DavidJohnson-xr2rz
      @DavidJohnson-xr2rz 4 роки тому +1

      UPDATE 14 APRIL 2020
      Installing the motor on CojoTruk #1 ran into some serious problems. Not insurmountable, but we didn't have on hand the stuff we needed to continue and were not ready to commit the #2 design described above, so we booted up CojoTruk #3. Which will probably be re-named #2.
      This one will be manual only, no motor. Triangular frame with a "floor" panel for carrying small amounts of stuff. Construction primarily fiberglass. The cargo compartment will be a detachable accessory. Front end is a lightweight pneumatic 8 inch wheel on a Swagtron K8 fork. 20" X-cores with pneumatic tires. We don't yet how we're going to do brakes but when the thing is built I'll get desperate and we'll figure out something. Sorry, at the moment no pix.
      Thus far we have the front end assembly completly built, and the frame and axle assembly very nearly finished. Just barely got started on the seat. Our next step is to attach the front assembly to the frame -- a very difficult procedure that has to be done right: otherwise the thing will break, or it will steer off to the side. I'm guessing finished weight will run about 28 pounds but haven't actually weighed anything yet and we're not fighting for every gram on this one.
      The smaller front wheel will allow the feet to above the wheel (as on the SmartScoot). That allows the wheelbase to be a lot shorter, which then allows for much shorter handlebars.. This will improve considerably the ability to navigate it in tight spaces. With the 20 inch rear wheels however, I won't be able to get it onto the public bus.

    • @DavidJohnson-xr2rz
      @DavidJohnson-xr2rz 4 роки тому +1

      23 April Update on manual-only version: Previously dubbed #3 because a motorized design that's on hold preceded it. This manual only version will be rebadged #2 since it's actually happening.
      We finished the frame structure today, except for the seat support. Front end and rear wheels have been installed. I also installed handlebars although it can be steered with the rear wheels so the handlebar assembly is optional. I've faked the seat (quite a bit of the seat structure has already been fabricated.) I can look at it and roll it around a bit but can't sit on it yet.
      Feels like it's going to steer well both by rear wheels and by handlebars, but without putting a 180 pound fatguy load on it there's no way of knowing for sure.
      I think the weight of the thing is less than 30 pounds. However there are no brakes, and no rear cargo compartment (it will be detachable) and those things will add weight. There is some cargo space in front, enough to carry two 6-packs (that's a minimum requirement for a CojoTruk). I may fix the brakes situation by throwing on a different front fork assembly that has a real front driving/parking brake--- which however will weigh a lot more, making it harder to loft the front wheel over a curb.
      Now here's the part that came as a surprise.
      It's the best damn looking wheelchair on the planet. And hasn't even been painted yet.
      Cojotruk #1 got a lot of looks and a few questions until everyone in the neighborhood had already seen it. I'm imagining what'll happen when THIS shows up in a public place where folks ain't seen it.
      "What's the top speed?" [A. On the level, as fast as your triceps can flail. Downhill, that would be an experiment involving a surveyor's chain, a stopwatch, a brick wall, and 6th grade arithmetic.]
      "How much do they cost?" [A. Depends on how many you buy. This one cost me about $50,000 plus 30% Federal tax.]
      "My grandfather raced Norton Manxes back in the day, but they only got two wheels and that thing you're riding's got three. My life's dream is to be as good as gramps, but y'know how genetics works, I only inherited 1/4 of his talent. I need an edge, and that thing may be it. Here's my wallet with $100,000 cash in it and my driver's license. Will ya hold it for me while it borrow that thing from ya for about an hour?" [A. Show me a photo of your gramps on a Norton Manx, and you can borrow it all day. ]
      "I smell an old fart, but no engine exhaust. Only fuel burns that clean is ethyl alcohol. How many miles to the gallon do you get on ethyl alcohol?" [A. Buy me a gallon of Everclear and check back with me next year. If you want an answer sooner, let's see if Descheutes Brewery will sponsor the experiment with however much India Pale Ale may be necessary." ]
      ******* Sorry, no photo or video yet, or sound file of me trying imitate the sound of a Harley Sportster with straight pipes.

    • @DavidJohnson-xr2rz
      @DavidJohnson-xr2rz 4 роки тому +1

      UPDATE 28 APRIL 2020 ....... GLOAT! GLOAT! GLOAT!
      We paid a helluvalotta attention to detail, hard work, and it paid off.
      The thing's not finished yet, but enough structure was there to ducktape a seat to the thing and take it for a spin.
      There's no noticeable steering wobble, unlike the last one. All the work we put into creating a rigid join between the downtube and the frame paid off. The steering axis viewed from the direction of travel is within a gnat'ass of vertical, so no wanting to veer off to one side. It's incredibly light although I haven't found a way to weigh it yet. I'm guessing a hair over 20 pounds. Steering axis is always a compromise between trail (necessary for being able to steer it from the rear wheels) and flop (the tendency to want to go into a sharp turn once a turn has started). It's more floppy than I'd like, but I'll get used to that. Meanwhile just rotating the handlebars 180 (which couldn't be done on the previous CojoTruk) unexpectedly dials in a new steering mode-- zero trail, zero flop. Can't be steered with the rear wheels, but you point it where you want to go and it takes care of the rest ....don't have to fight it even on a sidehill. .........Going over curbs is not fast due to the little 1.35" width tires, but very easy. .....The "pickup truck bed" will be a detachable accessory, not yet started. Meanwhile even without that, it's got a forward-of-the-axle platform that can haul a couple 6-packs of India Pale Ale geezer fuel no problem. Unexpectedly clearance turned out to be about 5 inch max on a curb, but that won't be a problem because the front end is so light you won't get hung up. We'll add a Kevlar felt impact pad underneath, the kind they make for kayaks to protect against rock impact.
      No pics yet, but even unfinished in raw material colors the thing looks better than any wheelchair ya ever seen.

    • @DavidJohnson-xr2rz
      @DavidJohnson-xr2rz 4 роки тому +1

      Previous incarnations have mostly had 12 inch wheel front ends. The switch to 8 inches was difficult (no more bicycle type stuff available), but it was the right thing to do. Helps keep things more compact and lighter weight, and what was previously a steering geometry nightmare becomes pretty simple.
      We did this one in fiberglass round tubing, mostly 1.255 paint pole tubing and 1.06 Westwinds kite tubing. No "expensive and hazmat" CF this time. Hard lesson. Round and flat don't mix well, and in round stuff, tubing and pipe are two different animals. I spent half of what's left of my short life sanding stuff and trying to fit square pegs into round holes. ...... Once upon a time, fiberglass was king of composites. CF is a lot more expensive but took over the market because the market is fragmented and the cost of developing product is greater than the cost of making product.
      The moral to this story: next time, stop asking what square CF tubing and sandwich materials cost, and just buy them. We're wearing dust masks these days anyhow. So do it all the easy way. Don't think saving a few ounces, think the difference between joining flat surfaces versus round surfaces. Of course if you have aluminum welding capability, it's a whole different thing. But composites, you can do those in your apartment living room. Without power tools other than an electric drill and a cheap drill press. Small machine shop work, there are outfits that will do that but it takes a while to find them.

    • @DavidJohnson-xr2rz
      @DavidJohnson-xr2rz 4 роки тому +1

      STEERING GEOMETRY. If it's a 2-wheeler, give it 1 to 2 inches of trail and it may not be great but at least it'll work. Zero trail may work, too. If it's a three-wheeler you intend to steer from the rear wheels, trail is an absolute necessity, zero or negative trail means you cannot steer it from the rear wheels. But there are so many other considerations, like handlebar geometry, front brakes if any, etc. Nothing replaces actually building the damn thing and then taking for a drive. Until then you won't know what to think of the steering.

  • @DavidJohnson-xr2rz
    @DavidJohnson-xr2rz 4 роки тому +1

    ALSTDI forum member? Sorry, a year ago they changed forum software and in the process they screwed up some accounts, including mine. I can't log on, change password, or create a new account. I tried to work with ALSTDI to fix it, but their IT person wasn't able to fix it. I still have some energy for some battles but not that one. So that's why I'm no longer posting or responding to PM's at ALSTDI.

    • @DavidJohnson-xr2rz
      @DavidJohnson-xr2rz 4 роки тому +1

      UPDATE 27 JUNE 2020
      Unboxed the ComfyGo wheelchair.
      Frame is misaligned, seat doesn't lock in place. Left caster fork head axle seized. So it isn't going to be a wheelchair. Was supposed to be lithium batts but charger says lead acid. Haven't opened that up yet to see. Various bolts are whatever lengths they had handy, like this is a beta test unit and not an actual released product.
      The drivetrain assembly is not as shown in the sell sheet. However it is a setup that can be attached to almost any frame design. In order to find out of the electricals and drivetrain work, we'll have to prop it up with the wheels off the ground.

    • @DavidJohnson-xr2rz
      @DavidJohnson-xr2rz 3 роки тому +1

      24 March 2021 UPDATE: ALSTDI fixed my forum logon problem, I'm now compiling CojoTruk information in the "Living with ALS" forum. The ALSTDI forums are private, so anyone who wants to be able to read the posts will have to register on the forum first. .....There's a longer range plan to sort it all out and put it on a website, but for the moment that's more of a wish than a plan since I'm in hospice. Was supposed to have been dead months ago but I'm still quite alive if not quite functional.