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My 3x3 Recumbent off-road trike

Discussion in 'Other Toys/Hobbies' started by Sam_Q, May 5, 2010.

  1. Sam_Q

    Sam_Q Member

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    hi guys this is a slow worklog for the construction of my fourth trike, I have had this also on one of the recumbent forums for a little while. Now I know this is a bit wacky but stay with me.

    I will only ever have very slow progress as I have a very hectic life for now and will only do the occasional machining on a Sunday or weeknight.


    As above this will be my third trike and I do seem to be the only off road trike rider in Australia that I know of. I have been in off-roading trikes for long time and I just do it just for fun, nothing serious about it. Below is my current trike (3) which is the traditional front crank, front twin steer, rear drive, tadpole design, 16" front wheels, 19" Trials back with 24 gears originally but now 16.

    [​IMG]

    [​IMG]


    This was made a while ago now and the pics are quite old as well, I have since made some minor updates but nothing big.

    My new trike is still being worked out in design but so far the planned spec at this particular moment is as below:

    - 3 wheel drive
    - front wheel steer
    - 3 x 19" Nimbus Trial rims
    - Some very chunky 2.5" Creepy crawler tires.
    - mid mount gears with dérailleur
    - tubular cro-mo frame
    - electric assist for burst use only
    - twin stage gear reduction for main drive

    I was originally aiming for 17kg without power assist but that was before I decided to go for the very heavy trials 19" rim and tires. So allowing for that I want to make it 19kg which is very difficult considering the complexity of the driveline and frame to accommodate it. Right now I don't have much to show for it apart from a few smaller parts I have worked on and a pile of drawings that has taken me a very long time to come up with.



    This is one of the single closest trike models out there compared to what I wish to build:

    [​IMG]


    I think it's increadibly well engineered however even though it's 3 wheel drive it doesn't quite suit my application. I want to make a tricker and much more resiliant version of this Russian creation.



    Latest update:

    [​IMG]

    Assembled rear wheel with home-made hub (post 219)


    Now into the individual parts:


    this is my center power coupling:

    [​IMG]

    it holds two BMX ratcheting sprockets together mechanically. One of each of the front drive-shafts goes to a sprocket. This acts like a crude differential in that it lets either of the wheels freewheel on the outside of a corner. It should work for me because compared to a diff its light, compact, easy to package, simple, reliable and gives full traction all the time.

    Note: it still needs to be finished off and zinc coated



    Now here is a drawing of my driveline simplified:

    [​IMG]

    Although a bit hard to understand it goes something like this: power comes from the front crank which is out of sight, goes to the cone shape on the far right which is my gear cluster, it's fixed to the shaft running through it just like the two other sprockets (drawn as a line only), the middle sprocket turns the chain for the rear wheel and the left one turns the short chain which turns the center power coupling which is right in the middle. The axles are not drawn in in this picture beyond just being a line. This design looks so simple but I have at-least 20 other drive concepts I have gone through to get to this.

    Another thing to note is the center coupling is moved forward from the center line of the wheels, this is when driving straight lets the uni joints be on a 7 degree angle on either side. This is a bit hard to understand but this lets me reduce the amount of angle the inside wheel uni-joint sees around a corner by evening out the shaft angle from the acherman compensation between the wheels. If all goes to plan I will be able to still drive my inside wheel around a corner at a 45 degree angle which will be my full lock.
     
    Last edited: Jul 3, 2012
  2. OP
    OP
    Sam_Q

    Sam_Q Member

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    Inspired by a recumbent rider in Enumclaw USA who has a page titled Trails in the snow I want to be able to ride on fire trails on the closest mountain during the short snow season here.

    I have had an idea oh how I could in theory make the rear triangle of the frame un-boltable to depending on the conditions have something very different bolt in.

    What I am thinking is having my trike so three of these can be swapped on:

    [​IMG]

    Compared in size to my trusty old BMX:

    [​IMG]


    These are originally intended for a quad, and despite having a steel construction they are only 2 to 3kg each complete. What I am thinking is that by swapping the rear triangle to something that holds one of these and also have extra chain rollers so that it clears the tire built into the removable part. For the front I would just need a different set of spindles that would slide on. I would lose about 70mm of ground clearance however I could make up for it partially by tilting the rear fork further down.

    I am thinking of this design so that when I am ready I can in the future have the option of riding in the snow and I think these tires would help. I know thats a bit hard for me living where I am here in the bottom of Australia but there is a mountain about an hour away that is seasonly open for skiing. I will see if there other bike/fire access paths that are normally unused in winter that I can go up.


    UPDATE: I have updated my plan to make a tank like track that can pivot on the original rear axle that would be made mostly from Aluminium angle and for the front still have the quad tires but have fold down mini skis. But still thinking about the concept. I would have the trike running first as is before I go to the snow and even then I would be tempted to give it a shot with my existing tires.
     
    Last edited: May 5, 2010
  3. OP
    OP
    Sam_Q

    Sam_Q Member

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    This is what I have for my front driveline on the steering ends:


    [​IMG]

    Technically I won't have front hubs as such but instead spindles. I will use a pair of 6805ZZ cartridge bearings (25/37/7) that are not drawn in this diagram to support a 25mm diameter Cro-mo axle with a little over 2mm wall thickness and I will make my own spoke flanges that will be welded/brazed on. Uni joint is shown facing up just as a diagram of how it is at full lock but obviously it won't face that when steered. Now with these quad wheels I can just make another pair of spindles with flanges in there instead for the wheels to bolt on instead of spoke flanges like normal. All up this whole thing should be seriously light compact and rigid. The added bonus is it should be very easy to work on to service.



    Although I am having some issues with my lathe chuck resulting in a lot of rejects I managed to do some work to end up with something usable.

    [​IMG]

    Two tubes bored out a little, sintered bronze bushes machined down and pressed in either side. This will be my kingpin pivot housing. It is considerably larger and tougher than a normal trike. This is because there is more leverage and hence load than a conventional design. Also I wanted the thin bushings to last as long as possible.


    [​IMG]

    25 x 2.2mm wall axle machined up, uni joint fitted and with a circlip slot to hold it in place. I now need to make up 4 spoke flanges. This one particular spindle will be for a snow tyre so it will have a hub type plate on it instead.


    UPDATE: I will now remake these as I am going to use bushes made from a material called Vesconite which I will press in, machine press out, weld the outer tubes on and then finally press them back in.
     
  4. OP
    OP
    Sam_Q

    Sam_Q Member

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    As mentioned in my first post I on my machine had a change in plan with my wheels. I have always run a 19" trials tire in my current running trike, however recently I changed to a Maxxis "Creepy crawler", the gain in traction was massive and I could climp up an embankment at a slow speed despite the incline. I found the tread would just grab the grass and pull its way up. It looks like this below:

    [​IMG]

    I was going to use some 20 x 2.25" maxxis "max daddy" tires on road type 20" rims. Relatively light and easy to work with but the alure of having 3 of the above tearing their way over everything is too much for me to resist. The catch is weight.. approximetly 2kg (4.4lb) more overall. Seconday I already have 3 of the 20" wheels and 4 spare tires. Now I will need to source 3 of the above in tires and rims and while affordable, cheap they are not. Oh and yes in the bottom right corner it ironicly shows that these are sold through unicycle distributers for guys going off-road with one wheel, and here I was thinking what I am doing is unusual!

    This means my aimed weight has to be shofted from 17kg (37.4 lb) to 19kg (41.8lb) without electric assist, which if achieved would still be quite an achievement I think.






    well it looks like I have found the solution to my surface finish problem with my lathe. I was concerned about it as the cro-mo shafts where not being very co-operative and I wanted a slick finish so they would be a neat smug fit through the bearings. So in a surprisingly short amount of time I came up with this yesterday:


    [​IMG]

    [​IMG]

    [​IMG]


    The guys in the garage journal forums have politely let me know that the abrasive material coming off the stone is highly desructive to my lathe though so I will will run a coolant pump and at the very mimimum a tray under my work to collect the junk. However after that I should be fine and now I should be able to start making my own parts up to a very high accuracy.
     
  5. OP
    OP
    Sam_Q

    Sam_Q Member

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    In other news I am just about finalised my rear hub design, unhappy with what I can buy I am looking at making my own from scratch. I am looking to do some unusual steps to save weight though. For a start instead of a 9.7 (3/8") solid axle I am thinking about using a 17mm (21/32") axle with only a 0.75mm (31 thou) wall. The maths say that in theory it's heaps stronger. This combined with some very small and thin bearings (17-26-5) and a very minimalistic hub design. I would thread it to suit a screw on BMX freewheel.

    alright I will see what I can do in the next few weeks. I may make a camera attachment to my trike so I can get some riding footage.

    Now I have made some more small progress, I bought this today:

    [​IMG]


    which I then put in my lathe to machine it to this point:

    [​IMG]


    As shown in the picture I used a four jaw chuck to have the highest accuracy. I centralised the section, skimmed the outside, faced the front then reversed the piece and did the same for the other end. What I have done as shown in the picture is machine the section that will be threaded for the freewheel sprocket. This has a groove on the inside to allow the sprocket to wind in to the shoulder. I also cut a radiused bend from this shoulder up to what will be a spoke flange. I also drilled a 23mm (29/32") hole through which will later be bored out to 25mm (1") for the main diameter and 26mm (1-3/128") for the bearing recesses.

    So if all goes well on Monday I will cut a thread for the freewheel at my local night school. I have never cut a thread before but I am going to take a gamble here by trying to do it right the first time. I am not doing it on my lathe as I missing one power feed gear that's needed to cut a 24 tooth pitch and my variable speed drive is not connected yet giving me 4 very limited gears in the meantime.
     
  6. OP
    OP
    Sam_Q

    Sam_Q Member

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    well that's it for now, interested to hear advice, feedback, questions and so on.

    But the whole "weird bike" and stuff is getting a bit old though. I am not trying to be different on purpose.
     
  7. BigDave

    BigDave Member

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  8. OP
    OP
    Sam_Q

    Sam_Q Member

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    thanks, I know about Aussie Jester, interesting guy and I wish I had his drive and dedication.

    The video was interesting, I read about in the build but never got to where he actually had it running let alone smoking.

    In a way it's a real downer being the only guy I know of that's into this kind of stuff in this country, I think it would be fun to meet up with something and do some mud crawling or something like that.
     
  9. OP
    OP
    Sam_Q

    Sam_Q Member

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    well I managed to cut the thread onto my hub, finish that side off, machine the other side and then tried some polishing out. Also during the machining I put a nice radius from the spoke flanges to the outer diameter on the ends for good stress distribution. While the polishing worked unusually well on a lathe I had a few issues and my spoke flanges are going to be a lot closer than I originally planned. It's ok though as it should be fine due to the lack of weight on the wheel.

    Moving onto pics:

    [​IMG]



    [​IMG]



    [​IMG]


    Next up spotting and drilling the spoke holes (36x) followed by machining the center out of the hub.
     
    Last edited: May 7, 2010
  10. OP
    OP
    Sam_Q

    Sam_Q Member

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    forgot to mention I now have one of two handlebars I will use and my cantilever brakes also arrived. These brakes are the only type of cable type brakes that clear the 2.5" tyre. I am not a big fan of disk brakes really.

    Pic:

    [​IMG]
     
  11. Raydragon

    Raydragon Member

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    The electrician in me shudders at that Grinder-attached-to-lathe contraption, especially with the switch just sitting on the side there.
    Wouldn't some super fine emery do just as good a job at polishing it?
     
  12. kbekus

    kbekus Member

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    enjoying your build thread totally. Love seeing hand machined stuff come together.
     
  13. Quan-Time

    Quan-Time Member

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    this is fairly cool. I wanna see where it goes..
    *subscribed*
     
  14. Bort

    Bort Member

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    Awesome build - looks like it's going to be really interesting, especially with the three wheel drive setup. I guess you would have read about Julian Edgar's building of recumbent trikes with suspension? However, incorporating 3WD + suspension would bring a whole world of complication and weight.
     
  15. alvarez

    alvarez Member

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    Good to see some other machinist on these forums.

    I built a bit more basic recumbent back in high-school to do a paper route on.
    I eventually took it to the tip but I spotted it again soon after, one of the local schools has picked it up for the jaycar solar vehicle challenge.
     
  16. crag_v

    crag_v Member

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    Love your work, love the idea - can't wait to see the end result, whenever that ends up being! Well done :)
     
  17. motas

    motas Member

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    That looks awesome. How hard is it to ride p hills and stuff it looks like it would struggle a bit because of the weight.
     
  18. OP
    OP
    Sam_Q

    Sam_Q Member

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    thanks for the support guys, although as I have said a few times already I am not like Aussiejester and his heroic efforts. I will have very irregular updates but I will do this. I have been planning this for a very long time and I don't plan on giving up up even if it takes me 4 years to do.


    Raydragon: I think I might get a comment about that but I can put you to ease on this one I think, despite how it looks the earth lead was connected and also the terminals have a clear PVC sheath over them. Regardless though I now have my proof of concept and I can now make a proper enclosure. Oh also I conveniently have an electrical liecence I don't really use anymore. As for the use it's not specificly about surface finish as like you said that can be acheived very easily with some sand paper like I did with the hub. It's so I can grind down my shafts to a very fine tollerance so they tightly slide through the bearings. I would cut it very close with the tungsten tip then finish it off to specification with the grinder.


    Bort: yes I have been on autospeed for many years, he has an interesting approach and I saw his issues with weight coming a long way before he published anything about it. I am sure he would scoff at what (hes good at that) I am doing because it's meant to be an off-road machine and it has no suspension. I could in theory incorperate it with a double wishbone design easier than what you might think, you see I already need a spline and twin universal joints so the provison in there, but yes I would have a complex steering system and a lot more weight. For the back of the trike it would be increadibly easy to have the suspension, all it would take is one chain tension and a small frame redesign. I actually don't want it though funny enough. Because of the type of riding I do- slow but calculated I think it would quite a hinderance, much like how the trial bike riders have solid rear trianges (usually?) on their frames I like the direct control. Also I often go to the very limit of tipping over and past it at times, I actually get past some things by stopping myself from tipping over by having my hand on the ground while I am still going forward, if I had suspension it would automaticly lean and shift my CG to make me more prone to tip over.


    alvarez: funny that, oh well in your position I would consider it a compliment and be happy it went to a good home. I have thought for a long time it would be indeal for a paper route. With the machining I don't have my mill running yet so I go to night school to use theirs. However once again it's all time. Speaking of which I beleive my machine is very rare:

    [​IMG]

    This is without both (yep two at once!!) heads bolted onto it, on the right is the hyraulic follower that allows it to trace a template and control the table in all 3 axis to machine two copies at once. It's called a True-trace. It can be used in a completely manual mode though.


    motas: it's a hard question to answer as a person who is used to an upright bike will struggle at first. There is a muscle just above the knees that normally isn't used that gets pushed hard on a recumbent. Because of this I find it hard to compare. However I think there is a distinct disadvantage and it does seem slower. However in another way its easier, this is in the fact I can gear down as low as I like to slowly crawl up the hill and stop whenever I like. To stop I just "lock" my leg completely straight and rets as long as I like effort free. Although most ironically I often find I have the urge to stand up and stretch my legs to "rest" during a break. As for weight 90kg trike and rider isn't bad, should be on par with my crappy unused mountain bike.
     
    Last edited: Nov 20, 2011
  19. OP
    OP
    Sam_Q

    Sam_Q Member

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    OMG :shock:

    No wonder I got all these replies all of a sudden, my trike pic is on the main page.. far out. I guess I better do another update and show some of my existing work.

    Oh and thanks Agg!
     
    Last edited: May 11, 2010
  20. OP
    OP
    Sam_Q

    Sam_Q Member

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    I plan on having electric assist on this bike, I have had many times where I have been stuck in the mud or on the edge of the a rock/branch and my feet got stuck in the dead zone (90 and 275 degrees relative to gravity). Would also help me with some of the obscene climbs I want to do. So these bits in mind:

    [​IMG]

    Brushless outrunner made for big mofo R/C aeroplane. Rated at 3250W with 37V behind it, but I plan on using 2 x 18.5V packs in parallel for a theoretic power of 1625W, more than what I need.


    [​IMG]

    Two of these borrowed from my modified drill/impact driver/blower/whipper snipper for the day.



    [​IMG]

    and one of these servo testers to eradicate the need for any remote control. I will if it works out de-solder the pot and make a finger throttle.

    I will have a twin stage reduction with the first using a 6.35mm / 1/4" pitch chain (pocketbike). I want to adapt a pocketbike interchangeable 6 or 7 tooth gear on the motor end and go to a high tooth count sprocket. However the Chinese made rear sprockets where known to be out of round and the 78 tooth model I was going to use was too heavy for my liking so I decided to do some machining. I started by centering the sprocket on a rotary table using the other edges of the teeth instead of the center bore. I proceeded to machine out the middle of the sprocket and then I drilled in five parts 4 13mm lightening holes for every one 6mm mounting hole. Here is what I ended up with:

    [​IMG]


    and here is the spider I optimistically want to make to adapt it to the axle:

    [​IMG]

    This has and will take more serious thought, it's much harder to work out from a maths point of view than I expected.
     
    Last edited: May 12, 2010

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