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Thread: Italjet Dragster conversion

              
   
   
  1. #21
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    Yes, thanks folks. The problem solving is enjoyable. My problem is when I can't find a solution or can't implement it that I get disheartened and distracted quickly. But I want this one to work out and it should be simple enough to get going without too much technical difficulty.

    Anyway, I've had some DIY chores to get done and couldn't pass up the great weather to cook and eat outside today so not much done on the build unfortunately. I'm waiting for the generator puller tool so I can split the crankcase and measure things up.

    I did have to go in the garage a few times for tools etc and couldn't help some musings. I threw the drive assy into the frame to see what room there is for batteries. I'm a bit worried to be honest. Definitely don't think a QS swingarm will fit without long wheelbase. Not the end of the world but pushes me ever more towards keeping the original drive. Pics:

    I stand corrected, don't think I can exceed the previously mentioned 95mm motor & mount plate width to avoid sticking out too far and looking odd...





    Room for batteries is looking slim. I'll get some proper measurements and sketch it up this week then work out what and how many cells can fit...
    I'd love to stack cylindrical cells vertically with perspex side covers on the battery box to show off the cells behind the trellis frame. I might have to put some cells under the seat too. Thankfully the Dragster has its fuel tank under the rear seat so there is room for controller, dc-dc and hopefully on board charger too! Need the body panels to show that though.



    Next I fiddled with the CVT to see about deleting the clutch, damn that's a heavy lump of wasted energy... weight to open the clutch shoes when it spins and springs to keep them closed!

    Anyway, I think by cutting the shoe mount plate down and reversing it, similarly cutting the clutch drum off its diameter, the 2 will taper together perfectly to weld all round the outside and fuse them.

    Having just written that I realise then I cannot secure the clutch plate (shoes) to the drive hub as it bolts down before the drum fits over so they move freely usually. BUT by getting the spacing correct the clutch drum will secure both correctly to the gearbox shaft. So I think it'll be fine. I might use a wider nut with more threads for security. Pics:

    Clutch drum (fixed to gearbox input by spline shaft). See threaded end of the shaft, this would have to hold both drum and plate onto the shaft if welded as described above.



    Clutch plate (shoes on back side) will be cut down, probably to outside of the bulge. Note large thread with flats, this carries all the torque from the CVT belt pulley into the clutch. If I weld the plate and drum I cannot fit this nut. But looking at the picture now, I could use the 3 pins that carry the shoes as studs through holes in the drum so they are still separate. I'll have a look and think about that...



    Here you can maybe see how the 2 tapers/cones of the plate and drum would meet with the plate reversed.



    Well, wow, I must have been in the garage longer than I thought, that took some typing to write up.

    Batteries, I must figure these out to make this build viable. Otherwise it'll be a low power 20 mile scoot for my daughter and I'll not get to do the fun rides out I was hoping...

    Cheers
    Tyler

  2. #22
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    Motor solutions update 2:

    5: fabricate own swingarm using new QS mid drive motor design (see Revolt Motors - India design) with motor pivoting with wheel but much shorter wheelbase.
    Would work with cradle of 4 or without, or alternative design of stock engine assembly mount.

    Revolt RV400 motor:



    I'm not as keen on this option unless the QS mid drive swingarm kit is too long and won't fit in my wheelbase, or replaces too much battery space limiting the range.

    I've decided against this and if I can't mount a suitable motor to the stock drive case I'll use a QS swingarm kit.

    Cheers
    Tyler

  3. #23
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    Motor solutions update 3:

    Motors... I'm trying to find an IPM motor as large as possible without being too wide for max continuous power. With the narrow width I've got of 100mm. This means at the least making a new front motor plate to mount to my scoot engine. I can extend this to 120mm if I use a fancy (and costly) face plate design that resets the motor into the casing a bit but I haven't found a motor to take advantage of this.

    Reason for pursuing IPM is higher rpm (scoot had a 2t motor doing over 8krpm and is geared thus) and getting 'free' torque with field weakening.

    Depending on the torque performance (peak/max) I haven't decided whether to delete the CVT and go fixed speed but I suspect I'll need to do this to get the speed I'd like.

    Now, the Eastgem motors are very nice but not IPM. But I've been looking at some outrunner motors also, 80100 is ok but I found a 120100 form that is the ideal size. But there aren't many and they're not cheap. Figure to get one and run it as is then later look at rewinding for better quality/performance. Yes I know, it's not an IPM motor.

    Edit: here's an example:
    https://epowerhobby.com/product/e-po...r-80kv-25000w/

    Or a smaller possible option, but I'm sure the longer 100mm (60mm stator) will fit:
    https://epowerhobby.com/product/e-po...r-80kv-18000w/

    I've also seen some high quality/performance UAV outrunner motors with halback array magnets which gives excellent power density but they're rated for flight use so over quoted for an EV. Bit pricey and a gamble on what performance I'd get in the scoot.

    Anybody know of other motor options please? Or sources for a 120100 outrunner? Thanks

    Cheers
    Tyler
    Last edited by tylerwatts; 11 April 2020 at 1531.

  4. #24
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    I found a Turnigy CA120 motor for sale. Anybody know much about these. I'm not sure using Tapatalk to search the forum is very good because I didn't find much useful info.

    I'm thinking an outrunner running the motor shaft backwards through the mount would be ideal for space and power density in my build. And look cool in the side of the scooter. Plus it should have good power output up to higher rpm.

    Cheers
    Tyler

  5. #25
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    So, the generator removal tool arrived...

    What's worse than Italian build quality? Chinese made Italian build quality!




    Threads are damaged/deformed and won't engage, and the plating is terrible! I only need to use it once I guess...

    More progress soon I hope. See battery post updates. Measurements taken and I hope to model the volume in CAD and start designing a battery mounting system. 3D printing seems like the hail Mary for packaging. I'll doodle my ideas soon to get some feedback.

    Cheers
    Tyler
    Last edited by tylerwatts; 15 April 2020 at 0441.

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  7. #26
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    Battery update, moved from battery post:

    So here's some dimensions of the frame and you can see it is a compound trapezoidal shape everywhere so gets complicated to fit a battery shape. I'll likely build a battery housing to match the internal shape of the frame and fill the space as best I can with cells and spacing/padding to match the shape.









    Update: some more frame pics for potential battery placement.








    Cheers
    Tyler

  8. #27
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    So, quick update. Double actually, yesterday and today's brief forays into the garage...

    Firstly, I finally got the generator flywheel off, no thanks to the Chinese Italian tool... It was essentially welded on the shaft, frightfully over engineered.



    But here is the other side of the motor. I'll split the casing tomorrow and pull the crank to see about making a coupling somehow to run a motor from the generator side to the CVT.



    And better dimensions, bit larger than initially thought which bodes well for the Cyclone and other mid sized motors.





    Secondly I've stripped down the clutch wheel so that it can be reversed and welded to the clutch bell.



    By reversing it the dish is opposite the bell and they meet up Dominican weld them to join the 2 and delete the clutch.



    I need to cut it down some to move the bell in closer. Here it is fitted without the clutch disc and is fully engaged onto the shaft spline.



    But currently with the clutch disc reversed it pushes the bell out too far. About 5mm less thread/spline engagement.



    I need to reduce the distance correct though so that the disc is engaged on its seat (without retaining nut) and the bell is fully engaged on the spline. Ideally slightly less so that the clamping of the bolt slightly flexes the 2 like a spring washer and locks the nut on the thread. You can see the clutch three through the bell here:



    Cheers
    Tyler
    Last edited by tylerwatts; 22 April 2020 at 1008.

  9. #28
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    I've been thinking more about motors and sizes and mounting. I've had the idea that I can fit the drive shaft to the drive assembly, mount the stator of an outrunner over the shaft and to the casing then fit the rotor over the stator and shaft. This depends a lot on how the rotor secures to the shaft but the outer end must key onto the shaft somehow.

    Anyway, this is building a strong argument that the Turnigy CA120 is a good candidate for my build, good torque ratio and capable of high rpm power. I don't need high torque output so can limit this and use higher rpm and foc to gain high power at higher rpm, similar to the stock ICE engine. This helps the controller also due to the low impedance of the high pole count outrunner motors. And if performance isn't satisfactory I can first rewind the motor then even fit different magnets/arrays to improve performance and efficiency.

    So it seems like a Turnigy motor and Nucular controller are strong candidates for the drive train.

    I want to measure up the QS mid drive motors also and verify they do or don't fit.

    Cheers
    Tyler

  10. #29
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    I found something interesting on ScooterLab today. Not sure how real this photo is but it's a Dragster with a QS Mid drive rear end fitted. Looks great. I might have to give up on the stock drive assembly and go this route. I'll have to decide about that later.

    QS_elec_Dragster.jpg

    In other news, there is a guy selling a Turnigy CA120 outrunner RC motor on eBay and he has some great data I'm mulling over for whether the motor will suit my build.

    Turnigy_CA120_rcgroups_data.jpg

  11. #30
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    HI,
    i do know these motors from model flying.
    That brand has its followers actually, most of them beeing of the cheap is best fraction.
    Not to say these won`t deliver what advertised but there are definetly far better brands out there.
    biggest problem with using motors designed for model building is operation time.
    A motor designed for model flying for example will deliver x Watts but as our lipos seldom exceed say 10 or 12000 mah fling is limited to say 8-10 mins and appart from a few impressive upward figures or one minute of troqueing the plane usually they only will be asked to deliver a third of their rated power .
    Thus cooling and bearings and all is designed to withstand, to stay with the example 2-3 mins max power within 10 mins use.
    This and other cheapo brands are also known for throwing bearings or magnets after a couple of weeks use...
    Would it be wise to use?
    Up to you.
    If youi still considering model motors,
    Hacker, Plettenberg (my favorite brand), or even Jeti comes to mind and all of their motors will offer tripple quality but of course being MUCH more expensive...
    as usual you get what you pay for.. and these will still be toy motors..

    Just food for thought

    Greets

    Flo

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