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A tadpole trike configuration would allow for the weight towards the two wheeled end for maximum stability, and the making of a very aerodynamic shape. With the tadpole configuration, you could pack a sh*t load of batteries between those front wheels, and shape it to get a low drag coefficient, with two riders riding tandem in back. The safest way to propel a 3 wheeled vehicle in a tadpole configuration is with the power driving the front wheels, especially in turns. If driven from a single rear wheel, in tight turns the back tires pushes on the wheel on the outside of the turn. The Slingshot and Can-Am are perfect examples of how not to make a 3 wheeled machine. Looks like Aptera is back, only in electric form. :)

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Discussion Starter · #22 · (Edited)
This is not a recommendation (most I can do with CAD at this point is to download the software). More of a 'make aware of' message. Anyway, a lot of my 'interweb friends' started using Solidworks, when the Experimental Aircraft Association worked a deal where members could get a slightly crippled version for free. After that deal expired, many of them switched to FreeCAD. Completely free, and IIRC, there's an FEA program available (also free) that can be fed FreeCAD files. It does run wholly on your PC (unlike Fusion 360, etc), and it isn't supposed to take massive computer or graphics card power to work well. I've watched a lot of instructional videos on it, and while it does have some 'features' that can bite if you're not aware, but problem areas seem to be only one of the ways you can do a particular thing, and other methods of achieving the same thing are built in, and pretty well documented by users.

FWIW....

Looking forward to seeing the electric bike build. Be sure to to include motor source, controller source, etc. If it's over 50 HP, I've got a light aircraft that could use something similar.
Thanks for the lead, I'll look at that as another alternative when my student licenses expire.

Both motor and controller were sourced from QS Motor Ltd manufacture Bicycle Motor, Scooter Motor, Car Motor. From what I've seen, a LOT of people doing EV conversions are using these hub motors.

For aircraft, have a look at EMRAX. Extremely energy dense, high RPM axial flux motors. These will do what you need. Their smallest motor (weights just 7kg) will give you 30kw continuous and 52kw peak outputs and they just get better from there. 188 (52kW | 90Nm) - EMRAX
 

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Discussion Starter · #23 ·
UPDATE:
The shortened steering stem has been sent for CNC machining (from 1045H), and the axle stays and spacers have been water jetted and sent back. The feedstock also came in for the side covers of the electrics box... 1m long heatsinks are quite imposing :D

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There are a lot of really good, free, solid modeling CAD programs out there as has been pointed out. But I just wanted to correct something rv7charlie said about Fusion 360 not running wholly on your PC.

I have been running the free version of Fusion 360 for about 6 months now on a very ordinary PC and it works great. It is actually CAD/CAM software and even the free version can develop 2 and 3 axis toolpaths. I don't know if the free version includes FEA though.
 

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Maybe I phrased that requirement statement poorly.
Fusion 360 requirements
Fusion 360 file storage location
So the software does run wholly on the local PC, but cloud storage is apparently required. And when I pulled up the requirements page, it looks like they no longer support Windows 7, which I still run. Most of the free stuff will run on any platform, with local storage.

I didn't intend to knock the program itself; it seems to be easy to learn & use and is likely more bug-free than FreCAD. But some people (especially in the CAD world) seem to be less than happy that all their work product has to be stored on someone else's cloud server. It also means you're required to have a broadband connection to use it, and the unfortunate fact of life in the USA is that almost a quarter of US households can't get broadband (probably more than that, if you use a reasonable speed to define broadband).
 

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Fair points. It is true that all files are stored on Fusion's cloud and if you have a slow internet connection that could be a pain. To me, having all my files stored and backed up on Fusion's cloud is a good thing since I have a fast connection.

Fusion can export to any of dozens of formats and these can be stored locally or sent out for manufacturing.

But like I said before, there are lots of great programs our there and we should be thankful that so many of them are free to use.
 

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$200 bucks for Rhino3D. Good enough for NASA. Extremely intuitive. Exports to every type of CNC program language I've heard of. $1000 if you're aren't a student. The student version is the same as the $1000 dollar version. They know once they have you hooked, you're hooked. It is self contained. I order the CD so I always have a back up. I have 6 Terabytes of storage on the computer I just built. Rhino runs without using much resources, though in a CAD model, you make things in layers so you can work your GPU faster. ;)
 

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Discussion Starter · #29 · (Edited)
The new micrometer arrived today so I was able to validate the original shaft tolerances on the KZ and KTM stems. All tolerances are now locked in on the diagram so this should be all you need to adapt a KTM Duke 390 front end to a KZ440/440LTD using the KZ440 allballs bearing kit. The KTM stem easily pops out using a 12T workshop press after heating the lower triple clamp. The new one can be pressed back in reverse. PM me for the high res drawing file and STEP file if needed.

The KTM forks are very close in length to the KZ forks, but have less static compression. The KZ steering stop also works perfectly for this front end, with the forks having plenty of tank clearance when using the handle risers. Will be looking to match a new set of adjustable shocks on the rear once the bike is together and the final weights are measured.

I'll have designs for a steering lock and a 320mm floating brake disc conversion for the OE KZ front wheel in the coming weeks also. Just waiting for this stem to arrive so I can get everything fitted up and measured.
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Here is a pic of the new axle stays and spacers test fitted. Waterjet cut from 0.375" mild steel plate.
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Discussion Starter · #32 ·
Update time! The custom steering stem finally arrived today! They weren't quite able to hit the clearance fit tolerance at the top so I had to remove about 20 microns of material, but half an hour later with some 600grit and the fit was perfect. Super excited to get the new front end together this weekend.

The custom shaft on the left next to the KTM part on the right:
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