Mk. 4.5, the better E-Tard

Farfle

100 kW
Joined
Jun 27, 2010
Messages
1,759
Location
Redmond OR
Heya all, After flogging the crap out of mk.4 for a season, the already three year old battery took a dump over the winter. I have some new cells, but they dont fit into Mk.4's skinny frame.

So, I am building a new frame and re-using the swingarm, forks, motor, wheels and concentric pivot system from mk.4.

It damn near made me cry cutting that frame up, but the next one will be so much better, its all worth it.

20140715_212539_zpse2d00e72.jpg


20140715_223636_zps474d70f6.jpg


FB_IMG_14054896126071738_zps4c341a59.jpg
 
Here is the tentative design for 4.5, I havent done the simulation on the linkages yet, so they will probably end up a different shape, but this is the rough idea for now. Inside the square panels in the center of the frame there will be a CNC cut sheetmetal trellis.


IMG_18955871001409_zps93e6ac6c.jpg
 
Here are some shots of the real modeled linkages, and the CNC plasma cut center structure which I am now referring to as the cobweb.





 
It's sad to see the other frame cut up but guess it's all in the name of progress. I am really looking forward to watching this build. I love the idea of the swing-arm pivot being the motor since it really simplifies the chain tension situation. Your packaging of the rear suspension looks like a great solution. It also seems like it would reduce the un-sprung weight of the swing-arm since it doesn't have to lift half of the shock weight vertically. I'm no suspension expert but it seems like every little bit would help. Does the software that you use for simulation take into account the loads and stresses on the parts or is it simply the geometry of the travel that its simulating?

Very cool! Thanks for posting it!
 
DanGT86 said:
It's sad to see the other frame cut up but guess it's all in the name of progress. I am really looking forward to watching this build. I love the idea of the swing-arm pivot being the motor since it really simplifies the chain tension situation. Your packaging of the rear suspension looks like a great solution. It also seems like it would reduce the un-sprung weight of the swing-arm since it doesn't have to lift half of the shock weight vertically. I'm no suspension expert but it seems like every little bit would help. Does the software that you use for simulation take into account the loads and stresses on the parts or is it simply the geometry of the travel that its simulating?

Very cool! Thanks for posting it!

It has the option to do the physical sim aswell, but I am going seat-of-pants on this one. The biggest advantage of the linkages is that it lets me adjust the effective rates and progressivness of the suspension with only a linkage change.
 
Just got the chromoly ordered. 28 feet of 1.25 Dia .049 wall tubing.
 
I love machining 4340. Its stupid strong, and machines into a beautiful finish :D . The shavings are very strong, and wicked sharp though. :shock:


20140725_131134_zpsdbc35e70.jpg


20140725_135202_zps75f863c1.jpg


20140725_143006_zps8beb3c70.jpg
 
spinningmagnets said:
Thats a very clever configuration for the rear suspension shock, I'm looking forward to how this turns out...

I would like to say it was my idea, but Its an adaptation of whats on the brittan V1000
 
Britten_V1000_1995.jpg
for referance.
Anxious to see how it turns out team farfle.
 
What are those giant slots? I'll give you a useful hint though it's probably too late...all centrifugal fans intake at the center and exhaust at the perimeter, and if you can combine that with good flow from one side to the other for fresh air flow through the air gap as well as through the stator, then air cooling can make ideas like dumping water into the motor that's sure to cause traction problems unnecessary. To me the potential for better cooling in such a manner combined with the greater torque of perimeter magnets designs for a given weight, make outrunners the clear motor of choice giving you a distinct advantage over the field.
 
John in CR said:
What are those giant slots? I'll give you a useful hint though it's probably too late...all centrifugal fans intake at the center and exhaust at the perimeter, and if you can combine that with good flow from one side to the other for fresh air flow through the air gap as well as through the stator, then air cooling can make ideas like dumping water into the motor that's sure to cause traction problems unnecessary. To me the potential for better cooling in such a manner combined with the greater torque of perimeter magnets designs for a given weight, make outrunners the clear motor of choice giving you a distinct advantage over the field.


Giant slots?
 
20140725_135202_zps75f863c1.jpg

Giant slots=lathe face plate maybe?

Loving the handy work J.
 
Oh, I thought those were the motor's side covers with the cutting tool in the picture making cogs to match the sprocket. I don't have cool tools so I guess I'm way out in left field pulling my pud while Farfle is cutting some shiny cool clamps.
 
Aaha lol. Yeah, those are slots in the rotary table.

Heres the finished product:


20140727_173226_zps897ff4fc.jpg


20140727_173231_zps069f1bb6.jpg


20140727_173236_zpsd39a8ca3.jpg
 
Finally got most of a day to work on the frame. And got a visit from a friend of mine and helped him finish his lightsaber handle that will probably become a high powered laser or flashlight. That was a bit of a machining exercise. :shock:

20140801_150519_zpsfdb82515.jpg


ROTJplansrev_zps0086a347.jpg


received_m_mid_1406931226722_fa7b97dca16c941650_0_zpsb154147c.jpg
 
More progress! Still have to finish up the last bit of welding on the trusses and then throw the forks, seat and wiring on! :mrgreen:



 
jansevr said:
beautiful work. looking forward to seeing the finished product and how it compares to your last bike

Thanks, I am hoping that the chatter goes away, this frames mass is so much more centralized, and the progressive rear shock is going to be ages ahead of the slightly antiprogressive suspension on Mk.4. Speaking of which, shock linkage magic happening today!

20140805_193542_zps26341077.jpg


20140805_193521_zps7110c28e.jpg


20140805_192054_zpsc36c8cf9.jpg


20140805_193300_zps8d427f47.jpg
 
Linkages are tacked in place and the range of motion looks good! :mrgreen: :twisted:


20140806_140002_zps91763ebb.jpg


20140806_140010_zpsca395b1b.jpg


20140806_140017_zpsa9b93d4a.jpg
 
Back
Top