render showing frame modification to take right hand engine mount

belt drive assembled

Here is the belt drive final assembly, with the belt in place. It has not run under power yet but spinning it by hand it is extremely smooth with no tight spots or jolts. It feels like gears running in oil.

belt tensioner trial fit

Many thanks to Marc and Robert of the Dassault Aviation model club for their help machining this part on the lathe. It's eccentric mounted, the bolt you see is 6mm off center relative to the axis of rotation, so by setting the position of the central hub you can change the belt tension.

22-112 final drive

The 22-112 final drive in place.

state of the build

The battery trays are now welded into the frame.

Sponsor: RN12 Auto

Big thanks to RN12 auto for their gift of driveshafts and hubs from a 1999 ford fiesta zetec. Hanging above their sales counter are spare exhausts for Audi R8 and Ferrari Modena... not your average breakers yard.

Rear Axle & Motor Frame - final version

The final rear subframe housing the motor, belt drive, and brakes. The motor is not in this picture but will be attached as per the previous blog posts; as you can see the lower part that takes the motor and differential is still the same part, only the top structure is new. Mounting is directly metal on metal, possibly with some spacers, but no rubber mounts are necessary since no vibration is expected.

Driven Pulley Analysis

Rear Axle With Motor

Final Drive using a 8 mm pitch Gates Poly Chain Carbon. There will be over a ton of pull in the belt. 

The motor attached to the rear axle frame.

the big picture

Motor is a Netgain Transwarp built by  Jim Husted. The controller is a Zilla1K, batteries are by Derek Barger and will be charged with a Manzanita PFC40 charger. Viscous Limited Slip Differential by Westgarage. Chassis is a Sylva Riot. 

Rear Axle

Rear Axle in Construction

I'm lucky to have Michel Robin working doing metal fabrication for me on this project. He built structural parts for Mirage fighter jets, so this is pretty easy going for him. This structure would have looked more attractive made out of machined aluminum plates,  but I have a liking for thinwall steel tube. It's very efficient structurally, and if you leave it in a hole in the earth, it just turns to rust.

Rear Axle Render

a clearer view of the structure. Will be supported on three points: the two "horns" that stick out of the frame, and the end of the motor.

Rear Axle Render

A render with the complete structure. The material is thin wall steel tube.

Rear Axle Render

The drive system (motor, belt, rear axle). The structure that links the motor to the rear axle is not complete yet in this picture.