2015-12-29 Initial Sketchup Model for the Electric Handcycle

This post will review an initial Sketchup model for the Electric Handcycle. It is based on measurements made at our kickoff meeting. Mostly, we'll use the design parameters of the Travel Bike, but with a 20" instead of a 16" wheel.

This model was made using my instructions by:

Geoff Bostwick

sketchuptutors@gmail.com

303 919 8131

Note that the real design is being done by Cody Wojcik using Solidworks. This model is for visualizing the machine. It's reasonably accurate, but not at all suitable for dimensioning parts like the Solidworks model will be. Still, it is efficient, because Geoff made the model in 90 minutes based on my instructions over a Skype screen share. I had previously searched for lots of bike components, so we were ready to move quickly.

Key parameters for the Electric Handcycle:

Overall length: 72"

Front wheel: 20"

Head tube angle: 55 degrees

Pedal height: 39 inches

Pedal tube offset from head tube: 4 inches

Rear track between tire centers: 24.5 inches

With these parameters, Geoff and I were able to collaborate (with him driving Sketchup) to make the model

Side view. Overall length, tip of front wheel to tip of back wheel is 72"

Front view. Width is 24.5" to the center of the wheels. Overall width including the hubs will be a few inches wider. This width is from the NEH bike, which has a wider track. That bike is 28" wide overall, compared to 25" wide overall for the Travel Bike. But the travel bike has a major focus of indoor use, and those extra 3" matter a lot. The Electric Bike will also go indoors, but will be focused more on outdoors and speed. So an extra few inches of track width gives better stability.

The electric motor will be supplied by Bionx   This is a 350 watt motor that runs at 48 V. It is supposed to perform well without much drag if you are paddling on your own. It is an assist-based motor system that multiplies your own energy.

The Bionx kit shown with a 26" wheel. It can also be mounted in a 20" wheel.

An earlier post showed the gearing range of the NEH vs Travel Bike. The NEH has a much wider gear range due to an intermediate derailleur. The Electric Handcycle will also have an intermediate derailleur. We're hoping to use a 9 to 44 tooth derailleur used on mountain bikes that use a single chainring.

Click the link below to download the Sketchup Model. It was made using Sketchup 2015.


Click on the link above to open the Sketchup model (made with Sketchup 2015)