I just noticed this thread this morning. Been tinkering a bit with a 3d printer and my sewing machine. I started a thread in the Innovators Workshop, but it seemed like there was little interest in the project, so I quit updating it.
I've been commuting in Seattle year round on DF's (with and without e-drives) for decades, with proper rain gear and stayed pretty dry. After a neck injury and surgery, I bought a T50 to take the pressure off my neck. I also added a Grin Tech All Axle motor/Phaserunner/CA3 kit. Sweet setup.
It's great, but man, it's bath time in the rain. I gave up winter commuting on it and started driving again.
I've been working on this project for a month or so, and I'm now on my 3rd iteration of the project and feel pretty confident that it'll hold up to the wear and tear of daily rain commuting.
As for staying dry, after approx 40 miles of rain testing, other than wind driven spray through the view slot (15-20mph ebike speeds), I wear my street clothes and a cycling jacket. In one nasty downpour, I donned a poncho and clipped the front of the poncho to the aft edge of the fairing (loosely to allow for steering) and was warm and dry for the 10 mile trip. When the rain stops, I unclip the canopy's leading edge and slide it back, convertible style.
By adjusting the canopy leading edge up and down, the view "slot" can be narrowed to keep out the rain. But after 20mph or so there's a tendency for the water to push up the fairing and spray my face with every bump. I'm working on a deflector, and toying with a flip up/down windscreen for complete coverage.
Removing the setup takes a minute or so and it stores flat. Assembly is about two minutes. The "hard points" remain on the bike. One behind the seat, two on the bar ends and one bolted to the headlight bracket up forward. Adapting to different rider heights/lengths could accomplished by using longer/shorter rod lengths at the hard points. The view slot uses a pair of sliding hooks that hold the leading edge of the canopy in various positions with parachute cord, allowing for steering, and can be adjusted on the fly.
After some aero testing using my CA3 (watt hours/distance), with various combinations of fairing and canopy, I found that the fairing adds approx 2/10th of a watt hour over a 1/2 mile course. The canopy, in it's up/rain position, adds approx 1/3 watt hour. No discernible difference in the down/convertible position.
I measured upwind and downwind 4 times in each configuration and averaged the numbers. No huge losses, but long distances will need to be calculated to leave battery wiggle room. I now have a stiffer/flatter canopy design that I need to test. More later...
I used various lengths of 3/16", 1/4" and 5/16" fiberglass rod, 2 yds - Silnylon fabric, 30'ish - nylon 1" grosgrain, 3 yds - 1/8" parachute cord, 2'-3/16" shock cord, zip ties, 5@6mm stainless bolts/nylocks and various 3d printed PETG parts. Approx $40.
More than happy to share my .stl files. Stay Dry!
