The RalE-Izip. My first EV

[puddleglum]

Improving your aero drag will make a huge difference to your top speed. I noticed I can usually go faster coasting in a full tuck down a hill than sitting upright and pedaling. I think you might find it worth the $30 to upgrade to the DNP freewheel with your aero package though. Looking forward to seeing it. have you seen this?
Endless-sphere.com • View topic - Aerodynamic Factors

[Grant-53]

The original article for zzipper.com was published in Scientific American Dec. 1983 and since then I have gathered a great deal of info on vehicle aerodynamics. I have posted in the Motorcycle forum along with sendler. The goal is to produce a design that is easy for DIY projects and sell the plans.

[puddleglum]

Thought about it after I sent the link that it is probably old news to you. Maybe it will be helpful to someone though. Do you have a link to your design thread?

[Grant-53]

A blog is on my to 'do list' but don't hold your breath. I want to build and test before putting stuff out there. There is the matter of copyrights also. For those who are interested I will say to start by taking a picture of someone in a comfortable riding position. Draw a shell around that using a 3:1 airfoil profile or a 5:1 with a 2/3 Kamm length. The shell will be about 24" wide and cover from the shoulder to just below the knee when the leg is extended to the bottom of the stroke. Attach securely to the frame, NOT the handlebars. Many of the techniques used by the people at recumbent.com will apply. Sailplane plans are a good source. See www.vintagesailplaner.com/Sheet1bis-9.pdf or the Aptera for ideas as well. Much of what is discussed in the Motorcycle and Aerodynamics forums will apply. If the shell has rounded sides and is attached to the frame the problem of side winds will be manageable. For materials, use what is available. Sheets of 4mm Coroplast, ABS, .016" aluminum, Luan, milk carton paper have been used with success. For bulkheads plywood, honeycomb aluminum, or foam insulation panels work well. I have used hard nylon tubing for curved ribs and angle stock aluminum for spars. This is a wide open field and new ideas can be tried with little expense or risk. Paper model techniques for the skin and composite cut and fold methods for the rigid supports are great. Some have tried PVC tubing frames or conduit but I think they are not as rigid for the weight.

[puddleglum]

Thought I would give a little update on this project. I didn't get to ride it a lot since I built it until this summer. I really enjoyed it when I could ride it but it just wasn't feasible to use it for commuting so I didn't get it out much. This summer has been different. I've been commuting with it since spring (except for the rainy days) and I love it. I've got about 700 km on this year. That's more than I've rode in the last 20 years combined. I have a short commute anyway but it's even shorter on the bike. It's actually faster for me to ride the bike than drive. I'm really not looking forward to having to park it for the winter. It's been pretty trouble free so far. I changed out the cheap rear shock and I think I may have to replace a sprocket this winter but otherwise it's great. I can ride comfortably at 30-35kph and hit 40 sometimes.