Streamlining project

[veloman]

I've spent a great deal of time reading and enjoying the build process for the Last Vetter Fairing. Recently I started working on my own streamlining. I am not 100% sure what machine this will go on right now. I have a fully operational converted electric motorcycle (ke100) which is naked.
Rich's 1994 Kawasaki KE100

I also have been working on an ex250 conversion, but that is far from road ready at this time. The ex250 is definitely going to be the right choice for a highway motorcycle. The ke is really too small and the steering lock is too wide to put a nosecone over. It can easily go 66mph, it's just a small bike. The ex250 won't require any additional power to move at steady speeds, and has tons more space for batteries, cargo, and a passenger.

So here is where I am at with my nosecone mold. It is about 20" wide. I started with some partical board for the bottom and rear. The inside is styrofoam that I found at someone's trash on the curb and some from the recycling center. I built a hot wire cutter using 26 awg nichrome wire and about 25watts of power supply. It is the ONLY way to cut styrofoam. A knife or saw is way too messy. That gave me the general shape.

I then tried air dry clay, but that cracked. No good. So I've been using plaster (20lb bag at home depot for $20) I've used maybe 5lbs so far. This has been working well. The only downside is that you have about 3 seconds to work it onto your surface before it sets. About 5 minutes before it sets in your bowl and becomes unusable. So you do a little at a time. I found that a piece of foam is the best tool for spreading it on your piece. Goes on real smooth.

My mold is certainly not perfect or completely symetrical, but it's just cosmetic. It is definitely going to be good enough for the wind to move past. In the future I will try to make it more perfect.

I've done about 6 coats of plaster, sanding with a heavy grit paper in between. It's fun to go back and forth, applying the plaster while indoors (it's 100 degrees outside and it sets way too fast there), and bringing it outside in the yard for the sanding. A dusk mask is essential, it's very dusty. A hand brush is used to push the dust off the mold and clean the sand paper.

So in case you haven't read CV's site, the idea is to make one mold, and with two of these together, a nosecone is formed. I plan to try thermoforming with plastic sheets.
This site is good to read up on as well The Recumbent Bicycle and Human Powered Vehicle Information Center

A backup plan would be fiberglass, using some old t-shirts as cloth. I just hate the fumes of that stuff. Plastic probably stinks too, though.

The rest of the streamlining would just use plastic sheeting, and coroplast for the tail. The hard part is the nosecone with those compound curves.

Pic updated - now it's sanded and I'm pretty happy with it. Still not perfect, but I'm itching to get a fairing built.

[JRMichler]

Polyester resin is the stuff that stinks. Epoxy resin has almost no smell, and is a better resin. It does cost several times as much as polyester.

[Grant-53]

The alternative to making a fiberglass nose piece from a mold is to use a rib and skin construction as used in vintage aircraft. If you want to make several copies a mold might be justified. Sailplanes have been mass produced using
1 inch square tubing welded into a space frame and aluminum skin

[veloman]

Yes, that could work. But the mold is already finished and has excellent compound curves. To replicate that with aluminum would require a lot more work, shrinking or stretching.

I originally tried that and it didn't work too well. The hard part is done - I have the mold finished.

[Grant-53]

Understood. Use the concept to size the fiberglass cloth to get an even thickness. Check into the paper model techniques. See the thread at recumbents.com General Topics, High speed aerodynamics. We are working on skins for nose cones

[veloman]

I attempted doing a plastic fairing with this mold, but my oven didn't get hot enough with two 1100w burners.

For now... I ended up doing a coroplast front fairing. It's built around a front rack made from bicycle handlebars and a sheet of plywood. Also used a bike rim up top. I'm not crazy about how it came out, but it works. I see a noticeable reduction in wattage above 35mph and the bike coasts better. It's fun to tuck in behind this. I plan to swap out the chunky seat for a smaller thinner one which should drop me 2" and so I won't need to tuck much to get completely out of the wind.
The headlight is from a gsxr. Can you believe this passed inspection last week? haha

With this full coverage front fairing, riding in the cold is going to be much more enjoyable, though that's 6 months away. The coroplast goes underneath to keep the air clean down there too. There is still so much work to do. Maybe even a small tailbox.

As for wind/handling. I haven't noticed anything yet.

[Grant-53]

Looks great! The curves are such to minimize side winds effects. I used plastic tubing instead of the bicycle rim for the curve support. I am mindful of how materials deform on a collision. The tail box will add to the drag reduction.