2012 Vetter Challenger Build ( 1981 Yamaha SR185 streamliner)

[euromodder]

Originally Posted by bschloop

Full fairing with tail, I am going for 24" overall width, and 8' overall length. it will likely be somewhat boxy looking, as I am trying to go for as few compound curves as possible.

Search for the thread on the streamlining template, and try to get close to that shape in plan and side view..

Compound curves do help though, but so do simple curves.

i read somewhere (can't remember where) that even a brick with rounded edges has better aero than a motorcycle

The aerodynamics of a mc + rider are awful, so it's fairly easy to improve upon them

the biggest obstacle will probably be cooling the engine since it's an air cooled bike

There's no way around cooling @ 70mph, so it's going to cost some of the potential aero improvements

With some careful ducting, you could use the principals of a steam- or waterjet vacuum pump to extract the heat out of the cowling.

If you can get rid of most of the heat from the header, that'll be a bonus.
In addition to wrapping it you could try to duct the header's heat away, separately from the engine cooling.

[redyaris]

Originally Posted by bschloop

I was hoping to find some chloroplast for all the simple curves, because it's very lightweight and rigid I will need to make a Fiberglass nose cone, but I am going with a much smaller one than Craig. I found some solar/uv curing resin that I am going to try for this. it's supposed to make the whole fiberglass thing much easier, as you have infinite working time in the shade, then you just set it in the sun and it cures. if this resin works I could make nosecones for as little as $50 each.
Does anyone know how much cooling airflow i'll need? I can get small fans meant for venting the engine compartment in a boat, but I don't know if they are big enough.

I would recomend a book The Racing Motorcycle, A technical guide for constructors, by John Bradley. Pages 225 - 228
The amount of cooling air flow needed is much less than most people emagin. the key is managing the air... with respect to velocity and amount. You want to slow the air down going past the fins of the engine so it can pick up heat and then speed the air up before re-entering the ambiant air stream.

[bschloop]

ok, I'm going to try the 4" blower it's rated at over 200cfm and only draws about 4 amps, and if it's not enough I can get another, and have one on each side. to offset the electrical load I can swap the headlight and taillight for LED units.

also more pics
1 side profile against "ideal teardrop shape"
2+3 sanding jig for the nosepieces
4 more finished sketchup model
5 cooling setup idea

[redyaris]

I suggest that the fan be on the outlet side and that the inlet side be open to airflow due to forward motion. That way you only need the fan on when standing still. I suspect that 200cfm is more than you may need for such a small 185cc engine, if the ducting is done properly.

[bschloop]

maybe like this?

[redyaris]

Looks good to me as a basic concept. The reason for haveing the fan behind the "radiator"/fined head and cylinder, is that it interfears with the cooling air flow to the object being cooled, thus requirering more power...

[Electictracer]

Originally Posted by redyaris

Looks good to me as a basic concept. The reason for haveing the fan behind the "radiator"/fined head and cylinder, is that it interfears with the cooling air flow to the object being cooled, thus requirering more power...

My buell xb12r uses this concept very effectively to cool the rear cylinder. It takes less then you would think. It also has a big oil cooler that does a lot of the work.

[Grant-53]

Ducting looks good with a NACA scoop inlet. I like thin aluminum sheet bonded to gasket paper for insulated ducts. Check out the shape of Fred Hayes' diesel bike, it looks like a commercial unit. I use 4mm coroplast and large nylon tubing for ribs. Hex steel mesh bonded between tarp weight sheet plastic is more flexible. Consider the Morelli/ Aptera shape profile; the radius at the edges should at least 10% of the width i.e. 2.5 - 3"

[Grant-53]

See airtech-streamling.com for shells and components. Blue Sky Design, Zzipper, and Mueller make canopies for recumbent HPVs.

[bschloop]

I've been to airtech, and I pretty much can't afford anything they have. Fred Hayes is using an airtech landspeed fairing that costs $4000, (almost as much as a new 250cc bike, so I don't think I'm competing with him on aero. Mostly I want to show that anyone can meet the vetter conditions without shelling out the big bucks. so far my whole project is still under $700. The bike only cost me $450, and I've added a new rear sprocket (from a honda xr50) for $20, and I spent about $100 on last years homemade bags and fairing. So far this year I've ordered a fan for $20 a set of handlebars for $30, some fiberglass resin for $26 and a spare oil filter cover for $18 the rest has been random scrap that is lying around my garage. I will have to buy a few more things, but most of the investment is time, blood, sweat (lots of sweat last year), and tears/expletives.