Fairings?

[Snax]

I suppose it was more of a food for thought suggestion, although it would be easier to implement an effective one on a recumbent. And no, it's not a scoop if you cover the forward surface of it. Regardless, my point is that focusing on the front without attention to the rear would be ignoring more than half the problem aerodynamically.

 

[augidog]

agreed...and agreed...my lil joke was only a joke. i was playing with paint shop pro and each half always seemed incomplete without the other, the rear section-only always came out looking like more impedence than benefit.

i think that as the competitive aspect grows, we'll see 'bents dominating the land-speed events.

 

[RATRODER]

Maybe something like thishttp://blog.wired.com/gadgets/2007/09/bike-hits-1307-.html

 

[Zev0]

Would it not help if you used those aerodynamic wheel covers?

 

[Snax]

I suspect that for that record, aerodynamic aids for the bike were not allowed. Regardless, I don't think the wheel covers are really all that effective on a bike. Having them on the front is just wishing for calamity, and the airflow over the rear wheel is already so spoiled by turbulence, the reduction in drag is likely very little without matching the width of the tire precisely to the width of the rim. Bladed spokes are nearly as effective from tests I read long ago.

 

[Zev0]

I suspect that for that record, aerodynamic aids for the bike were not allowed. Regardless, I don't think the wheel covers are really all that effective on a bike. Having them on the front is just wishing for calamity, and the airflow over the rear wheel is already so spoiled by turbulence, the reduction in drag is likely very little without matching the width of the tire precisely to the width of the rim. Bladed spokes are nearly as effective from tests I read long ago.

Hmmm odd. Wonder why all the professional racers use them? Their MUST be something gained from them. Ever watch the Tour de France? They all use them. Of course they pedal instead of motor, but their must be some advantage.

 

[smitty]

Did you notice the fins on the backs of his lower legs?

 

[skyl4rk]

If you get the software here:

http://www.carlsondesign.com/#Fun_Shareware

You can use the software to design fairings. The software is intended for designing boat hulls out of plywood. You can use a mouse to move curves around and make a chine boat shape (chine is the corner where two pieces of plywood meet on a boat). The software then calculates the shapes of flat panels to cut out and gives you offsets, so that when you stitch the cut outs together, will give the 3d shape you designed. The software takes a little getting used to but once you figure it out it does not take long to get a set of offsets to plot out on your panels.

Design a fairing with the right dimensions for your bike, get the offsets, plot it out on some coroplast (?) sign material, cut it out and stitch it together with zip ties. Fit it over the bike, and cut the fairing behind the rider position to make a tail box. Use some aluminum bar or conduit to make a simple frame. Put the front half on a hinge at the front so you can lift it to get in or out. Make a place for the back half of the fairing front to drop into to lock it into place. Personally I prefer wind in the face so I would make a small hole in the top for my head to stick out. Its not as streamlined but it will be much, much faster than a non streamlined bike.

I have not made one yet but if I get a recumbent I will be making a cloroplast fairing.

 

[Snax]

Did you notice the fins on the backs of his lower legs?

I've often thought that a similar fairing on a un'bent rider's back might work as well.

 

[skyl4rk]

Attached is a drawing of a fairing I designed using the Hull Designer software, for my dad's Bike-E, which is a fairly short wheelbase recumbent. The widest part is right at the riders shoulders, you have to imagine the riders head and helmet above the top of the fairing. The fairing was never built.

The fairing looks a little odd because it is so short. The fairing is actually a fairly tight fit around the rider. It is not the best streamline shape, however it would be a big improvement over no fairing at all.

It would be made of aluminum frame, coroplast and zip ties. This fairing could be built for less than $100, maybe less than $50 if you use stuff from your junk drawer. By bending the coroplast into shape and tying it together, the fairing would be stiff. The ribs in the coroplast would have to be across the short dimension of the panels, so the panels would bend correctly.