* * * Aerodynamics * * *

[Lowell]

A lot more people might take up racing if the vehicle was a lot more "portable" and could be stored easily and cleanly in the house/apartment/condo. And there might be a lot more places to race without the noise. A light racer won't destroy pavement, either.

There are already plenty of ways to get into racing on 2 and 4 wheels, all it takes is time and money. I have a double garage at home for the 2 wheeled toys, and a well equipped shop closer to the race track complete with a hoist for the 4 wheel toys.

Karting is a great way to get into competitive motorsports on a budget...

 

[Lessss]

Rohorn. Off topic but I was thinking that bike on the ceiling could use more wheels. Specifically wheels like a kickstand to stabilize the bike at a stop, one drops down from each side via a lever, so your legs never have to leave the cage at all.
Also 4 small wheels in the four upper corners to catch the bike if it spills while in a corner. Please excuse the crappy drawing.





The funny thing is I was thinking of designing something similar except without the dual steering.

 

[Anonymous]

A lot more people might take up racing if the vehicle was a lot more "portable" and could be stored easily and cleanly in the house/apartment/condo. And there might be a lot more places to race without the noise. A light racer won't destroy pavement, either.

There are already plenty of ways to get into racing on 2 and 4 wheels, all it takes is time and money. I have a double garage at home for the 2 wheeled toys, and a well equipped shop closer to the race track complete with a hoist for the 4 wheel toys.

Karting is a great way to get into competitive motorsports on a budget...

There are definitely some great entry level motorsports classes. As far as bikes go, pitbikes are taking off in both dirt and motard classes in lots of areas. But those and karts are near impossible to accomodate in living quarters without a garage. I have my own home, so that sort of thing isn't a problem for me, but for a lot of people, it's impossible to store or work on anything gas powered or weighs too much to carry.

There are several very good kart tracks within a few hours of Denver Metro here, but a lot of peope won't travel more than 20 minutes. Whether or not they would have the motivation to race in a nearby stadium lot or that sort of thing is also unknown to me.

 

[Anonymous]

Rohorn. Off topic but I was thinking that bike on the ceiling could use more wheels. Specifically wheels like a kickstand to stabilize the bike at a stop, one drops down from each side via a lever, so your legs never have to leave the cage at all.

It would be safer and all sorts of othr good things to do that. A lot of recordbreaker type HPV streamliners and Bonneville bikes do that. But my feet were paid for and work well, didn't add any weight, and cost nothing.

But for a paraplegic racer, that would make a world of difference.

When I first designed that bike, I had in mind a much heavier version with a lot of lead acid batteries. That would have required a retractable landing gear setup as you described.

 

[Lowell]

"There are several very good kart tracks within a few hours of Denver Metro here, but a lot of peope won't travel more than 20 minutes. Whether or not they would have the motivation to race in a nearby stadium lot or that sort of thing is also unknown to me."

True racers don't mind travelling. If someone won't travel more than 20 minutes to compete, they're not commited to the sport, whatever that might be for them. For the armchair keyboard warriors there's

http://www.nasasimracing.com/

 

[Anonymous]

True racers don't mind travelling. If someone won't travel more than 20 minutes to compete, they're not commited to the sport, whatever that might be for them.

True - but when the Denver GP comes to town, they run it downtown, not out in the middle of nowhere. The big sports arenas and stadiums are downtown. The arts & entertainment centers are downtown.

There's a reason for that.

 

[fechter]

This one looks a lot like safe's bike with aerodynamics:
http://burro-zvobikes.com/kits.html
There's a video here:
http://burro-zvobikes.com/images/BonnevilleShortweb.mov


65mph with a 500w motor! Same BMC motor I have on my Vego (but mine runs a tad more than 500w).

Safe, you just need to make a fairing and head off to the Bonneville salt flats and set a new speed record

BTW: If you haven't seen it, you should see the film "World's Fastest Indian" I highly recommend it. I used to live in Salt Lake City and watched the races on the salt flats back in the '70's.

 

[safe]

That's the bike that I posted a link to at the end of the Voltage Forum days. Very cool, and a great example of what can be done with gears. He uses the Rohloff 14 speed rear hub... and I guess it worked fine... I'm VERY AWARE of his accomplishments!

P.S: It's "Twin" 500 Watt motors... not just one, so my guess is a 1200 Watt motor should equal what he has. (my calculations put me right in the ballpark of where he is for top speed at about 57 mph... aerodynamics will make the difference one way or another)

http://www.badseyscooters.com/machine-x_burro_bike.htm

 

[TylerDurden]

He mighta made 67mph if he had remembered to put his visor down...

 

[RatoN]

Has anyone tried one of these Zzipper fairings on an upright bike?

http://www.zzipper.com/Gallery/DF/index.htm

I'd like to, but they're out of my price range.

Jay

Hmm, pretty cool.

No info on prices. How much DO they cost?? (The small upright one).

 

[Jay]

The zzippers for upright bikes are about $200-$300:
http://www.zzipper.com/OrderForm.pdf

As someone else said, it seems to be a fair price for a very low-volume item, and I've read elsewhere that their stuff is very well made. But for now I'm gonna save up for my next bike.

My preferred method for reducing drag would be to just slow down (my kids are right - I am so boring), but I'm trying to keep my commute time down to an hour.

Jay

 

[safe]

My preferred method for reducing drag would be to just slow down (my kids are right - I am so boring), but I'm trying to keep my commute time down to an hour.

I think this qualifies as an "insult" to anyone into top speed and improved aerodynamics... :wink:

What would this guy think?

 

[RatoN]

…

What would this guy think?

http://burro-zvobikes.com/images/BonnevilleShortweb.mov
''Thoughts? Not many. Put the visor down''

He mighta made 67mph if he had remembered to put his visor down...

Roflmao

Thanks for the info Jay, and yes those prices are insane. Quality or not.

Xyster, did you found out more about cold-forming Lexan. I would like to experiment with Lexan too, especially considering the price of the prefabs ''bubbles'' :?

 

[xyster]

Xyster, did you found out more about cold-forming Lexan.

Good info here:
http://www.knoll.com/techdoc/ImagoPrints%20Fabrication%20061603.pdf

There was also a member of the old V who constructed a very professional looking fairing for his Ego EV from Lexan....the thread is somewhere in the site backups which are somewhere :?

 

[safe]

What about fiberglass?

I know it sounds "scary" but it's really easy once you get into it. All you do is make the mold with wood or whatever you want and then cover it with plaster, clay or (this is good one) automotive bondo. If you use bondo you can sand it smooth and even redo mistakes along the way and it's stronger. You then create a female mold by applying the sheets of fiberglass cloth and working the resin into it. You then pop this out and you can then create the final copy by doing the same thing on the inside. They even have special first layers that you can lay down before the fiberglass that ends up giving a nice finish. Then all you need is a very small piece of clear plastic for the part that you actually look out of. On my old "gravity bike" I trimmed a piece of clear plastic and simply bent it and then attached it to the fiberglass. The whole thing weighed less than 5 lbs.

You could even skip the female mold making phase and just build a single copy. It would weigh more and not be as perfectly smooth, but it might get you going quicker.

It really depends on how good you want it to be. If you just want a "bent sheet of plastic" then this is more than you want to do, but if you really want to get serious about aerodynamics the way to go is fiberglass.

It's the same process as "Carbon Fiber", but the cloth is different...

 

[xyster]

Polycarbonate is the bullet-proof in "bullet-proof glass"*. It's a rather unique polymer that isn't terribly expensive or difficult to find or work with. It's very light, doesn't crack like fiberglass can, and is virtually shatter proof. Very important qualities for use on light vehicles.

* http://science.howstuffworks.com/question476.htm

Another lexan source:
http://tinyurl.com/35q3ya

 

[safe]

It depends on the shape you plan to make. Something that is a smooth bend that doesn't have any close tolerances to worry about can be a big sheet of bent plastic. Otherwise you need to make a mold first and then stretch the plastic over it. That idea isn't bad if you can do it well... (the first fairing I ever made was bent plastic... it failed miserably, but yours might be fine)

Fiberglass is very adaptable and you can also vary the thickness and by selecting different types of cloth even vary the flexibility or stiffness of an area. The final product can have thin and flexible areas and also stiff areas. For instance, when you make a seat you normally want the area that you sit on to be thick, strong and rigid. The tail section can be thinner and lighter and more flexible. It's sort of the best of all worlds for people on a low budget.

In a "perfect world" you would want injection molded plastic, but that's reserved for the manufacturers because the startup costs are insane.

So all things have their advantages and disadvantages... you just can't blindly say one thing is better than another. (well you can, but I'll call you on it! :lol: )

 

[swbluto]

As long as the material doesn't have a surface rougher than dimples, I really doubt the aerodynamics are going to be terribly effected. Simply, if it feels smooth, the aerodynamics are near optimal for that shape.

 

[Freddyflatfoot]

You guys need to have a good look at recumbents. They are king when it comes to being aerodynamically efficient.
I ride a SWB (Short WheelBase) that I built myself, and weighs in at around 20 Kg!
And I ride regularly with roadies, except going uphill, I am faster than them, especially in a headwind or going downhill.
I can coast downhill faster than they can pedal!
And yes, they were banned by the UCI back in 1934, because an 'unknown' rider entered with a bent, and beat the competition. Bents were deemed to have an unfair aerodynamic advantage, and hence the double triangle 'diamond' frame was entrenched as the basis for competition cycling.
Now here is real efficiency, Sam Whittingham just broke the world speed record for a human powered vehicle in a fully faired recumbent, also known as a Streamliner. He clocked 132.5 kph! Now that is serious speed!