Old 08-20-12, 10:12 AM
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Notso_fastLane
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Join Date: Dec 2011
Location: Layton, UT
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Bikes: 2011 Bent TW Elegance 2014 Carbon Strada Velomobile

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Aero improvements on a (recumbent) bicycle.

I've got some new goodies lined up in the near future to add to my recumbent.
Recumbent:

Aerotrunk:
http://store.cycledifferent.com/mm5/...gory_Code=BAGS
Fairing:
http://www.hostelshoppe.com/images/p..._gx_bubble.jpg

I'd like to design a good test of the aero improvement I get from this setup by coasting down a hill to a predetermined speed.

So what's the best way to do that, and control for the added weight of the components?

Here's my idea:
1. With the bike in its current commuting configuration, Find a hill,
1a. start the run at a predetermined speed (I'm thinking 10.0 mph, just below the speed where the aero starts to make a significant difference)
1b. Stop the run at a predetermined speed (i'm thinking maybe 5 mph, or maybe back to 10 mph).
2. Weigh all the components before adding them to the bike.
3. Add the wieght to my current commuting setup and and repeat 1 - 1b. This shoudn't be too hard to just add stuff to the small bag I have on the back of the seat. I can use my camelback to add water and fine tune it to get pretty accurate.
4. Add the new bag to the bike, and do it again. Note the difference in distance. (I wish my GPS app were accurate enough to really map the acceleration differences too).
5. Add the fairing and do it one more time.

I realize that the added mass of these items will negatively affect my uphill performance, but with all my commuting gear, I'm adding a significant amount of mass on a typical day, over and above my 'dry' weight, anyway. I just have to find a hill with a decent runout where I won't have to worry about traffic or braking for turns.

I might even go find my arodynamics book and see if I can calculate the different coefficient of drag for each configuration.

Any other ideas?
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