Possible aero mods for conventional frame bicycle

[sendler]

The future of personal transportation 100 years from now will be a faired recumbent with electric motor. Renewable energy efficiency of of 800 mpgE at 40 mph will be quite average.
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[Grant-53]

Hopefully high efficiency recumbents will be part of our transportation system sooner than later. Some modifications to buses and trains will allow a roll on roll off system for recumbents.

What distinguishes a high end group from the common equipment is a bit of weight and finish quality. For a commuter the extra difference is not as important as reliability. My Jamis Aragon has been an amazing bike for the money for the last 15 years. Whether we use coroplast or some other common materials, a complete fairing can be made with simple tools.

Three versions I expect would be based on back angle. One for mountain bikes, one for road bikes, and one for triathlon style bikes.

[Sven7]

Originally Posted by Grant-53

As fascinating as the high speed recumbents and Shell mileage vehicles are they have limitations in urban traffic situations. The cost of such vehicles is considerable as well. For us po' folk who commute we are dealing with bikes in the $300-400 USD range. In traffic a rear camera might be worthwhile.

If you frame the purchase as "personal transportation" and compare it to the price of cars, it's easier to put down $600+ for a good bicycle, then add a couple hundred for mods to make it more usable and reliable. After all, I doubt few even on this forum would consider car shopping with a price cutoff of $400. That's not to say you can't do it inexpensively, but if it's going to be main transportation for a year or more, I strongly recommend spending enough to get a solid rig. Used is a great option, but you'd have to have more know-how to get things set up well. Rim brakes in particular can be a real pain.

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As for the "universal" upright fairings, I personally doubt that would ever truly work. On an upright you shift around a lot without realizing it, especially when "floating" your body over bumps, which is a good practice for wheel and butt longevity. There aren't many mounting points on the average bike, either. The best you could probably do would be to build fairings off front and rear racks, but then you need to have rack mounts or spend a lot of money. And you still couldn't really fair your legs or arms. Look at the picture below, and consider how much you can't even fair! (Unless you go Full Crazy for the 70's IHPVA seed pod look)



I think our best bet for efficient carbon-zero transportation is to build low-cost faired recumbent velomobiles. With a recumbent of course you don't have the issue of the rider moving around, since they're sitting down. With three wheels, you don't have the issue of staying upright at stoplights, or having escape hatches to put your feet or landing gear down. I imagine if recumbent trikes were put on one of the standard Taiwanese production lines and they found a more economical way to produce fairings, you could buy a faired bent for $1500. That price, considering you don't pay insurance or gas or parking, competes with a car in urban areas no matter how you slice it.

Until then, we make do. There's a reason the HPV scene migrated to 'bents...

[Grant-53]

Sven7, I understand your reservations but I am building these bikes successfully for the simple reason that I use sound engineering methods. We were taught to list our assumptions and then design to meet the lawful conditions needed to make the project work. My solid rig is a 2000 Jamis Aragon aluminum framed city bike. I paid $300 USD for it new. I added fenders, a horn, mirror, and LED lights. This bike came with spring seat post and stem. The V brakes are more than adequate even for towing. Winters here are similar to Michigan so I use 700C cyclo cross tires in the snow. The point I want to make is that how much you spend is no substitute for good planning.

As for mounting a fairing system all that is needed is a spar clamped to the head tube and one mounted on the seat tube. If you want to use a rear rack for hauling heavier cargo, that can be done also. The fairings can accommodate some wiggle room while covering from shoulder to calf. I am building three bikes, one to test each configuration so we can have some solid data for comparison. My coast down hill drops 30 ft in 0.1 mile so I can get repeatable data.

Will an upright beat the recumbents in the time traps? Not at all likely. A Toyota Corolla is not designed to beat a F1 racer. My efforts are toward the commuter market where 35-40 mph is plenty fast. Locally a mountain bike is the most popular commuter. We have more than our fair share of rough roads and pick up trucks even in town.

I hope states will allow for electric trikes up to 45 mph with a standard driver's license soon. Keep after the state legislators to update the e-bike rules where needed.

[Grant-53]

This is a rendition using software developed for both recumbent and upright bikes.
For more information go to recumbents.com, Forums, Technical/Bike Building, Shell Design Software, pg. 7

[Sven7]

Link for above image

Originally Posted by Grant-53

Sven7, I understand your reservations but I am building these bikes successfully for the simple reason that I use sound engineering methods. We were taught to list our assumptions and then design to meet the lawful conditions needed to make the project work. My solid rig is a 2000 Jamis Aragon aluminum framed city bike. I paid $300 USD for it new. I added fenders, a horn, mirror, and LED lights. This bike came with spring seat post and stem. The V brakes are more than adequate even for towing. Winters here are similar to Michigan so I use 700C cyclo cross tires in the snow. The point I want to make is that how much you spend is no substitute for good planning.

As for mounting a fairing system all that is needed is a spar clamped to the head tube and one mounted on the seat tube. If you want to use a rear rack for hauling heavier cargo, that can be done also. The fairings can accommodate some wiggle room while covering from shoulder to calf. I am building three bikes, one to test each configuration so we can have some solid data for comparison. My coast down hill drops 30 ft in 0.1 mile so I can get repeatable data.

Will an upright beat the recumbents in the time traps? Not at all likely. A Toyota Corolla is not designed to beat a F1 racer. My efforts are toward the commuter market where 35-40 mph is plenty fast. Locally a mountain bike is the most popular commuter. We have more than our fair share of rough roads and pick up trucks even in town.

I hope states will allow for electric trikes up to 45 mph with a standard driver's license soon. Keep after the state legislators to update the e-bike rules where needed.

Good info here. I will admit that I haven't yet attempted to streamline a bicycle, and maybe I should- the clamp system seems reasonable. It's possible to get a bike for cheap these days, but I've found that the features I want (rack and fender mounts, for one) tend to dwindle the options or push the price up. Your bike would cost over $400 in 2015 dollars! My 700C commuter was $500 in January 2014. I've never ridden a bike that cost over $1000.

Of course there are improvements to be made but there is a big gap between a slightly faired mountain bike and a recumbent land speed bike. Can you go 35mph on your Jamis without an electric motor? I assume you're taking something else into account.

I still would like to see legislation and infrastructure improvements to accommodate a wider variety of vehicles. I partly resist because I can only go so fast on the sidewalks with blind driveways and many through-roads are off-limits in SE Michigan. If roads were opened up, a faster bike or trike would make sense and I might be more apt to experiment.

I don't have an issue going 10mph for daily local transport. I am building the recumbent to have a more expeditious option for longer trips (the hour or longer ride to downtown Detroit, for one), and I realize that other people have different expectations for their transportation options.

I probably shouldn't be so hard on you guys about aero DF bikes. Feel free to build, experiment and test. Have you done ABA tests down your 1/10th mile hill? That would be an interesting thread, and could be linked to in threads like this and the other few floating around the Alt Transport forum. I would enjoy doing stuff like that but am tied up a bit with off-road trains of thought, including making my fatbike amphibious to get to uninhabited islands or across rivers without a canoe. I've adapted to the slowed down lifestyle and at this point prefer to put my effort into exploring nature.

PS- I also should note that I recently moved to be literally a mile away from work, not accidentally, to save myself trouble. Those of you who ride over 10 miles a day will have a different viewpoint on things.

[bikin' Ed]

I have been checking out bike aerodynamics a lot this year. Here are some of my findings. Your position is most important. I use aero bars but am not down on them during certain parts of my commute.

While on aero bars, a h2o bottle mounted between your forearms can actually lower resistance. Otherwise try mounting a bottle horizontally on your top tube.

If you carry stuff, a backpack low on your back is better than panniers. A helmet is more aero than your head. No gloves are more aero than with gloves.

You could make disc covers out of coroplast, like I did for racing and get a deep section front wheel.

Wear tight clothes and shave your legs(yes it's been proven faster--almost a minute in 40k).

All of this together, on a 20 mile commute may save you 2-3 minutes. If you catch the lights green.

[Sven7]

Quite an interesting discussion we've got going here. It really speaks to the personal nature of bicycles- since they fit your body and offer relatively small cargo capacity stock, the rider has to choose what is most important to him or her.

[freebeard]

Originally Posted by bikin' Ed

You could make disc covers out of coroplast, like I did for racing and get a deep section front wheel.

And/or flat carbon fiber spokes.

The trick to a full fairing would be to enable ingress/egress without adding weight.


http://ecomodder.com/blog/diy-aero-fairings-honda-125cc-motorcycle-214-mpg/

[Grant-53]

Where do I start? For testing I allow one descent to warm up the tires. I start at 0 mph on the incline at a marked spot and start rolling. I monitor my digital speedometer at the same mark each time and look for maximum velocity. I average three runs in each configuration. I record bike weight, my weight, temperature, tire type, and tire pressure.
So far the commuter fairing gives a consistent top speed of 16 mph. Without the fairing the top speed is 17 mph. This is due to a larger cross sectional area. I tuft tested indoors in a hall with a box fan close 12" to the fairing. The flow is smooth except for turbulence at the brake arms. I have tried a waste basket as a tail box but since it was not the same width or height as my torso it had no effect on speed. The use of bar end grips mounted 5" either side of the stem does lower my shoulders enough to gain +1 mph without the fairing. The back angle is 54 degrees from horizontal. My BMI is 36.4 and I typically cruise at 10-12 mph on my 4 mile commute through town using an under seat bag and a fanny pack. In winter I use a Bell full face motorcycle helmet.

To get the speed of 35 mph as Upright Dave has recorded one would need a full body fairing on a time trial bike. The thread is also in the recumbents.com forum of Technical / Bike Building. The record of 51 mph is held by a vertical wing faired Moulton. The question of speed must be qualified by distance and the rider's output in watts.

The issue of a motor involves our state laws in New York. Currently motorized bicycles are illegal on public roads and one could be arrested on the spot. As a practical matter there is much confusion and little enforcement. For example, I asked my neighbor who is a former county sheriff and town justice about the law on motors and he was unsure. He rides a recumbent trike. The kids on our street ride electric powered scooters and no one says much. The helmet law requires those 14 and under to wear a bike helmet. Word I get is that no one will bother if the speed is under 20 mph and there is no accident.

The Bicycle Man sells electric motors and NYCE is a major retail outlet. NYC is still trying to sort out which is an electric moped and which is an e-bike. A moped must be purchased from a certified manufacturer and registered with the DMV in one of three classes based on top speed. As it currently stands I can build a homemade motorcycle but not a motorized bicycle. Back in the 1980's bike motors were popular and the Aqua Bug made Popular Mechanics. I purchased a 23cc 2 stroke motor kit. It is a 1 hp friction drive unit and allowed me to go 25 mph on my Huffy 3spd with a Plexiglas motorcycle windshield. Since the Jamis has V brakes I would have to modify the mounting system. It would be legal in nearby Pennsylvania.

Current bike prices at a shop for a decent city bike are $400 USD here and the local store carries Giant mostly. I see plenty of ragged box store bikes in the racks around town. Trailers are gaining popularity over panniers as the cost per volume ratio is shifting.