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rickmantoo
recumbent enthusiast

USA
274 Posts

Posted - 08/09/2017 :  17:29:24  Show Profile  Reply with Quote
Osiris
You do not have to be a millionaire but you have to invest something. Time or money. I have had good suscess using pink foam from Home Depot. You have the CAD skills so cut you selected model into sections evert 12 to 16 inches and assemble the series of sections and cover them with 1/2 inch thick foam strips. Sand and cover with 2 layers of 8 oz fiberglass. Apply the previously mentioned duratech sand some more. Remove from stations and test the design out.

Rick Wianecki
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Grant-53
recumbent guru

USA
526 Posts

Posted - 08/10/2017 :  13:47:41  Show Profile  Reply with Quote
These guys are experts in making bodies. The hard part is designing a light and simple drive train. Take a look at the local gym and measure the length of stroke on the rowing or leg press machines. That's how long the rack length would be. A section of chain attached to some square tubing or other stock could rest on the top rear sprocket and held down with a retainer. The other end of the tube would attach to a lever arm or a pedal and support roller. This could be made from used parts. Take notes on dimensions and what breaks first. Just an idea for starters.
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Speedbiker
human power expert

USA
3702 Posts

Posted - 08/10/2017 :  16:18:45  Show Profile  Reply with Quote
Rick's not a millionaire? Huh....
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rickmantoo
recumbent enthusiast

USA
274 Posts

Posted - 08/11/2017 :  13:31:18  Show Profile  Reply with Quote
Mr. Biker

Not a Millionaire YET!

Rick
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Garrie L Hill
human power supergeek

USA
1689 Posts

Posted - 08/11/2017 :  13:39:33  Show Profile  Reply with Quote
How do you make a small fortune in recumbents?

Start out with a BIG fortune! Bada-Bing! Thank you, thank you! I'll be here all week, and remember to tip your waiters.............

Garrie "carbon based lifeform" Hill
HPRA Co-Dictator of the East
for pics of some of my time and money sucking projects
http://s58.photobucket.com/albums/g277/cfbb/
and videos
http://vimeo.com/5513519


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Speedbiker
human power expert

USA
3702 Posts

Posted - 08/11/2017 :  13:46:22  Show Profile  Reply with Quote
Spoken like someone who's lived it! Much to the benefit of many in the bent community.

Rick is rich in skills, experience, and knowledge!
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Osiris
Starting Member

USA
27 Posts

Posted - 08/12/2017 :  06:28:07  Show Profile  Reply with Quote
Given all the known functional constraints of street going velomobiles, a question worth asking is whether the "perfect" velomobile already exists, and whether any new designs will therefore follow the same template. It seems fairly well settled that the hulls will be constructed of some light-weight material like CF, that the drive-train, wheels, etc., will be of the conventional type already in use, and that the basic proportions are already known.

Are we likely to see significantly different incarnations of the velomobile in the future, or will it follow the evolutionary trajectory of the bicycle, which hasn't really changed since its introduction in the late 19th century?



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Speedbiker
human power expert

USA
3702 Posts

Posted - 08/13/2017 :  06:06:07  Show Profile  Reply with Quote
There's the $64 question. The problem is "infrastructure for human powered transportation". Much of Europe has it. America doesn't. So they benefit from development. Many Europeans use velos for daily transportation, here it is more recreational. The Netherlands has bigger velomobile meets than we have recumbent meets. So your question is more about demographics than design.
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Osiris
Starting Member

USA
27 Posts

Posted - 08/13/2017 :  06:33:34  Show Profile  Reply with Quote
quote:
Originally posted by Speedbiker

There's the $64 question. The problem is "infrastructure for human powered transportation". Much of Europe has it. America doesn't. So they benefit from development. Many Europeans use velos for daily transportation, here it is more recreational. The Netherlands has bigger velomobile meets than we have recumbent meets. So your question is more about demographics than design.



No, my question IS solely about design. I lived in Amsterdam for a number of years. Bicycles are everywhere and many streets have dedicated cycling lanes. Despite that, bicycle development has not progressed there. The Dutch today are riding essentially the same bicycle invented two centuries ago.

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Grant-53
recumbent guru

USA
526 Posts

Posted - 08/13/2017 :  10:06:09  Show Profile  Reply with Quote
Demographics follow geography which influences design. Small flat coastal countries or plains states lend themselves to velomobiles and the perennial 3 speed upright touring bike. The diamond frame is a classic design with good strength to weight. The main difference between my father's Royce Union and my Jamis Aragon is in materials, brakes, gearing, and suspension. This is evolutionary refinement. The velomobile or streamliner broke onto the scene in the early 1980s. Aircraft design was applied. We see refinement in geometry and materials. From a design and marketing view the question is whether an alternative drive train has the potential for greater efficiency and weight reduction along with better rider protection. The racers have optimized the aerodynamic package. The body shells give good protection for road rash. Decide what are the desired performance goals. Safety and weight reduction at acceptable cost for the various demographic groups. Where would a velo have an advantage compared to say a scooter or some other mode of transportation?
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DougC
Starting Member

USA
10 Posts

Posted - 08/13/2017 :  12:18:52  Show Profile  Reply with Quote
I think most users would be more comfortable with a linear drive system (in particular one that allows variable-length pedal strokes) but there's no way it's going to be anywhere near as light-weight and simple as 'normal' round crank arms.

quote:
Originally posted by Osiris ...Below is a working computer model I completed years ago of the 1829 Stourbridge Lion. The sheer complexity of its drive system is mind boggling. If the geometry isn't exactly right, the system simply freezes at a certain point, and you'll spend hours trying to figure out why.

Hmmm.
It was my understanding that with D-valve steam locomotives, the left and right wheels were offset by a quarter-turn--so that if one side came to stop in either of its "dead spots", the other side was always in the middle of the power stroke.
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DougC
Starting Member

USA
10 Posts

Posted - 08/13/2017 :  12:44:15  Show Profile  Reply with Quote
quote:
Originally posted by Osiris...No, my question IS solely about design. I lived in Amsterdam for a number of years. Bicycles are everywhere and many streets have dedicated cycling lanes. Despite that, bicycle development has not progressed there. The Dutch today are riding essentially the same bicycle invented two centuries ago.

There was a web page somewhere that had a study of Dutch bicyclists on it.
What it found was that most Dutch cyclists didn't ever ride very far on their "city" bikes. The figures were something like 95% rode less than five miles total per day, and 50% only went about 1.5 miles total. They only ride as far as they need to, to get to some other form of public transportation.
Also there's no hills there, at all.
If you are only riding a mile or two and on flat ground, you don't need ANY kind of high-end bike to do it. The bike doesn't really need to be greatly comfortable, or efficient. It only has to be easy to carry stuff on, and be faster than walking.

When they did ride recreationally, they went much farther distances and Dutch riders did use the more typical drop-bar road bikes.
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Speedbiker
human power expert

USA
3702 Posts

Posted - 08/13/2017 :  15:43:51  Show Profile  Reply with Quote
Doug, I think that falls under the categories of "how much does a bike commuter have/want to spend. And what performance are they looking for. Tough to beat the centuries old design for cost and convienence.
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Osiris
Starting Member

USA
27 Posts

Posted - 08/14/2017 :  06:15:07  Show Profile  Reply with Quote
quote:
There was a web page somewhere that had a study of Dutch bicyclists on it.
What it found was that most Dutch cyclists didn't ever ride very far on their "city" bikes. The figures were something like 95% rode less than five miles total per day, and 50% only went about 1.5 miles total. They only ride as far as they need to, to get to some other form of public transportation.
Also there's no hills there, at all.
If you are only riding a mile or two and on flat ground, you don't need ANY kind of high-end bike to do it. The bike doesn't really need to be greatly comfortable, or efficient. It only has to be easy to carry stuff on, and be faster than walking.

When they did ride recreationally, they went much farther distances and Dutch riders did use the more typical drop-bar road bikes.



Yes, but I don't think my question is being addressed. My point was that the high end CF bikes you're referring to are NOT fundamentally different in design from the type of steel frame bikes that made their debut in the 19th century. The sorts of design changes we've seen over the span of a century are only incremental ones; the basic design is fundamentally the same.

My question with respect to velomobile design was whether it's design, like that of the bicycle, is already at such a state of refinement that a velomobile made a century from now will be essentially the same vehicle we see today. (An example of a fundamental design change is the replacement of a structural frame with a unibody design.)
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Osiris
Starting Member

USA
27 Posts

Posted - 08/14/2017 :  06:21:35  Show Profile  Reply with Quote
quote:
Originally posted by Speedbiker

Doug, I think that falls under the categories of "how much does a bike commuter have/want to spend. And what performance are they looking for. Tough to beat the centuries old design for cost and convienence.



One other point those who haven't lived in Holland may fail to appreciate is that bike theft is epidemic there. Nobody is going to buy a top of the line $8000 bicycle and leave it tethered to a tree or lamp post only to have it stolen. What you see everywhere in Holland is rusty, dirty, and inexpensive bicycles which aren't going to attract thieves.
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Speedbiker
human power expert

USA
3702 Posts

Posted - 08/14/2017 :  11:42:32  Show Profile  Reply with Quote
Andrew, diamond frame bikes have been forced to stay the same by the UCI for the sake of competition. Much like NASCAR. Even if they never allowed bents, you would still see a much improved design. Engineering doesn't define the basic concept of the diamond frame bike, rules do. Recumbents are like the wild west. When I started in the 90s a P-38 was considered a competitive race bike. Thanks to adventurous designers and builders, our competitive race bents look different and wildly out perform P-38s. In 2013 I informally raced and beat an F-40 ridden by a well known racer in a 90 mile test. In coast down tests my NoCom was equal to the F-40. That's how far we've come. Similarly, velo design is driven by engineering. But we have quickly seen how aerodynamics controls much of it's design. To stray much from a Daniel Fenn is to stray from competitive performance. And few people want a cool looking, but slow velomobile.
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Osiris
Starting Member

USA
27 Posts

Posted - 08/14/2017 :  12:23:10  Show Profile  Reply with Quote
quote:
Originally posted by Speedbiker

Andrew, diamond frame bikes have been forced to stay the same by the UCI for the sake of competition. Much like NASCAR. Even if they never allowed bents, you would still see a much improved design. Engineering doesn't define the basic concept of the diamond frame bike, rules do. Recumbents are like the wild west. When I started in the 90s a P-38 was considered a competitive race bike. Thanks to adventurous designers and builders, our competitive race bents look different and wildly out perform P-38s. In 2013 I informally raced and beat an F-40 ridden by a well known racer in a 90 mile test. In coast down tests my NoCom was equal to the F-40. That's how far we've come. Similarly, velo design is driven by engineering. But we have quickly seen how aerodynamics controls much of it's design. To stray much from a Daniel Fenn is to stray from competitive performance. And few people want a cool looking, but slow velomobile.



Well that's what I was wondering about. It seems to me that there has been a convergence of opinion as to what constitutes the objectively "best" formula for velomobile design. All of them have three wheels instead of four. All of them have two wheels in front and one in back, rather than the reverse. All of them use the same circular pedal arrangement, and all of them (at least the pricier ones) use a light weight mono-body with no separate frame. There are still some noticeable differences in the overall shape, with some being quite a bit longer than others, but the basic design seems to have been pretty much nailed down.
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Garrie L Hill
human power supergeek

USA
1689 Posts

Posted - 08/14/2017 :  12:52:39  Show Profile  Reply with Quote
You just described the concept of convergent evolution in engineering.

Garrie "carbon based lifeform" Hill
HPRA Co-Dictator of the East
for pics of some of my time and money sucking projects
http://s58.photobucket.com/albums/g277/cfbb/
and videos
http://vimeo.com/5513519


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Speedbiker
human power expert

USA
3702 Posts

Posted - 08/14/2017 :  13:43:06  Show Profile  Reply with Quote
Adrew, there are sound engineering reasons for each of the elements you noted. Some ideas are pretty poor, but builders use them just to be different. Somea are willing to give up a little performance just to gain something like greater handling or stability. But it's pretty easy to build something "unique" just to stand out from the crowd, only to end up standing out because your fancy machine under performs. Remember, the best riders are lucky to produce 1/3 of a horsepower during an hour ride. Most are more like half that. How much fun you can have with 1/6 to 1/3 of horsepower is very dependant on a good design. Great designs like the Milan SL and Daniel Fenn are popular because they go, turn, and stop very well for human powered vehicles.
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Grant-53
recumbent guru

USA
526 Posts

Posted - 08/14/2017 :  16:16:36  Show Profile  Reply with Quote
So how often are cars or motorcycles stolen?
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carolina
recumbent guru

USA
516 Posts

Posted - 08/14/2017 :  20:26:55  Show Profile  Visit carolina's Homepage  Reply with Quote
13 thousand cars per day.

velosRus.com
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Osiris
Starting Member

USA
27 Posts

Posted - 08/15/2017 :  05:58:21  Show Profile  Reply with Quote
quote:
Originally posted by SpeedbikerGreat designs like the Milan SL and Daniel Fenn are popular because they go, turn, and stop very well for human powered vehicles.



That's what I want to find out. If you could list all the things that make Fenns and Milans such successful designs, what would they be?
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Speedbiker
human power expert

USA
3702 Posts

Posted - 08/15/2017 :  06:28:43  Show Profile  Reply with Quote
Nope, because that would take a book. Not to mention including an education in aerodynamics, handling, braking, ergonomics, vehicle dynamics, structures, etc. And that would likely be followed by arguments from people who have never successfully built anything.
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carolina
recumbent guru

USA
516 Posts

Posted - 08/15/2017 :  06:41:36  Show Profile  Visit carolina's Homepage  Reply with Quote
Ditto speedbike. "But" They are the most helpful, nicest, shareing, care'ing, people on the planets though! Look what they helped me do. Netherlands, demark, cz republic, Germany, france. All hardwares come from europe.

velosRus.com
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Grant-53
recumbent guru

USA
526 Posts

Posted - 08/15/2017 :  09:44:40  Show Profile  Reply with Quote
The short answer is an elegant design has a high degree of fitness for use with a minimum of complexity and cost. The rest is looking at the numbers. The tricky part may be deciding what the customer really wants to do. Any product must be safe, efficient, convenient, and cost effective. If anyone is interested I can post some of my favorite reference books that I came across during 15 years of technical sales and twenty years in manufacturing. Many of you have had similar careers and have been generous with your wisdom.

Edited by - Grant-53 on 08/15/2017 09:59:45
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