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Unfaired Recumbent vs. Upright Speed Comparisons
We all know that fully-faired recumbents own all of the human powered speed
records. But what about unfaired recumbents vs. upright (DF) bikes? Here's an interesting web page which cites several experiments attempting to answer this question. It includes thoughtful narrative from several riders who offer sincere observations on the topic. http://www.neci.nj.nec.com/homepages...a/compare.html From the data available on Sandiway Fong's website, it looks like the aero efficiency (speed vs. power input) of unfaired high-racers, quasi-lowracers and lowracer recumbents differs only slightly from each other; but produces a noticeable speed advantage over DF bikes (at a given power output). Hard shell fully faired recumbents, as one would imagine, really start to show off their superior aero advantage in the upper extremes of speed (40mph+). Here is a chart excerpted from Mr. Fong's website (I didn't see any copyright declarations, so I hope it's OK.) V = velocity at a constant power output of 250 W P = power needed to maintain constant speed of 40 km/h (~25mph) V(mph) P(W) Bike Description 19.8 469 road bike (touring position) 21.7 362 road bike (racy position) 23.9 277 recumbent (seat hight 60 cm) 24.5 259 recumbent (seat hight 40 cm) 25.4 234 recumbent (seat hight 20 cm = low racer) 27.9 180 recumbent (seat hight 20 cm, with tail fairing) 31.6 135 recumbent (seat 20 cm, with full fairing, soft material) 42.8 75 recumbent (very aerodynamic hard fairing) The difference between DF/uprights and unfaired lowracers is significant; but the difference between unfaired and fully-faired lowracers is just amazing. Yes, folks, according to this study, that same 75 watts of power that produces ~10 mph on your hybrid upright bike would have you screaming along at 25 mph in a fully-faired lowracer. Wow. The difference in aero efficiency between an upright/DF racing bike and an unfaired high-racer recumbent is about 23% at 25mph. From my observations riding alongside a Bacchetta Strada in fast club rides, this seems about right. The Bacchetta owner in our local club, Bruce, is able to pull a paceline longer than all but the very strongest DF riders (and at higher speeds). He's fresher and much more animated at the end of the race - er, I mean ride ;-) - and continues chatting pleasantly at speeds that make the DF riders (including myself) hunker down and groan with pain. I pulled a muscle trying to keep up with Bruce this summer on my lovely new Soulcraft road bike. I could see that it aggravated the competitive riders when Bruce would cruise up from the back at 28mph and pleasantly chat with them as he slotted into the lead to pull for a while. Bruce gets a kick out of it, for sure. Once we get past the aero advantage issues, the next topic is riding position. Open vs. closed: which is better for making power?Personally, I'm of the belief that a closed position is faster. I think I'm in good company here. Then there's high BB vs. low BB. I've ridden them all, and I don't know which one is faster (if any). I think once you get your legs out in front of you, it's all about the same. Any speed advantages probably have more to do with cardiovascular advantages. Just a guess. Anybody have any good data on this topic? Since I'm getting ready to buy a Velokraft carbon lowracer, I'm revisiting this topic. When my DF riding buddies want to know why I ride a lowracer, it's nice to have some data to help make my case. One look at all that beautiful carbon weave and I don't think there will be too many dissenting voices. -=Barry=- 2000 RANS Rocket Coming Soon: 2003 Velokraft |
Unfaired Recumbent vs. Upright Speed Comparisons
"B. Sanders" wrote in message
news:lLoob.49717$mZ5.311118@attbi_s54... We all know that fully-faired recumbents own all of the human powered speed records. But what about unfaired recumbents vs. upright (DF) bikes? snip V = velocity at a constant power output of 250 W P = power needed to maintain constant speed of 40 km/h (~25mph) V(mph) P(W) Bike Description 19.8 469 road bike (touring position) 21.7 362 road bike (racy position) 23.9 277 recumbent (seat hight 60 cm) 24.5 259 recumbent (seat hight 40 cm) 25.4 234 recumbent (seat hight 20 cm = low racer) 27.9 180 recumbent (seat hight 20 cm, with tail fairing) 31.6 135 recumbent (seat 20 cm, with full fairing, soft material) 42.8 75 recumbent (very aerodynamic hard fairing) snip Yes, folks, according to this study, that same 75 watts of power that produces ~10 mph on your hybrid upright bike would have you screaming along at 25 mph in a fully-faired lowracer. Wow. Doh! Make that *42.8 mph*, not 25 mph. Can you believe these numbers? 42.8 mph for 75 watts of input? That is incredible; but it does begin to explain how Sam Whittingham was able to power a faired bike to 81+ mph on level ground. (remember: wind drag increases as the *cube* of velocity). -Barry |
Unfaired Recumbent vs. Upright Speed Comparisons
B. Sanders wrote:
V = velocity at a constant power output of 250 W P = power needed to maintain constant speed of 40 km/h (~25mph) V(mph) P(W) Bike Description 19.8 469 road bike (touring position) 21.7 362 road bike (racy position) 23.9 277 recumbent (seat hight 60 cm) 24.5 259 recumbent (seat hight 40 cm) 25.4 234 recumbent (seat hight 20 cm = low racer) 27.9 180 recumbent (seat hight 20 cm, with tail fairing) 31.6 135 recumbent (seat 20 cm, with full fairing, soft material) 42.8 75 recumbent (very aerodynamic hard fairing) Doh! Make that *42.8 mph*, not 25 mph. Can you believe these numbers? 42.8 mph for 75 watts of input? That is incredible; but it does begin to explain how Sam Whittingham was able to power a faired bike to 81+ mph on level ground. (remember: wind drag increases as the *cube* of velocity). I think you had it right the first time - the MPH figure was labeled as being obtained with 250 W of input. The power figure is labeled as watts at 25 MPH. -- Russ --kill the wabbit to reply "No, see, it's not something you 'experience' - it's something that you posess. You know, that fine 'recumbent butt' - a distinguishing characterisitic of a recumbent cyclist." -Geoff Adams, on 'BROL |
Unfaired Recumbent vs. Upright Speed Comparisons
"cbb" wrote in message
om... "B. Sanders" wrote in message news:L_oob.52992$9E1.241427@attbi_s52... "B. Sanders" wrote in message news:lLoob.49717$mZ5.311118@attbi_s54... We all know that fully-faired recumbents own all of the human powered speed records. But what about unfaired recumbents vs. upright (DF) bikes? snip V = velocity at a constant power output of 250 W P = power needed to maintain constant speed of 40 km/h (~25mph) V(mph) P(W) Bike Description 19.8 469 road bike (touring position) 21.7 362 road bike (racy position) 23.9 277 recumbent (seat hight 60 cm) 24.5 259 recumbent (seat hight 40 cm) 25.4 234 recumbent (seat hight 20 cm = low racer) 27.9 180 recumbent (seat hight 20 cm, with tail fairing) 31.6 135 recumbent (seat 20 cm, with full fairing, soft material) 42.8 75 recumbent (very aerodynamic hard fairing) snip Yes, folks, according to this study, that same 75 watts of power that produces ~10 mph on your hybrid upright bike would have you screaming along at 25 mph in a fully-faired lowracer. Wow. Doh! Make that *42.8 mph*, not 25 mph. Can you believe these numbers? 42.8 mph for 75 watts of input? That is incredible; but it does begin to explain how Sam Whittingham was able to power a faired bike to 81+ mph on level ground. (remember: wind drag increases as the *cube* of velocity). -Barry I think you are reading the chart wrong. it is 42.8 mph @ 250 watts and 25 mph @ 75 watts. Thanks Craig. Yeah, you're right; I did misread it. Still....adding a fairing can more than *double* your speed for a given power input. That's big news. -=B=- |
Unfaired Recumbent vs. Upright Speed Comparisons
[Strange, when I post from the Slurp.net newsreader, my posts never show up on
the MSU Newsreader. Slurp maybe hosts some spammers and MSU bounces all their posts??] There's been talk about a world unfaired record but I guess no one can agree on what that means. The Euro unfaired class allows tailboxes, for instance. Maybe they should have brand-based stock classes, like sailing has design classes. The winning time for the Eurostyle unfaired hour race this year was about 31mph. These racers aren't totally elite, so that would seem to put them on par with the best UCI bikes. If the best UCI racers adapted to these Eurostyle (tailboxed) lowracers maybe they could go, what, 35 miles in an hour? I think that totally unfaired lowracers are still faster than UCI bikes. Andreas Weigel isn't a bigtime racer at all, I gather, but he came in a close second to pro Sean Wallace in a 20km USCF TT in San Diego. I lapped a USCF field with mine and I don't normally do that. : ) Tim Brummer won his age division at the USCF TT 40k Nat'ls against very fast people and he's not a pro either I don't think. -- Jeff Potter **** *Out Your Backdoor * http://www.outyourbackdoor.com publisher of outdoor/indoor do-it-yourself culture... ...offering "small world" views on bikes, bows, books, movies... ...rare books on ski, bike, boat culture, plus a Gulf Coast thriller about smalltown smuggling ... more radical novels coming up! ...original downloadable music ... and articles galore! plus national "Off the Beaten Path" travel forums! HOLY SMOKES! |
Unfaired Recumbent vs. Upright Speed Comparisons
When you kick their collective asses, you won't need any data!
B. Sanders wrote in message news:lLoob.49717$mZ5.311118@attbi_s54... We all know that fully-faired recumbents own all of the human powered speed records. But what about unfaired recumbents vs. upright (DF) bikes? Here's an interesting web page which cites several experiments attempting to answer this question. It includes thoughtful narrative from several riders who offer sincere observations on the topic. http://www.neci.nj.nec.com/homepages...a/compare.html From the data available on Sandiway Fong's website, it looks like the aero efficiency (speed vs. power input) of unfaired high-racers, quasi-lowracers and lowracer recumbents differs only slightly from each other; but produces a noticeable speed advantage over DF bikes (at a given power output). Hard shell fully faired recumbents, as one would imagine, really start to show off their superior aero advantage in the upper extremes of speed (40mph+). Here is a chart excerpted from Mr. Fong's website (I didn't see any copyright declarations, so I hope it's OK.) V = velocity at a constant power output of 250 W P = power needed to maintain constant speed of 40 km/h (~25mph) V(mph) P(W) Bike Description 19.8 469 road bike (touring position) 21.7 362 road bike (racy position) 23.9 277 recumbent (seat hight 60 cm) 24.5 259 recumbent (seat hight 40 cm) 25.4 234 recumbent (seat hight 20 cm = low racer) 27.9 180 recumbent (seat hight 20 cm, with tail fairing) 31.6 135 recumbent (seat 20 cm, with full fairing, soft material) 42.8 75 recumbent (very aerodynamic hard fairing) The difference between DF/uprights and unfaired lowracers is significant; but the difference between unfaired and fully-faired lowracers is just amazing. Yes, folks, according to this study, that same 75 watts of power that produces ~10 mph on your hybrid upright bike would have you screaming along at 25 mph in a fully-faired lowracer. Wow. The difference in aero efficiency between an upright/DF racing bike and an unfaired high-racer recumbent is about 23% at 25mph. From my observations riding alongside a Bacchetta Strada in fast club rides, this seems about right. The Bacchetta owner in our local club, Bruce, is able to pull a paceline longer than all but the very strongest DF riders (and at higher speeds). He's fresher and much more animated at the end of the race - er, I mean ride ;-) - and continues chatting pleasantly at speeds that make the DF riders (including myself) hunker down and groan with pain. I pulled a muscle trying to keep up with Bruce this summer on my lovely new Soulcraft road bike. I could see that it aggravated the competitive riders when Bruce would cruise up from the back at 28mph and pleasantly chat with them as he slotted into the lead to pull for a while. Bruce gets a kick out of it, for sure. Once we get past the aero advantage issues, the next topic is riding position. Open vs. closed: which is better for making power?Personally, I'm of the belief that a closed position is faster. I think I'm in good company here. Then there's high BB vs. low BB. I've ridden them all, and I don't know which one is faster (if any). I think once you get your legs out in front of you, it's all about the same. Any speed advantages probably have more to do with cardiovascular advantages. Just a guess. Anybody have any good data on this topic? Since I'm getting ready to buy a Velokraft carbon lowracer, I'm revisiting this topic. When my DF riding buddies want to know why I ride a lowracer, it's nice to have some data to help make my case. One look at all that beautiful carbon weave and I don't think there will be too many dissenting voices. -=Barry=- 2000 RANS Rocket Coming Soon: 2003 Velokraft |
Unfaired Recumbent vs. Upright Speed Comparisons
I just know my top cruising speed went up 10-15% from a carbon fiber racing
upright to a dual suspended steel semi-low racer. Interesting gain with the tail fairing though. "B. Sanders" wrote in message news:lLoob.49717$mZ5.311118@attbi_s54... We all know that fully-faired recumbents own all of the human powered speed records. But what about unfaired recumbents vs. upright (DF) bikes? Here's an interesting web page which cites several experiments attempting to answer this question. It includes thoughtful narrative from several riders who offer sincere observations on the topic. http://www.neci.nj.nec.com/homepages...a/compare.html From the data available on Sandiway Fong's website, it looks like the aero efficiency (speed vs. power input) of unfaired high-racers, quasi-lowracers and lowracer recumbents differs only slightly from each other; but produces a noticeable speed advantage over DF bikes (at a given power output). Hard shell fully faired recumbents, as one would imagine, really start to show off their superior aero advantage in the upper extremes of speed (40mph+). Here is a chart excerpted from Mr. Fong's website (I didn't see any copyright declarations, so I hope it's OK.) V = velocity at a constant power output of 250 W P = power needed to maintain constant speed of 40 km/h (~25mph) V(mph) P(W) Bike Description 19.8 469 road bike (touring position) 21.7 362 road bike (racy position) 23.9 277 recumbent (seat hight 60 cm) 24.5 259 recumbent (seat hight 40 cm) 25.4 234 recumbent (seat hight 20 cm = low racer) 27.9 180 recumbent (seat hight 20 cm, with tail fairing) 31.6 135 recumbent (seat 20 cm, with full fairing, soft material) 42.8 75 recumbent (very aerodynamic hard fairing) The difference between DF/uprights and unfaired lowracers is significant; but the difference between unfaired and fully-faired lowracers is just amazing. Yes, folks, according to this study, that same 75 watts of power that produces ~10 mph on your hybrid upright bike would have you screaming along at 25 mph in a fully-faired lowracer. Wow. The difference in aero efficiency between an upright/DF racing bike and an unfaired high-racer recumbent is about 23% at 25mph. From my observations riding alongside a Bacchetta Strada in fast club rides, this seems about right. The Bacchetta owner in our local club, Bruce, is able to pull a paceline longer than all but the very strongest DF riders (and at higher speeds). He's fresher and much more animated at the end of the race - er, I mean ride ;-) - and continues chatting pleasantly at speeds that make the DF riders (including myself) hunker down and groan with pain. I pulled a muscle trying to keep up with Bruce this summer on my lovely new Soulcraft road bike. I could see that it aggravated the competitive riders when Bruce would cruise up from the back at 28mph and pleasantly chat with them as he slotted into the lead to pull for a while. Bruce gets a kick out of it, for sure. Once we get past the aero advantage issues, the next topic is riding position. Open vs. closed: which is better for making power?Personally, I'm of the belief that a closed position is faster. I think I'm in good company here. Then there's high BB vs. low BB. I've ridden them all, and I don't know which one is faster (if any). I think once you get your legs out in front of you, it's all about the same. Any speed advantages probably have more to do with cardiovascular advantages. Just a guess. Anybody have any good data on this topic? Since I'm getting ready to buy a Velokraft carbon lowracer, I'm revisiting this topic. When my DF riding buddies want to know why I ride a lowracer, it's nice to have some data to help make my case. One look at all that beautiful carbon weave and I don't think there will be too many dissenting voices. -=Barry=- 2000 RANS Rocket Coming Soon: 2003 Velokraft |
Unfaired Recumbent vs. Upright Speed Comparisons
"Robert Haston" wrote in message
link.net... I just know my top cruising speed went up 10-15% from a carbon fiber racing upright to a dual suspended steel semi-low racer. Actually, I didn't experience that same increase in speed when going from an upright to a lowracer recumbent, which was surprising. I bought an M5 Lowracer last year, with the expectation of noticeable speed gains over all my other bikes (including a Ryan Vanguard LWB). The speed gains didn't happen. Going into a strong headwind, the M5 Lowracer was incredibly aero-efficient. In every other situation, the M5 was about the same or somewhat slower (that is, for a perceived output power). That's not what I expected. My hypothesis is that the M5 was certainly capable of being faster; but my muscles were producing less power for a given perceived effort due to the high BB, which I wasn't accustomed to. So, I worked just as hard, but produced less power on the M5. I know I can produce a *lot* of power on an upright road bike in a sprint, and can hit speeds that I never even approached on the M5. With the obvious differences in aero advantage between lowracers and DF's at those speeds (32 mph+), it's clear that there was something amiss with my power production on the M5. This is what I'm curious about with the Velokraft: Will I be able to produce power on it, and actually take advantage of its superior aerodynamics? Or will I produce less power than I do on my upright/DF road bike, and fail to see any significant speed benefits? This is the question that I intend to answer through experimentation. Interesting gain with the tail fairing though. Yes, very interesting. Quite significant, and without impeding the practical use of the bike as a full fairing could. A tail fairing would be a nice performance addition to a Velokraft; but it's a shame to ruin those gorgeous, flowing lines. I'm already thinking about a full carbon fairing, though, for special occasions, like fast club rides ;-) My neighbor across the alley is a carbon fabricator (as a hobby). He produced carbon fiber wheelchairs for some Olympic athletes a while back, and knows all about fabbing carbon in a garage with minimal expense and tools. A blown plastic fairing (like the WISIL guys produce) would be another option. I'm curious to know what it's like to cruise on a recumbent at 43 mph on level ground :-) -=Barry=- "B. Sanders" wrote in message news:lLoob.49717$mZ5.311118@attbi_s54... We all know that fully-faired recumbents own all of the human powered speed records. But what about unfaired recumbents vs. upright (DF) bikes? Here's an interesting web page which cites several experiments attempting to answer this question. It includes thoughtful narrative from several riders who offer sincere observations on the topic. http://www.neci.nj.nec.com/homepages...a/compare.html From the data available on Sandiway Fong's website, it looks like the aero efficiency (speed vs. power input) of unfaired high-racers, quasi-lowracers and lowracer recumbents differs only slightly from each other; but produces a noticeable speed advantage over DF bikes (at a given power output). Hard shell fully faired recumbents, as one would imagine, really start to show off their superior aero advantage in the upper extremes of speed (40mph+). Here is a chart excerpted from Mr. Fong's website (I didn't see any copyright declarations, so I hope it's OK.) V = velocity at a constant power output of 250 W P = power needed to maintain constant speed of 40 km/h (~25mph) V(mph) P(W) Bike Description 19.8 469 road bike (touring position) 21.7 362 road bike (racy position) 23.9 277 recumbent (seat hight 60 cm) 24.5 259 recumbent (seat hight 40 cm) 25.4 234 recumbent (seat hight 20 cm = low racer) 27.9 180 recumbent (seat hight 20 cm, with tail fairing) 31.6 135 recumbent (seat 20 cm, with full fairing, soft material) 42.8 75 recumbent (very aerodynamic hard fairing) The difference between DF/uprights and unfaired lowracers is significant; but the difference between unfaired and fully-faired lowracers is just amazing. Yes, folks, according to this study, that same 75 watts of power that produces ~10 mph on your hybrid upright bike would have you screaming along at 25 mph in a fully-faired lowracer. Wow. The difference in aero efficiency between an upright/DF racing bike and an unfaired high-racer recumbent is about 23% at 25mph. From my observations riding alongside a Bacchetta Strada in fast club rides, this seems about right. The Bacchetta owner in our local club, Bruce, is able to pull a paceline longer than all but the very strongest DF riders (and at higher speeds). He's fresher and much more animated at the end of the race - er, I mean ride ;-) - and continues chatting pleasantly at speeds that make the DF riders (including myself) hunker down and groan with pain. I pulled a muscle trying to keep up with Bruce this summer on my lovely new Soulcraft road bike. I could see that it aggravated the competitive riders when Bruce would cruise up from the back at 28mph and pleasantly chat with them as he slotted into the lead to pull for a while. Bruce gets a kick out of it, for sure. Once we get past the aero advantage issues, the next topic is riding position. Open vs. closed: which is better for making power?Personally, I'm of the belief that a closed position is faster. I think I'm in good company here. Then there's high BB vs. low BB. I've ridden them all, and I don't know which one is faster (if any). I think once you get your legs out in front of you, it's all about the same. Any speed advantages probably have more to do with cardiovascular advantages. Just a guess. Anybody have any good data on this topic? Since I'm getting ready to buy a Velokraft carbon lowracer, I'm revisiting this topic. When my DF riding buddies want to know why I ride a lowracer, it's nice to have some data to help make my case. One look at all that beautiful carbon weave and I don't think there will be too many dissenting voices. -=Barry=- 2000 RANS Rocket Coming Soon: 2003 Velokraft |
Unfaired Recumbent vs. Upright Speed Comparisons
"B. Sanders" skrev Yes, very interesting. Quite significant, and without impeding the practical use of the bike as a full fairing could. A tail fairing would be a nice performance addition to a Velokraft; but it's a shame to ruin those gorgeous, flowing lines. Ah ruin schmuin ;o) http://community.webshots.com/photo/...95148217fwrVir M. |
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