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

"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

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

"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=-

[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!

I read some of the "negative" commentary by the long distance rider
about his relative speeds ufaired bent vs. DF. When you consider he
was riding an unfaired Tour Easy, it's no wonder he was a bit
disappointed. He could have picked a MUCH faster unfaired bike.
Something like a Ti Aero would give him the kind of performance he was
looking for. Also, I wonder why he didn't use a fairing? Some
regulation for the rides he was doing? Put a Zzipper and sock on the
TE, and he'd be a much happier camper. It seems to me that one of the
great thing about so many bent designs is that one can mount a very
effective fairing so easily. If you can't beat 'em, put on a fairing
and a sock, and beat 'em!

Scott



(Scott) wrote in message . com...
Thanks, Barry. Very interesting!

Scott



"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

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

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

"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

"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.