Dr. Diesel has checked in

DieselFan · Post by **DieselFan** » Wed Nov 17, 2004 4:38 pm

For 100 dollars Dr. Deisel, what is your name?

uhhh

10 seconds Dr Deisel

Hmmm...I was earning some money...but I'm back now. Dr. Diesel, would be Dr. Scott Diesel. Enjoying my relative anonymity...I will not reveal the 'real' last name.

JansenFan · Post by **JansenFan** » Wed Nov 17, 2004 4:49 pm

DieselFan wrote:
For 100 dollars Dr. Deisel, what is your name?

uhhh

10 seconds Dr Deisel

Hmmm...I was earning some money...but I'm back now. Dr. Diesel, would be Dr. Scott Diesel. Enjoying my relative anonymity...I will not reveal the 'real' last name.

Sorry, I was actually referring to a skit from Cheech and Chong called "Let's Make a Dope Deal", in which the player Bob is asked his name to win the game....at the end of time, they say 10 seconds Bob to which he answer....uuuhhh bob? BOB!!!

Funny stuff, but only if you have heard it :lol:

As far as being named Scott, that still afford you relative anonymity here, as about 25% of theHogs.net members are apparently named Scott. :lol:

NC43Hog · Post by **NC43Hog** » Wed Nov 17, 2004 5:14 pm

I found a picture of the DieselFan:

Quite the leaper!

General Failure · Post by **General Failure** » Wed Nov 17, 2004 5:15 pm

Is it wrong to kill a mime with your bare hands when they look at you?

tcwest10 · Post by **tcwest10** » Wed Nov 17, 2004 11:43 pm

Yes, but it is perfectly legal to drive him crazy by playing a blank tape at full blast all night long.

DieselFan · Post by **DieselFan** » Thu Nov 18, 2004 10:54 am

NC43Hog wrote:I found a picture of the DieselFan:

Quite the leaper!

There goes my anonymity!!!! Damn!

DieselFan · Post by **DieselFan** » Thu Nov 18, 2004 10:55 am

General Failure wrote:Is it wrong to kill a mime with your bare hands when they look at you?

It is never wrong to kill a mime...in any fashion. Bonus points for killing a French one.

JansenFan · Post by **JansenFan** » Thu Nov 18, 2004 12:22 pm

DieselFan wrote:
General Failure wrote:Is it wrong to kill a mime with your bare hands when they look at you?

It is never wrong to kill a mime...in any fashion. Bonus points for killing a French one.

Or if you can do it while there in the little box or walking against the wind.

tazlah · Post by **tazlah** » Thu Nov 18, 2004 2:18 pm

What is the air-speed velocity of an unlaiden swallow? :hmm:

DieselFan · Post by **DieselFan** » Thu Nov 18, 2004 3:12 pm

tazlah wrote:What is the air-speed velocity of an unlaiden swallow?

Hmmm...let me provide an indepth analysis:

To begin with, I needed basic kinematic data on African and European swallow species.

South African Swallow
(Hirundo spilodera) European Swallow
(Hirundo rustica)
Although 47 of the 74 worldwide swallow species are found in Africa,1 only two species are named after the continent: the West African Swallow (Hirundo domicella) and the South African Swallow (Hirundo spilodera), also known as the South African Cave Swallow.

Since the range of the South African Swallow extends only as far north as Zaire,2 I felt fairly confident that this was the non-migratory African species referred to in previous discussions of the comparative and cooperative weight-bearing capabilities of African and European swallows.3

Kinematic data for both African species was difficult to find, but the Barn or European Swallow (Hirundo rustica) has been studied intensively, and kinematic data for that species was readily available.

It's a simple question of weight ratiosA 54-year survey of 26,285 European Swallows captured and released by the Avian Demography Unit of the University of Capetown finds that the average adult European swallow has a wing length of 12.2 cm and a body mass of 20.3 grams.4

Because wing beat frequency and wing amplitude both scale with body mass,5 and flight kinematic data is available for at least 22 other bird species,6 it should be possible to estimate the frequency (f ) and amplitude (A) of the European Swallow by a comparison with similar species. With those two numbers, it will be possible to estimate airspeed (U).

In order to maintain airspeed velocity, a swallow needs to beat its wings forty-three times every second, right?Actually, wrong. By comparing the European Swallow with bird species of similar body mass, we can estimate that the swallow beats its wings 18 times a second with an amplitude of 18 cm:

Species Body mass Frequency Amplitude
Zebra Finch 13 g 27 Hz 11 cm
European Swallow 20 g ¡Ö 18 Hz? ¡Ö 18 cm?
Downy Woodpecker 27 g 14 Hz 29 cm
Budgerigar 34 g 14 Hz 15 cm

Note that even the tiny Zebra Finch flaps its wings no more than 27 times a second while cruising.

If we ignore body mass and look only at bird species with a similar wingspan, we can estimate an average frequency of 14 beats per second and an amplitude of 23 cm:

Species Wingspan Frequency Amplitude
Budgerigar 27 cm 14 Hz 15 cm
European Swallow ¡Ö 28¨C30 cm ¡Ö 14 Hz? ¡Ö 23 cm?
Downy Woodpecker 31 cm 14 Hz 29 cm
European Starling 35 cm 14 Hz 26 cm

By averaging all 6 values, we can estimate that an average European Swallow flies at cruising speed with a frequency of roughly 15 beats per second, and an amplitude of roughly 22 cm.

Skip a bit, BrotherLast month¡¯s article on The Strouhal Number in Cruising Flight showed how simplified flight waveforms that graph amplitude versus wavelength can be useful for visualizing the Strouhal ratio (fA/U), a dimensionless parameter that tends to fall in the range of 0.2¨C0.4 during efficient cruising flight.

For a European Swallow flying with our estimated wingbeat amplitude of 24 cm, the predicted pattern of cruising flight ranges from a Strouhal number (St) of 0.2:

... to a less efficient 0.4:

If the first diagram (St = 0.2) is accurate, then the cruising speed of the European Swallow would be roughly 16 meters per second (15 beats per second * 1.1 meters per beat). If the second diagram (St = 0.4) is accurate, then the cruising speed of the European Swallow would be closer to 8 meters per second (15 beats per second * 0.55 meters per beat).

If we settle on an intermediate Strouhal value of 0.3:

We can estimate the airspeed of the European Swallow to be roughly 11 meters per second (15 beats per second * 0.73 meters per beat).

Three shall be the number thou shalt countAirspeed can also be predicted using a published formula. By inverting this midpoint Strouhal ratio of 0.3 (fA/U ¡Ö 0.3), Graham K. Taylor et al. show that as a rule of thumb, the speed of a flying animal is roughly 3 times frequency times amplitude (U ¡Ö 3fA).5

We now need only plug in the numbers:

U ¡Ö 3fA
f ¡Ö 15 (beats per second)
A ¡Ö 0.22 (meters per beat)
U ¡Ö 3*15*0.22 ¡Ö 9.9
... to estimate that the airspeed velocity of an unladen European Swallow is 10 meters per second.

Oh, yeah, I agree with thatWith some further study, it became clear that these estimates are accurate, though perhaps coincidental.

An actual study of two European Swallows flying in a low-turbulence wind tunnel in Lund, Sweden, shows that swallows flap their wings much slower than my estimate, at only 7¨C9 beats per second:

°Compared with other species of similar size, the swallow has quite low wingbeat frequency and relatively long wings.¡± 7
The maximum speed the birds could maintain was 13¨C14 meters per second, and although the Lund study does not discuss cruising flight in particular, the most efficient flapping (7 beats per second) occurred at an airspeed in the range of 8¨C11 meters per second, with an amplitude of 90¨C100¡ã (17¨C19 cm).

And there was much rejoicingAveraging the above numbers and plugging them in to the Strouhal equation for cruising flight (fA/U = 7 beats per second * 0.18 meters per beat / 9.5 meters per second) yields a Strouhal number of roughly 0.13:

... indicating a surprisingly efficient flight pattern falling well below the expected range of 0.2¨C0.4.

Although a definitive answer would of course require further measurements, published species-wide averages of wing length and body mass, initial Strouhal estimates based on those averages and cross-species comparisons, the Lund wind tunnel study of birds flying at a range of speeds, and revised Strouhal numbers based on that study all lead me to estimate that the average cruising airspeed velocity of an unladen European Swallow is roughly 11 meters per second, or 24 miles an hour.

Whew! My fingers are hurting from typing all that. Next Question!

tcwest10 · Post by **tcwest10** » Thu Nov 18, 2004 5:27 pm

So, what's that ? Like, pretty fast ?

REDEEMEDSKIN · Post by **REDEEMEDSKIN** » Fri Nov 19, 2004 3:49 pm

If quizzes are quizzical, what are tests?

cvillehog · Post by **cvillehog** » Fri Nov 19, 2004 3:49 pm

REDEEMEDSKIN wrote:If quizzes are quizzical, what are tests?

Testy.

General Failure · Post by **General Failure** » Fri Nov 19, 2004 3:50 pm

There's this giant fireball in the sky that hurts my eyes when I look at it. What is this, and will it kill me?

REDEEMEDSKIN · Post by **REDEEMEDSKIN** » Fri Nov 19, 2004 3:54 pm

cvillehog wrote:
REDEEMEDSKIN wrote:If quizzes are quizzical, what are tests?

Testy.

Waiting on official word from Dr. Diesel, the source for all things testic....involving tests. :lol:

JansenFan · Post by **JansenFan** » Fri Nov 19, 2004 3:56 pm

Is it true that if you are near a volcano and it erupts, you should duck and cover?

Texas Hog · Post by **Texas Hog** » Fri Nov 19, 2004 6:34 pm

Can man destroy the earth?

General Failure · Post by **General Failure** » Fri Nov 19, 2004 6:35 pm

Is pepperspray really just another word for love?

tcwest10 · Post by **tcwest10** » Fri Nov 19, 2004 11:22 pm

Huh.
Must be a golf course nearby.

NC43Hog · Post by **NC43Hog** » Sat Nov 20, 2004 6:36 pm

Is it true you CAN really get TOO much of a GOOD thing?

1niksder · Post by **1niksder** » Sat Nov 20, 2004 8:02 pm

Even at TheHog.net you have to wait forever before the doctor will see you :explode:

General Failure · Post by **General Failure** » Sat Nov 20, 2004 10:55 pm

Damn HMOs.

tcwest10 · Post by **tcwest10** » Sun Nov 21, 2004 12:47 am

I'm so bitter, I'm gonna try and sneak out past the receptionist without taking care of my co-pay.
The least he could've done was leave some old magazines around.
Not so much as a Jehovah pamphlet.

General Failure · Post by **General Failure** » Sun Nov 21, 2004 1:50 am

*hides the only copy of Highlights for Children*

... Yes, no magazines ...

JansenFan · Post by **JansenFan** » Mon Nov 22, 2004 9:21 am

General Failure wrote:Damn HMOs.

Please leave sexual preference out of it :lol: