serial_thrilla
Premium Platinum
- Mar 25, 2014
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NaturalDisaster: Stop. Who would cross the Bridge of Death and submit their team sheets must answer me these questions three, ere the other side he see.
MWPP: Ask me the questions, bridgekeeper. I am not afraid.
NaturalDisaster: What... is your name?
MWPP: My name is MWPP of the Las Vegas Bears.
NaturalDisaster: What... is your quest?
MWPP: To submit my team sheet.
NaturalDisaster: What... is your favourite colour?
MWPP: Blue.
NaturalDisaster: Right. Off you go.
MWPP: Oh, thank you. Thank you very much. [Submits team sheet]
Cadsky: That's easy! [The other captains all rush to the team sheet thread]
NaturalDisaster: Stop. Who approacheth the Bridge of Death must answer me these questions three, ere the other side he see.
Cadsky: Ask me the questions, NaturalDisaster. I'm not afraid.
NaturalDisaster: What... is your name?
Cadsky: Cadsky of the West Coast Wonders.
NaturalDisaster: What... is your quest?
Cadsky: To submit my team sheet.
NaturalDisaster: What... is the difference between the first and second interchange player? [pause]
Cadsky: I don't know that! [he is thrown over the edge into the ravine by an unseen force] AUUUUUUUUGGGH!
[TheInjuryFactory prepares to cross, and the NaturalDisaster stops him]
NaturalDisaster: Stop. What... is your name?
TheInjuryFactory: TheInjuryFactory of the Coney Island Warriors.
NaturalDisaster: What... is your quest?
TheInjuryFactory: I seek to submit my team sheet.
NaturalDisaster: Who... is your favourite Bomber?
TheInjuryFactory: BLUEALLTHRU —no! [he is also thrown over the edge] KOHPHIIIIIIIIIIIIIIIIIIIIII!
NaturalDisaster: [Chuckling at TheInjuryFactory's demise, then turns to serial_thrilla] Stop. What... is your name?
serial_thrilla: It is serial_thrilla, Captain of the Dragons.
NaturalDisaster: What... is your quest?
serial_thrilla: To submit my team sheet.
NaturalDisaster: What... is the air-speed velocity of an unladen A Swallow?
serial_thrilla: What do you mean? An African or a European A Swallow?
To begin with, we need basic kinematic data on African and European A Swallow species: Although 47 of the 74 worldwide A Swallow species are found in Africa, only two species are named after the continent: the West African A Swallow (Hirundo domicella) and the South African A Swallow (Hirundo spilodera), also known as the South African Cave A Swallow.
Since the range of the South African A Swallow extends only as far north as Zaire, I am 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 A Swallows.
Left: South African A Swallow
Right: European A Swallow
Kinematic data for both African species is difficult to find, but the Barn or European A Swallow (Hirundo rustica) has been studied intensively, and kinematic data for that species was readily available.
We must then consider weight ratios. A 54-year survey of 26,285 European A Swallows captured and released by the Avian Demography Unit of the University of Capetown finds that the average adult European A Swallow has a wing length of 12.2 cm and a body mass of 20.3 grams.
Because wing beat frequency and wing amplitude both scale with body mass, and flight kinematic data is available for at least 22 other bird species, it should be possible to estimate the frequency (f ) and amplitude (A) of the European A Swallow by a comparison with similar species. With those two numbers, it will be possible to estimate airspeed (U).
By comparing the European A 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 | ≈ 18 Hz? | ≈ 18 cm? |
| Downy Woodpecker | 27 g | 14 Hz | 29 cm |
| Budgerigar | 34 g | 14 Hz | 15 cm |
| Species | Body mass | Frequency | Amplitude |
| Zebra Finch | 13 g | 27 Hz | 11 cm |
| European Swallow | 20 g | ≈ 18 Hz? | ≈ 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 | ≈ 28–30 cm | ≈ 14 Hz? | ≈ 23 cm? |
| Downy Woodpecker | 31 cm | 14 Hz | 29 cm |
| European Starling | 35 cm | 14 Hz | 26 cm |
| Species | Wingspan | Frequency | Amplitude |
| Budgerigar | 27 cm | 14 Hz | 15 cm |
| European Swallow | ≈ 28–30 cm | ≈ 14 Hz? | ≈ 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 A Swallow flies at cruising speed with a frequency of roughly 15 beats per second, and an amplitude of roughly 22 cm.
Now, 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 0.2–0.4 during efficient cruising flight.
For a European A 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 A 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 A 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 A Swallow to be roughly 11 meters per second (15 beats per second * 0.73 meters per beat).
We can also calculate that A Swallow will be playing his 150th SFA game this weekend, and will qualify for Dragons FFC Life Membership.
NaturalDisaster: Huh? I... I don't know that. [he is thrown over by his own spell] AUUUUUUUGGGGGGGGGGGHHH!!
Barrybran: How do you know so much about A Swallows?
serial_thrilla: Well, you have to know these things when you're a captain, you know. [serial_thrilla and Barrybran begin to submit their team sheets]
A Swallow SFA Statistics
| Games | 149 |
| Club(s) | SDR |
| Hitouts | 29 |
| Kicks | 991 |
| Marks | 307 |
| Handballs | 918 |
| Tackles | 277 |
| Frees For | 143 |
| Frees Against | 102 |
| Goals | 98 |
| Behinds | 58 |
| Disposals | 1909 |
| Dreamteam Points | 7350 |
| Mobbs Medal Votes | 22/13 |
| W-D-L | 76-4-69 |
| Games | 149 |
| Club(s) | SDR |
| Hitouts | 29 |
| Kicks | 991 |
| Marks | 307 |
| Handballs | 918 |
| Tackles | 277 |
| Frees For | 143 |
| Frees Against | 102 |
| Goals | 98 |
| Behinds | 58 |
| Disposals | 1909 |
| Dreamteam Points | 7350 |
| Mobbs Modal Votes | 22/13 |
| W-D-L | 76-4-69 |
Debut
Season 21, Round 01 - (Dragons FFC) vs. Gold City Royals
Awards
SFA Premiership Player (S28)
Dragons FFC Heritage Round Team Selection (S30)
Dragons FFC Best Rookie [Blaze Storm Medal] (S21)
Dragons FFC Best Clubman [Pie 4 Life Medal] (S29, S30)
Highest DreamTeam Points:
114 DT Points - Season 30, Round 05 - Roys FFC vs. (Dragons FFC)
100+ DreamTeam Points:
x6 occasions
Highest Disposals:
32 Disposals - Season 21, Round 11 - Gumbies FFC vs. (Dragons FFC)
20+ Disposals:
x32 occasions
Highest Goals:
5 Goals - Season 29, Round 12 - West Coast Wonders vs. (Dragons FFC)
Highest Tackles:
11 Tackles - Season 30, Round 05 - Roys FFC vs. (Dragons FFC)
(thanks to Hate for these statistics)
Good luck for the weekend, A Swallow! Go Dragons!
Season 21, Round 01 - (Dragons FFC) vs. Gold City Royals
Awards
SFA Premiership Player (S28)
Dragons FFC Heritage Round Team Selection (S30)
Dragons FFC Best Rookie [Blaze Storm Medal] (S21)
Dragons FFC Best Clubman [Pie 4 Life Medal] (S29, S30)
Highest DreamTeam Points:
114 DT Points - Season 30, Round 05 - Roys FFC vs. (Dragons FFC)
100+ DreamTeam Points:
x6 occasions
Highest Disposals:
32 Disposals - Season 21, Round 11 - Gumbies FFC vs. (Dragons FFC)
20+ Disposals:
x32 occasions
Highest Goals:
5 Goals - Season 29, Round 12 - West Coast Wonders vs. (Dragons FFC)
Highest Tackles:
11 Tackles - Season 30, Round 05 - Roys FFC vs. (Dragons FFC)
(thanks to Hate for these statistics)
Good luck for the weekend, A Swallow! Go Dragons!
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