Is the Peregrine Falcon's Supersonic Speed a Myth?

[1colonel]

Every where one reads that Peregrine Falcons can reach speeds of 200+ mph. This seems impossible given the huge amount of air resistance at such speed. Is such possible or is this urban legend?

 

[phinds]

"Everywhere" is not a recognized citation on this forum.

 

[Nugatory]

A human in free fall can reach speeds well in excess of 100 mph, and a peregrine falcon has an appreciably more aerodynamic shape than a human. So the claim is not absurd on the face of it.

 

[A.T.]

Every where one reads that Peregrine Falcons can reach speeds of 200+ mph. This seems impossible given the huge amount of air resistance at such speed.

These are peak dive speeds. In level flight a falcon isn't much faster than a pigeon.

 

[dauto]

It's not urban legend.

 

[phinds]

A human in freefall has broken the sound barrier, so 200mph doesn't seem impossible.

He went almost 1,000 mph (mach 1.2+ as I recall)

http://www.telegraph.co.uk/science/space/9607604/Skydiver-Felix-Baumgartner-attempts-to-break-sound-barrier-live.html

 

[Baluncore]

Firstly, welcome to PF.

This seems impossible given the huge amount of air resistance at such speed.

Air resistance at 200 mph is only 4 times that at 100 mph.

Is such possible or is this urban legend?

There may be many quotes, claims or assumptions that 200 mph is possible.
Until a reference to an accurate measurement is found, the claim must be treated as unreliable.

Given[/PLAIN] enough time, ideal falcons can reach top speeds of 89-112 m s-1 in a vertical dive, the higher speed for the heaviest bird, when the parasite drag coefficient has a value of 0.18.

200 mph = 89.4 m/sec, so yes, it does appear to be technically possible.

http://jeb.biologists.org/content/201/3/403.short
Download the free PDF from the above link.

– estimates of top speeds range up to 157ms-1 (351 miles h-1) (Brown, 1976; Clark, 1995; Dement’ev, 1951; Hantge, 1968; Lawson, 1930; Mebs, 1975; Orton, 1975; Savage, 1992; Tucker and Parrott, 1970).
While these estimates may be correct, their accuracy is unknown because the speed of a diving falcon is difficult to measure. The required instrumentation is complex, and the dive is a brief, rare event that takes place at unpredictable places and times, usually at a long distance from the observer. Alerstam (1987) used radar to overcome these difficulties, and he measured diving speeds of no more than 39ms-1 in a peregrine. Clark (1995) doubts that diving speeds exceed 41ms-1.

Someone must have put a GPS tracker on a falcon by now.
It is a case of web searching or following a citations index in the hope of finding that article.

 

[CWatters]

 

[Baluncore]

CWatters
I don't have video bandwidth here, how about a synopsis of the video.

 

[sophiecentaur]

It's in the Guinness Book of Records. If that's not a reputable source then what is?

 

[PeroK]

CWatters
I don't have video bandwidth here, how about a synopsis of the video.

Falcon released from aircraft at 12,000 ft dives at 240mph.

Crazy Brit, complete with obligatory Union Jack crash helmet and specially designed suit, makes like a giant falcon and reaches 300 mph in free fall.

 

[AlephZero]

CWatters
I don't have video bandwidth here, how about a synopsis of the video.

http://www.airspacemag.com/flight-today/falling-with-the-falcon-7491768/?no-ist

Max speed: 240 mph.

 

[sophiecentaur]

Falcon released from aircraft at 12,000 ft dives at 240mph.

Crazy Brit, complete with obligatory Union Jack crash helmet and specially designed suit, makes like a giant falcon and reaches 300 mph in free fall.

Saucy! Most Americans seem to use the 'obligatory' Stars and Stripes whenever possible - even outside their houses. You only find that in the UK during World Cup Fever. We are sooo laid back about these things.

 

[Nugatory]

Saucy! Most Americans seem to use the 'obligatory' Stars and Stripes whenever possible - even outside their houses. You only find that in the UK during World Cup Fever. We are sooo laid back about these things.

OK, it's off-topic, but I have to offer up a line I heard in a duplicate bridge tournament many years ago: "Only mad dogs and Englishmen bid like that... and you're no subject of the queen".

 

[sophiecentaur]

OK, it's off-topic, but I have to offer up a line I heard in a duplicate bridge tournament many years ago: "Only mad dogs and Englishmen bid like that... and you're no subject of the queen".

 

[Baluncore]

The semiotics of flags can be fascinating.
There is an interesting sub-conscious parallel here. A falcon flies, as does a sky diver, the flag also flies.

In the USA, flying the Stars and Stripes demonstrated acceptance that the “recent unpleasantness” of the civil war was over. Anyone now not flying the Stars and Stripes is seen as divisive and as an enemy of the economy, which includes the disadvantaged, who cannot afford a flag or a pole to fly it from.

In Britain, Everyone except the aristocracy was impoverished, so the Union Jack was not needed on every home in the country. There had always been sufficient nationalistic enemies in Europe to unite Britain and maintain the class structure. The rise of the United States of Europe may encourage a resurgence of the Union Jack in Britain as part of a marketing campaign.