# Science, Woodpeckers and flight without wings

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Played a game of Trivial Pursuit, got a question going: How fast does a Woodpecker peck?

The answer said 2000 km/h (If you're running on miles, do the math yourself :).

Googled a bit and alot of information stated that a woodpecker can peck 15-20 times a second, and if the distance is about 14cm a peck that makes the 2000 km/h.
Another piece of information said a woodpecker will be able to peck continuously for upto one hour.

Giving these facts my question is, would a woodpecker be able to create enough updraft by pecking to fly without using it's wings?

GoJoe
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Commented:
15-20 times per second sounds correct.

14 cm (5.5 inches) sounds wild.  2000km/hr is breaking the sound barrier.

I would believe 14 mm (0.5 inches).  200 km/hr is like a major league fast ball.

Although there is a substantial amount of energy in the pecking, you need the proper shape
a wing or airfoil) to generate lift.  I doubt that a woodpecker's has evolved for that purpose.
Commented:
This site (which is no easier to trust) tends to support the Trivial Pursuit numbers:

http://www.everything2.com/index.pl?node=woodpecker

>>   1200g = 1200 x 9.8 m/s^2  =  11,760 m/s^2

If you assume the decelleration happens in 1/40th of a second (half of a 1/20th of a second peck)

Avg speed  =  (11,760/40) m/s  =  294 m/s  =  (294 x 3.6) km/h  =  1058 km/hr

The shape of his head is still going to be a problem though.
Commented:
Trivial Pursuit is not a superb source of factual information.   IIRC it's had lots of wrong info, like you can see the Wall of China from orbit, or from the Moon.  One intentional mistake, Columbo's first name.

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Commented:
at 2000km/hr, which I don't believe, shape of a woodpecker's head, or almost any shape, could generate enough lift to fly.
It would also generate enough drag that I doubt a that bird that hadn't evolved to deal with the decelleration that a woodpecker's head undergoes would survive it.

Commented:
So Ozo,

What you're saying is - that if we were to believe the 2000 km/hr, the woodpecker could fly without using it wings, but the landing would kill it??
Commented:
The total length of the largest wood pecker is less than 50 cm. So 14 cm peck is wrong. It will be only a fraction of it.

Scientifically, the velocity at impact of the woodpecker beak is calculated as 600 to 700 cm/s
(which is about 21.6 - 25.2 kilometer/hour).
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=pubmed&cmd=Retrieve&dopt=AbstractPlus&list_uids=454236&query_hl=3&itool=pubmed_docsum
Commented:
I am quite embarrassed by the deceleration calculations in my second post.

The 1200 g peak value could be correct.
But the deceleration time is certainly much less than a 40th of a second.

neopolitan's numbers make much more sense.
Commented:
>>>almost any shape, could generate enough lift to fly.
Not true. Lift is caused by the shape as well as the velocity. If wing is reversed, it causes downforce (used previously in F1 racing cars)
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Commented:
I did say "almost" any, and the shape of an F1 racing car in the proper orientation could generate enough lift to fly if you pushed it hard enough.

The landing at 2000 km/hr might kill it, if it hadn't already been killed by the air resistance.
Commented:
2000 km/hr is faster than the speed of sound. The woodpecker's beak would make a sonic boom.
Commented:
2000 km/hr is more than mach 3.
Animal organs can survive up to about 50g acceleration.
Woodpeckers are very selective in pecking. Never peck continuously, and rarely healty solid wood.
Commented:
zero to mach 3 (at sea level) and back to zero again, in a 40th of a second. I think the woodpecker would probably burst into flames instantaneously, in the same way that santa would to be able to deliver all his presents on christmas eve.

:)

Commented:
i want someone to calculate the energy needed to accerlate a mass the size of Woodies head from 0 to 2000kph, then give me the power nessisary to do this in 1/20th of a second?
Commented:
Its been a while since my last math class, but...

1/20th of a second is the total cycle time. back -> forward -> back again... so its 1/40th of a second for his head to be fully back and then fully forward... so an average of 2000kph over the 40th of a second, meaning 0kph->4000kph->0kph...

4,000kph -> 1,111.11m/s
->88,888.89m/s/s (for 1/80th of a second acceleration then the same deceleration in 1/40s)
->9,070g

Woody is toast.

Commented:
it seemed like he'd a bigger radiator than you normally seen on woodpeckers. thanx for doing the math nigel5.

Commented:
As you can see I've been pleased by so many of the contributors so I divided the points like a politician how never knows which side to support without checking up on a poll first :-)

/GoJoe

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