From: Chris Malcolm on
In rec.photo.digital Neil Harrington <secret(a)illumnati.net> wrote:
> Chris Malcolm wrote:
>> In rec.photo.digital D. Peter Maus <DPeterMaus(a)worldnet.att.net>
>> wrote:

>>> No one has ever said that the bumblebee can't fly. Clearly it
>>> can, it happens every day. Science has never been so blind as to
>>> make such a claim. But what Science HAS said, is that the bumblebee
>>> is UNSTABLE in flight, an aerodynamically unsound design. This
>>> doesn't mean or even imply that it can't fly. Just that there would
>>> be easier and better ways to achieve flight.
>>
>> Not so. What science said until recently was simply that according to
>> our understanding of fixed wing aeroplane flight the bumblebee had
>> insufficient wing area to fly.

> That's the story as I always heard it too, "insufficient wing area to fly."

> But the idea that "SCIENCE said" that is something I'm very skeptical about.
> What sort of science could possibly arrive at such a conclusion?

> In the first and most obvious place, a bumblebee is in no way comparable to
> a fixed wing aircraft. What it is comparable to is an ornithopter, and I
> don't think anyone ever built an ornithopter that could actually fly, so
> that's a kind of aircraft that you wouldn't expect there to be enough
> scientific data on to arrive at any conclusions about bumblebees.

>> Not that it was unstable. It is in fact
>> unusually stable in flight due to its relatively low centre of gravity
>> and large effective dihedral.

> How do you establish the "effective dihedral" of wings that are beating at
> such an incredibly fast rate, though?

The point about dihedral is that as the plane (or insect) tips over to
one side the effective length of the wing on the lowered side
increases, increasing the lift on that side, and the effective length
of the other wing decreases, decreasing the lift. So the forces
naturally restore level flight. At a first approximation you could
simply average over the range of motion of the flapping wing. As a
second approximation you could assume simple harmonic motion of the
wing and average over that, which would lead to much the same result
:-)

Or experimentally you could use high speed photography to map the
trajectory of the flapping wing and integrate, or simply measure the
forces (recent analysers of bee flight have developed various ways of
doing all that).

> I don't believe dihedral has anything
> to do with it.

I didn't say it had anything to do with the claim of bees not being
able to fly. You raised the red herring of that claim having something
to do with stability. I used the dihedral and low centre of gravity of
the bee to point out that stability wasn't a problem in bee flight,
and wasn't what the controversy was about. Bees are amongst the most
basically stable of insect fliers, simply because their "design" is
optimised for the carrying of heavy loads -- they're big nectar
tankers for transporting nectar loads back to the hive. Regardless of
exactly what the exact effective dihedral of a bee's wings is, there's
no doubt that there's quite a fair dihedral. Modern high speed
photography has shown that.

> Even if you could calculate the AVERAGE dihedral of a
> bumblebee's wings, you'd still have to establish the incidence in order for
> it to mean anything. Dihedral produces lateral stability only because (or
> if) the wing also has positive incidence.

I think you're confusing incidence with angle of attack. Given a bee's
bent and rather unaerodynamic shape, and the fact that it flies with
its undercarriage down, it would be hard to decide what the
longitudinal aerodynamic axis of a bee's body in flight actually
was. The bee wing angle of attack varies all the time as the wing
moves. But what the angles are doesn't matter. All that matters for
dihedral to work is that lift is being generated by wings. It doesn't
matter how. Since bees do actually fly then lift is obviously being
generated therefore dihedral effects occur.

>> The problem was that theoretically the
>> wings weren't large enough to do the job they clearly were doing. So
>> something was wrong with a simplified analysis of bee flight based on
>> fixed wing aerodynamics.
>>
>> In the 1990s the important missing factor was discovered -- the
>> trailing edge vortices which are such an important source of lift loss
>> in fixed wing aerodynamics were exploited to add lift in the flight of
>> many insects. In the 2000s high speed cinematography and mechanical
>> simulations of bee wing motion demonstrated in practical detail that
>> this was in fact what the bee was doing.

> That's interesting.

> I'd still like to know where the original "insufficient wing area" story got
> started, though. Absent some proof of a serious scientific analysis in the
> past claiming that, I'm inclined to believe it may be more of an urban myth.

It has been difficult to track down the source of the claim. According
to Wikipedia the earliest published claim comes from the introduction
to "Le Vol des Insectes" in 1934 by the entomologist Antoine Magnan,
who was relying on unspecified calculations done by his assistant
Andre Sainte-Lague.

But the story was verbally current long before that publication.

What Wikipedia says about that is that

"Some credit physicist Ludwig Prandtl (1875-1953) of the University of
Gottingen in Germany with popularizing the myth. Others say it was
Swiss gas dynamicist Jacob Ackeret (1898-1981) who did the
calculations."

and more generally

"It is believed that the calculations which purported to show that
bumblebees cannot fly are based upon a simplified linear treatment of
oscillating aerofoils. The method assumes small amplitude oscillations
without flow separation."

> It's a popular one anyway, and will probably go on forever -- like the
> widely held belief that before Columbus everyone thought the earth was flat.

Such beliefs would soon die out if we gave our children a better
scientific education. The problem is that a lot of people, especially
in the US, think that our children are already being exposed to too
much science, which carries the danger of encouraging scepticism about
the literal truth of religious scriptures believed to be the Word of
God. The "according to science bees can't fly" is a very popular
simple way of explaining to ignorant gullible people why they
shouldn't trust science. And so long as plenty of people are making
plenty of money out of encouraging people to distrust science it's
bound to go on.

--
Chris Malcolm
From: Bob Larter on
Ray Fischer wrote:
> Bob Larter <bobbylarter(a)gmail.com> wrote:
>> SMS wrote:
>>> Bob Larter wrote:
>>>
>>>> Don't you think it's kind of hypocritical that on the one hand
>>>> right-wingers oppose abortion, calling it murder, and yet on the other
>>>> hand, they support the death penalty?
>>> Actually no. With abortion I can at least understand their opposition,
>>> even if I don't agree with it.
>>>
>>> At what number of weeks in the pregnancy would you say that abortion is
>>> no longer acceptable? Clearly few people would support it at 38 weeks.
>>> What about 27 weeks?
>> Given that my son was born at 26 weeks, & is now a perfectly healthy 8
>> year old, abortions as late as that do bother me a lot.
>
> Less than 1% of all abortions occur in the 3rd trimester and those few
> are almost always done for medical need.

In such cases, I don't have a problem with them.

>> That said, I
>> still believe that the woman's right to choose trumps the rights of the
>> foetus.
>>
>>> While their opposition to RU486 is pretty
>>> ridiculous, at least you can see where they are coming from in opposing
>>> abortion after the fetus is more than a few weeks old.
>> My personal dividing line is at the point where the foetus is viable
>> outside the womb. Currently, I think that's around 24 weeks.
>
> Only if you have a million dollars to spend on medical care. A more
> practical limit of viability would be around 33 weeks.

Not so. Here in Australia, where we have free, universal healthcare, my
son's birth & followup treatments didn't cost his mother or I a single cent.

--
W
. | ,. w , "Some people are alive only because
\|/ \|/ it is illegal to kill them." Perna condita delenda est
---^----^---------------------------------------------------------------
From: Bob Larter on
SMS wrote:
> Bob Larter wrote:
>
>> Given that my son was born at 26 weeks, & is now a perfectly healthy 8
>> year old, abortions as late as that do bother me a lot. That said, I
>> still believe that the woman's right to choose trumps the rights of
>> the foetus.
>
> My daughter was 27 weeks, son was 32 weeks, and both are fine. The
> memory of the NICU ordeals will remain with me forever, as I'm sure it
> does with everyone that goes through it.

You're not kidding.

>>> While their opposition to RU486 is pretty ridiculous, at least you
>>> can see where they are coming from in opposing abortion after the
>>> fetus is more than a few weeks old.
>>
>> My personal dividing line is at the point where the foetus is viable
>> outside the womb. Currently, I think that's around 24 weeks.
>
> There are cases where there are extremely serious problems that are not
> known until the third trimester, cases where there is no reason to
> continue the pregnancy. This is where the right-wingers come up with
> their "only god can decide" schtick. Of course they don't apply the same
> criteria to other parts of others lives.

Of course not.

--
W
. | ,. w , "Some people are alive only because
\|/ \|/ it is illegal to kill them." Perna condita delenda est
---^----^---------------------------------------------------------------
From: Bob Larter on
Bill Graham wrote:
>
> "Bob Larter" <bobbylarter(a)gmail.com> wrote in message
> news:4ab33be9$1(a)dnews.tpgi.com.au...
>> Bill Graham wrote:
>>>
>>> "wrbrown13" <wrbrown3(a)bellsouth.net> wrote in message
>>> news:xz99h2s243hc$.9skloajqavx8.dlg(a)40tude.net...
>>>> On Thu, 10 Sep 2009 15:36:20 -0700, Bill Graham wrote:
>>>>
>>>>> "Bob G" <mrbobjames(a)yahoo.com> wrote in message
>>>>> news:adbcdb79-6c7f-4021-8fc0-3adf608d7083(a)w10g2000yqf.googlegroups.com...
>>>>>
>>>>>> Republicans would rather get jerked around by the corporations
>>>>>> than by
>>>>>> the government. Wait until you get a horrible diseaase and your
>>>>>> health
>>>>>> insurance company drops you like a hot potato.
>>>>>>
>>>>>> The fact is that this nation is now an oligarchy (and has been for
>>>>>> some time) and not a democracy.
>>>>>>
>>>>>> How does that go, from the corporations, by the corporations, and for
>>>>>> the corporations?
>>>>>
>>>>> That is what litigation is supposed to correct.....You still have
>>>>> the right
>>>>> to sue. But I never said that government couldn't regulate. Your
>>>>> health
>>>>> insurance policy should list the stuff it doesn't cover, in large
>>>>> ten point
>>>>> type.......I would vote for a law like that.
>>>>
>>>>
>>>> Now there's a thought. Sue a large corporation who has any number of
>>>> lawyers on their staff and can drag litigation out intil you don't
>>>> have a
>>>> penny to your name. Great in theory, but a joke in reality.
>>>
>>> They usually settle out of court. Why? Because juries are very
>>> sympathetic to the little guy, and have been known to award many
>>> millions of the big companies money to him.
>>
>> After years of litigation, during which the plaintiff may have died of
>> their illness.
>
> Better yet....Then his poor widow collects even more money....

Gee, I'm sure that's a huge comfort to her.

--
W
. | ,. w , "Some people are alive only because
\|/ \|/ it is illegal to kill them." Perna condita delenda est
---^----^---------------------------------------------------------------
From: Bob Larter on
C J Campbell wrote:
> On 2009-09-18 00:46:40 -0700, Bob Larter <bobbylarter(a)gmail.com> said:
>
>> C J Campbell wrote:
>>> And no -- bureaucratizing health care is unlikely to get rid of waste
>>> and corruption. Far to the contrary. A national health care plan
>>> would vastly increase waste and corruption.
>>
>> Really? In every other country with 'socialised' health care, they
>> spend much less than the USA does.
>
> They also ration their health care.

Rubbish. My family & I have taken full advantage of our 'socialised'
health care system, & I've never even heard of it being rationed.
Believe me, it'd be front page news if it happened.

> If we included all the patients from
> countries with socialized health care who come to the US for care as
> part of the cost of their care, and subtracted it from what we spend, I
> think the numbers would be dramatically reversed.

How many Australians come to the USA for medical treatment?

--
W
. | ,. w , "Some people are alive only because
\|/ \|/ it is illegal to kill them." Perna condita delenda est
---^----^---------------------------------------------------------------