left curves

Common oversimplified misconception of lift, now thoroughly discredited.

Q.: How does an aeroplane fly inverted?

</correction>

 

By sheer horsepower.

I'd like to see some evidence of the discrediting of lift from wing
camber. And in which case, why do they still camber wings if it is not
a factor?

If you look at an inverted aircraft it will have an increased angle of
attack to force the air to flow faster over the what is now the upper
surface (previously the lower surface) of the wing, therefore creating
a lower pressure zone on the wing.

And no. I can't be fucked googling it. And as I have an aerobatic
endorsement on my pilot's licence I can tell you I can feel the
difference with the aircraft inverted and it is quite different to
normal flight (well duh) and you have to rely on angle of attack and
momentum/horsepower.

If you do have links to evidence along those lines, I'd be quite
interested to read them.

 

Well I can't be fucked if you can't be fucked.
The evidence is there - all through Google-land.
Hell - it's in the HSC syllabus for Engineering Studies.

Short response:
A very *small* amount of lift is generated by the Bernoulli/Coanda effect.
Incorrect assumptions (such as equal travel time over both surfaces) lead to
the belief that a great amount of lift is generated.
Much more is created by Newton's 3rd and the angle of attack.

Sheer horsepower baloney. Tell that to the glider pilots.
Explain that to the paper aeroplane builders.

As a fully endorsed aerobat, you must wonder why the Pitts Special is
frequently built with a symmetrical aerofoil. Ye Gods! How would it obtain
lift in straight and level flight? Oh yes... Sheer horsepower. (Sheer
horse..something).

Look - the Bernoulli/Coanda produces a *little* lift, but not as much as
angle-of-attack.
Stick your hand out the window of your car, palm down, fingers out straight
and together (like a "wing"). Rotate your hand at the wrist and feel the
"lift" when you hit a few degrees above horizontal.

....and don't tell me your hand is formed as an aerofoil.

 

Buggered if I know about that. I am a recent ppl, and all of my text
books are accordingly recent. They all cite he Bournouli effect caused
by the increased travel path of air over the camber of the upper
surface as being the major contributor toward lift in conventional
wing design.
There is a lot about this - drag etc overcome by thin wing delta wings
with lift created by velocity or, failing that, horsepower.
I could go on and on but I won't. I would like to see the cite for the
article/s that discredit Bournouli though.

 

How does a Tiger Moth do it then? I've been in one, in a loop. I think the
Guzzi has more HP.

Theo

 

Sheesh.
Is everyone's Google broken?

Here's some links from the *first* page of results I just looked at:

http://www.teachersdomain.org/resource/phy03.sci.phys.mfw.airfoil/
link to a text

http://wiki.answers.com/Q/What_causes_the_lift_of_an_airplane
confused but mostly correct

http://xkcd.com/803/ most incisive link so far

http://amasci.com/wing/airfoil.html nice summary

http://www.pprune.org/tech-log/355523-why-do-aircraft-fy-flat-plate-lift-vs-bernoulli-4.html
a forum post (apply usual filters)

http://mb-soft.com/public2/lift.html tl;dr but interesting when skimmed

http://forum.avsim.net/topic/30021-bernoullis-principle-some-myths/
more forum discussion

http://www.physicsmyths.org.uk/bernoulli.htm
the Pommy perspective

 

Postscript:

Almost forgot one of my favourites:

http://en.wikipedia.org/wiki/List_of_common_misconceptions

....about halfway down the page, in the "Physics" section.

 

Torque about lift, a yachts keel and banking!
Yes it is all on topic.

 

It seems the case against Bournouli relies on Newton's third. For
Pete's sake, Bournouli's principle in itself relies on the same law.
Stuffed if I'm going to Google dodgy links when I have a whole library
of recognised texts used to teach and ultimately test knowledge of the
principles of flight.

 

----- Original Message -----
From: "GWD" <>
Newsgroups: aus.motorcycles
Sent: Friday, January 14, 2011 2:14 PM
Subject: Re: left curves

Oh yes? Pliz to explain how pressure-differential-causes-lift
= air re-direction downwards causes lift.

....just after you asked for them...

Translation:

[fingers wedged in ears]
"la la la.. I can't hear you..."

 

Increased velocity over upper curved surface of a body moving in a
fluid increases momentum of the fluid over the curve, and pressure
differential in the boundary layer results. It's all in the texts and
is explained fully (without maths) in the elementary stages of
Principles of Flight. The maths is actually high school grade and even
I can grasp the concept.

Of course it does - that's always been recognised.

Seems I did not make myself clear, I asked for a cite, but I should
have precluded non authoritative Google links. Sorry about that.

Heh, spoken like a true charlatan

 

Using inertia, the same way a brick would.

Nev..

 

Sighhh...
You appear to be disingenuously missing my point (deliberately?)

We all understand the conventional explanation as summarised above.

My point is simply that this is only a *contribution* (and a small one at
that) to the total lift generated by the system.

If you're not prepared to spend ten minutes doing some research, and (of
course) you won't begin to consider my point, then I'm done.

Cheers

 

OK, in that case I'm sure I'll be able to understand it too. So tell me
again: when an aircraft is flying upside down, the differential air
pressure is doing ... what?

One of the links he pointed you to is 'xkcd', a web comic created by the
physicist and robotocist Randall Munroe; a particularly apt web-comic in
my view. I suggest you take a look at it. I suspect that Randall Munroe
knows a great deal more about physics than you do.

For all everyday purposes it doesn't matter in the least whether the
earth rotates about the sun or vice versa. For this reason false
hypotheses about what is going on can be perpetuated. Personally, I
believe aircraft fly because of the phlogiston in the wings; fortunately
for you, I'm not an aircraft designer.

 

Tiger Moths have surprisingly little inertia (they don't weigh a lot)
and they are quite high in drag which also acts to slow them down pretty
quickly.


G-S [1]


Pilot but not aerobatic endorsed like KevGl ;-)

 

Pulling the aircraft towards the ground

This could be countered by angling the plane (angle of attack) to create
a thrust vector from the engine with enough power (in the vertical
component) to counteract the weight of the plane and the negative lift
of a non symetric inverted wing [1]


G-S

[1] How did I do?

 

Betty's Bend on Mayfield Rd is a left hander, as is Tara's Folly.

I doubt that either lady would describe their respective corner as "more
comfortable" though...


BTH

 

On most aerofoil cross-sections the raised profile is more like 1/3 of the
distance from the leading edge.

Happy to help.


BTH

 

How odd that the last airliner I rode on was equipped with both leading
edge slats and trailing edge flaps to increase the wing's lift?

Say Nev, why do skydivers bother fooling around with parafoils when a
simple flat 'chute is clearly going to be just as effective?


BTH

 

Heh - that's one of the better old jokes. I don't think it will ever
die