The Impossibility of Flying Heavy Aircraft Without Training

In article . net,
Richard Lamb wrote:

This has all been very interesting, but there is a basic assumption
that seems to be glossed over.

I was thinking, that to really get anything out of all this,
shut the engine off!

Everybody has been _assumin'_ straight and level flight.
I suppose that's ok for academic discussion, but for learnin'
aerodynamics, let's just assume the engine quit and take it
from there.

L / D

Just a thought...


Richard

It doesn't really make any difference.

In a constant glide, the aircraft now does have momentum with respect to
the earth, but it is *still* incurring the same forces.

--
Alan Baker
Vancouver, British Columbia
"If you raise the ceiling 4 feet, move the fireplace from that wall
to that wall, you'll still only get the full stereophonic effect
if you sit in the bottom of that cupboard."

Alan Baker wrote:

In article . net,
Richard Lamb wrote:


This has all been very interesting, but there is a basic assumption
that seems to be glossed over.

I was thinking, that to really get anything out of all this,
shut the engine off!

Everybody has been _assumin'_ straight and level flight.
I suppose that's ok for academic discussion, but for learnin'
aerodynamics, let's just assume the engine quit and take it
from there.

L / D

Just a thought...


Richard


It doesn't really make any difference.

In a constant glide, the aircraft now does have momentum with respect to
the earth, but it is *still* incurring the same forces.

Right.

But now we might actually get something from the discussion.

Like how much power is actually required for S&L?

Effects of speed on glide angle?

And, what happens when you get a wee bit too slow?

Or, if that's too boring...

What happens to the boundary layer?
Is it ticklish?

And what about those long and short bubbles?

wrote

Because the wing is not of infinite weight. The upper atmosphere in
fact =is= deprived of air while the airplane is in flight... that air is
squeezed down below the wing, increasing the pressure on the surface of
the earth, in an amount exactly equal to the weight of the airplane
(divided by the area of the earth).

I think that the downflow dispaces other air which flows up to
replace it--conserving momentum and mass.

I think I will create a new award. I'm not sure what the prize or trophy
will be yet.

I'm calling it "Rec.Aviation Geek of the Decade", or perhaps of "The
Century."

I am in total awe and amazement, that you and Jose have tied for this award,
based on how long you two have kept this amazingly boring subject alive. I
just CAN'T believe it !!!

Now, continue on, or not.

Please, use your restraint, and common sense. Use the "or not." g
--
Jim in NC
(mostly, using his right to use the "ignore thread" button! g

let's just assume the engine quit and take it
from there.

L / D

What is L? What is D?

That's the fundamental question being discussed. The engine (or the
earth's gravity) merely supplies the force. But once you introduce the
idea of gliding, you also need to address the things that gliders
address - ridge lift, thermals, messy stuff like that, which are all
ways of getting free energy from the sun.

Calm air, flat ambient earth, no engine, the airplane will descend.

Now explain to me how autogyros work.

Jose
--
Money: what you need when you run out of brains.
for Email, make the obvious change in the address.

Morgans wrote:

...

Now, continue on, or not.

Please, use your restraint, and common sense. Use the "or not." g


Well I'm really hoping that Jose tries the card thumbtack soda straw
thing.

--

FF

I am in total awe and amazement, that you and Jose have tied for this award,
based on how long you two have kept this amazingly boring subject alive.

Great discoveries are often made in the seventh decimal place.

Jose
--
Money: what you need when you run out of brains.
for Email, make the obvious change in the address.

Well I'm really hoping that Jose tries the card thumbtack soda straw
thing.

Actually, I did try it and it didn't "work" (that is, the card didn't
float, which is what I think you expect to happen). I'm probably doing
it wrong so I'll keep at it. When I get it to work, I'll report what
happened and why (in newtonian terms) I think it did.

Jose
--
Money: what you need when you run out of brains.
for Email, make the obvious change in the address.

wrote:
Matt Whiting wrote:

wrote:


A fluid can transmit force without flow in the conventional sense.
That is the basis for hydraulics.

I guess it depends on what you mean by "conventional sense."

Nothing can transmit a force without some deflection. Some molecules in
the fluid have to move in order to generate a force and typically
movement of a fluid, however minute, is flow.



One does not generally refer to compression as flow.

A fluid can transmit force without molecules flowing from the
point of origin to the point of application.

True, but most hydraulic systems of any usefulness require the fluid to
flow to some degree. I hydraulic system that simply statically supports
a load isn't a very interesting system and could easily be done without
using a fluid and for much less money. :-)

Matt

On Fri, 3 Mar 2006 at 15:21:11 in message
, "00:00:00Hg"
wrote:
On Fri, 03 Mar 2006 01:27:46 +0000, David CL Francis wrote:

Above
Mach one the air does not detect the approaching aircraft! :-)

If it did, what would happen?

The whole point is that disturbances in the air are propagated at or
near the velocity of sound. It follows that at supersonic speeds
nothing happens to the air until it reaches the supersonic aircraft, or
vice versa.
--
David CL Francis

On Fri, 3 Mar 2006 at 02:27:02 in message
. net, Richard Lamb
wrote:
I hate to be a spoil sport (or dullard?), but...

the (stationary) air does WHAT (as the wing passes by)???

The nature of things is such that the situation does not change if you
change the frame of reference. It is normal in doing calculations to
start with a frame of reference based on the aircraft. If you follow the
aircraft then the air is going past it.

The presence of the wing changes the air flowing past the aircraft in
the same way as if you consider the aircraft passing through the air.
The 'stationary' air as you call it has its local velocity and direction
changed by the aircraft.
--
David CL Francis