FYI: Dec 12 MythBusters: Airplane Hour

On Dec 9, 12:26 pm, "Dale Alexander" wrote:
I would be interested in knowing which airport that is. I know that they
have used Alameda and Hamilton in the past. Which airport are you referring
to?

Dale Alexander

KMER, in the central valley. I only heard this through word of mouth,
so it may not even be correct.

And which myth did they test at Hamilton? I flew over that airport
recently and it's almost completely bulldozed away now...

Well, they did the stud gun that launched a stud from a gun trying to
pretend that they were wall-crawling super-heroes. They also did the flying
with a sheet of plywood...and the poor crash test dummy has seen his share
of crashing. But these were earlier episodes and what infrastructure there
is probably gone as you say. I remember several years ago when an airshow
was put on at Hamilton. Last time I saw the BD5-J Silver Bullet fly was
there.

Dale Alexander

"buttman" wrote in message
...
On Dec 9, 12:26 pm, "Dale Alexander" wrote:
I would be interested in knowing which airport that is. I know that they
have used Alameda and Hamilton in the past. Which airport are you
referring
to?

Dale Alexander

KMER, in the central valley. I only heard this through word of mouth,
so it may not even be correct.

And which myth did they test at Hamilton? I flew over that airport
recently and it's almost completely bulldozed away now...

In article ,
"Morgans" wrote:

"Some Other Guy" wrote

A friend of mine was absolutely convinced that if you are flying into a
strong headwind close to stall speed and make a U-turn, you will stall
(because now the wind is coming "from behind").

The basics of flight just isn't obvious to some people.

Partially so. IF you could do a 180 degree turn super fast, like .1
second, you would stall.

Nope. Wrong.


At least for the amount of time it takes the airplane to accelerate, the
wind would be making you go too slow.

The turn has to include the acceleration.


Of course, no plane can make a 180 degree turn that fast, so we are all safe
from the dreaded downwind turn. g

I think one thing that people don't realize is that while a car can make an
instant turn, an airplane can not.

Well, all but Shawn Tucker's plane. I think he could make the turn in less
time than .1 second, from the crazy crap I have seen him do!

--
Alan Baker
Vancouver, British Columbia
"If you raise the ceiling four 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."

lOn Mon, 10 Dec 2007 02:45:43 GMT, Matt Whiting
wrote:

Some Other Guy wrote:
" Vacant lot wrote:
I don't understand the premise of the conveyor belt thing. If you are
talking about thrusting an aircraft forward, like a catapult, you already
know the answer, and if the belt is running so the the wheels of the
aircraft are spinning madly while it stays still then again you already
know the answer. What are they trying to prove? I've seen the show but I
watch very little tv, have they run out of urban myths?

A friend of mine was absolutely convinced that if you are flying into a
strong headwind close to stall speed and make a U-turn, you will stall
(because now the wind is coming "from behind").

The basics of flight just isn't obvious to some people.


Yes, and they aren't obvious to others just as proper use of grammar
isn't obvious! :-)

Matt

Suggest you take a look at this site.
www.aeroexperiments.org/brainteasers.shtml

Ed Sullivan

Ah, but if you are flying near stall with the wind, and the wind suddenly
slows, will you stall?

Yes -- Your momentum needs to catch up with your new (reduced) airspeed.

.OR.
If you are slow on approach, into a gusty head wind, and a gust suddenly
resides, will you stall?

It depends on how much margin you have between stall and airspeed to
begin with. If the margin is less than the (now non-existent) gust, you
will stall. Otherwise, you will see a sudden increase in sink rate. I
guess it might not be fair to call it a stall.

Everyone, remember that this is not a real airplane, but instead it is a
theoretical airplane, like in physics class, where they tell you to figure a
problem without any friction being taken into account.

This airplane was going 70 knots (airspeed) north, with a 30 knot wind out
of the north, and it suddenly, and instantly is going to be going south, in
..1 second.

That means it had 40 knots worth of momentum. When that sudden reversal of
direction takes place, it will have the same momentum, for that first
instant of reversed flight, until the wind blowing at its back starts to
blow on it and accelerate it. That means the 40 knots of momentum will have
the airspeed component of the tailwind subtracted from it, so 40 knots minus
30 knot wind means it will see an airspeed (only for an instant) of 10
knots, until the tail wind plus the thrust starts accelerating the plane
back to its original airspeed of 70 knots.

I would agree that the airplane would develop a VERY serious sink rate.
Would that be a stall, though? g
--
Jim in NC

On Dec 9, 9:03 am, "Blueskies" wrote:
"Maxwell" wrote in ...

"B A R R Y" wrote in messagenews:ghrnl3h2rm847jvivviio87sa7arlkjvo7@4ax .com...
On Sun, 9 Dec 2007 09:12:27 -0400, " Vacant lot
wrote:

I don't understand the premise of the conveyor belt thing. If you are
talking about thrusting an aircraft forward, like a catapult, you already
know the answer, and if the belt is running so the the wheels of the
aircraft are spinning madly while it stays still then again you already know
the answer. What are they trying to prove?

If it were so cut and dried, why does it generate threads of several
hundred messages here? G

Only because there are one or two nit pickers on here.... G

Maybe we should start the thread drift right here and now....

You know, people would fully understand that a plane on a treadmill will not start flying if we had a good educational
system. Liberal use of aerodynamic principles leads to stall spin accidents, and everyone knows the dreaded downwind
turn was by global warming...

Hear, hear!

Of course it won't fly...nothing for the bugger to push against.

WWII proved that with the German flying disc experiments.

snerk

On 2007-12-09 07:03:09 -0800, "Blueskies" said:




Maybe we should start the thread drift right here and now....

You know, people would fully understand that a plane on a treadmill
will not start flying if we had a good educational
system. Liberal use of aerodynamic principles leads to stall spin
accidents, and everyone knows the dreaded downwind
turn was by global warming...

I knew it was the liberals!
--
Waddling Eagle
World Famous Flight Instructor

On Dec 10, 12:16 am, Ed Sullivan wrote:
lOn Mon, 10 Dec 2007 02:45:43 GMT, Matt Whiting
wrote:





Some Other Guy wrote:
" Vacant lot wrote:
I don't understand the premise of the conveyor belt thing. If you are
talking about thrusting an aircraft forward, like a catapult, you already
know the answer, and if the belt is running so the the wheels of the
aircraft are spinning madly while it stays still then again you already
know the answer. What are they trying to prove? I've seen the show but I
watch very little tv, have they run out of urban myths?

A friend of mine was absolutely convinced that if you are flying into a
strong headwind close to stall speed and make a U-turn, you will stall
(because now the wind is coming "from behind").

The basics of flight just isn't obvious to some people.

Yes, and they aren't obvious to others just as proper use of grammar
isn't obvious! :-)

Matt

Suggest you take a look at this site.www.aeroexperiments.org/brainteasers.shtml

Ed Sullivan- Hide quoted text -

- Show quoted text -

Ah, something to do while I am staring at that 6" snowfall with a
30'x100' driveway to be cleared including the plow berm from the state
which will contain all the snow off a 16' wide stretch of highway.

Gonna be a fun project for both of them

Harry K

On Dec 10, 12:58 am, "Morgans" wrote:
Ah, but if you are flying near stall with the wind, and the wind suddenly

slows, will you stall?

Yes -- Your momentum needs to catch up with your new (reduced) airspeed.

.OR.
If you are slow on approach, into a gusty head wind, and a gust suddenly
resides, will you stall?

It depends on how much margin you have between stall and airspeed to
begin with. If the margin is less than the (now non-existent) gust, you
will stall. Otherwise, you will see a sudden increase in sink rate. I
guess it might not be fair to call it a stall.

Everyone, remember that this is not a real airplane, but instead it is a
theoretical airplane, like in physics class, where they tell you to figure a
problem without any friction being taken into account.

This airplane was going 70 knots (airspeed) north, with a 30 knot wind out
of the north, and it suddenly, and instantly is going to be going south, in
.1 second.

That means it had 40 knots worth of momentum. When that sudden reversal of
direction takes place, it will have the same momentum, for that first
instant of reversed flight, until the wind blowing at its back starts to
blow on it and accelerate it. That means the 40 knots of momentum will have
the airspeed component of the tailwind subtracted from it, so 40 knots minus
30 knot wind means it will see an airspeed (only for an instant) of 10
knots, until the tail wind plus the thrust starts accelerating the plane
back to its original airspeed of 70 knots.

I would agree that the airplane would develop a VERY serious sink rate.
Would that be a stall, though? g
--
Jim in NC

I suspect it would pile in very shortly after the turn began. Making
a turn at "near stall speed" into a head wind to begin with....

Harry K

I'm amazed that this argument is happening. You are arguing about the
behaviour of a non-existent aircraft doing something that real aircraft
cannot do. Why don't you discuss what a real aircraft, turning downwind at a
normal rate will do. Every pilot has to make a downwind turn entering the
pattern, it appears to be a fairly survivable manoeuvre.