Spinner strobing as a "Bird Strike Countermeasure"

"Airbus" wrote in message
...
In article , says...



"Airbus" wrote in message
...
In article , says...



"Airbus" wrote in message
. ..
In article ,
says...


Hence the reason an aircraft propeller will
appear to be revolving slowly backwards at times.

Not when being observed directly. That only happens in movies and
video
due
to the interaction between the imaging rate and the rotation rate of
the
propeller.

Wrong again you clueless twit.



No, he is right this time.

No he isn't.


Wellllllllll..............
The world is listening . . .


Indeed.

Still listening . . .

Simple question, to get you started on your explanation;
Have you ever been in a propeller-driven airplane?



I have been a pilot since 1972.

soaringpilot2 wrote in
:


I wonder about doing the candy stripe spiral on them, or painting the
blades different colors...


The candy stripe spiral on the spinner was a recognition thing, the
Germans started doing that in the summer of '44. The Japanese did
something similar thru the war years by painting the inboard leading
edge of the wing yellow. Quick recognition by your comrades in a
dogfight when head on...

This is the first I've heard of the 1/3 and 2/3's strobe effect, I
thought it was also for recognition...Maybe I'll try it on my 172...


I asked in my shop and sure enough I was told that our spinners have the
spiral on them for bird avoidance.
We also used to turn our radar on in cavu weather for the same reason, but
now we turn it on for every flight anyway..

Bertie

Airbus wrote in
:

In article ,
says...


When observed directly under artifical light that "flickers", the most
obvious being a strobe light, but there are other types of artificial
lights that have flicker.

--


Fine - but which ones cause you to see the propellers turning in
apparent reverse? Do you frequently operate your airplane indoors?
Propellers are usually observed in natural light, which does not
flicker. At night, on the rare occasions where you actually see the
props clearly, it is from the aircraft's own lighting, which is DC. I
have nbever seen the props turning backwards on a real plane - see
it frequently in movies though. . .

At least one exception. If you look at a prop through your own prop arc...


Bertie

"Airbus" wrote in message
...
In article , says...
Wrong again you clueless twit.

No, he is right this time.


Rule #1: MX is never right

Rule #2: Is by some wild mistake (think monkeys typing) , MX is not actually
incorrect, see rule #1

In rec.aviation.piloting Airbus wrote:
In article , says...


When observed directly under artifical light that "flickers", the most
obvious being a strobe light, but there are other types of artificial
lights that have flicker.

--


Fine - but which ones cause you to see the propellers turning in
apparent reverse? Do you frequently operate your airplane indoors?
Propellers are usually observed in natural light, which does not flicker. At
night, on the rare occasions where you actually see the props clearly, it is
from the aircraft's own lighting, which is DC. I have nbever seen the props
turning backwards on a real plane - see it frequently in movies though. . .

Any light that flickers at an appropriate rate will cause the prop to
appear to turn in reverse.

The likelyhood of being somewhere with lights that flicker is irrelevant.

The original statement was that it -ONLY- happens in movies and video, and
that absolute statement is false as are most of MX's absolute statements.


--
Jim Pennino

Remove .spam.sux to reply.

"Yes - I have a name" wrote in
newss_4j.1920$QS.1236@trndny03:

"Airbus" wrote in message
...
In article ,
says...
Wrong again you clueless twit.

No, he is right this time.


Rule #1: MX is never right

Rule #2: Is by some wild mistake (think monkeys typing) , MX is not
actually incorrect, see rule #1


We'll have to make up a Wickepedia entry with his as the opening paragraph.


Bertie

In article twV4j.1755$QS.57@trndny03,
"Yes - I have a name" wrote:

"Airbus" wrote in message
...
In article ,


The frame-rate was increased from 16 to 24 at the introduction of sound
(not
color). The increased linear speed was desirable to improve fidelity of
the
analog optical soundtrack on the film. In either case, 24 or 16 FPS, each
image
is projected three or two times (respectively) to produce an effective
rate of
48 - this was done to avoid perception of flicker.


Anyone know off hand what the frame rate was for home movies (8mm)?

It was supposed to project at 16fps, which makes for a bit of adjustment
when converting old home movies to DVD.

"Airbus" wrote in message
...
In article ,
says...


When observed directly under artifical light that "flickers", the most
obvious being a strobe light, but there are other types of artificial
lights that have flicker.

--


Fine - but which ones cause you to see the propellers turning in
apparent reverse? Do you frequently operate your airplane indoors?
Propellers are usually observed in natural light, which does not flicker.
At
night, on the rare occasions where you actually see the props clearly, it
is
from the aircraft's own lighting, which is DC. I have nbever seen the
props
turning backwards on a real plane - see it frequently in movies though.
. .


Do you really think you see and visualize motion constantly. Perhaps you
should spend a little more time around and airport yourself. Many
propellers, especially the large diameter props found on radial engines,
will appear at times to be rotating slower, or backwards. It's a fainter
image than recorded on film, but the partnership of the human eye and brain
does not realize fluid motion.

Motion pictures captured on film greatly exaggerates the phenomenon. Some of
the new video equipment will seem to even stop a prop to the extent it's
distracting to the quality of the recording. But the human visual system
well do so as well, just to a much lesser extent.

"Airbus" wrote in message
...
In article ,
says...


When observed directly under artifical light that "flickers", the most
obvious being a strobe light, but there are other types of artificial
lights that have flicker.

--


Fine - but which ones cause you to see the propellers turning in
apparent reverse? Do you frequently operate your airplane indoors?
Propellers are usually observed in natural light, which does not flicker.
At
night, on the rare occasions where you actually see the props clearly, it
is
from the aircraft's own lighting, which is DC. I have nbever seen the
props
turning backwards on a real plane - see it frequently in movies though.
. .


Apparently, you aren't familiar with the trick of calibrating your
tachometer with the 120Hz flickering of mercury or sodium ramp lights.

Bill D

On Mon, 03 Dec 2007 21:52:04 -0800, Airbus wrote:

In article , says...


When observed directly under artifical light that "flickers", the most
obvious being a strobe light, but there are other types of artificial
lights that have flicker.

--


Fine - but which ones cause you to see the propellers turning in
apparent reverse? Do you frequently operate your airplane indoors?
Propellers are usually observed in natural light, which does not flicker. At
night, on the rare occasions where you actually see the props clearly, it is
from the aircraft's own lighting, which is DC. I have nbever seen the props
turning backwards on a real plane - see it frequently in movies though. . .

Night, near one of those big off-amber ramp lights, run the RPM up and
down, there's a range where it will look like it's going backwards. I
thought it was kind of interesting.

It's something similar to the poor-man's "is my RPM somewhat right"
test, it'll appear stopped at (I forget what RPM now) RPM and if your
tach is somewhat near, viola.