Spinner strobing as a "Bird Strike Countermeasure"

In a previous article, "Morgans" said:
"Gig 601XL Builder" wrDOTgiaconaATsuddenlink.net wrote
Someone that is getting tired of his constant crap ruining a perfectly
good forum.

The ONLY thing that will get rid of him is totally ignoring him.

The danger of that is that his blatant misconceptions could get somebody
killed if not challenged.


--
Paul Tomblin http://blog.xcski.com/
....life suddenly made much more sense, the day I fully grokked that people
are stupid.
-- Frank Sweetser

Mxsmanic wrote:
dgs writes:


Who cares? You posted this statement: "I'm only here to discuss
aviation."

Why are you discussing yourself instead of aviation?


Because most recent posts in this thread--including yours--persist in
discussing me, instead of the topic at hand.

So, you lied. You aren't only here to discuss aviation. You obviously
can't simply ignore posts discussing yourself. You continue to lie.

Seek help, Anthony. You're seriously damaged, you lying hypocrite.
--
dgs

(Paul Tomblin) wrote:

The danger of that is that his blatant misconceptions could get somebody
killed if not challenged.

The upside is that the Darwin Award list, always needs new material...

Darrel Toepfer wrote in
. 18:

(Paul Tomblin) wrote:

The danger of that is that his blatant misconceptions could get somebody
killed if not challenged.

The upside is that the Darwin Award list, always needs new material...


But "guy dies of deep vein thrombosis while playing MSFS" is never going to
compete with the rocket car story.


Bertie

"Paul Tomblin" wrote

The danger of that is that his blatant misconceptions could get somebody
killed if not challenged.

A boilerplate response such as what Mortimer was doing would take care of
that.

Besides, I think the chances of anyone showing up and not catching on to
what is happening is pretty slim. He is so far off base as to be
ridiculous. Plus, most of what he responds to is off topic, anyway, so no
danger there.

I'll do the boilerplate statement, if everyone would quit their MXed habit.
Anything, to make it all stop.
--
Jim in NC

On Dec 5, 2:05 pm, wrote:
In rec.aviation.piloting Harry K wrote:





On Dec 4, 8:25 pm, wrote:
In rec.aviation.piloting Harry K wrote:

snip
Harry K- Hide quoted text -

- Show quoted text -
After thinking that over...
It gets worse. There will be multiple rpm that will show the effect
under strobe conditions. With a 2 blade prop it can be sychronizing
every 1/2 rev. 3-blade prop every 1/3 or 2/3 rev, etc. in addition to
synching on the harmonics.

It isn't that bad.

Synchronization only occurs on integral fractions and engine RPM is
usually 1000 and about 2700 RPM so the possibilities are limited.

For a 2 bladed prop:

7200/2= 3600 - 1800 RPM

7200/3= 2400 - 2400 RPM and 1200 RPM

7200/4= 1800 - 1800 RPM and 900 RPM

etc.

I leave it to someone else to show how many blades you see at each RPM.

--
Jim Pennino
Since the prop appears stationary, you would see all the blades.

Yes, but how many virtual blades will you see?

Simple example: You are illuminating a 2 bladed prop running at 1000 RPM
with a strobe light pulsing at 4000 pulses per minute.

In the time between pulses, the prop makes 1/4 of a turn.

The prop is therefor lite up every 1/4 turn and it appears as though
the prop has 4 blades.

--
Jim Pennino

Remove .spam.sux to reply.- Hide quoted text -

- Show quoted text -
Nope. The prop appears stationary and you see only the two.
What you see is the complete image (frame), not a composite of 4
'frames'.

I'm talking about eyeballs and strobed light here, there are no "images"
or "frames" involved.

What you see is a prop blade in whatever position it is in when
the light goes off.

If the light is going off every quarter turn, you see a particular
blade end in four different places each a quarter turn apart.

If the light is going off every sixth of a turn, you see a particular
blade end in six different places each a sixth of a turn apart.

--
Jim Pennino

Remove .spam.sux to reply.- Hide quoted text -

- Show quoted text -

Yes, but you will see them (along with all the others) one at a time.
Not the entire sequence at once or even a composite. It is the same
as taking a snap shot with shutter speed fast enough to stop the
motion, it will show all blades, in this case it will show two blades
and no 'virtual' blades. You can prove it with a fan and a variable
strobe light but I suspect that will not be a common kitchen
appliance .

Harry K

On Dec 5, 9:38 am, Mxsmanic wrote:
Harry K writes:
Nope. The prop appears stationary and you see only the two.

What you see is the complete image (frame), not a composite of 4
'frames'.

You are both incorrect.

It snowed here last night.

Harry K

cavelamb himself wrote:
Yes - I have a name wrote:

"Gig 601XL Builder" wrDOTgiaconaATsuddenlink.net wrote in message
...


Shut the **** up, MX.




So Say We All!




So, which way is the naked lady spinning?

http://www.sonnyradio.com/spinninglady.html

The reflection of her raised leg on the floor lasts only half a turn,
moving from right to left. The leg is farther from the viewer during
that time, and there's not enough floor space in front of her to reflect
the leg when it's up close. So she's going CCW.

But I will *continue* to study this.

In article ,
says...


Airbus writes:

Forget it dude - I'm not like you - will not make categorical statements
about subjects I know nothing about.

Then why are you making categorical statements about me?




Well, that happens to be a subject I know something abvout - being a simple
subject, with few facets and little depth. . .

Airbus wrote:
In article ,
says...


On Dec 5, 2:05 pm, wrote:

In rec.aviation.piloting Harry K wrote:






On Dec 4, 8:25 pm, wrote:

In rec.aviation.piloting Harry K wrote:

snip

Harry K- Hide quoted text -

- Show quoted text -

After thinking that over...
It gets worse. There will be multiple rpm that will show the

effect

under strobe conditions. With a 2 blade prop it can be

sychronizing

every 1/2 rev. 3-blade prop every 1/3 or 2/3 rev, etc. in

addition to

synching on the harmonics.

It isn't that bad.

Synchronization only occurs on integral fractions and engine RPM is
usually 1000 and about 2700 RPM so the possibilities are limited.

For a 2 bladed prop:

7200/2= 3600 - 1800 RPM

7200/3= 2400 - 2400 RPM and 1200 RPM

7200/4= 1800 - 1800 RPM and 900 RPM

etc.

I leave it to someone else to show how many blades you see at each

RPM.

--
Jim Pennino

Since the prop appears stationary, you would see all the blades.

Yes, but how many virtual blades will you see?

Simple example: You are illuminating a 2 bladed prop running at 1000 RPM
with a strobe light pulsing at 4000 pulses per minute.

In the time between pulses, the prop makes 1/4 of a turn.

The prop is therefor lite up every 1/4 turn and it appears as though
the prop has 4 blades.

--
Jim Pennino

Remove .spam.sux to reply.- Hide quoted text -

- Show quoted text -

Nope. The prop appears stationary and you see only the two.
What you see is the complete image (frame), not a composite of 4
'frames'.

I'm talking about eyeballs and strobed light here, there are no "images"
or "frames" involved.

What you see is a prop blade in whatever position it is in when
the light goes off.

If the light is going off every quarter turn, you see a particular
blade end in four different places each a quarter turn apart.

If the light is going off every sixth of a turn, you see a particular
blade end in six different places each a sixth of a turn apart.

--
Jim Pennino

Remove .spam.sux to reply.- Hide quoted text -

- Show quoted text -

Yes, but you will see them (along with all the others) one at a time.
Not the entire sequence at once or even a composite. It is the same
as taking a snap shot with shutter speed fast enough to stop the
motion, it will show all blades, in this case it will show two blades
and no 'virtual' blades. You can prove it with a fan and a variable
strobe light but I suspect that will not be a common kitchen
appliance .




Don't agree - I agree with Jim, and I do frequently use scientific strobe
analysers for decomposing motion. With such a tool, one must be very careful to
avoid harmonic illusions. Obvjects may appear to be moving in reverse, and
indeed phantom members may appear - a fan or prop or spoke for example may
easily appear to have more blades than it really has. Our eyes do not
immobilize instantaneous images beyond a certain speed - this makes it
possible for us to watch movies - or to be fooled by stroboscopic images.



One of my favorite stunts while checking out a new engine installation
was to use a cheap variable rate party strobe to see if anything was
moving. Amazing was a little variable rate stop action looking can spot.