Prop performance in clouds question

"Doug Palmer" wrote in message


I would look at how the video camera compensates for the lower light
level in the cloud. If it changes its scan/shutter rate it would
cause the apparent change in relative movement of
the propeller. ... What you are witnessing is the sync of the prop
with the shutter and any variation in either can cause the illusion of
movement.

That's my guess, as well.

--
John T
http://sage1solutions.com/blogs/TknoFlyer
http://sage1solutions.com/products
NEW! FlyteBalance v2.0 (W&B); FlyteLog v2.0 (Logbook)
____________________

On Mar 3, 9:56*am, "John T" wrote:
"Doug Palmer" wrote in message





I would look at how the video camera compensates for the lower light
level in the cloud. *If it changes its scan/shutter rate it would
cause the apparent change in relative movement of
the propeller. *... What you are witnessing is the sync of the prop
with the shutter and any variation in either can cause the illusion of
movement.

That's my guess, as well.

--
John Thttp://sage1solutions.com/blogs/TknoFlyerhttp://sage1solutions.com/products
NEW! *FlyteBalance v2.0 (W&B); FlyteLog v2.0 (Logbook)
____________________

I am using a Kodak Easy Share camera. Does that adjust based on what
it "sees"?

I just put it on Movie and point and shoot, thus me being intrigued
figuring it was the airplane and and not the camera end.

Unless of course if the frame rate can change based on what the camera
sees being "so automatic"?

I sure don't know myself, but pretty coincidental seeing the strobe
change in VMC vs IMC.

Allen

wrote in message


I am using a Kodak Easy Share camera. Does that adjust based on what
it "sees"?

Cameras typically use a combination of shutter speed, aperture and exposure
to maintain the "best" picture (as defined by the software). I haven't
researched your camera, though I suspect it manipulates all three based on
the video I've seen on your channel. I know for certain your shutter speeds
are way different from mine based on the prop filtering.

Unless of course if the frame rate can change based on what the camera
sees being "so automatic"?

Possible, though I doubt actual frame rate is changing (different from
shutter speed).

I sure don't know myself, but pretty coincidental seeing the strobe
change in VMC vs IMC.

I don't doubt a small change in prop speed as I've seen similar changes in
my own prop "strobe," but I'd put it more to general atmospheric (or, more
likely, attitude changes) rather than specific to clouds as I've seen
similar changes well outside clouds on "severe clear" days.

Try this: Take video during a flight on a clear VMC day. Maintain level
flight as absolutely as you can, then enter climbs and descents. See what
that does to your prop strobe. I suspect even slight attitude changes will
show different strobe patterns without touching engine or prop controls.

--
John T
http://sage1solutions.com/blogs/TknoFlyer
http://sage1solutions.com/products
NEW! FlyteBalance v2.0 (W&B); FlyteLog v2.0 (Logbook)
____________________

On Mar 3, 1:19*pm, "John T" wrote:

Try this: Take video during a flight on a clear VMC day. Maintain level
flight as absolutely as you can, then enter climbs and descents. See what
that does to your prop strobe. I suspect even slight attitude changes will
show different strobe patterns without touching engine or prop controls.

Actually, with my Sundowner, prop controls will be one less variable
in the equation. (one month down time will feel like eternity!)

The trick will be to maintain the "exact" flight "attitude" throughout
the cloud as YOU ARE RIGHT, any pitch up or pitch down will affect the
RPM as I noticed this on my ILS approaches in my Sundowner. (Video
was in a Piper).

I like to listen to the engine noise as well as watch the strobing to
associate the quality of the approach, I.E the less power changes I
hear, the more stable the approach, and strobing remains "constant"
whether it be clockwise, or counter clockwise or even standing still.

It may be that there was a pitch change in the plane that I couldn't
feel in the video that just may have existed even though I didn't feel
it in the seat of my pants (I was passenger holding the camera). Of
course in IMC, we will really never know but gauges were steady as
they can be.

Allen