If this is your first visit, be sure to check out the FAQ by clicking the link above. You may have to register before you can post: click the register link above to proceed. To start viewing messages, select the forum that you want to visit from the selection below. |
|
|
Thread Tools | Display Modes |
#31
|
|||
|
|||
Spinner strobing as a "Bird Strike Countermeasure"
On Dec 3, 2:45 pm, Just go look it up! wrote:
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.- Hide quoted text - - Show quoted text - Been a long, long time but my rusty math skills says it would be about 3600 unless I am wrong (per wife that is my normal state). That is the 1/2 harmonic of the rpm/flicker rate. 60 X 120 = 7200. The phenomenon should appear at 1/2, 1/4, double rate etc intervals. Harry K |
#32
|
|||
|
|||
Spinner strobing as a "Bird Strike Countermeasure"
|
#33
|
|||
|
|||
Spinner strobing as a "Bird Strike Countermeasure"
|
#34
|
|||
|
|||
Spinner strobing as a "Bird Strike Countermeasure"
|
#35
|
|||
|
|||
Spinner strobing as a "Bird Strike Countermeasure"
Maxwell writes:
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. This is completely incorrect. Human vision produces no such artifact. Anything moving beyond a certain speed is simply a blur; it never appears to move backwards. Motion pictures captured on film greatly exaggerates the phenomenon. No, motion pictures PRODUCE the phenomenon. It's an artifact of the motion picture, not human vision. 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. That is a function of shutter speed. But the human visual system well do so as well, just to a much lesser extent. No, the human visual system will not do it at all. |
#36
|
|||
|
|||
Spinner strobing as a "Bird Strike Countermeasure"
Maxwell writes:
Guess again. It wasn't a guess. |
#37
|
|||
|
|||
Spinner strobing as a "Bird Strike Countermeasure"
Yes - I have a name writes:
My phonograph turns at either 33-1/3 or 45 RPM, which is just as relevant to this conversation as your mention of turbofans. At any given moment there are thousands of aircraft powered by turbofans in flight. |
#38
|
|||
|
|||
Spinner strobing as a "Bird Strike Countermeasure"
|
#39
|
|||
|
|||
Spinner strobing as a "Bird Strike Countermeasure"
"Mxsmanic" wrote in message ... The original assertion was that it was an artifact of human vision, which is never true. Keep digging, and guessing. God you are stupid. |
#40
|
|||
|
|||
Spinner strobing as a "Bird Strike Countermeasure"
"Mxsmanic" wrote in message ... This is completely incorrect. Human vision produces no such artifact. Anything moving beyond a certain speed is simply a blur; it never appears to move backwards. No, motion pictures PRODUCE the phenomenon. It's an artifact of the motion picture, not human vision. That is a function of shutter speed. No, the human visual system will not do it at all. Keep digging, you are half way to China already. |
Thread Tools | |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Thread Starter | Forum | Replies | Last Post |
Spinner strobing as a "Bird Strike Countermeasure" | Jim Logajan | Piloting | 259 | December 13th 07 05:43 AM |
Saturday 072807 in Oshkosh Pt 6 - Warbird show pix I forgot to post earlier [10/33] - "Bird Dog.jpg" yEnc (1/1) | Just Plane Noise[_2_] | Aviation Photos | 0 | July 31st 07 10:48 PM |
"British trace missile in copter strike to Iran" | Mike[_7_] | Naval Aviation | 8 | March 10th 07 08:20 PM |
Bird strike | Bob Chilcoat | Piloting | 5 | September 6th 05 07:05 AM |
Bird strike | Jase Vanover | Piloting | 16 | May 17th 05 11:44 AM |