View Full Version : Saab 340 with ducted fans!

2nd Dec 2003, 14:46
I took this photograph from an Air New Zealand (Air Nelson) Saab 340 last week with the cheap digital camera in my Palm Pilot . . . the propeller blades provide for an interesting effect . . .


With thanks to the very patient and understanding Woomera.

Post modified by Woomera to post the picture, rather than the link........... :}

2nd Dec 2003, 16:50
Dumb FA here who doesn't know what a ducted fan is... But I think it is a cool shot. Saved it as my desktop.

2nd Dec 2003, 17:11

I became quite intrigued with this phenomenon and took a whole bunch of shots in different flight regimes – climb, cruise, descent and flight idle. The effect was similar in all photos, which leads me to think it has something to do with the low quality of the Palm camera. Send me an email if you would like me to forward them to you as I don’t want to test the limits of Woomera’s goodwill by asking him to host them on his server.



You can email them to me if you wish and I'll load them on the server and post the link here.


3rd Dec 2003, 06:34
Looks more like a groovy set of venetian blinds than a ducted fan:D

Seriously though, it looks like some sort of strobing effect. If you spread your fingers in front of the screen you are looking at, focus on the screen and then waggle your hand from side to side you will see you suddenly grow many more fingers. Something to do with the scan rate of the monitor and the motion of the fingers.

I reckon you have some strange confluence of prop speed and the horizontal scan rate of your camera.

One hopes the Captain was looking out for VFR traffic in E airspace while you were conducting your experiment.:8

3rd Dec 2003, 08:38
It looks to me like some sort distortion due to the window. I may be wrong though(I often am).

3rd Dec 2003, 14:48
No problem with Class E airspace in NZ, got rid of that some time ago!

4th Dec 2003, 05:14
Glad to hear everybody is striding forward in different airspace directions...