FORUMS: list search recent posts

Helicopter Blade / Frame Rate synch?

COW Forums : Panasonic Cameras

<< PREVIOUS   •   VIEW ALL   •   PRINT   •   NEXT >>
Frank Napolski
Helicopter Blade / Frame Rate synch?
on Dec 8, 2011 at 11:25:35 pm

Hi All,

Any suggestions how I could recreate a shot of a helicopter hovering with its blades virtually unmoving?

How would you calculate the necessary frame rate? Take into account number of blades and RPM?

I'm using an HPX-170--would any other cameras be better suited for variable frame rate shooting?

Thanks for any help

-Frank













Return to posts index

Dave LaRonde
Re: Helicopter Blade / Frame Rate synch?
on Dec 9, 2011 at 6:39:54 pm

Something tells me that wasn't planned. Weather plays a role in this. My station used to have a new helicopter, and the pilot told me the thrust is better in cold weather, so you use lower RPM. Hot outside? Higher RPM.

You'd have to consult a pilot on the main rotor's RPMs and pick a suitable shutter speed & frame rate. Or run tests. Lots of tests. And pray for consistent WX conditions.

Dave LaRonde
Sr. Promotion Producer
KCRG-TV (ABC) Cedar Rapids, IA


Return to posts index

Matthew Romanis
Re: Helicopter Blade / Frame Rate synch?
on Dec 12, 2011 at 11:52:49 pm

Helicopter blades spin from 120-600rpm depending upon the size of chopper, length of blade, number of blades, and supersonic tip characteristics.
I'm led to believe an Apache at hover is spinning around 400-450 rpm.
Shutter speeds around the same value would need to be used.



Return to posts index


Jonathan Barnes
Re: Helicopter Blade / Frame Rate synch?
on Jan 23, 2012 at 2:21:38 am

One thing to remember is that you don't need to match the rpm with your frame rate, you just need to match the time of one blade moving into the position of the blade in front of it. For instance, you have a two blade fan with a rotation of 100 rpm, you only need to shoot 1/2 the rpm, not the whole revolution. With a four blade, whole, 1/2, 1/4, 3/4 of rpm. the same with five, six, or whatever blades.

You just need to do some math fractions and figure accordingly.
So if you are shooting a two wing/blade jet ranger revving @ 60 rpm, you can freeze the blade action at 1/60 or 1/30 fps. As someone else has said, you will probably need to test shoot like crazy to get the rate dead on & cross your fingers that all the variables remain consistent.


Return to posts index

<< PREVIOUS   •   VIEW ALL   •   PRINT   •   NEXT >>
© 2018 CreativeCOW.net All Rights Reserved
[TOP]