Photographing helicopters and propeller aircraft cannot be left to “AUTO” mode on your camera, as this is likely to leave you with unrealistic looking “fixed” blades and propellers. So, to make your pictures look more like the human eye sees them, you need to make sure you capture a reasonable amount of “prop blur”, by shooting in Shutter Priority mode. Different aircraft types need varying shutter speeds, to cater for the different speeds that their blades rotate at.
Be aware though, that shooting at too slow a shutter speed will mean that camera shake will be more noticeable, so a decent balance taking account practice and experience is also needed.
Below is a selection of images taken at varying shutter speeds, to allow for a more realistic image to be obtained.