Thank you, guys.
@ Oshyan and Badger: right now I am trying to render this animation in higher resolution. For testing purposes I'll leave Detail blending at 0 to see if the flickering is acceptable.
@ Cyphyr: no, I didn't. Actually I haven't used it yet. I'll have to do some tests with it.
Some additional information: In 3ds max I rendered the helicopter and the rotors separately. First I rendered the helicopter in mental ray without motion blur which I added in postwork (MB in mental ray is very slow to render depending on the materials you use).
Then I rendered the animated rotors with the default scanline renderer with a simple lightsource that's not even casting shadows. The motion blur is a camera effect which in this case renders the blur in 56 passes per frame. Sounds much, but each frame took less than a minute and a half to render. The helicopter body has a matte/shadow material assigned to it which makes it invisible but cuts out the areas where it's in front of the rotors.
Then I comped it together and adjusted the brightness and contrast, did some color grading and added some chromatic aberration which I'm addicted to