Are Inspire 2 white props less stiff than the red props?

stephan_f · Jul 17, 2017

Hello fellow pilots!

When I checked the props after a flight during those hot summer days, I've noticed a strange thing.
It seems that the "white" props are less stiff than the red ones.
I currently have no means of doing a "scientific" check because I don't have a dynamometer at hand.
But I have done blind tests of 3 sets of props (with my hands, tested replacement props after the original red props rattled) - and I have been able to distinguish all 6 white props from the red ones just by feeling the flex of the rotor tips.

Please don't shoot me because of this absurd thesis - but this sounds as if the white props were are made of another material which is getting less stiff when temperatures rise above 25°C. Or they are a little bit thinner? I don't have a clue.

Many greetings,
Stephan

Steve@AerialImagesPro · Jul 17, 2017

Less stiff is not a bad thing. As a matter of fact, using the very stiff Carbon fibre props can do damage. Yes, they make the bird more responsive, but at the expense of shock and vibration absorption.

There is a balance, but just don't go into this experiment thinking flex is bad. Look at giant Jet Airliners. If you've ever watched one take off and focused on the amount of flex in the wing, you'd swear the wing was going to fall off..

It amazes me how much the wings bend up when getting up to threshold speed.

Also, you can't measure the flex of a blade simply by pulling up at the ends. The lift generated by the prop is spread out across the entire prop surface. And the way they are designed with that irregular shape distributes the weight different at different points of the prop.

There's a TON of aero engineering that goes into blade shapes and flex.

stephan_f · Jul 17, 2017

Hi Steve, thank you for your reply!
I agree with every single point, especially that flex per se isn't a bad thing.
It is just the perceptible difference between both types of blades which makes wonder - and when I said "strange" (= to me), I didn't mean "bad"

Kind regards,
Stephan