Direct replacement arms for the Z600 and Z700, may fit other brands as well to super – size your quad!
Upper frame holes: 22mm and 16mm
Lower frame holes: 20mm
Motor mount holes: 16x19mm
2 Arms (White)
I bought these to increase the size of my F550. Big mistake. The quality of the plastic and build is quite poor. For the length, you would expect these to have been designed to be much stiffer, but the plastic is actually less stiff as the original F550 arms, and they can twist very easily because of this. Also the metal encapsulated nuts are not that well anchored in the plastic. I managed to pull one out of the plastic (didn't give me a sense that these would be very secure handling the forces they are expected to on a multirotor). Also the plastic moulding around these encapsulated nuts was excessive, blocking the screw holes themselves. I had to cut it away with a craft knife before I could get a screw to go anywhere near the encapsulated nut. I ended up throwing these in the trash and simply buying carbon fibre extensions for the original arms - all in all, a much better, more secure and stiffer result. I honestly don't know why HK sell crap like this, and its bizarre when the arms supplied on the HK 550 and 450 quads are much better made than these z600/700 arms - from the same manufacturer!Edit: to be honest, I put these on a f550 hex to supersize it. I don't know how they will work on other applications.