Raptor 60 and Mavrikk 700mm 14/4 blades?

[Darren]

A buddy of mine has a Raptor 60 with a YS80. I had a spare set of Mavrikk
700mm blades I was gonna give him. These blades are 14mm roots with 4mm
brass sleeve inserts. Can you fly these blades without the brass sleeves?
This seems to make them 5mm, a perfect fit for his Raptor. I just wasn't
sure if they were designed to be flown without any brass sleeve.

Thanks,

Darren


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[Mike]

It's a guess rather than a fact, but I would say that the brass sleeve is more
hard wearing than the blade material, and as such is more able to a) take the
punishment of the blades twisting and pulling on the bolts, and b) more able to
distribute the load through the various layers of blade material.

On that basis, it might be all right to run the blades without sleeves for a
while, but sooner or later the wear round the bolt holes may be so great that
small movements set in, and then the blades will part company with the material
round the root. Remember the centrifugal force on the blades are considerable,
and the only thing keeping them on the helicopter is the bolt running through
the blade root.

It might be worth running some strain tests on broken blades, if anyone has
such a thing (surely someone must have some somewhere ;-) ) to see what gives
first.

The other problem your friend will face is that the brass sleeve often acts as
a spacer, being slightly larger than the blade itself, so the bolt tightens on
the sleeve not the blade. Without the sleeve, the blade grips will act directly
on the blade root and they will therefore be subjected to even more stresses.