[hpv-boats] re CF Blades

[Rick Willoughby]

Rick
        How much of a weight difference is there
between the CF blades and steel ones?
Do you provide a slot in the hub for the shaft
or do you leave it blank. Being a nylon hub
it wouldn't be hard to drill.

Ian

Ian
The normal stainless blades weigh 70g.  Remember this is quite a  
small prop.  The CF blades currently have an aluminium core and weigh  
20g.  The core is needed for twist strength as I am only using  
unidirectional fibre lengthwise on the blade to resist bending.

The next ones I mould will have a stainless steel strip for the  
core.   This will add a bit of weight and should help deployment as  
well as stiffness against twisting.

There is much less effort in making these blades compared with  
grinding stainless steel.

I was surprised how easy it is to get a perfect blade from the  
mould.  The mould cost a bit but it is well made and virtually  
guarantees a good result.  The mould maker had not used CF for  
reinforcing before so it was an experiment for him as well.  He has  
made a mould for a larger fibreglass prop used for wind turbine and  
thousands of others moulds but mine is tiny by comparison with these.

Rick Willoughby
rickwill at bigpond.net.au