To Julch,

The original Whopper blades (undercambered) are not the best when compared to the replacement set that are longer with clark Y type airfoil.

Try Helicopters unlimited (Paul Gold) in Conn.
or contact Robbe, I think the web address is,
www.robbemodellsport.com. There is also the Robbe distributer in England, but not sure of name.

There is a different pitch set up for the newer blades. If you can find a set of new blades and don't get the instructions for them, I can supply.
The Whopper is definetly happier with the newer blades.

Don't feel bad about breaking the old undercambered blades, they had way too much drag.
And if you had a take off tip over with the old blades, they would probably survive anyway. Wait for the newer blades if you can.