okikuma
Member
Finally, the secrets of how Ken Wallis manufactured his wooden rotor blades have been revealed in an old 31 March 1966 article in FLIGHT International magazine. The following link was previously posted by Kolibri282 (Juergen) under the Builders Thread of this forum.
http://www.rotaryforum.com/forum/showthread.php?t=23862
I know there's been previously much discussion pro and con on building wooden rotor blades, and the construction methods used.
In the article Flight International article, it explains the materials and processes use to build the rotor blades. What is interesting is that all the materials used were of 1930 - 1940s technology. I should also add, well documanted and proven technology.
To quickly summarize, first a .125 inch birch ply skin is laid. Then a strip of Ultra High Tensile (UHT) strength steel is glued to the plywood skin with Aerodux 185 resorcinol-phenol-formaldehyde resin adhesive. Then multi layers of Hydulignum (a Horden-Richmond Aircraft Company product of heat pressed thermoplastic resin laden plywood that was used to make propeller blades for British Aircraft during World War Two) laminates that are laid up to form the "D" structure spar, followed by one more layer of .125 inch birch ply skin. The outside of the blade is then covered with Madapolam, a cotton linen fabric and aircraft grade dope is used to glue down and seal the Madapolam. The following is a cross section of one of Ken Wallis wooden blades.
http://i289.photobucket.com/albums/ll224/my-pics-are-here/wallisblade.jpg
It is to my understanding that the wooden rotor blades on the WA-116 gyroplane "Zeus III" that Ken Wallis often seen flying in were manufactured by him well over 30 years ago! Now that is unlimited life rotor blades!
Wayne
http://www.rotaryforum.com/forum/showthread.php?t=23862
I know there's been previously much discussion pro and con on building wooden rotor blades, and the construction methods used.
In the article Flight International article, it explains the materials and processes use to build the rotor blades. What is interesting is that all the materials used were of 1930 - 1940s technology. I should also add, well documanted and proven technology.
To quickly summarize, first a .125 inch birch ply skin is laid. Then a strip of Ultra High Tensile (UHT) strength steel is glued to the plywood skin with Aerodux 185 resorcinol-phenol-formaldehyde resin adhesive. Then multi layers of Hydulignum (a Horden-Richmond Aircraft Company product of heat pressed thermoplastic resin laden plywood that was used to make propeller blades for British Aircraft during World War Two) laminates that are laid up to form the "D" structure spar, followed by one more layer of .125 inch birch ply skin. The outside of the blade is then covered with Madapolam, a cotton linen fabric and aircraft grade dope is used to glue down and seal the Madapolam. The following is a cross section of one of Ken Wallis wooden blades.
http://i289.photobucket.com/albums/ll224/my-pics-are-here/wallisblade.jpg
It is to my understanding that the wooden rotor blades on the WA-116 gyroplane "Zeus III" that Ken Wallis often seen flying in were manufactured by him well over 30 years ago! Now that is unlimited life rotor blades!
Wayne