Many years ago, about 1970, I acquired a pair of Hughes-269 rotor blades that the previous owner had sawed a taper at the root end to mimic Bensen metal blades. His attempts at flying them on a gyro had ended in failure; broke ground but just barely.
I recognized the built in “helicopter” twist of 8 degrees was backwards for gyro use and the blades would have to be inverted and run in the opposite direction to suit a gyro.
Anyhow, as I set out to build a hub, my good friend Willy (WA Roberts) said, “Chuck, them things won’t autorotate.” I said, “Why not, Willy, they autorotate on a helicopter?” Willy replied,”autogyro blades have to be flat bottomed.”
Anyhow, fly they did, outperforming existing metal gyro blades including Bensen, Rotordyne and Stanzee.
In 1972 for the PRA flyin at Rialto CA, I disassembled my gyro, built a crate for it and shipped it to Rialto. People in Rialto just couldn’t believe some nut from Florida would try to fly with symmetrical airfoil rotor blades but fly it did, out performing traditional rotor blades. I let everyone at Rialto who wanted to fly my Hughes rotor on their own gyro do so. We had to safety wire the Bendix prerotator gear down to keep it from engaging from a “backwards” rotor. Most people just couldn’t get over how much better it flew than their existing rotor, commenting about how much cooler the Mac ran when flying my Hughes blades.
So, here we are 50 years later, still hung up on the same misconceptions and still using Bensen’s 8H12 miscarriage. The NACA 8H12 was an early NACA attempt at fitting a laminar airfoil to a helicopter. Didn’t work because laminar boundary layers don’t stay attached under the influence of centrifugal force on rotors or propellers.
I recognized the built in “helicopter” twist of 8 degrees was backwards for gyro use and the blades would have to be inverted and run in the opposite direction to suit a gyro.
Anyhow, as I set out to build a hub, my good friend Willy (WA Roberts) said, “Chuck, them things won’t autorotate.” I said, “Why not, Willy, they autorotate on a helicopter?” Willy replied,”autogyro blades have to be flat bottomed.”
Anyhow, fly they did, outperforming existing metal gyro blades including Bensen, Rotordyne and Stanzee.
In 1972 for the PRA flyin at Rialto CA, I disassembled my gyro, built a crate for it and shipped it to Rialto. People in Rialto just couldn’t believe some nut from Florida would try to fly with symmetrical airfoil rotor blades but fly it did, out performing traditional rotor blades. I let everyone at Rialto who wanted to fly my Hughes rotor on their own gyro do so. We had to safety wire the Bendix prerotator gear down to keep it from engaging from a “backwards” rotor. Most people just couldn’t get over how much better it flew than their existing rotor, commenting about how much cooler the Mac ran when flying my Hughes blades.
So, here we are 50 years later, still hung up on the same misconceptions and still using Bensen’s 8H12 miscarriage. The NACA 8H12 was an early NACA attempt at fitting a laminar airfoil to a helicopter. Didn’t work because laminar boundary layers don’t stay attached under the influence of centrifugal force on rotors or propellers.
