Posted by Lee Stofer on January 05, 2003 at 20:34:06:
In Reply to: Hirsbrunner "nylon" rotors posted by Steve on January 02, 2003 at 09:38:28:
Steve,
These rotors were referred to as "tryplen" rotors, that consisted of a titanium shaft, a plastic valve core, and then a bronze outer shell. The HB-2 CC that my undergrad school owned as early as 1976 had tryplen rotors, and they were still in use in 1986, as the Army Ground Forces Band here in Atlanta has one that dates to then.
Lee Stofer