Lu you have always wondered where Frank Robinson's extra 18-degrees of phase angle went. Much searching has been done on PPRuNe over the years and it is time that the true story becomes known.
The honest to goodness truth is that; on a Saturday night in late October many years ago, Frank came up with the design that he wanted for his rotorhead. Before going to bed, he sketched this design on a sheet of paper, for the shop to make on Monday. Because he was quite tired, he simply used the hours of the clock to define the azimuths of the various components in the plan view.
The next morning he got up, took another sheet of paper, and sketched out the flight controls for this rotor. Again, he used the hours of the clock to define the azimuths of the various parts in the plan view.
On Monday the shop built the rotorhub and flight controls. The following day these parts were attached to the mast of a test helicopter. All the tests were a success. The Robinson hub was born and the rest is history.
Years later, Frank's biographer discovered that on that particular Saturday night the time changed. Frank had laid out the azimuths of the rotorhub during Daylight Saving time and then laid out the azimuths of the flight controls during Standard Time. This caused the controls to be out of phase with the rotorhub by one hour; so to speak. However, everything worked well, so it was decided that the lost phase angle would stay lost.
And lost it was, until the sleuth Sherlock Zuckerman (alias; Lu to a few) went looking for the elusive 17-degrees.
