Dennis Wingo Status update, late morning, January 8, 2014
Well we are back in the saddle again! Have run two tapes with the head that we though was having bearing problems with no trouble.
The way these heads work is that you have four head tips mounted at 90.00 degrees angle from each other on a rotary drum. The drum with the tips rotates against the tape at 15,000 rpm. The tape is moving by at 12.5 inches per second and thus a relationship between the two is fixed. Any drag on the head or slowing down or speeding up of the tape transport throws this timing off. Since we are dealing with RF signals in the Mhz range, timing is everything.
The magnetic flux is converted into a current at the tips and the windings on the tip. The current is transferred from the rotary drum to what is called a rotary transformer as you cannot have a wire carrying signal from the rotating drum to the fixed head assembly. There are several mechanical parts that have to fit together very closely, yet not rub against each other in order for this to work. What we were getting yesterday was a drag of the rotary part against the fixed part of the head. It was extremely subtle, slowing the head down just a bit, but you could hear the sound.
Ken Zin spent a lot of time checking adjustments and he readjusted the relationship between the mechanical parts and now the head is working fine. This goes to show just how important it is to have someone with a lot of experience in this field working on the project.
We are through tape G4-035 today and current G4-036 is running. This means we are down to 441 tapes to go!
Official website of the Lunar Orbiter Image Recovery Project (LOIRP)