How to use the 8 Day Clock

[corn_flake]

This is going sound crazy.  Does any one have instructions on how to use the 8 day clock.  I figured out how to "wind up" the clock by turn the knob on the lower left corner.  I can also adjust the time by pulling the knob out.  What I can't figure out is the purpose of the red long hand and red short hand.  If I turn the center knob clock-wise. It makes clicking sound and move the red long along at the same rate.  The red short hand seems to move some of the time when turning the center knob clock-wise, but stay still at other times.  If I turn the center knob counter-clock wise, both red long and short hands move counter-clock wise at the same rate.  

Also, my clock loses about 30 minutes in 24 hours.  Is this normal for a clock from the 60s?  

Edited October 6, 2019 by corn_flake

[Jerry 5TJ]

The 8 day clock in my 64 E not only kept perfect time, it added lots to it.  There is a mechanical adjustment inside the housing and you may be able to adjust it.  But it won’t be as accurate as a cellphone linked to GPS.  

The red hands are for timing turns, legs, and approaches.  They will work just fine for you if glance at your iPad to verify things now and then.  

[N201MKTurbo]

Mechanical clocks should be serviced every 5 years. Yours probably hadn’t been cleaned or oiled in 55 years. It’s a miracle it works at all! 

[Andy95W]

These folks have a booth every Airventure and are located in OSH.  They say they will work on these clocks, might be worth a call.

https://millerclockservices.com/

[RLCarter]

I'd talk to a local watch repairman, they should be able to repair/clean/adjust it

[Hank]

Wind at the bottom left, as you've been doing. Pull out on the winding stem and set the time (backwards, forwards, whatever). On my checklist (from the Owners Manual), I wind and set at the beginning of each flight.

The red hands use the little brass knob in the middle of the face. First wind and set the clock (white hands). Spin the center knob CCW until the red & white hour hands overlap, then spin CW until the minute hands overlap. Every time the minute hands overlap again, lean down and switch your fuel tank. When you shut down, the difference between the red and white hand sets is the flight time for your logbook.

Since this clock is used to time your flights, hourly fuel tank switches, those annoying ATC calls about when to expect further clearance and a diminishing  number of instrument approaches, does the accuracy beyond your maximum fuel endurance really matter?    Yes, I'm a little punchy after 1.5 hours in a Cessna (4 flights) followed by 4 Mooney hours home into the wind, hitting storms at sundown . . . . But some good bourbon made it all better, but may not do much for my posts.

[corn_flake]

Thanks @Hank That's exact what I'm looking for.  In another word, the red hand doesn't move once it is set.  It is used to mark the beginning of flight.  

[mark21m20c]

I had mine overhauled in June .

Jacobs instruments 1822 S Longfellow cir  #12 Wichita KS 67207.

The price for overhaul was $224.07 shiping included . They did a very nice job it looks like new . I set my red hands for off time( Takeoff time) works great. It would cost to much to build that clock today.

[tigers2007]

Sounds like it’s time for a nice Davtron digital clock. Ever since the hangar fairy repaired the wiring it’s been gold.


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[BDPetersen]

All I know is that when Mickey’s big hand is on the 12 and his little hand is on the 5 it’s time for the early bird specials . . .

[Shiny moose]

Don't over wind these clocks, meaning don't wind up to the stop tightly.

In my early days of flying it was said if the wind up  clock don't work,  you don't fly the plane.

 

[1964-M20E]

12 hours ago, Shiny moose said:

Don't over wind these clocks, meaning don't wind up to the stop tightly.

In my early days of flying it was said if the wind up  clock don't work,  you don't fly the plane.

 

Yeah that 's because the clock was connected to the big fan up front.  Now we have much better rubber bands. 

[corn_flake]

After fiddling with the clock for few days, I noticed it is rather inconsistent in its ability to keep time.   It may start out with 10 second faster in the first 10 minutes.   For the next 30 minutes, it may end up with 90 seconds slower.  Should I even consider sending this in for overhaul or just buy a digital replacement?  In another word, will a overhaul bring the accuracy of this clock to at least +/- 5 seconds for 24 hours period?  

[carusoam]

In a one word answer... yes...

Clock cleaning and lubrication can cost a few bucks...

Sounds like you will be happier with a more modern digital solution...

If you have a few mechanical watches and a grandfather clock that requires winding, at home.... this is a perfect addition to your collection...

For more detail about your clock... find the word wakmann around here... https://mooneyspace.com/search/?&q=Wakmann&search_and_or=or&sortby=relevancy

Wakmann belongs to a big name in time pieces...

Best regards,

-a-

[N201MKTurbo]

These mechanical clocks are amazing machines. Most people don’t realize the level of mechanical perfection that they represent. The metal used in hair springs cost about twice as much as gold to manufacture. It has amazing temperature characteristics that took about 100 years to perfect. 

https://en.m.wikipedia.org/wiki/Elinvar

[chriscalandro]

Mine has been being rebuilt for just about a year now. I should probably check up on it....