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Quick question.

My tach quit on my last flight to KSLC. SLC no longer has any GA maintenance on the field. They do have an avionics shop that can install a digital RPM gauge I ordered, but can't get to it til the end of May because of all the ADSB procrastinators. Any chance the FAA will issue a ferry permit? My mechanic really doesn't want to do the install at my shade hangar.

Thanks

 

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I knew someone who flew a Mooney home from Oshkosh with a portable optical Tach. 

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No work takes 15 minutes on airplane, let alone digital Tach replacing mechanical. 

But Chris is right, see if your A&P would sign your install. It is not that hard.

 

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9 minutes ago, gsxrpilot said:

I knew someone who flew a Mooney home from Oshkosh with a portable optical Tach. 

I have used a tachometer app on my smartphone to test the digital tach after installing an engine monitor.

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51 minutes ago, gsxrpilot said:

I knew someone who flew a Mooney home from Oshkosh with a portable optical Tach. 

 

51 minutes ago, gsxrpilot said:

I knew someone who flew a Mooney home from Oshkosh with a portable optical Tach. 

That's what my mechanic is checking on.

Thanks

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Is the cable bad? After pulling the top engine panel and the avionics top panel it takes only one minute to unscrew the 1930’s style tach cable and inspect the ends. A replacement cable is $90 or so from Spruce and only takes about 15 min to replace.
My ‘64 M20D takes a 35” Right-Lay style cable. Read the literature on how to properly measure and feel free to talk to an Aircraft Spruce product support specialist if you need advice on ordering a cable

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Cables break if not kept lubricated, so check that first as an easy fix. I‘d unscrew it at the tach and pull the cable core out to check.

You don’t need the tach to safely operate the engine - just leave the prop set to high rpm and set appropriate MAP.

Ferry permits are at discretion of the local FSDO but an inop tach shouldn’t be a problem. 

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Cable is broken. The Mooney replacement is $325 from the factory. With that price I decided to go digital.

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“Engine RPM” app for my iPhone is accurate to within 25 RPM from my tach.


Sent from my iPhone using Tapatalk

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Cable is broken. The Mooney replacement is $325 from the factory. With that price I decided to go digital.

Nothing wrong going digital but a new cable is $90. It’ll last you ownership of the plane.

Three installation options:
1. Hangar Fairy Magic
2. A&P
3. Owner per guidance of Coleal Letter/ Decision; (may perform) “simple or minor preservation operations[tasks]” and “replacement of small standard parts not involving complex assembly operations”.
Removing and replacing the cable is literally unscrewing each end. There is a firewall seal that is two bolts. That’s it. The cable is so much a “standard” part that the design is used universally for cars trucks boats and planes.
Obviously if you’re not up to the task I would contact an A&P.
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5 hours ago, Igor_U said:

No work takes 15 minutes on airplane, let alone digital Tach replacing mechanical. 

But Chris is right, see if your A&P would sign your install. It is not that hard.

 

You got that right, mine failed but was the tach not the cable.  replaced with a digital primary unit took a couple hours but was simple job. 

 

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Don Maxwell once told me that the R1 Tach was the only replacement tach he'd install. If you brought him a Mooney with a broken tach, you were getting an R1 (if not full primary engine monitor like the EDM900) or you'd have to go somewhere else. That was good enough advice for me.

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39 minutes ago, gsxrpilot said:

Don Maxwell once told me that the R1 Tach was the only replacement tach he'd install. If you brought him a Mooney with a broken tach, you were getting an R1 (if not full primary engine monitor like the EDM900) or you'd have to go somewhere else. That was good enough advice for me.

I wish I had that kind of power over my customers!

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23 minutes ago, M20Doc said:

I wish I had that kind of power over my customers!

If my Mooney is ever in your shop, I will absolutely take your advice! No questions asked!

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I heard about 3 half turns out puts you about where you want to be for cruise and all the way to the firewall for take off and landing works well to.

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Broken Tach cable?     All it is a standard  car speedo cable

Unscrew both ends, pull cable out of housing from engine end and instrument end to get both pieces for the correct length

Find a hot rod shop that does speedo cables and get the correct spiral wrap lay and have them square the instrument end and squeeze the drive end on.    Get some light grease  (synthetic wheel bearing grease will do or Lubriplate in a small tube at the auto shop) and lube the cable as you push it in from the engine end. Rotate the engine end drive fitting as you hook up the instrument end (to align the square drive)  and slide it into the instrument.  Screw on the engine end and then tighten the instrument end.  End of job card!  Maybe $30. Your A&P can sign it off. "Replaced tach cable" .      Make it an OPP if you want.   

No different than making up flexible oil lines for an A&P but nobody wants to do it any more. Same with grinding valves in cylinders. Used to be a normal shop activity. Pull the jug , grind the valves, hone the cylinder and reassemble with new rings.  Most A&Ps today are just parts changers. Repairing anything is a lost art now. 

Sorry my old curmudgeon attitude is showing.  

BTW, constant speed prop?  Leave it full forward and fly it home. Its been done many times, probably thousands of times. Can't over speed the engine. 

Edited by cliffy

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5 hours ago, gsxrpilot said:

Don Maxwell once told me that the R1 Tach was the only replacement tach he'd install. If you brought him a Mooney with a broken tach, you were getting an R1 (if not full primary engine monitor like the EDM900) or you'd have to go somewhere else. That was good enough advice for me.

The SLI tach works great. 500 hours in, its within 10-20 rpm of my JPI830

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1 hour ago, cliffy said:

Broken Tach cable?     All it is a standard  car speedo cable

Unscrew both ends, pull cable out of housing from engine end and instrument end to get both pieces for the correct length

Find a hot rod shop that does speedo cables and get the correct spiral wrap lay and have them square the instrument end and squeeze the drive end on.    Get some light grease  (synthetic wheel bearing grease will do or Lubriplate in a small tube at the auto shop) and lube the cable as you push it in from the engine end. Rotate the engine end drive fitting as you hook up the instrument end (to align the square drive)  and slide it into the instrument.  Screw on the engine end and then tighten the instrument end.  End of job card!  Maybe $30. Your A&P can sign it off. "Replaced tach cable" .      Make it an OPP if you want.   

No different than making up flexible oil lines for an A&P but nobody wants to do it any more. Same with grinding valves in cylinders. Used to be a normal shop activity. Pull the jug , grind the valves, hone the cylinder and reassemble with new rings.  Most A&Ps today are just parts changers. Repairing anything is a lost art now. 

Sorry my old curmudgeon attitude is showing.  

BTW, constant speed prop?  Leave it full forward and fly it home. Its been done many times, probably thousands of times. Can't over speed the engine. 

The prop thing has happened to me twice now. governor arm broken.  NBD.  

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"Leave it full forward"-  Only if the tach cable is broken Nothing else,     :-) :-)

Have a good story on a prop control arm on a P-51 breaking  in a Finals Unlimited race 45 years ago. 

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13 hours ago, Rjfanjet said:

Quick question.

My tach quit on my last flight to KSLC. SLC no longer has any GA maintenance on the field. They do have an avionics shop that can install a digital RPM gauge I ordered, but can't get to it til the end of May because of all the ADSB procrastinators. Any chance the FAA will issue a ferry permit? My mechanic really doesn't want to do the install at my shade hangar.

Thanks

 

Wow KSLC has changed a lot since I used to instruct out of there. They were always trying to push GA out, but didn't think maintenance would go too. Hopefully they will at least start taking better care of U42 now. 

I used to deal with the KSLC FSDO and they may issue a permit, but when is the question. You could take the plane apart, flatbed it, and drive it to your mechanics house before they would even look at the request. Should be a really quick fix though like others have said.

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I think it’s a 91.205 required instrument. Whether they’ll issue a ferry permit will be interesting.  We went to AirMods a couple weeks ago. They have to trailer their planes in there from gear-up landings which adds a ton of costs. Their FSDO says “no ferry permits”

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