Hobbs

Larry R wrote:
Ok, I am *almost* embarrased to ask this question, but here goes. Do
Hobbs meters ever "go bad"?

Sure, it's a mechanical device.

On two occasions over the last few years, my Hobbs has failed to move.

For this reason, I always note my tach time and time off. The extra
start numbers will help just in case I don't notice for a while that the
Hobbs isn't running, and I need to have a fuel consumption figure.

In article ,
B A R R Y wrote:

Larry R wrote:
Ok, I am *almost* embarrased to ask this question, but here goes. Do
Hobbs meters ever "go bad"?

Sure, it's a mechanical device.

On two occasions over the last few years, my Hobbs has failed to move.

For this reason, I always note my tach time and time off. The extra
start numbers will help just in case I don't notice for a while that the
Hobbs isn't running, and I need to have a fuel consumption figure.

Sometimes, unscrupulous owners will wire the Hobbs to the master switch,
so you get charges whenever the MS is ON.

I have hated Hobbs ever since I discovered them 40+ years ago, since you
pay full rate for taxi and hold times.

An air switch is available, but hardly anybody uses them.

On 7/2/2007 3:31:14 PM, Orval Fairbairn wrote:

Sometimes, unscrupulous owners will wire the Hobbs to the master switch,
so you get charges whenever the MS is ON.


Isn't that true for the Hobbs installed by the aircraft manufacturer in newer
aircraft? I was taught that all the newer model C172s' Hobbs are wired to the
master, which results in about a 20% greater difference between their
readings and the tach.

--
Peter

On Mon, 2 Jul 2007 16:35:20 -0400, "Peter R."
wrote:

On 7/2/2007 3:31:14 PM, Orval Fairbairn wrote:

Sometimes, unscrupulous owners will wire the Hobbs to the master switch,
so you get charges whenever the MS is ON.


Isn't that true for the Hobbs installed by the aircraft manufacturer in newer
aircraft? I was taught that all the newer model C172s' Hobbs are wired to the
master, which results in about a 20% greater difference between their
readings and the tach.

The new 172,182,206 are all activated by oil pressure not the master
switch.

On 7/2/2007 4:42:14 PM, Peter Clark wrote:

The new 172,182,206 are all activated by oil pressure not the master
switch.

Ah, OK, then I was taught incorrectly. But then again, it has been at least
five years since I actually cared about a Hobbs meter.

--
Peter

On Mon, 2 Jul 2007 17:06:55 -0400, "Peter R."
wrote:

On 7/2/2007 4:42:14 PM, Peter Clark wrote:

The new 172,182,206 are all activated by oil pressure not the master
switch.

Ah, OK, then I was taught incorrectly. But then again, it has been at least
five years since I actually cared about a Hobbs meter.

No problem. It is rather hard to keep track of all the different
hobbs hookups.....

On Mon, 2 Jul 2007 16:35:20 -0400, "Peter R."
wrote in :

I was taught that all the newer model C172s' Hobbs are wired to the
master,

Usually there's an oil pressure switch in series with the Hobbs meter,
so that it is only energized when the engine is running. I have no
idea if that is true of the newer aircraft, but it should be.

Peter R. wrote:
On 7/2/2007 3:31:14 PM, Orval Fairbairn wrote:

Sometimes, unscrupulous owners will wire the Hobbs to the master switch,
so you get charges whenever the MS is ON.


Isn't that true for the Hobbs installed by the aircraft manufacturer in newer
aircraft? I was taught that all the newer model C172s' Hobbs are wired to the
master, which results in about a 20% greater difference between their
readings and the tach.

Bonanza's don't even have recording tachs anymore. All they have is the
hobbs. My plane is similar, but it's on the gear so I don't pay for taxi.

On 7/3/2007 6:50:49 AM, Ron Natalie wrote:

Bonanza's don't even have recording tachs anymore. All they have is the
hobbs. My plane is similar, but it's on the gear so I don't pay for taxi.

Interesting. So Hobbs time is what gets logged in the aircraft/engine
logbooks?

--
Peter

Peter R. wrote:
On 7/3/2007 6:50:49 AM, Ron Natalie wrote:

Bonanza's don't even have recording tachs anymore. All they have is the
hobbs. My plane is similar, but it's on the gear so I don't pay for taxi.

Interesting. So Hobbs time is what gets logged in the aircraft/engine
logbooks?

Exactly. Time in service.