Piper Seminole Hobbs Question???

[Driven]

I have heard many different rumors from many different people and was wondering if someone could put an end to this nagging question I have?

Do the older Piper Seminole Hobbs run off of one engine. Eg. If I only run the left engine will the hobbs not click over or will it, and visa versa.

Thanks for an input, this is probably a really silly question to be asking but I really would like to find an answer.

 

[Superpilot92]

it goes off of the right engine. so if you are paying for it then taxi out on the left engine. why do you think your instructor always shuts down the left engine all the time???

 

[wheelsup]

it goes off of the right engine. so if you are paying for it then taxi out on the left engine. why do you think your instructor always shuts down the left engine all the time???

In all the pipers I've been in the hobbs was connected to the battery master. Not sure if that's true for the seminole (can't remember) but that was the way it worked in the arrow, 6, and seneca, and it wouldn't surprise me if it worked that way in the seminole...

~wheelsup

 

[erj-145mech]

When we bought new planes, we spec'd them out without hour meters. We could install them cheaper than what the factory charged for them. On the twins, we used air switches on the bellys to activate the hour meters. Once you reached 20-25 kts, it started to tick away. For a power source, we came off of the hot side of the master relay, like the clock, so that the position of the battery switch made no difference.

We used the planes for charter work, so we didn't want to count taxi time against maintenance. The instructors also didn't teach the lesson plans in the plane, on the ground, with the engines running either. Everything was briefed before the flight began.

 

[User546]

On the twins, we used air switches on the bellys to activate the hour meters. Once you reached 20-25 kts, it started to tick away. For a power source, we came off of the hot side of the master relay, like the clock, so that the position of the battery switch made no difference.

So wouldn't it be possible for the Hobbs meter to be running if the airplane was tied down on the ramp with a stiff headwind?

 

[BushwickBill]

So wouldn't it be possible for the Hobbs meter to be running if the airplane was tied down on the ramp with a stiff headwind?

Sure if you turned the master on...

Seriously, though on the new model seminole vesicle you can turn the master off when your taxing, just be sure to bring your handheld to keep it "safe" and then you can shave a bit of time off the hobbs. I guess it would work if no one noticed the beacon was off. I never did it but was tempted, .1 on 200 bucks an hour is 20 bucks.

 

[User546]

Sure if you turned the master on...

But our Mechanic friend here said...

For a power source, we came off of the hot side of the master relay, like the clock, so that the position of the battery switch made no difference.

Without getting too technical here, isn't the master essentially the same as the battery switch? Those Piper clocks still continue to run even after you remove all electrical power from the aircraft.

 

[BushwickBill]

But our Mechanic friend here said...

Without getting too technical here, isn't the master essentially the same as the battery switch? Those Piper clocks still continue to run even after you remove all electrical power from the aircraft.

yeah i guess it wouldn't matter if the master was on or off.

 

[erj-145mech]

So wouldn't it be possible for the Hobbs meter to be running if the airplane was tied down on the ramp with a stiff headwind?

We didn't have that problem. I'm not and aerodynamic expert, and I've done my share of work on the ramp, but the wind doesn't seem as stiff under an aircraft when I'm outdoors. Maybe the landing gear and doors disturb the airflow that close to the ground, conjucture on my part. The only consistant problem that we encountered was the linemen breaking off the airswitch vanes while they were washing the aircraft.

 

[NoPax]

I flew a 402 with 2 hobbs on it

1 - master switch on - billing hobbs
2 - gear up - mx hobbs

I never understood it, though it was aerial survey, so I could see the need for billing hobbs, given the computers and laser in the back, and we started working the minute the master was on.

 

[kaj837]

Had a Dutchess once that had the Hobbs wired to the radio master.

 

[CRJ puppy]

The hobbs meters could be wired any number of ways and as has been stated, it is not unusual to have two hobbs on a plane, like the Seminole; one for "billing" and one for maintenance. The "billing" hobbs could be wired to the master switch, to engine oil pressure, to weight off wheels; which ever way the owner chose to have it wired. The maintenance hobbs usu. are oil pressure activated or weight on (off) wheels activated.

If you are into trying to save money so much that you're trying to figure out how to defeat the hobbs switch, may I respectfully suggest that you consider another career. You will be horribly dissapointed on your return on investment in flying!