akschu

akschu

Well Known Member
Patron
My efis vendor provides a hour and tach meter. Does this mean I can omit the seperate Hobbs/tach? If so is that advisable? Saving some money and panel space would be great.

Schu
 
Don't need it

I have the AFS 2500 engine monitor. It has flight and tach times. That's all you need.
 
My GRT EIS/EFIS provides all the Tach and time recording functions I need - and I haven't had a Hobbs in any airplane I've owned for 25 years!
 
If this is going to be an IFR plane, I believe you will need a clock/watch that you can reset it. I know it has a certain requirement but I don't remember the details. I use the one that is built in my transponder.

Mehrdad
RV7A - IO360M1B
 
Both of my Dynon's have hobbs features and count up and count down clocks.

No need for either a hobbs or a clock.
 
They do but I found them not very usable for IFR...probably because I only have a sigle Dynon.

The easiest way to get the required IFR timer is to buy an oven timer from Radio shack..They work really well for timing approaches.

Frank
 
One nice thing about the hobbs meter is it probably won't get upgraded. When you decided to switch from steam to glass or upgrade your glass you will still have the hobbs meter showing the total hobbs time.

I suspect you can manipulate the hobbs time on glass systems but I haven't tried.

That's about the only "pro" hobbs meter thing I can think of. That and you can stick your head in the plane anytime and see the total time without turning anything on.
 
Somebody with a 12 was grounded recently with a bad oil pressure sender. Anybody know if the oil pressure switch for the hobbs could be used as an independent low oil pressure warning? I guess it depends on how much pressure is required to close the switch.
 
boom3 said:
...I suspect you can manipulate the hobbs time on glass systems but I haven't tried...
Click to expand...
Yep, they can be set to any number you like.

mbell said:
Somebody with a 12 was grounded recently with a bad oil pressure sender. Anybody know if the oil pressure switch for the hobbs could be used as an independent low oil pressure warning? I guess it depends on how much pressure is required to close the switch.
Click to expand...
By ?12?, I?m assuming you are talking RV-12. If that is the case, there is no need for such a warning with the Dynon. You simply set the alarm to go off at a given high or low oil pressure. You then get a red bar across the bottom of your screen and a tone in your ear. As I said, no need for a separate alarm.
 
mbell said:
Somebody with a 12 was grounded recently with a bad oil pressure sender. Anybody know if the oil pressure switch for the hobbs could be used as an independent low oil pressure warning? I guess it depends on how much pressure is required to close the switch.
Click to expand...

Mine is suppose to close at around 15 lbs.
 
I guess I wasn't clear. It sounds like the Rotax sender is less than reliable. If it fails in flight but the Hobbs switch doesn't indicate low oil pressure then there's no urgent need to get back on the ground, or to be stranded somewhere. Again, unless the Hobbs switch turns on at a really low pressure.
 
I have a mechanical Hobbs and really like that it is "always on" in terms of seeing the time. I usually forget to look at the Dynon timer until after I shut down, which means I would have to power up again to see the Dynon Hobbs.

greg
 
If the EFIS fries itself..

....you can't reliably state your engine/airplane's total time. I think that a separate, small Hobbs is good for many of the above reasons....just a glance in the cockpit for TT after an annual while you're filling out the logbooks.

My .02c,
 
I installed a separate Hobbs clock...

...and also use the electronic Hobbs / Tach built into the AFS engine monitor. The Hobbs is mounted on the instrument sub-panel, so the only way to view it is on the ground with the tip-up...tipped-up.

The reason is, I fully expect the electronic gizmos to fry at a time and place of their own choosing, and if (when) the engine monitor contributes its mass to the great smoke cloud in the sky, I will have a Hobbs clock that I can refer to for maintenance log entries.
 
pierre smith said:
....you can't reliably state your engine/airplane's total time.
Click to expand...

This will most likely be another religious discussion with no correct answer, just the one you like the most.

In my Cherokee, the tachometer had been replaced several times over thirty year period. You just had to go through the logs to find total time. I suspect the same would be true for EFIS.

Also, the Hobbs meter died shortly after I purchased the Cherokee, so they aren't 100% full proof either. I took it out and replaced it with another device that had an electronic timer.

I'm just going to use the EFIS timer in my RV-10. My recommendation is to install whichever device your prefer. The opinion that counts is yours.
 
Your logs will....

pierre smith said:
....you can't reliably state your engine/airplane's total time. I think that a separate, small Hobbs is good for many of the above reasons....just a glance in the cockpit for TT after an annual while you're filling out the logbooks.

My .02c,
Click to expand...

I would think your logs would reliably state that.
In regard to being able to reset your own, I know the JPI requires you to return it to the factory to be reset. Not sure if they would ask any questions or not. Hobbs meters can be manipulated too. So, nothing reliably states the TT except the honesty of the owner.
 
Dont forget that if you turn on your x96 GPS for every flight, it records them all (dates, flight times, destinations, etc) and makes it very easy to fill out your log book at a later date.

erich
 
Hobbs vs. Tach

Hobbs meters are not needed or required in your plane. They are for billing purposes for rental planes. All maintenance and records should be in tach time. The hobbs meter runs from start up to engine shutdown and you could conceivably reset it to zero before each flight (of course they are not designed for doing that). The tachometer ticks off time based on engine RPM so will click off time slower than a hobbs meter.

To get your flight time simply look at your watch or take your tach time and multiply by 1.3.

The GRT records tach time and displays flight time separately but the flight timer does not start timing until certain parameters are met. This time always seems to be somewhere between hobbs and tach time. I use it mostly for my fuel tank change time.
 
It's Hobbs and EFIS for me

I kept my electro-mechanical Hobbs meter when I installed my AFS 3400 EFIS. I glad I did since it takes about a minute for the EFIS to boot and I use the Hobbs for measuring flight time for my log book after each flight. Having to wait a minute just to get the time would be a pain.
 
You must log in or register to reply here.