Checking the mags.. What's what?

[BellyUpFish]

OK, I'm going to show my ignorance, but that's ok..

I can't, for the life of me remember how this goes and had a guy picking up his private ask...

During a mag check, when selecting say, from "Both" to "R" are you-

A.) actually checking the left mag for function and "turning off" the right mag..

or

B.) actually checking the right mag for function and "turning off" the left mag..


Another scenario:

While doing a mag check and you go from "both" to "R" and get a good mag check.

Then go from "both" to "L" and it is running rough, is this the right mag that is bad or the left mag?

Seems like it's B but something in my "files" is telling me it was actually the opposite of what you think you are doing..

 

[COFlyBoy]

You are selecting the mag that is on. So item B was correct.

 

[BellyUpFish]

You are selecting the mag that is on. So item B was correct.

That's what I thought, but something kept telling me different..

 

[TMetzinger]

What's confusing is the switch sometimes goes OFF-R-L-Both, because the switch grounds the OTHER mag (so when you're on R, you're grounding L), and that's why the switch is "out of sequence".

 

[BellyUpFish]

What's confusing is the switch sometimes goes OFF-R-L-Both, because the switch grounds the OTHER mag (so when you're on R, you're grounding L), and that's why the switch is "out of sequence".

Makes sense..

 

[MachFly]

A good way to understand these things (not just mags) is what is selected is on. See you don't select something when you want it off, you select it when you want it on. For example when "both" is selected both are on, not off, or your caps lock key on the computer keyboard.

 

[Tom-D]

OK, I'm going to show my ignorance, but that's ok..

I can't, for the life of me remember how this goes and had a guy picking up his private ask...

During a mag check, when selecting say, from "Both" to "R" are you-

A.) actually checking the left mag for function and "turning off" the right mag..

or

B.) actually checking the right mag for function and "turning off" the left mag..


Another scenario:

While doing a mag check and you go from "both" to "R" and get a good mag check.

Then go from "both" to "L" and it is running rough, is this the right mag that is bad or the left mag?

Seems like it's B but something in my "files" is telling me it was actually the opposite of what you think you are doing..

Yep..

 

[Geico266]

FYI, when you turn the switch over to "Start" only the left mag is firing. That is so the impulse coupling can fire the left mag at 0 degrees TDC for easy starting. When released the key and it returns to "Both" then both mags are firing at 25 degrees before TDC.

Most experimentals have mag switches and you need to start on the left mag only. Ask me how I found this out, the hard way.

 

[timwinters]

FYI, when you turn the switch over to "Start" only the left mag is firing. That is so the impulse coupling can fire the left mag at 0 degrees TDC for easy starting. When released the key and it returns to "Both" then both mags are firing at 25 degrees before TDC.

Most experimentals have mag switches and you need to start on the left mag only. Ask me how I found this out, the hard way.

Interesting, I didn't know that.

What about us with push button starters? I always turn mags to both and push the button. Should I be on left only?

 

[Geico266]

Interesting, I didn't know that.

What about us with push button starters? I always turn mags to both and push the button. Should I be on left only?

Certainly not cast in stone so check the POH. I would think you would, but not all models are the same obviously. You might not have impulse couplings to retard the firing to zero TDC with a push button, or maybe the push button grounds out the right mag also? Do you have a key with Left Right Both?

 

[Anthony]

Certainly not cast in stone so check the POH. I would think you would, but not all models are the same obviously. You might not have impulse couplings to retard the firing to zero TDC with a push button, or maybe the push button grounds out the right mag also? Do you have a key with Left Right Both?

I can only speak for my Tiger which has had dual impulse couplers installed. I start on "Both", but others that don't have the dual impulse couplers start on "Left".

 

[Geico266]

I can only speak for my Tiger which has had dual impulse couplers installed. I start on "Both", but others that don't have the dual impulse couplers start on "Left".

I was too cheap to buy duals for my RV-10.

I opted for fine wire plugs to improve starting. Man what a difference on hot starts.

 

[Anthony]

I was too cheap to buy duals for my RV-10.

I opted for fine wire plugs to improve starting. Man what a difference on hot starts.

Yeah, but the RV-10 is the airplane the Tiger WISHES it could be. It solves many of the shortcomings, maybe all the shortcomings of a Tiger, albeit with two more cylinders. Horsepower is king! I forgot you had one. Very, very nice. What engine? (I know thread creap).

Looking at the RV-10 specs it is eerily similar to the STC'd re-engined, 260 HP, Saber Tooth Tiger.

 

[Dan Thomas]

FYI, when you turn the switch over to "Start" only the left mag is firing. That is so the impulse coupling can fire the left mag at 0 degrees TDC for easy starting. When released the key and it returns to "Both" then both mags are firing at 25 degrees before TDC.

Most experimentals have mag switches and you need to start on the left mag only. Ask me how I found this out, the hard way.

Not always. The small Continentals have the impulse mag on the right, so the right mag fires for starting. Things vary between engines. In the O-235, both mags are impulse mags.

Dan

 

[SCCutler]

Yeah, but the RV-10 is the airplane the Tiger WISHES it could be. It solves many of the shortcomings, maybe all the shortcomings of a Tiger, albeit with two more cylinders. Horsepower is king! I forgot you had one. Very, very nice. What engine? (I know thread creap).

Looking at the RV-10 specs it is eerily similar to the STC'd re-engined, 260 HP, Saber Tooth Tiger.

A Tiger with 260HP?

Hubba!

 

[Anthony]

A Tiger with 260HP?

Hubba!

Spike. There are only a few around. Ron knows a lot more about them, but yeah, the performance numbers are pretty impressive. The reason there are so few around is that it is pretty costly to do the conversion.

The RV-10 is really the way to go instead of doing the STC for the Tiger.

 

[timwinters]

Certainly not cast in stone so check the POH. I would think you would, but not all models are the same obviously. You might not have impulse couplings to retard the firing to zero TDC with a push button, or maybe the push button grounds out the right mag also? Do you have a key with Left Right Both?

Yes, keyed L/R/both switch w/ a pushbutton start hidden behind the floating panel.

POH? What's that?

My encyclopedic 74 page owner's manual says to start in the "both" position. I still have a copy of the voluminous 36 page owner's manual for the '57 172 that I used to own and it says "both" also.

 

[bsdunek]

That's why you have to know your airplane. Many Lycomings have the impulse on the left mag only. As Dan said, some Continentals have the impuls on the right mag only. My C-145 has impulses on both mags.
Know your airplane, or it may cost you a lot of money!