Jump to content

Mags: IRAN Or Exchange?


AlexLev

Recommended Posts

11 hours ago, jetdriven said:

they replace the impulse coupler spring and fly weights every 500hr?

I’m not sure why they replaced the spring, but there was an SB on the distributors.  The mags come back like new, and haven’t missed a beat on this Mooney.

Clarence

Link to comment
Share on other sites

I went with Aircraft Magneto Service per advice of the MSr’s here. This is what I paid for exchanged units in Nov 2017:
d0dde36e845fbf34d016393c3975200e.jpg
Minus the 300 core fee so $1582 plus return shipping of the cores.

  • Like 1
Link to comment
Share on other sites

45 minutes ago, M20Doc said:

From these pages, my guess is that more mags fail to say attached to the engine because of poor installation, than mags that fail internally.

 

I would agree with you there is a lot of poor installations, and poor installations have a far more catastrophic effect which is why they are so notable. 

However, I would want you to think about coils for a minute. You notice they are missing from your picture and that is no reflection on those folks in Montana. They are the best in the world IMHO, but they follow the book in a competitive business. Think about this. We can visually (sometimes with a glass) inspect everything in the magneto but the coil and make a statement about its condition. The one thing we cannot inspect is the coil. Nor can we stress test a coil. Sure we can test the resistance, but we know resistance changes dramatically with heat, but more important, the dielectric properties of the insulation within the coil break down under heat and long term vibration. So we replace everything we can visually check, but do little with the one component we cannot faithfully inspect. Does that make sense?

Nor are the effects of poor coil performance immediately apparent. It backs up onto the points and condenser and sometimes aids the aging of the caps and wires. People are often at a loss about point deterioration blaming the condenser when in fact, it is bad coil performance.

I had an old auto mechanic who told me on battery systems, to replace the coil every 50K miles. I was part a the classic car community and I found his advice resulted in a lot less point maintenance. He also issued a caveat that if it was a Lucas system, every 20K because well, Lucas is the prince of darkness. :)

Link to comment
Share on other sites

6 hours ago, MikeOH said:

As a career EE I'm not so sure it is as 'crazy' as you think.  Beyond the dependence upon EXTERNAL electrical power, I have seen enough ESD caused electronic component failures to be VERY nervous with both mags being electronic.  Nearby lightning strike comes to mind.  Further, beyond easy starts (and, one E-mag will do that) I'm not convinced they provide much, if any, benefit for a stationary engine such as those in our aircraft.

I'm happy to keep my tractor mags:D

From what I understand, the bold is no longer the case.  

You may have a point with ESD... I would hope these things are shielded for that very reason.  I mean there are a plethora of jets flying around on FADEC.

You may also be correct about starting being the only major benefit, Especially in a TCed aircraft. 

Link to comment
Share on other sites

2 hours ago, Austintatious said:

From what I understand, the bold is no longer the case.  

You may have a point with ESD... I would hope these things are shielded for that very reason.  I mean there are a plethora of jets flying around on FADEC.

You may also be correct about starting being the only major benefit, Especially in a TCed aircraft. 

So far only electroair and Surefly are approved and neither self generate.  EMag has self generating mags but only experimental.  They’ve been taking many years to try to bring it to certification.  There are experimental guys flying with 2 Emags, but not for us yet.

Link to comment
Share on other sites

22 minutes ago, Ragsf15e said:

So far only electroair and Surefly are approved and neither self generate.  EMag has self generating mags but only experimental.  They’ve been taking many years to try to bring it to certification.  There are experimental guys flying with 2 Emags, but not for us yet.

As panels go glass and vacuum systems are removed, could a generator be installed on the vacuum pump pad and used as the separate power source for a second E mag?  Field approval, maybe?

tom

Link to comment
Share on other sites

2 minutes ago, 47U said:

As panels go glass and vacuum systems are removed, could a generator be installed on the vacuum pump pad and used as the separate power source for a second E mag?  Field approval, maybe?

tom

There are backup generator installations that go on the vacuum pump pad.   They'll power a lot more than just an E-mag.   

Link to comment
Share on other sites

Just now, EricJ said:

There are backup generator installations that go on the vacuum pump pad.   They'll power a lot more than just an E-mag.   

Absolutely!  Just like the co-pilot’s instrument generator that ran off the right hydraulic system on my -135 (back in the day).  Good discussion for an emergency or secondary bus to power part of that glass panel if the alternator quits.  Better solution than emergency battery power, I think.

tom

Link to comment
Share on other sites

If you wanted to power an electronic mag in a fail safe manner,  easy. Use a PMA. Permanent Magnet alternator encased with the unit. That is how a lot of FADECs on turbines are powered. Newer PMA's have a very strong field that can generate lots of juice.

 

 

Link to comment
Share on other sites

48 minutes ago, GeeBee said:

If you wanted to power an electronic mag in a fail safe manner,  easy. Use a PMA. Permanent Magnet alternator encased with the unit. That is how a lot of FADECs on turbines are powered. Newer PMA's have a very strong field that can generate lots of juice.

 

 

That’s how Emags works.  Only it’s not yet certified.

Link to comment
Share on other sites

2 hours ago, EricJ said:

There are backup generator installations that go on the vacuum pump pad.   They'll power a lot more than just an E-mag.   

Agreed, those are an option, but if I was using it as a failsafe for my electric mags I wouldn’t want it connected to anything else in the electrical system. A total electrical failure is bad enough without the engine going silent for lack of spark!  A PMA type arrangement self contained within the mag is probably the safest bet, but then we’re pretty much back to our traditional mags.

Link to comment
Share on other sites

No, we are much better off. We still have coil, but not a weak reversing coil, and we don't have points. We would also have variable timing, and a hotter spark. If you want LOP operations you must have a strong and durable spark. How do you think automobiles get away with .065 gaps? More voltage equals more potential to jump the gap and the larger the gap, the bigger the spark. In all my years of aviating with thousand of hours flying PMA's,  I have never seen a PMA fail.

 

Link to comment
Share on other sites

27 minutes ago, GeeBee said:

No, we are much better off. We still have coil, but not a weak reversing coil, and we don't have points. We would also have variable timing, and a hotter spark. If you want LOP operations you must have a strong and durable spark. How do you think automobiles get away with .065 gaps? More voltage equals more potential to jump the gap and the larger the gap, the bigger the spark. In all my years of aviating with thousand of hours flying PMA's,  I have never seen a PMA fail.

 

I agree, and yet Emag hasn’t been able to get theirs certified yet.  

Link to comment
Share on other sites

5 hours ago, GeeBee said:

No, we are much better off. We still have coil, but not a weak reversing coil, and we don't have points. We would also have variable timing, and a hotter spark. If you want LOP operations you must have a strong and durable spark. How do you think automobiles get away with .065 gaps? More voltage equals more potential to jump the gap and the larger the gap, the bigger the spark. In all my years of aviating with thousand of hours flying PMA's,  I have never seen a PMA fail.

 

Hmm, I'm not nearly as certain as you are that we are that much better off.  With a stationary engine variable timing isn't as advantageous as it is on, say, an automobile engine.  True, no points, but FETs used to switch inductive loads (i.e. the coil in ANY mag, EMAG or conventional) exhibit several nasty failure modes (read catastrophic).  Plus, all the control circuitry has been added vs. a three component system (coil, points, capacitor).  No idea how many transistors in that...and, you know what they say, "If it has tires, t*ts, or transistors it's eventually gonna give you trouble":D)

No argument on the PMA; very reliable (but I still of them as mags:))

  • Haha 1
Link to comment
Share on other sites

24 minutes ago, GeeBee said:

So which has a higher failure rate on cycles, points or FET's?

We have FET's going 1 million miles in giant electronically controlled diesels as cam sensors. 

 

A cam sensor (position sensor) application is NOT the same as switching a high current INDUCTIVE electrical load.

As far as reliability, I'd say points by a long shot...the caveat is they need to be inspected and serviced/replaced at proper intervals. It's not a question of cycles, it's a question of unintended transient events; points are immune, FETS not so much.  And, yes, I've had the FET ignition control module go out in two vehicles I've owned..stopped the car DEAD both times with NO warning.

And, I'm old enough to have had several cars with points.  Never stranded due to points; they tend to give a warning: the car starts running like crap.

Edited by MikeOH
Link to comment
Share on other sites

Just now, jetdriven said:

so electronics die suddenly, and points half die, and have to be worked on regularly.

Correct, IMHO.  Or, more exactly, electronics die suddenly and points have to be worked on regularly to prevent them from half dying.

Link to comment
Share on other sites

Just now, jetdriven said:

but which is more reliable. you have two mags.   PS the points themselves are ok, but theyre only 25hr from burning when the condenser wquits.

Sure, but there is ONLY one capacitor/condenser in a points based ignition system...just how many capacitors do you think might be in a FET controller circuit? (Hint: way more than one!)

And, as I previously agreed, having one EMAG would be fine for a two mag system.  This discussion/debate began when someone commented that it's 'crazy' that the FAA won't approve planes with TWO EMAGs.  I don't think they're crazy one bit.  And, I'm not an FAA fan-boy by any means:D

  • Like 1
Link to comment
Share on other sites

one data point to toss on the pile...
 

Swapped out a cam position sensor this week... the Ford Expedition has a twin cam engine...

With 200k miles on the odo... 

The only sign was the yellow engine light on the panel... Downloaded the trouble code, bought a pair of parts...

Cheap and Really easy to swap out.

Would make for a 1k hr preemptive swap for an airplane...

PP thoughts only, not a mechanic...

Best regards,

-a-

Link to comment
Share on other sites

Just now, carusoam said:

one data point to toss on the pile...
 

Swapped out a cam position sensor this week... the Ford Expedition has a twin cam engine...

With 200k miles on the odo... 

The only sign was the yellow engine light on the panel... Downloaded the trouble code, bought a pair of parts...

Cheap and Really easy to swap out.

Would make for a 1k hr preemptive swap for an airplane...

PP thoughts only, not a mechanic...

Best regards,

-a-

Yep, the engine controller can fall back to the crank sensor to keep the engine running.  Surprising though, the cam (and crank) sensors are commonly reluctance or Hall sensors which are extremely reliable (not a high current/high power application)

  • Like 1
Link to comment
Share on other sites

Not even sure you could pull accident data like this, but I'd be curious to know how many in-flight engine stoppages have been due to failed points?  Probably pretty low as one mag would really already have to be out.

Link to comment
Share on other sites

43 minutes ago, carusoam said:

one data point to toss on the pile...
 

Swapped out a cam position sensor this week... the Ford Expedition has a twin cam engine...

With 200k miles on the odo... 

The only sign was the yellow engine light on the panel... Downloaded the trouble code, bought a pair of parts...

Cheap and Really easy to swap out.

Would make for a 1k hr preemptive swap for an airplane...

PP thoughts only, not a mechanic...

Best regards,

-a-

200k miles / 35mph is 5714hr.  So easily a 2000hr preemptive replacement  and rhats a Ford part   Were it MB or BMW it would last twice that.  The technology is here. 

  • Like 1
  • Thanks 1
Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.