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QUESTION: M20E Vs M20F


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The 430 W, GTX345 and card compass will come out of the C and go into the F in place of the 430 non WAAS, GTX 327 and a regular compass.  That stuff will go into the C.

Thanks for the complements.  Yes the C is outstanding with a wonderful pedigree, but I injured my shoulder and can’t handle the Johnson bar gear any more.  I really hate to see her go, but given what the replacement is, I can deal with it.

When I bought the C, but had yet to take delivery, a super good guy who goes by “cnoe” on this forum, gave my wife and I a scenic tour around Galveston Island in his beautiful J or K, I don’t remember which.  He refused to let me buy him any gas.  He said to just make sure that I pass it on and do the same for someone else, so I am trying to honor my promise to Chuck.

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6 hours ago, PTK said:

Jeff, I will attempt to simplify your decision. Based on your mission as described I'd concentrate my efforts on a J.

Absolutely!

Let’s see... 5-10kts speed advantage over F (if the F is stock). 100-200lb payloads penalty over F (excepting the 2900lb MGW J models). And for the big win, a 30-60% purchase price premium. 

Special bonus if you get an A3B6D engine with the “single dual” mag and 20° timing!

:D:D:D:P

Edited by Shadrach
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4 hours ago, MBDiagMan said:

The 430 W, GTX345 and card compass will come out of the C and go into the F in place of the 430 non WAAS, GTX 327 and a regular compass.  That stuff will go into the C.

Thanks for the complements.  Yes the C is outstanding with a wonderful pedigree, but I injured my shoulder and can’t handle the Johnson bar gear any more.  I really hate to see her go, but given what the replacement is, I can deal with it.

When I bought the C, but had yet to take delivery, a super good guy who goes by “cnoe” on this forum, gave my wife and I a scenic tour around Galveston Island in his beautiful J or K, I don’t remember which.  He refused to let me buy him any gas.  He said to just make sure that I pass it on and do the same for someone else, so I am trying to honor my promise to Chuck.

@cnoe flies a really nice J and flies it very well and often. 

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3 hours ago, Shadrach said:

Absolutely!

Special bonus if you get an A3B6D engine with the “single dual” mag and 20° timing!

:D:D:D:P

@Shadrach humor aside, you’ve now opened a whole new can of worms!! :) Be mindful I am a card carrying Mooney wannabe/newbie. What is the issue/concern/challenges associated with the A3B6D engine and mag combination? 

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Without research, I believe that is the mag that, although it consists of two separate magneto’s they have a common plastic gear shared between 5hem providing a single point of failure.  This does away with the redundancy advantage of two totally separate mags separately geared to the flywheel.  If I am wrong, someone please correct my statement.

Yes Paul, Chuck is a very good pilot and IIRC, he said he tries to fly at least one approach per week, so he keeps that beautiful plane in the air a lot.

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7 hours ago, bluehighwayflyer said:

Interestingly and inexplicably, the A3B6Ds all have 25 degree timing, Ross.  Just FYI. 

Jim

You're indeed correct Jim! In my haste to poke fun at Peter, I misread the TCDS.  The A1B6D and -A3B6D are  timed to 25° BTDC exclusively.  Unless of course the mag housing separates from the engine,  then the timing tends to wander a bit! :D:P

Edited by Shadrach
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1 hour ago, Jpflysdfw said:

@Shadrach humor aside, you’ve now opened a whole new can of worms!! :) Be mindful I am a card carrying Mooney wannabe/newbie. What is the issue/concern/challenges associated with the A3B6D engine and mag combination? 

Let me start by saying I have and would again fly behind an A3B6D engine.

The issue issue is that the dual mags are mounted in a single housing and driven by a single input (as opposed to mounted separately and driven separately like conventional mags).  There have also been reports (likely overstated) of the housing separating from the accessory case.

The concern is a lack of redundancy do to the single point of failure.

The challenge as with most things involving airplanes is proper maintenance 

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1 hour ago, Shadrach said:

Let me start by saying I have and would again fly behind an A3B6D engine.

The issue issue is that the dual mags are mounted in a single housing and driven by a single input (as opposed to mounted separately and driven separately like conventional mags).  There have also been reports (likely overstated) of the housing separating from the accessory case.

The concern is a lack of redundancy do to the single point of failure.

The challenge as with most things involving airplanes is proper maintenance 

The other concern is that parts and repairs to the dual mag may get harder and harder as time goes on, since the parent company of Bendix is TCM, the biggest competitor of Lycoming, so they have little incentive to support the Bendix dual mag.

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2 hours ago, Shadrach said:

Let me start by saying I have and would again fly behind an A3B6D engine.

The issue issue is that the dual mags are mounted in a single housing and driven by a single input (as opposed to mounted separately and driven separately like conventional mags).  There have also been reports (likely overstated) of the housing separating from the accessory case.

The concern is a lack of redundancy do to the single point of failure.

The challenge as with most things involving airplanes is proper maintenance 

How are conventional mags driven separately? How many crankshaft gears are driving the idler gears in the accessory housing?

And please cite one case of d mag drive gear failure. 

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Okay, thanks for the info, you guys are confirming are reminding me of the line from Kung Fu, many years ago “grasshopper, you have much to learn”  and I of course am grasshopper

So, thanks for your patience, I now understand the context of a single dmag. I think I’ve pieced together that the “D” engine was introduced with the 201 and the +5D on timing was a means to eek out a couple of extra ponies.  Assuming I have that right(and if I don’t please correct me), I’m not following the downside of the “D”. I am assuming that it brings the added benefit of an O/H sooner than a non-D. Am I in the general ballpark?

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1 minute ago, Jpflysdfw said:

Okay, thanks for the info, you guys are confirming are reminding me of the line from Kung Fu, many years ago “grasshopper, you have much to learn”  and I of course am grasshopper

So, thanks for your patience, I now understand the context of a single dmag. I think I’ve pieced together that the “D” engine was introduced with the 201 and the +5D on timing was a means to eek out a couple of extra ponies.  Assuming I have that right(and if I don’t please correct me), I’m not following the downside of the “D”. I am assuming that it brings the added benefit of an O/H sooner than a non-D. Am I in the general ballpark?

I believe the 25° timing predated the 20 degree timing. It was used as method to reduce CHTs in applications with subpar airflow. 

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18 minutes ago, PTK said:

How are conventional mags driven separately? How many crankshaft gears are driving the idler gears in the accessory housing?

And please cite one case of d mag drive gear failure. 

I hope you have your cam followers inspected and lubed IAW Bendix’s 100hr interval recommendation.

ReportGeneratorFile.ashx?EventID=2005080

 

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Lack of proper maintenance is not the mag’s fault. How do you know the cam follower wasn’t installed backwards? Causing the nylon part to be very close to the points? The correct way is to have the spring steel part of the cam follower be on the inside next to the movable points. They can be installed backwards very easily. And it has happened. Again not the fault of the mag.

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On 7/17/2018 at 6:05 PM, PTK said:

Lack of proper maintenance is not the mag’s fault. How do you know the cam follower wasn’t installed backwards? Causing the nylon part to be very close to the points? The correct way is to have the spring steel part of the cam follower be on the inside next to the movable points. They can be installed backwards very easily. Again not the fault of the mag.

It’s a great mag! Glad you're enjoying it!

Edited by Shadrach
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2 hours ago, Jpflysdfw said:

So, thanks for your patience, I now understand the context of a single dmag. I think I’ve pieced together that the “D” engine was introduced with the 201 and the +5D on timing was a means to eek out a couple of extra ponies.  Assuming I have that right(and if I don’t please correct me), I’m not following the downside of the “D”. I am assuming that it brings the added benefit of an O/H sooner than a non-D. Am I in the general ballpark?

The dual-mag was the standard for IO-360's (A3B6D and A1B6D) in M20J's out of the factory.  It's only been in the last 10 years or so that Lycoming has been selling new and remanufactured engines with 2 separate mags (A3B6).  There is no difference in power or really any operational difference between them.  There is no difference in official TBO.

The change from 25 deg to 20 deg on the timing gives slightly less power and slightly cooler temps.  There's plenty of debate over how significant this is.  The A3B6 and all other IO-360/O-360's can be set to either as an option, but the dual mag motors MUST be set at 25 deg.

If you're a believer in redundancy, the dual mag setup is less desirable.  As you can see, there is a fair amount of debate as to how significant this is.  Realistically, it may be a theoretical risk and there is little data to quantify that risk.

There seems to be a general consensus (myself included) that Slick magnetos, the type used in the A3B6, suck balls in terms of quality and durability compared to the Bendix dual mags.  I'll be the first to admit this may simply be that all the dual mags out there are (by necessity) old ones that have stood the test of time, so this may be an unfair conclusion.

Edited by jaylw314
Changed the typo on 25 to 20 degrees
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Just now, bluehighwayflyer said:

Very well said, and agreed. As I think you will agree, though, you have a typo here ...

“The change from 20 deg to 25 deg on the timing gives slightly less power and slightly cooler temps.”

In fact the change was from 25 deg to 20 deg timing with those effects.

Jim

Doh!  :blink:  You are correct!

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27 minutes ago, bluehighwayflyer said:

I think some of the latest J models might have also come from the factory with A3B6 engines. The MSEs and Allegros. Those planes are above my pay grade though, unfortunately, so I am not certain. :)

Jim

I think it was just the Allegros that came without the dual mags

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2 hours ago, bluehighwayflyer said:

The dual mag is fine as long as it is installed and maintained properly, and Ross knows it. He was just being funny and taking a little good spirited jab at us J drivers. 

No harm no foul.  When you own the best you have to learn to rise above these things. :)

I just wanted everyone to know that the dual mag was inexplicably omitted from the unfortunate Lycoming SI or SB that rolled most of the Lycoming fleet back to 20 degree timing from their original 25. 

Jim

Agree on all counts! The best is subjective!  Whats your useful load?

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41 minutes ago, bluehighwayflyer said:

Ha!  Not so bad, actually. 970 pounds with 64 gallon bladders and an OEM Prestolite starter and alternator.

It would be comfortably over 1000 pounds if I still had wet wings, not even taking into account the weight of the fuel that would perpetually be leaking out. :)

My J is very purposefully pretty bare bones, though.  As you know the Fs are the useful load masters of the four cylinder Lycoming-powered Mooney fleet.

Jim

That's the same as my C, which would also be higher without that heavy Hartzell 3-blade on the nose. But I can load up full fuel, add people / baggage to 970 and fly for 5-1/2 hours (theoretically); my longest leg so far is 4:45, landing with 12 gallons = another 1:20 to completely kill both legs . . . .

It's all how you slice it.

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2 minutes ago, bluehighwayflyer said:

Yep. Most of the real world differences between the similarly-powered Mooneys are pretty inconsequential in the greater scheme of things, I think. 

:P   My C at 7500 msl:

20161002_133311.thumb.jpg.f11b7e8a6a71501ea413891f5a8add84.jpg

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19 minutes ago, Marauder said:

 


My F at 3000. LOL

3f6d85a38d1dd462b29c014ce79221de.jpg
 

 

I was burning 9 gph in cruise, traveling with my wife, not running wide open on a speed run.

P.S.--gave an F pilot a ride to pick up his plane. Well over an hour later, I was still close enough to watch his pattern entry into downwind; then the ridgeline blocked him. That was before my doghouse resurrection and carb heat rebuild gave me an additional 8-10 mph.

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4 hours ago, bluehighwayflyer said:

Very well said, and agreed. As I think you will agree, though, you have a typo here ...

“The change from 20 deg to 25 deg on the timing gives slightly less power and slightly cooler temps.”

In fact the change was from 25 deg to 20 deg timing with those effects.

Jim

 

He had me at “ball sucking”....

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