M20K 252 with "black" instrument panel?

[MRussell]

Greetings!

Can anyone explain why an 1988 M20K 252 with round window corners would have:

1. an STec 60-2 rather than a KAP 150 autopilot

2. A completely black instrument panel (the whole thing) rather than the white or cream colored IP that is so signature to same-era Mooneys? Others shopping for 252s will probably know the plane I'm talking about; it seems to be the only 252 for sale at the moment that *doesn't* feature the white panel. 

Thanks for any info!

-Matt

[carusoam]

Welcome aboard, Matt.

lighter colors came in the 90s...?

BK was the standard in the early 90s.

With enough dough, an owner could choose what he wanted or didn't want..

Some APs have been added after the first day of ownership...

Some PP ideas that come to mind.

What part of NJ do you hale from?

Best regards,

-a-

 

 

 

[Zwaustin]

S-tec was likely installed when the expensive KFC-150 needed work or overhaul and the S-Tec could be added much cheaper. I have heard of 20K figures to replace some KFC units depending on what it needed. Personally, I prefer the KFC-150 and 200 units to the S-tec units i have used but have not used the 60-2 though just the 20 and 30 models. I will take my KFC-200 all day over those as it is crisp, flies coupled approaches very well and is very capable in rough weather. As for the color of the panel, my K model is black as well and although it has been updated it looks to be that black was the factory color. 

[gsxrpilot]

I've got a 1987 M20K 252 with the original KFC-150 and a white panel. Zwaustin and I both launched out of KHYI this morning within a minute of each other under IMC conditions. 

I looked at that 252 as well when I was shopping for mine.  I think it's also the only one in the country for sale with an S-tec autopilot.

[LANCECASPER]

Years ago I considered N622MA (picture below) that had a black instrument panel, Century 2000 A/P and one alternator, no oxygen, no speed brakes, no HSI - thankfully I didn't buy it. 

I learned that there were a few stripped down 252's produced, without the 2 alternators (look for the split Alternator Field Switch next to the Master - the one alternator models don't show L and R). Apparently one of their flaws is that they eat batteries like crazy. Other examples of a one alternator 252's would be N252AR and N252PB that are for sale on Controller.

 

[MRussell]

Really grateful for the answers, guys, this is a kickass forum! I'm based in Clifton at the moment, former Hunterdon County resident. 

[Fly Boomer]

I know this thread is more than six months old but I'm learning as much as I can about the Mooney and when I look at photos of N252PB, it looks to me like it DOES have the "split Alternator Field Switch next to the Master".  What am I missing here?

Thanks!

[LANCECASPER]

17 hours ago, Fly Boomer said:

I know this thread is more than six months old but I'm learning as much as I can about the Mooney and when I look at photos of N252PB, it looks to me like it DOES have the "split Alternator Field Switch next to the Master".  What am I missing here?

Thanks!

Notice that above the switch it does not have a label for both L and R, meaning it just has the one alternator. Also if you have a picture of the right hand panel you'll notice that it does not have a breaker for ALT 2. At the time of purchase the option for two alternators was a few hundred dollars now it would be many thousands.

[carqwik]

N252A (a 252 also) had one alternator and no built-in O2...at least when I flew it in the late 1980s.

[LANCECASPER]

I think there were only 231 252's made. It would be interesting to know how many "stripped-down" versions there were.

[carusoam]

The left three switches are often...

1) Master

2) Alternator field

3) Instrument panel

In order of which they get used at start-up...

Some more modern instrument panels have some glass panels alive with engine monitoring data.

A second alternator would be nice.

I'm not sure the purpose of the split rocker switch compared to two separate switches...

Best regards,

-a-

[Fly Boomer]

Thanks to LANCECASPER for that explanation regarding the split Alternator Field Switch.

[Hank]

On 4/9/2017 at 2:40 PM, carusoam said:

The left three switches are often...

1) Master

2) Alternator field

3) Instrument panel

In order of which they get used at start-up...

Some more modern instrument panels have some glass panels alive with engine monitoring data.

A second alternator would be nice.

I'm not sure the purpose of the split rocker switch compared to two separate switches...

Best regards,

-a-

It takes up the same panel space as planes built with a single alternator. The manufacturer (or modifier back when the cost was reasonable) didn't need to do anything to the panel,  just replace one wide switch with the split switch.

[Mcstealth]

On April 9, 2017 at 4:40 PM, Fly Boomer said:

Thanks to LANCECASPER for that explanation regarding the split Alternator Field Switch.

@LANCECASPER holds an unofficial record in the Mooney world that has made him a wealth of information.  

[kortopates]

1 hour ago, Hank said:

It takes up the same panel space as planes built with a single alternator. The manufacturer (or modifier back when the cost was reasonable) didn't need to do anything to the panel,  just replace one wide switch with the split switch.

Not exactly true Hank, but almost. The 252' with Dual alternators have a Dual Load meter between the clock and key on the left that showed simultaneous outputs on each of the two alternators as well as total load and pushing a button it showed system voltage rather than total load. Then there is the added CB for Alt 2 and a over voltage light for Alt 2 on the far right. There are also 3 separate fuses for the Load meter below the quarter panel on the far right. Perhaps the single alternator would share some of those fuses -I don't know.

The Dual alternator option should have been a no brainer but some new owner pass it up sadly. It has so many advantages in addition to the obvious redundancy. The #2 is a belt driven alternator which turns faster than the engine driven alternator which does 2 things. First it absorbs most of the load because of its higher output from turning faster. Secondly it's coming in speed rpm is lower so you don't have to idle as high to turn off the low volt light or ride the brakes on taxi to keep the light off and thirdly the #2 by taking more of the load helps extend the life of the more expensive to maintain engine driven #1 while the belt driven #2 is much cheaper to maintain.

[LANCECASPER]

4 hours ago, Mcstealth said:

@LANCECASPER holds an unofficial record in the Mooney world that has made him a wealth of information.  

That's funny David - most of the time I'm clueless. Every once in awhile a blind squirrel finds an acorn.

[wpbarnar]

10 hours ago, kortopates said:

The #2 is a belt driven alternator which turns faster than the engine driven alternator which does 2 things. First it absorbs most of the load because of its higher output from turning faster. Secondly it's coming in speed rpm is lower so you don't have to idle as high to turn off the low volt light or ride the brakes on taxi to keep the light off and thirdly the #2 by taking more of the load helps extend the life of the more expensive to maintain engine driven #1 while the belt driven #2 is much cheaper to maintain.

My Encore has two alternators but the arrangement is reversed.  #1 is belt driven and #2 is the engine driven one.  Odd that the arrangement is reversed on basically the same airplane.

Bill

 

 

[kortopates]

4 hours ago, wpbarnar said:

My Encore has two alternators but the arrangement is reversed.  #1 is belt driven and #2 is the engine driven one.  Odd that the arrangement is reversed on basically the same airplane.

Bill

Hi Bill, You had me wondering how that could be true; especially if the second alternator was still optional on the Encore, since it would make zero sense with birds produced with only 1 alternator which is always going to be the engine driven and therefore has to be #1.  So I looked at your Encore POH and sure enough, see top page 7-27, it clearly refers to the optional alternator as #2 and says it carrys most of the load do to its higher RPM (from being belt driven) as I said above. Makes me wonder if your leads are reversed on the Load meter or alternator switch on the panel to cause that but something is not right. I'd suggest pulling the #2 field CB on the far right panel and see if that causes the #2 to drop out on the load meter - i.e., to check consistency. (I assume you are already failing #2 at the alt switches on each run-up and seeing #1 take the load).  

[wpbarnar]

Paul-  Mystery solved!   After looking closer at the split alternator switch, it is labeled "left and right" not "1 & 2".   I knew which switch physically controlled which alternator but never had looked at the split switch label closely until yesterday.   I was positive the switch on the left contolled the belt driven driven generator, just did not realize or remember it said "left" not "1".

Also I do not have the dual load meter. According to the service manual that stopped with S/N 25-1224.   Maybe that is when they changed nomenclature.

They did not update the POH with the change to left and right nomenclature.   Mine has the exact verbiage you quoted in your earlier post.

Thanks for prompting me to go look at my airplane with a more critical eye.

Bill

[Bryan]

On 4/11/2017 at 7:23 PM, kortopates said:

The Dual alternator option should have been a no brainer but some new owner pass it up sadly. It has so many advantages in addition to the obvious redundancy. The #2 is a belt driven alternator which turns faster than the engine driven alternator which does 2 things. First it absorbs most of the load because of its higher output from turning faster. Secondly it's coming in speed rpm is lower so you don't have to idle as high to turn off the low volt light or ride the brakes on taxi to keep the light off and thirdly the #2 by taking more of the load helps extend the life of the more expensive to maintain engine driven #1 while the belt driven #2 is much cheaper to maintain.

Encore here as well, with Left and Right switches, without the dual load meter.  Question:  I have heard of pilots turn off one of the alternators in-flight at cruise maybe to save the load instead of running both?

I cannot find any procedure or checklist item in my POH in not running both the Alternator Field Switches in the ON position all the time.  What is expected or common for dual-alternator aircraft?

[gsxrpilot]

I always turn #2 off once in flight. 

[Bryan]

Because of a procedure, habit, or reason?   Is #2 your belt driven alternator?   If so, I assume it just disengage the ALT Field and not stop the belt or physical activity of the alternator?

[gsxrpilot]

I get a little bit of a "whine" in the headset out of #2. So I'm only running #2 during taxi and runup as it supplies power at lower RPM. 

I have a dual amp gauge and #1 doesn't kick in unless #2 is turned off. So I typically turn #2 off as part of cleaning up the plane on the climb out. Gear, flaps, Alt2, etc.

[kortopates]

Really sounds like Paul's @gsxrpilot #2 alternator filter may have an issue or there is a shielding issue with the #2 since it shouldn't provide any more of a whine than #1 - these are identical systems electrically. 

Although Paul has a reason for turning off his #2 for the noise, with a fully functional system there is no benefit to doing so. In fact, you'll be transferring the load and wear and tear entirely to the #1 alternator when you would rather have the load absorbed by the #2. The #2 being the belt driven alternator is much more accessible and cheaper to maintain. Its out in a few minutes and be can very affordably maintained with new brushes and bearings periodically. When the #1 goes, its has the very expensive rubber coupler that was $900 last I knew some years ago and requires a quite a bit of work to R&R. Its the one you want to last as long as possible so its really ideal that #2 absorbs most of the load since it spins faster and is much cheaper and easier to maintain.

1 hour ago, Bryan said:

Because of a procedure, habit, or reason?   Is #2 your belt driven alternator?   If so, I assume it just disengage the ALT Field and not stop the belt or physical activity of the alternator?

Yes, disconnecting at the alt field switch still has the alternator turning at full rpm, but with no load on the alternator its going to spin easily. Although not a big deal on an alternator turning with a belt, the #1 being spun by the rubber coupler (to enable sheering with an alternator problem) is getting more wear as rubber coupler overcomes the resistance of the higher load. Normally there won't be any or much resistance with #2 taking the load.

I recently had to rewire the rear of my entire far right circuit breaker quarter panel because I was having similar but different issues Paul has with my #2 alternator (fluctuations and higher than actual load indications). Cleaning up the wiring fixed mine.

Edited April 23, 2018 by kortopates

[gsxrpilot]

So would an ideal scenario be to just run #2 all the time and only turn on #1 if there's a failure of #2?  

We spent some time trying to troubleshoot the whine on #2 back when I first bought the plane. But we never solved it. I'd love to be able to. It's much improved (quieter) with the PMA450a audio panel, but it's still there. And really not any fun to listen to for any length of time.