moosebreath

Sadly I had to cancel my planned trip for this year.  I have the following for sale:

Camp Scholler Weekly Camping Ticket beginning on Sunday ...  $180

Payment by Paypal and I will ship them via Priority Mail.

I hope someone can make use of these.

Trim servos are hard to find but surely you mean $900 not $9000!  What model is it?

Sold

New, in box.  I ended up with three of these and only need two.  

$200 shipped in the US.  Payment via PayPal.

Message me and I will send you my PayPal ID 

No it does not fault.  Hitting the end of travel does not generate a TRIM warning light or audible warning.  It just stops.  I speculate the computer senses a demand signal and no movement from the tach feedback and stops the motor.  There is no mention of how the end stops work in the manual that I could find.

In the course of troubleshooting a problem with the trim servo in my KFC 150 I attempted to find an engineering system description.  I knew this had to exist somewhere but it was not to be found in any resource I could locate for free.

The codex for the logic of KFC 150 operation is King Manual 006-5539-00 entitled "King KC 190,191,192 Autopilot Computer Maintenance / Overhaul".  There are no free sources that I could locate.  eFlightManuals.com has them available for .1 amu  or perhaps you can give your local shop a couple of six packs and take theirs to Staples.

However you acquire access to the manual, turn to Section 4 for your model computer and begin to learn how the system actually works in detail.  Expect that this will take a while and in some places be a bit of a steep learning curve if you are not an engineer and/or electronics enthusiast.  Here is a crib if you are interested in the trim servo.  The King terminology for what I would call the "trim system" is the "autotrim system".  I thought initially that was an option I did not have installed.

Even for the non-engineer, the Theory of Operation section of this tome is full of useful and interesting things not covered in the Pilot's Guide, which is primarily concerned with what button to push when rather than how the system actually functions.  Why King did not make this information easily available is a mystery to me.  Perhaps they thought only engineer pilots would care.  Here you can discover the one true answer to such mysteries as:

-  How to calculate the lead for level off when you hit altitude hold.  Answer: Lead the desired altitude by 15% of the rate of climb in feet.  I tested it yesterday, it works perfectly.

-  How does the system recapture after a losing the glideslope signal?  In distinctly different ways I discovered depending on the delay before the glideslope signal is again recieved.

- How in the world does it decide when to engage NAV mode once it is armed?  Well ... it depends on exactly how you engage NAV mode and the offset error from the desired course at the time it is engaged.  There is a whole section on just this topic.

- And the ultimate and final answer to that old chestnut:  Does the glideslope capture from above and below?  Answer:  Absolutely yes it does but it requires a null in the glideslope error signal to do so.  If you approach from above and then level off just at or above the glideslope capture never occurs.  (Guess now I know this ...)  Fly though the glideslope, like you do when level approaching from below, and it captures every time.

It is my hope that some other technical knowledge seeker will someday find this post and discover the path to KFC 150 enlightenment thus preserving their sanity.  Not to mention that you will be able to definitively determine the difference between how your KFC 150, or someone else's, is presently working and how it is SUPPOSED to work.

What you say is all true.  The question I had remaining is what happens when the trim goes all the way to the mechanical stop in one direction or the other.  Clearly the servos can not spin without limit then.

Being an engineer, I could not stand not knowing any longer.  If anyone else wants to discover exactly what your KFC150 is doing, and I understand if you don't, what you need is a copy of King Manual 006-5539-00, King KC 190,191,192 Autopilot Computer Maintenance / Overhaul.  There are no free sources that I could locate.  eFlightManuals.com has them or perhaps you can give your local shop a couple of six packs and take theirs to Staples.

However you acquire the manual turn to Section 4 for your computer and begin to learn how the system actually works in detail.  Expect that this will take a while and might not be helpful if you are not an engineer and/or electronics enthusiast.  Here is a crib if you are interested in the trim servos.  The King terminology for what I would call the "trim system" is the "autotrim system".  I thought initially that was an option I did not have installed.

The answer to my question is the following.  The trim servo has no stops or position encoding, which is why you can simply replace it and the system still works.  What it does have is tachometer feedback.  The computer monitors whether there is a command for the trim motor and then whether the trim motor is moving, at what speed, and in what direction.  It does this whether the autopilot / flight director is engaged or not.  King specifically says it monitors for actuation in a reverse direction and movement with no command signal.  In these cases it generates a trim fault.

What King does not say, explicitly, is what happens when the trim hits the mechanical stop.  It clearly senses a command to move with no tachometer feedback in this case.  I was curious as to whether the servo motor is commanded to stop or whether it has a clutch that releases and it keeps moving until you release the trim switch.  I did not want to buy the trim servo manual to find out.  The quest for the right manuals had already begun to make me feel like Groucho Marx in "A Day at the Races".

For the answer, I made a trip to the hanger and ran the trim to the stop.  I could hear the motor run once I silenced all the noisy panel fans and gyros.  When the trim hits the mechanical stop the motor stops.  Clearly there is logic in the computer to do this as it is perfectly clear from the schematics that there are no limit switches or encoders in the system.

I will make a separate slightly different post to document that the manual Theory of Operation section is just full of interesting things to know about how the system functions that are not documented in the Pilot's Guide such as how to calculate the lead for level off when you hit altitude hold (15% of the rate of climb in feet, I tested it yesterday, it works perfectly).  How the system recaptures after a lost glideslope (it depends on the delay before the signal is again recieved, did you know that?).  How it engages NAV mode once it is armed, (it depends on exactly how you engage NAV mode and the offset error when you do).  And yes, that old chestnut, does the glideslope capture from above and below.  The answer is YES.

Perhaps some other knowledge seeker will see this someday and also discover the path to KFC 150 enlightenment.  Why this information is not simply in the back of the Pilots Manual is a mystery to me.  King must have thought only engineer pilots would care.

I also have the KFC 150 Mooney installation STC.  This details installation and testing of the entire system.  It has no mention anywhere concerning setting a pitch trim servo datum.  There is trim position feedback.  Perhaps the computer remembers where the clutch disengages at the end of travel.

I have just had the KS179 removed, repaired, and reinstalled.  During this process the servo was run without being installed.  How does the KFC 150 know where the trim stops are?  The servo was removed and replaced without attempting to retain any datum point.  Does the servo simply run the trim until it hits the mechanical stop and then disengage the clutch?  This seems rather simple minded but perhaps that is how it works.  The trim currently runs from stop to stop just as it did before.

I have the installation, service, and operating manuals and I still can't figure this out.  Anyone out there know for sure?

It appears I might need a KS179 pitch trim servo, part number 065-0052-14. Does anyone have one available?

I just adjusted my panel gauges on Thursday, my right gauge was reading about 28 gallons when full and it was driving me crazy.

It is just a simple span and zero adjustment.  The best way to set zero is with the tank empty.  How you do that is an “exercise for the maintainer”.  Do it first.

Set the span on a level surface with the tank full.  You will have to exercise the span screw a bit and then make several adjustment trials to get it to read properly.  Mine did not have a simple linear change as you might expect.  The adjustment seems to persist once it is made however.

Be VERY VERY careful not to overtighten the gauge locking screw.  Use two fingers and stop when it is only a bit snug.  If you go further you will break the corner of the plastic gauge face.  Rochester will be glad to make you one to order for around $175 plus shipment.  Ask me how I know …

Once the above is done use the fuel totalizer and ignore the gauges.   I have my totalizer calibrated to within a few tenths of a gallon out of 50.  That is better than 1%.  It is easy to do and the procedure can be found searching here. The panel gauges are reliable within 5 gallons or so, maybe.

Pull the stall horn breaker AND the gear horn breaker to stop it.  It is crazy but that is how the wiring is done.  After that you likely need a new microswitch in the stall warning vane.  They are a standard part available from Mouser for less than $10.  Alternatively a new part from the manufacturer is around a grand.

Use the forum search function.  This has all been discussed before.  You will find discussion and applicable part numbers.

When I got mine you had to complete an approach on one engine under the hood to pass.  I missed it and had to do the missed and make it the second time ... on one engine under the hood.  I was beat!  Even a light Duchess at sea level does not climb very well on one engine.

I have no idea if you still have to do that or not.  Makes for a good story though.

20 hours ago, toto said:

Is this available online somewhere?  I have no Bonanza connections, but sounds interesting.

ABS (American Bonanza Society) material is on their members only website.  They have simply superb articles in their magazine on all phases of flight technique and decision making.  In addition they have webinars every month that are excellent.  It is the best $85 per year that I spend on aviation.  They are friendly to Mooney folks and many of their articles apply to our flying.

Sadly there is nothing remotely like it in the Mooney community.

I can’t post his article but you could certainly email him and ask.  Tom Turner asf@bonanza.org  I am guessing you will get a friendly answer and a membership application...

I can not help but respond to this thread.

If there is any chance of icing just do not go.  Yes, this means you can not fly many times during the winter.  Yes this means your plane is not a reliable source of scheduled transportation.  And yes, lots of people fly in possible icing conditions for years and have no problems.

I am not proud of the experience but I am an icing survivor.  Real icing.  The engine only works sporadically, you can not hold altitude, over the mountains, clouds to the ground, no nav radios, below the highest terrain, position unknown kind of icing.

It is one thing to discuss skew-t interpretation, freezing level forecasts, climb rates, and pilot report evaluation.  It is quite another to watch the ice build and listen to the engine sputter while helplessly descending in IMC knowing you and your passengers are almost certainly going to die.

Tom Turner the Director of the American Bonanza Society Air Safety Foundation has a gazillion hours in planes with performance quite similar to our Mooneys.  I do not know his personal experience with icing but he recently wrote an article in the Society magazine that said the same thing.  Any chance of ice, don’t go.

For me, it is just that simple.

2600 rpm / WOT. 100 deg ROP.  I did not pay all that money to go slow.

Regardless of mods absolutely make sure there are no SB 208 corrosion problems.  Further it is worth every penny to have one of the big name Mooney Service Centers do your pre buy inspection.  I personally would not buy any Mooney unless this was done.

My opinion on mods after 700 hours with a J that came stock with most of them is:

Speed brakes — Great fun and totally unnecessary 

GAMI — No benefit on Lyc IO 360 

Brackett Air Filter — No big deal, saves a bit of maintenance, cheap.  Sounds like a few guys have forgotten they are even an STC.

Bladders — Religious argument with Mooney owners, I installed them in my 97.  Install is only simple if you are lucky and I was not.  Weight penalty is 35 lbs I think, not at home to check just now.  Bladder to bladder tubes tend to leak until you double clamp them.  Filler caps are very cool looking but you lose your wing fuel gauges if installed.  They are not bad to have but you can do a LOT of reseal work for what they cost to install.  Big names in tank sealing have good records and a warranty. 

One piece belly — Nice for your shop but installation will not pay out even at $100+ per hour shop time.  No disadvantages.

In fact, I think the answer in general is there are not any STC I can think of that are either “essential” or ruin the plane. 

A more important consideration perhaps Is to buy a plane with an autopilot you want to keep.  They are very expensive to retrofit and one that either does not work properly or meet your needs will make you sad every time you fly.

I have a 97 J that came with a 2900 max gross.  I am at the beach just now but here are the numbers for stall at 0 bank angle from my manual at 2900 lbs.

Gear and flaps up ... 63 kts

Gear down flaps 15 deg ... 62 kts

Gear down flaps 33 deg ... 56 kts

1.3 times 63 is 82 so I guess that is where your “approach” number came from.  If you come over the threshold at 82 you had better be landing on the space shuttle runway!

Unless you have an emergency of some kind you will never be landing at 2900 lbs.  I try to operate under 2740 except on long cross country legs where carrying the extra fuel is advantageous.  The biggest problem at 2900 pounds is initial climb angle, not landing.

You can search the forum and find lots of opinions on flaps and landing speeds.  I find  75 kts full flaps, or a knot or two slower, over the fence perfectly fine at heavy weights which, as mentioned, is not often required.

My normal speed on short final is between 65 and 70 full flaps depending on my weight.  A knot or two slower than 1.3 times stall in the landing configuration has always worked well for me.

You will get many opinions ... my best advice is to find a nice long, wide, flat runway with no traffic and test different flap and speed combinations starting from 1.3 vso and see what you find comfortable.   The Space Shuttle might have landed shorter than a J will at 82 kts!

Have fun, Mooneys are great planes.

I learned to fly in a Colt 50 years ago.  In my opinion almost any other airplane is better.

- Bricks do in fact glide further

- Sounds like an oil can while gliding, or falling forward in the case of a Colt / Tripacer

- Ailerons totally ineffective at low speed. A standard Colt demonstration is to slow the plane to just above stall and move the yoke stop to stop observing the wings do ... nothing

- Cabin is tight and visibility low compared to about anything else

- They look funny and were called “Flying Milk Stools” 50 years ago

- They are slow, really slow.

- An old 150/172 feels like a Bonanza by comparison.

There are a lot of people in Alaska who think short wing Pipers are great.  I could never understand why.  They are never talking about PA-22 though i.e. the Colt / TriPacer but the taildraggers.

I might just stop flying if a TriPacer was the only choice.

Even though they are shown out of stock Lasar had two.  I bought one so ... they had one two days ago.

It is REALLY easy to access on the J.  It is on the pilot side of the firewall  as described above.  An oil leak had caused mine to malfunction.  Luckily the shop was able to save it by opening and cleaning.  BTW Globe Alabama quoted us one to two weeks for overhaul.

Thanks for the info.  One clarification, do you mean on the left side of the firewall inside the cowling or in the pilots footwell? 

It appears my cowl flap motor will have to be replaced.  I have read all the relevant topics and would like to know if there is any particular difficulty in accessing the motor.  There are many comments on the K model but none on the J.  It is not clear from the parts manual exactly where the motor is mounted.

I expect this will be clear when we remove the cowling but would appreciate any tips on replacement.  I would also be interested in the turn time from Globe if anyone has purchased a new/exchange/rebuilt motor from them since Covid.

DO NOT bend the tab. The tab is heat treated and will break.  You set the alarm speed by adjusting the mounting, the procedure is in the maintenance manual.  Inside the unit is nothing but a microswitch.  A common failure mode is for the switch to fail and the stall warning to sound either continuously or at random annoying times.  On my J you have to pull BOTH the gear and stall warning breakers to make it stop.

A new identical switch is available from Mouser for less than $10.  Buying the unit just to replace the switch is very expensive.  There is absolutely nothing subtle, complicated, or highly engineered about this sensor.
 

Search the archives, this has all been covered before.

Nope, love mine.