PT20J

I’m curious about something. The M20J has a 5 deg or so down elevator deflection when trimmed for cruise. I wonder if the shorter C does the same thing. Anyone looked back at your tail?

Anthony's comment got me thinking about how grease wears out. Does it really turn to rocks? I found interesting information about bearings and lubrication on Tinken's website. https://www.timken.com/pdf/5892_Bearing Damage Analysis Brochure.pdf. Always fun to learn new stuff! Skip

The entire trim system should be lubricated during the annual inspection (with the exception of the front gearbox and the jackscrew thrust bearings which are not accessible without significant disassembly and are generally dealt with on condition). The Maintenance Manual calls out low temperature oil for the U-joints (there shouldn't be grease on these). The jackscrew is heavily loaded and needs to greased with the proper grease. One of the few times I diverge from the manual is in the choice of lubricant for the trim wheel and trim servo chains: the manual calls out grease which makes no sense for a chain since it won't easily get into the rollers -- I use the same oil I use for the U-joints. Also, don't forget to put some oil on the trim wheel shaft and bushing and check the tension on the chain. This bushing is a common wear point leading to a wobbly trim wheel. I generally use electric trim, but I always manually reset the trim to takeoff position after landing so I can feel how the mechanism is working. Skip

A long and interesting discussion. I'll try to summarize the facts: 1. 14 CFR Part 1 states "VFE means maximum flap extended speed." If only a single VFE is specified, then it applies to all flap extensions. No other interpretation makes sense because it would require the maximum speed for other than full extension to be unspecified. 2. The TCDS defines the conditions for airworthiness. Pilots generally do not reference the TCDS, so the airworthiness conditions pertinent to operation are included the Airplane Flight Manual Limitations section. This section is regulatory and binding on the pilot. 3. Flaps do four things: 1) They increase CLmax while reducing the angle of attack at which CLmax occurs, 2) They decrease the angle of attack at which zero lift occurs, 3) They increase drag, 4) They create a pitching moment. 4. Mooney flaps are more effective at reducing stalling speed than flaps on many similar GA airplanes. To prove this to yourself, look up the Vs0 and Vs1 speeds (calibrated) for various airplanes. (Or, find the other thread where I did this). 5. The primary purpose of flaps is not to slow down. However, they do create drag. Should you forget to raise flaps after takeoff, your first indication may well be in inability to attain cruise speed. 6. There is no mechanism in any Mooney to raise the flaps in the event of an overspeed. Skip

I have a Battery Minder and run my avionics in the hanger and it works fine.

Not really a money issue for me - just want to understand it. Talked with the radio shop today and issue may be that I’m out of ports on 430W. Last owner didn’t get configuration info or wiring diagrams for 430W/Aspen Installation. I’ll find out when we open it up for GTX 345 installation. I get everyone’s gut response. Was hoping someone had researched this and had data, but now believe data is unavailable.

There's lots of advice about this depending on who you ask. Some regimens are pretty complicated; some are pretty simple. I thought Mike's article cited above pretty much nailed it. I recently put a factory rebuilt engine on my J and it seems to be doing fine just keeping three important points in mind: 1. Use the recommended break-in oil (a warranty consideration) 2. Run at high power for the first few hours to seat the rings and don't do low-power descents, stalls, and touch and goes. 3. Keep the cylinder head temperatures under control. An engine from the Lycoming factory (new, rebuilt or overhauled) will have been run in a test cell for an hour under varying conditions designed to test the engine and get the break in off to a good start. I instructed at several flight schools over the years. After a couple of hours test flying a new engine, the maintenance department would release it to the flight line and the only instructions were, "use mineral oil and don't do touch and goes." I've flown seaplanes for two part 135 operators and again, after a couple of hours of test flying, maintenance turns it over to the line pilots with the only admonition being to use mineral oil. These engines did just fine. On my engine, I never had high CHTs nor did I see them decrease significantly during the break in. Break in is considered finished when oil consumption stabilized which means that it it burns X hrs/qt consistently. Though Lycoming doesn't require it, I changed the oil and filter after 10 hours and will change to AD oil after another 25. I think the process can be stressful because it's something that we don't do often, there's a lot of money involved, and we don't want to screw it up. But, in the end, it's not magic. I'm sure you'll do just fine. Skip

Well, I’ll probably do it. I do appreciate all the opinions. Problem is, being an engineer, I was hoping someone had found some data. Without data, it’s a subjective emotional decision, and I hate making drcisions that way. I did some searching, but there is precious little data about the effectiveness of ELTs at all, let alone adding GPS. The “problem” is that there just aren’t enough crashes (thankfully) to have a large enough data set to anslyze, and ELT effectiveness data is not well captured. Years ago I recall some study concluding that the ELT didn’t even activate about half the time. That’s why I like flight following so much when I’m VFR.

OK, I get that. They put a new ELT antenna on the top near the baggage door rather than installing it under the dorsal fin. This also runs the cable across the tailcone to cabin junction. So there is a chance that the antenna may become disconnected during a crash. I'm assuming that if you activate the ELT before impact, that it would broadcast the GPS position -- is this right?

Well, I kinda figured that. But, it would help me get a clearer understanding if I knew the details of how it works. Don't the satellites locate a 406 ELT pretty precisely even without the GPS?

That's really interesting. Most of my experience is with Js, so I don't know many details about Ovations. I found a Oct-94 M20R service manual online (http://www.softoutfit.com/static/refs/smm-wiring.pdf) and section 27-50-00 doesn't mention this feature -- it shows essentially the same flap mechanism that's been used ever since they went electric. Likewise the Rev G 03-2000 M20R POH (http://www.softoutfit.com/static/refs/poh.pdf) system description doesn't mention this feature (though all the system descriptions in the POH are pretty lean on details). Does anyone know if this is the latest service manual or have one for a 2006 or later Ovation? I'd really like to know if Mooney added this feature (The DC-3 had this). Of course, if Mooney was to mess around with the flap actuating design, my vote would be to add an up lock so you didn't have to step over the darn thing (and worry about your passengers stepping on it - I leave mine down after shutdown to avoid that). Skip

The previous owner of my '94 M20J had a ACK E-04 installed, but didn't connect it to the GPS. I'm getting a GTX 345 transponder installed soon, and I'm thinking that might be a good time to connect the GPS to the ELT since the radio shop will have to mess with the GPS connector anyway. I'm sure some of you have thought long and hard about whether the GPS position really increases the likelihood of being rescued. What do you think: is it worth the cost and trouble?

Seems like the software fix and the AD crossed in the mail. Now that the government is back up and running, It should settle out shortly, I imagine.

Question for those who extend partial flaps above VFE: How do you determine a safe maximum speed for partial flap extension? The next higher limiting speed in smooth air is VNE. I mean, the AFM doesn’t say you can’t extend partial flaps at VNE, right?

14 CFR Part 1 defines VFE as "maximum flap extended speed". Part 23 certification rules define requirements at full flap extension because that is the worst case for the structure. (This was before the rewrite of Part 23 in 2016 to performance-based standards). The TCDS and Limitations section of the Airplane Flight Manual are regulatory documents that specify operating limitations. It is clear that VFE applies to full flaps. The manufacturer is under no obligation for certification to specify anything other than the maximum speed for full flap extension. Unless the TCDS or AFM specifies a different speed for partial extension, there is no way to know what higher speed might be acceptable for partial extension and you should treat the limitation as applicable to all extensions. Will the flaps fall off, be damaged, or compromise the airframe (in smooth air and unaccelerated flight) if you fly around with takeoff flaps at cruise power? Of course not - many of us have been the test pilot on that configuration. But I have always thought the flaps to be one of the weaker parts of the Mooney design. Just put them down and grab a hold of one and note the "give" in the mechanism. They are much less solid than on many other light singles. So, my point of view is, why push it when it's easy to develop techniques to operate the airplane effectively without the need to extend partial flaps above VFE? Skip

Thanks! That all makes sense. Skip

Well, I usually get all tangled up in the anchor line when I try that, so water brakes are the way to go.

I'm scheduled to have a GTX 345 installed in my J in March by a shop that has done a lot of 345 installs. From posts on MS and other forums, it seems that the most common source of dissatisfaction with GTX 345 installations arises from it not playing with other installed avionics as expected. I'm seeking feedback from those more experienced on my proposed installation as well as any configuration/setup/options gotchas that I should consider. Current avionics that will remain: GNS 430W, KAP-150 autopilot, Aspen 1000 PFD (connected to 430W and providing heading, nav and GPSS to autopilot), KMA 24 audio panel. New avionics: GTX 345 w/o GPS replacing KT-76A. The GTX 345 will connect to the GNS 430W via ARINC 429 for WAAS source and ADS-B In traffic and weather display. The GTX 345 will connect to the Aspen PFD via RS-422 for ADS-B In traffic and weather display. The GTX 345 will connect via Bluetooth to an iPad for AHRS and ADS-B In traffic and weather display. The GTX 345 audio will connect to the KMA 24 for traffic annunciation. The GTX 345 will connect to the current yoke-mounted IDENT button. The airplane originally had a Argus moving map (removed by a previous owner) and there remain two currently unused buttons on the right horn of the pilot's yoke from that installation. Anybody got any ideas of something useful to connect them to? Thanks in advance for the help, Skip

Good point - made me chuckle. All that prop cycling has always mystified me. I think it's a holdover from old military manuals since the hydramatic props sometimes required cycling several times to get reasonable response in cold weather (been there, seen that). I have no idea what's magic about three cycles, but that procedure even made it into my M20J POH! To Clarence's point about skipping run up: I've flown for two Part 135 seaplane operators, and the FAA-approved SOP at both was run up on the first flight of the day only. Airplanes are meant to fly. Engines don't cool so well on the ground, and there's sand and gravel and whatnot in the run up areas to erode your prop. Do we wear our airplanes out ground checking stuff too much? Something to think about. Skip

Orcutt’s shop does superior mag work. Bet they’ll run great.

Thanks for the info, David. I can feel some roughness when rotating the trim wheel to nose down, but not up. It's not very bad yet, but since I have lubed the front gearbox (which I had out to replace a worn trim wheel shaft bushing), all the u-joints, the King trim servo carrier bearing, and the rear jackscrew, the thrust bearings are all that's left. Skip

Nice, David. Can you give more detail about the shimming? How did you get the bearings off the shaft? Skip

I'll have to look at one next time I see one at a museum. You're probably right. The document you quoted isn't exactly clear in terminology: "Herb Nystrom led the team that designed the empennage and tail assembly. Following a series of engineering studies, he opted to include an all-moving tailplane similar to the one Kelly Johnson developed for the Lockheed JetStar. This configuration most effectively distributed pitch forces across the entire horizontal stabilizer assembly, widened the airplane’s center-of-gravity limits, and eliminated the need for both ballast and trim tabs" "Empennage and tail assembly" is redundant. "Tailplane" is another word for horizontal stabilizer. However, the reference to it being similar to the JetStar design would seem to indicate that the entire empennage pivots. Thanks!

I took the course 25 years ago when I owned my first Mooney and the manual was something you only got as part of the course. I think it's still that way. It was a nice reference but didn't include much original work except tables of Power/Attitude/Configurations for various models and flight phases which was interesting but something everyone can best work out for themselves based on how they prefer to fly the airplane. The rest was mostly excerpted from the POHs, Service Manuals, AIM, various ACs, etc. It's likely been improved over the years. I'm not saying that the course or material isn't worthwhile, but if you are well-studied and expecting to learn a lot of new things, you might be disappointed. Still, it was a good review and nice to have the material all in one book.

Do you have a reference for that? I believe that later versions of the U-2 had a variable incidence tailplane, but I don't think the entire empennage rotated as the Mooney. That would have been cumbersome in such a large structure. But, I'm not a U-2 expert.