PT20J

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.

The trim servo has a lot of torque. What seems to happen is that the mechanism gets stiff for whatever reason, and if you always use electric trim, you don't notice it until the trim motor isn't powerful enough to move it anymore. If it gets to that point, it may be hard to move it manually as well. There's a lot of trim change in a Mooney over the range of speeds and flap settings. Mooney flaps are more effective at increasing CLmax than on most other GA airplanes and contribute more pitching moment. The Mooney trim system changes the angle of incidence of the stabilizer. This design is favored when the amount of trim range would cause excessive elevator deflection with a trim tab. Common in jets. The M20J stabilizer trims through a range of about 6 degrees. This isn't really enough which is why the trim bungees are needed to bias the elevator along with the stabilizer movement. Even at only 6 degrees, it takes a zillion cranks of the trim wheel to go through the entire range. No wonder everyone likes the electric trim.

Was wondering about that 90-deg bank. Hey, thanks for the picture. I've been hoping for a charter there someday so I could see how the lake got it's name. Pretty.

Lots of good pix and advice on this thread. Also a lot of talk about -- grease. I'm in agreement that the best practice is to follow the manufacturer's directions in the Service Manual unless you absolutely know -- don't think, but know -- of something better. My M20J Service Manual specifically calls out Aeroshell 7 for the jackscrew and bearings. I'm not sure it's a good idea to use Aeroshell 5 which is a high temperature grease specified for wheel bearings. https://www.shell.com/business-customers/aviation/aeroshell/knowledge-centre/the-aeroshell-book/_jcr_content/par/textimage_1433441235.stream/1445042875796/1d024cf49b16b7091e0368a866e9ca6b0ef6f275ac75de066f2004ed372bbef1/aeroshell-book-5greases.pdf Grease is basically oil and a thickening agent. Not all greases are compatible with each other. The Service Manual calls out the following greases: MIL-G-81322 (now MIL-PRF-81322G) Common greases that meet this spec. are Aeroshell 22 and Mobilgrease 28 MIL-G-3545 (obsolete, superseded by MIL-PRF-81322) -- Aeroshell 5 MIL-G-23827 (now MIL-PRF-23827C Type I and Type II) Type I uses metallic soap thickener -- Aeroshell 33, Mobilgrease 33. Type II uses clay thickener -- Aeroshell 7. Type I and Type II are NOT compatible with one another. MIL-Specs can be found at: http://everyspec.com/ Qualified products meeting MIL-Specs can be found at: https://qpldocs.dla.mil/ Skip

Lyle Panepinto at Southern Seaplane teaches a really good seaplane safety class that includes emergency egress training in a dunk tank.

Appreciate real data - thanks Byron. Curious if you noted any CHT differences between 20 deg and 25 deg ROP and LOP. Did you wind up leaving it at 25?

The real “genius” of Al Mooney was figuring out how to package four people into the smallest wetted area with a cabin wider than a Bonanza.

A Mooney engineer, who had also worked for Cessna, told me years ago that it took 750 hrs. to knock out a Skyhawk and 2000 to build a M20J. Cessna tooled everything. A lot of the Mooney is “hand crafted.”

I thought the timing change was to lower CHTs. Anyway, Lycoming has been shipping all IO-360 engines (except Bendix dual mag versions) with 20 deg BTDC timing for a long time -- I have a Lycoming Operator's Manual from 1982 that states 20 deg BTDC as standard. Interestingly the current 1E10 TCDS (1-10-18) lists timing as 25 deg with 20 deg footnoted as optional. What that means is that you can change the timing back to 25 deg (with the appropriate changes to the magnetos internal timing, data plate, and a logbook entry). I confirmed this with the Lycoming factory rep. Does it make a big difference? I don't know. But the APS folks don't seem to think so. Here's a graph I got from the APS presentation when I attended a seminar in Ada, OK several years ago.

Thanks, Andy, One more mystery solved. Way back in the early '90s, I was working on a flight simulator project and since I owned a '78 M20J at the time, contacted with Mooney engineering. Rob McDonnell was VP of engineering at the time and we had a deal that if he sent me engineering data I needed, I would send him estimates of stability derivatives. He sent me some stuff but he freely admitted that Mooney had been through so many ownership, management and personnel changes that many reasons why things were done the way they were were lost. I can't imagine that it's gotten better over the intervening years. It's interesting to piece all this stuff together. Skip

I'm curious if your airplane has the aileron-rudder interconnect springs. The usual reason for such an interconnect is to alleviate some adverse yaw. If the aileron change made the yaw worse, the springs might have been added to help with that. If the yaw is due primarily to the wide chord of the ailerons, then I would think the springs would be part of the original design. Skip