PT20J

Seems like you could measure the old ones outside the worn area to determine the diameter, buy some Delrin rod, make a sketch and have a machine shop make some pretty easily.

Part 43, Appendix D, (e) (7) just states Wheels - for cracks, defects, and condition of bearings. That is subject to a lot of interpretation

Which system to buy is a recurring question. Wayne McGhee, Garmin NW Regional Sales Manager, just did a nice webinar on this on Jan 9. The recording is still available (as of today) on the Garmin training site by clicking the Register Here link https://www.garmin.com/en-US/aviation/webinars/americas/ A few interesting things I picked up. 1. The G3X/G5/GFC 500 (originally experimental only) were able to be certified because of a change in the part 23 rules in 2017 that allowed the certification of avionics based on performance rather than adherence to TSO. This happened right as the Txi was being finished. 2. The approximately 2X greater cost for the TXi is primarily due to additional development and testing effort required to comply with the TSO. They have to recoup that up front cost by charging more for the units. 3. The G3X and the TXi are more similar than different. A few differences: The TXi has a slightly higher resolution and brighter screen. The G3X allows remote control of Nav/Comms and Transponder. TXi has more interface options for legacy avionics especially autopilots. The G3X will drive the GFC 500 whereas the TXi needs a G5 or GI 275. The G3X is only available for single engine piston airplanes. So which should you buy? The G3X, G5, GFC 500 were designed to work together and installing that combination gets you as close to a "system" design as you can get short of a G1000. The TXi is a better choice if you plan to keep a legacy autopilot because it will operate with a wide variety of autopilots whereas the G3X really only works with a GFC 500 (This is because most of the GFC software is actually part of the G3X itself). The TXi is the only choice if you have a twin or a turboprop. Skip

So, here's what I've learned from all this: 1. The effect of raising the landing gear without tapping the brakes is a twisting force applied to the axels in a toe-out direction caused by gyroscopic precession. 2. The stress on the landing gear components must be negligible given that the same axels and other components must absorb landing forces which must be many times greater. 3. The precession reaction force should not affect the retraction force applied by the actuator or J-bar. The origin of the precession force is the retraction force. 4. Tapping the brakes won't hurt anything. It might keep the wheel wells cleaner if the tires are still spinning off water and dirt as they enter the wells.

Oh, man you made me go and draw vector diagrams. Getting signs right has always been my nemesis. But, I agree it is toe out on both sides.

I think all airplanes need some elevator input to takeoff properly. However, the term "rotation" is really specific to jets. There are certification requirements that the jet begin the rotation maneuver at a specific speed above V1, at a specified pitch rate, to a specified pitch angle such that the airplane will reach V2 at or before 35 feet AGL. That's very different than what we do in single engine piston airplanes. https://www.ecfr.gov/current/title-14/chapter-I/subchapter-C/part-25/subpart-B/subject-group-ECFR14f0e2fcc647a42/section-25.107

My 1978 M20J was tied down outside. I used to get very minor corrosion on the outer races due presumably to moisture getting past the felt seals. I could always dress it out with some Scotchbrite. Still on my 1994 M20J, even though it is hangared, I replaced the seals with the new rubber ones because I didn't want to bother taking things apart every year. We don't check the wheel bearings at annual -- my IA just checks the free play and spins the wheels listening for noisy bearings. I take a look at them if the wheels are off to change the tires but I don't usually repack them.

Both wheels are spinning in the same direction, but the rotation due to retraction is in opposite directions.

Now that I've actually thought about it, I believe you are correct. The effect is to try to toe out the right wheel and toe in the left.

Centripetal force would be the force on each increment of tire mass pulling it toward the axis of rotation and it would not change as the axis of rotation changes. What we want is the torque due to gyroscopic precession. Torque is defined as a vector perpendicular to the plane of rotation in a direction that, by convention, follows the right hand rule (curl your right hand fingers in the direction of rotation and extend your thumb which represents the direction of the torque vector). Consider the right main wheel. When the gear is retracted, the gear motion is a clockwise rotation (viewed from the rear looking forward) and a translation toward the center of the airplane. Only the rotation creates a precession torque and so the translation can be ignored. The rotation of the spinning wheel causes a change in angular momentum which creates a torque which, by the right hand rule, is represented by a vector pointed toward the nose of the airplane. The effect of this torque is to apply a twisting force to the axel which would tend to toe the tire out. Calculating the torque requires knowing the angular velocity of the wheel/tire, the moment of inertial of the wheel/tire the gear geometry and the angular velocity of the gear as it retracts. I doubt it is all that much, especially since the drag of the brake pads and the friction of the bearings causes the wheel to be decelerating fairly rapidly.

According to the IPC, 880030-501,503 are fuel flow transducers. 880007-501 is a fuel pressure transducer for S/N 24-0378-1417 and 1686-2999. The second part number you showed is a PMA replacement for the 880007-501 per the PMA Products, Inc website.

It would be really interesting if those with manual gear would try it both ways and report back on the difference in effort to raise the gear. Mooney’s present a unique opportunity to investigate this.

I’d just take it to a welder and have them make a replacement. My A&P has folks he uses for that kind of stuff; you might ask yours for a recommendation.

I have a 1994 M20J with Garmin G3X panel, 500 hour factory rebuilt engine, 1650 TT, original paint and interior (I did replace carpets and repair/paint the plastic). My carrier is USAIG. I've got about 5,700 TT and 1,300 MM. I didn't have any problem getting $250,000 hull and $1,000,000 smooth. $250K is about what I've got in it and pretty close to what the updated Vref came up with. Cost was $3,443 hull and $663 liability ($4,106 total). I'm the only named pilot. Skip

According to an old Beechtalk post, John Deakin claimed the practice is likely from old WW II aircraft manuals. https://www.beechtalk.com/forums/viewtopic.php?f=2&t=59754 Personally, I don’t bother. I already have enough to think about on takeoff

I’ll certainly defer to Ross @Shadrach since he’s used the tape on the oil cooler successfully. I used aluminum duct tape once to temporarily seal some baffle gaps and the air pressure deformed and tore it and made it very difficult to remove, so I’ve been leery of it since.

Are you talking about the landing gear actuator? Is it a Plessey or an Eaton? You might discuss it with Don Maxwell. He told me that a chattering sound can be due to a worn no-back spring.

TIS (sometimes referred to as TIS-A although the FAA never used that term) was an add-on to terminal radar mode-S transmissions that provided traffic information at selected terminal locations. With the advent of ADS-B, it became obsolete and has been phased out. ADS-B traffic comprises a number of services. TIS-B (Traffic Information Service Broadcast) is a broadcast of secondary targets from ground-based radar. Not all airspace requires ADS-B participation and so non-ADS-B out equipped aircraft would not be visible to ADS-B in equipped aircraft without TIS-B. TIS-B ground processing includes a tracker application that removes ADS-B targets from the TIS-B transmission to avoid causing so-called ghost targets to appear near the ADS-B aircraft. If there were a prolonged GPS outage and subsequent failure of aircraft to transmit ADS-B out position, I expect TIS-B would still function but I doubt that the ADS-B in equipment in the airplane would be able to process it without GPS position. The iPad, as I understand it, uses multiple GNSS receivers, so it may be a useful backup in the event of a GPS outage. Skip

Not to worry. https://www.faa.gov/about/office_org/headquarters_offices/ato/service_units/techops/navservices/gbng/vormon

Note 7 says the retrofit kit applies to all S/Ns.

I wonder if closing off the cooling to the radios is a good idea. My J doesn’t have that capability, so at some point Mooney quit doing that. A legacy stack can overheat pretty easily depending on what you have in there. I would not block off the oil cooler unless you know from experience that it is necessary. And, I would fabricate a plate to do it right. Aluminum tape will deform into the oil cooler from the air pressure and be difficult to remove.

There is a part number, so I’m sure it existed at one time. However, since the M20J has been out of production since 1997, it’s quite likely that Mooney doesn’t have any and the cost to make one might be prohibitive. But any MSC can check with the factory for you. It might be more cost effective to source used parts needed to add the blower from a salvage company. Skip

I don’t know. Garmin has turned into a software company. They have more releases than Microsoft.

Very cool

In addition to the small holes in the access panels, there are some ~1/4” holes in the lower inboard skins a few inches back from the leading edge.