PT20J

If you search the NASA Technical Reports Server for old NACA reports on beveled ailerons, you will find a lot of reports of wind tunnel and flight test results. Generally I believe the conclusion was that beveling reduces aileron effectiveness, decreases the section lift curve slope and reduces hinge moments. Here’s one example: https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19930093563.pdf Skip

Mine were $225 + shipping in late 2018. Kit includes die cut baffle seals, pop rivets and barrel screws -- everything you need. The original seals are attached with hardened staples. You need a Dremel with a cutoff wheel to remove them. Guy supplied a couple of cutoff wheels also. His SCEET tubing is double wall and much better than SCAT. With the finished ends, they should last at least to TBO. Skip

I recently practiced using the Foreflight synthetic vision display on my iPad (Bluetooth linked to a Garmin GTX 345) as a backup in case my Aspen PFD failed. I quickly lost control of the airplane. Fortunately it was VMC and I just as quickly recovered. It turns out after some investigation that the attitude part of the AHRS in the less-than-a-year-old Garmin transponder had failed (the heading part works fine). I have had mechanical gyros fail and the failure is pretty evident because, after various erroneous indications, eventually they just stop indicating. But, I learned from this that the AHRS can fail in a way that it appears to be working -- it's just not displaying anything like the correct pitch or bank angles. I took some video of the AHRS indications in a standard rate turn to the left and a standard rate turn to the right. The iPad display is Garmin Pilot, but Foreflight does the same thing with one important difference: Foreflight never flags whereas apparently Pilot figures out that the AHRS input doesn't make sense and flags DEGRADED as shown in the video. So the moral to the story is that digital devices can fail, their failure modes are not simple or obvious, and they will kill you unless you quickly recognize the failure, and you need a backup that is in your scan to detect the failure. Garmin tells me that the AHRS used in the GTX 345 is the same as used in their primary flight displays. Skip IMG_3409.MOV

You’re going to have to have it up on jacks for an extended time. I would get a pair of real aircraft jacks with safety locking collars and make a tail weight (there are kits available). Skip

Got to love Mooneyspace where a question about how to replace a $200 gauge turns into a recommendation to spend tens of thousands on new equipment. Skip

I understand, but that's why I compared the Mooney and Comanche -- because they are about as similar as two different airplanes can be. Similar airfoils, almost the same wing area, same MAC, same wingspan, dihedral within 1/2 degree, same forward sweep, essentially the same fuselage length. Hmmm. I hadn't thought of that. Maybe that's one reason for adding the aileron rudder interconnect. I wonder if the Comanche has one? Skip

Somewhere around the mid-1960s, I believe, Mooney beveled the trailing edges of the ailerons. I've heard it said, but do not know for certain, that this was done at the time of introduction of Positive Control to lighten the control forces for the roll servos. I've found lots of references describing beveling the trailing edges as being a method of aerodynamic balance used since the 1940s to reduce control forces, but I've yet to find a good analysis of exactly how it works. My understanding comes from some fairly cryptic comments in an old NACA report that I can no longer lay my hands on. The general idea is that increased hinge moments are caused by flow separation and thickening and beveling the trailing edge increases the camber at the trailing edge which reduces the adverse pressure gradient so that the flow can remain attached. Ron @Blue on Top, did I understand this correctly, or is there a better explanation? Skip

I think I understand that at Mooney speeds, the most efficient vertical stabilizer in cruise would be straight (measured at the quarter-chord line). Sweeping back looks jet-age cool, but is less efficient which means more wetted surface (and thus more drag) to achieve the same aerodynamic result. Sweeping forward slightly might be a small penalty in cruise but would improve the efficiency at higher angels of attack which occur (unaccelerated flight) at low speeds and thus low dynamic pressure. But.. in an earlier post, I compared the tail feathers of the Mooney to the Comanche (which is interesting because the airplane planforms are so similar) and found that the the Mooney vertical stab is actually slightly larger than the swept back Comanche vertical stab. So, before we crawl too far out on the Wikipedia limb, it might be good to compare a bunch of designs and figure out if the advantages are real or theoretical. Maybe I made a mistake.

An engineer friend worked at Boeing when the FAA was designing the test of the fire suppressant fuel additive. The FAA got sensitive that it was being called a "crash test" and insisted on calling it a CID -- Controlled Impact Demonstration. It took everyone about a minute to redefine the acronym as Crash in Desert. Skip

USB Power specs courtesy of Wikipedia: Power-related specifications[edit] See also: USB hardware § USB Power Delivery (USB PD) Release name Release date Max. power Note USB Battery Charging 1.0 2007-03-08 5 V, ? A USB Battery Charging 1.1 2009-04-15 5 V, 1.8 A [40] USB Battery Charging 1.2 2010-12-07 5 V, 5 A [41] USB Power Delivery revision 1.0 (version 1.0) 2012-07-05 20 V, 5 A Using FSK protocol over bus power (VBUS) USB Power Delivery revision 1.0 (version 1.3) 2014-03-11 20 V, 5 A USB Type-C rev1.0 2014-08-11 5 V, 3 A New connector and cable specification USB Power Delivery revision 2.0 (version 1.0) 2014-08-11 20 V, 5 A Using BMC protocol over communication channel (CC) on USB-C cables. USB Type-C rev1.1 2015-04-03 5 V, 3 A USB Power Delivery revision 2.0 (version 1.1) 2015-05-07 20 V, 5 A USB Type-C rev1.2 2016-03-25 5 V, 3 A USB Power Delivery revision 2.0 (version 1.2) 2016-03-25 20 V, 5 A USB Power Delivery revision 2.0 (version 1.3) 2017-01-12 20 V, 5 A USB Power Delivery revision 3.0 (version 1.1) 2017-01-12 20 V, 5 A USB Type-C rev1.3 2017-07-14 5 V, 3 A USB Power Delivery revision 3.0 (version 1.2) 2018-06-21 20 V, 5 A USB Type-C rev1.4 2019-03-29 5 V, 3 A USB Type-C rev2.0 2019-08-29 5 V, 3 A Enabling USB4 over USB Type-C connectors and cables. USB Power Delivery revision 3.0 (version 2.0) 2019-08-29 20 V, 5 A [42]

Probably lots of places, but Pacific Coast Avionics has complete fabrication facilities. They are on the same field as Vans and make a lot of custom RV panels.

The side panel on the pilots side of the console is held on with 5 sheet metal screws; two at the top that screw into Adel clamps with Tinnermans and three on the bottom that screw into the nose wheel well. If you take this panel off, you should be able to access everything in the center console. Skip

I'm less concerned about additives since I got the roller lifters and fly it regularly. The X/C is cheap and seems to work, so I'm going to stick with it.

I have about 170 hours on the factory rebuilt IO-360-A3B6 in my 1994 M20J. The first 40 hours I ran it on straight Aeroshell 100 for break in. Then I ran it on Aeroshell W100 for another 100 hours during which time it pretty consistently burned 1 qt every 8 hours. I tried my long-time practice of running it down to 6 and filling to 7. I also tried running it down to 5 and filling it to 6. Didn't matter. Eight hours/qt. At 140 hours, I switched to Phillips X/C 20W-50. Now it consistently gets 12 hours/qt. Cheaper oil and less of it seems good to me. I have no idea why the difference, but the C-210 owner in the hangar next to me had the same experience. Curious if anyone else had similar (or opposite) results. (A C-175 owner in the hanger nearby got less oil consumption switching from X/C 20W-50 to AS W100). Skip

It’s fixed now. Turned out to be a bad pin on the KX165 connector from the GI106A resolver. Skip

I looked in my '78 J manual and it shows 18.4 gph at 100%. My '94 J manual doesn't list anything above 75%. The specs I published are the current Lycoming acceptance test specs. Skip

Just for kicks, I figured out the rated power fuel flow for a Lycoming IO-360. Data supplied with my factory rebuilt IO-360-A3B6 shows maximum fuel flow specifications at various airflows (AF= airflow in lb/hr, FF = fuel flow in lb/hr) FF=52.6 @ AF=504 FF=86.3 @ AF=904 FF=95 @ AF=1000 FF is unspecified at rated power, but actual measured AF=1118.5 on my engine This data projects a rated power fuel flow of 104 lb/hr. According to Aeroshell's data sheet for 100LL, https://www.shell.com.au/motorists/shell-fuels/sds-tds/_jcr_content/par/textimage_278c.stream/1519809888867/e1579e2bb13c53e309e13bad6be6881908514236/avgas-100ll-pds.pdf the density is 0.718 lg/L or 5.995 lb/gal, so 104/6 = 17.3/gal/hr. My fuel flow normally reads about 17.2, FWIW. This may have nothing to do with your issue, but I post it in case there is interest in IO-360 takeoff fuel flow. Skip

LASAR or Great Lakes Aero Products

Normally, one would overhaul or replace all the accessories when overhauling the engine. Good time to IRAN the prop, also. Don’t forget the oil cooler. Hoses are probably due for replacement, too. Skip

A “backfire” from the exhaust (technically an afterfire as a true backfire is through the induction system) can be a symptom of a too rich mixture where excess fuel is unburned and ignites in the exhaust system. It might be running rough because it’s too rich. Operating on one mag slows combustion similar to leaning. 18.8 gph sounds a little high for an IO360 at sea level full power and this started after the fuel servo was overhauled. I would try leaning to somewhere between 17 and 18 gph during the climb and see if that has an effect. Skip

True, but it makes a difference at what altitude you do this. The winds are usually stronger up higher. So, in a strong wind it sometimes works best to fly the final in a crab and then convert to a slip for the last hundred feet or so. If you can't hold it in alignment with the runway by 50', give up and go around. Skip

The M20 was certified under Civil Air Regulations Part 3 which requires: § 3.145 Directional stability and control. (a) There shall be no uncontrollable looping tendency in 90-degree cross winds up to a velocity equal to 0.2 Vso at any speed at which the aircraft may be expected to be operated upon the ground or water. Skip

I finally got this sorted out with Peggy. Apparently some of us did not get transferred to the new website. There are evidently some issues with the developer. The old website isn't even supposed to be live any more. I couldn't get a hold of Peggy initially because I used the old mapa@mooneypilots.com email which isn't dead (it didn't bounce back) but apparently no one looks at it any longer. Skip

Wow, RCA back when RCA was a real company that made stuff!