0TreeLemur

The vacuum pump on my M20J gave up the graphite ghost on a trip this past weekend. It drives my backup AI. I have a 3rd backup (AV-20S), and a 4th (Stratus), so having a spankin' brand new one doesn't seem absolutely critical. Anybody have a working Rapco or Tempest 215CC vacuum pump burning a hole on a shelf you'd be willing to sell? DM me if so. Thx. -Fred

I love the 15 year gap in this thread! Here's photo of a twisted wing for those interested. Pretty wild looking.

How much power do I get per gallon per hour? For the IO-360-A, -C, -D, -J, and -K series engines, Lycoming provides curve No. 12699B, "Part Throttle Fuel Consumption". Pound per hour doesn't jive with my EDM, I want gph. Note that at 75%, 70% and 65% power, these curves agree with the M20J cruise power schedule in the manual provided by @PT20J, but this figure provides continuous info rather than tabular data. When you are controlling MP with the throttle, this is a useful figure. WOT you can use it with EDM engine power (%) to set fuel flows for "best efficiency". I made nothing up here. This is a reinterpretation of the data shown on the Lycoming curves. I think it is pretty useful. It also shows that at cruise (<75% power) "Best Power" settings are "Fuel Wasting" settings. Note: what I'm calling "Specific Fuel Efficiency" on this plot is (pounds/gallon)/BSFC.

Oh, I've seen that before. Yer problem is you got some clouds in the wing and you gotta open it up and scrape 'em out.

I plotted the data from this figure in a different way. On my plot above there is one point (2000 rpm, ~120 HP) where the specific power is 14.9, the stochiometric value used for LOP calcs.

RE: Lycoming LOP ops. Lycoming data shown on their Part Throttle Fuel Consumption Plot for the IO-360 series engines includes LOP ops. I converted that figure into specific power (HP/gph), and you can see that parts of those best economy curves lie at specific power > 14. The best economy mixture settings at 65% power and less are with specific power > 14 HP/gph are most certainly LOP.

bump.

I never thought to do that. Interesting idea. Good idea.

^^^ This. Jake can make an old KFC computer behave like a young KFC computer.

Around the time I bought my C model, Brittain started shutting down. Because I love the elegance of the Brittain PC system I started picking up (my wife would say hoarding) Brittain spare parts. I don't have new servo boots, but I've got the next best thing- servos with serviceable boots. To test them, I put my finger over the air inlet fitting and pulled. No motion, no leaks. The rudder servos are P/N 20420-0-0 and the aileron servos have P/N 20420-0-1, and I'm pretty sure the diaphragms are the same in both. Some of them don't have P/N's. Selling as is. Price includes shipping via UPS ground to you in CONUS. Elsewhere else or by other means, you pay. Not trying to make any money, just trying to help the community keep their Brittain systems working. Pretty sure I paid more for them than I'm asking. I'm selling them in lots. Lot 1 (SOLD) 1: a complete set of 2 aileron and 2 rudder servos. One of the rudder servos has 2017 as a service date. The others are pretty much illegible. I'll sell all 4 for $150. Lot 2: Two rudder servos. $75 for both. (two total) Lot 3: Two rudder servos and four aileron servos of various ages. All for $150. (six total) Lot 4: Two aileron servos and two rudder servos. Service tags indicate 2000 where legible. $150 and they are yours. (four total) Lot 5: One aileron and one rudder servo. $50. (two total) DM me if you want to buy and tell me which set. Don't ask me to split them up. Selling lots as defined.. I'll have more Brittain parts to list after this. Fred Addendum: Lot #1 and lot #4 are sold.

When I upgraded audio panel in my C, I worked out a deal with the installer where I pulled the wiring and installed the stereo jacks myself. That saved a lot of shop time. It wasn't hard. Just required patience. If you know how to remove/reinstall the interior in your plane it is not a big deal.

I think this AI generated press release from LASAR, which was previously posted IIRC, explains it all (straight story, no fluff): https://lasar.com/announcements/2025/10/24/whats-going-on-with-mooney-amp-lasar-the-straight-story

January 2nd I flew one holiday visitor to catch a commercial flight in HSV. Flew up there under the ceiling which was at 3,000 ft. Returned IFR into worsening conditions. Uneventful and fun. Love winter IFR in Alabama. Seldom is icing a concern.

xkcd nailed it.