1980Mooney

OK here it is for your 1967. You can find all the electrical schematics in the back of the Service Manuals which you will find in the "Downloads" Section of MS - just click on "Browse". Notice that they connected the hot + lead from the battery to the lug on the Aux/External Power Relay (Solenoid) instead of to the Power Relay like on later models. When the Aux/External Power Relay is energized (that is when the 3 pin connector plugged in and attached to a 12 v. power cart or car) then both the main ship battery and external power source are connected in parallel.

Note that it was an "Option" as shown in the drawing for E and F models. It was also an option for C and G using exactly the same schematic.

Here is the Mooney Electrical Schematic for your pre-J F model showing the Aux Power adapter.

That may be true on some Mooneys - maybe the later ones with multiple batteries. But on the M20J, the plane's battery and aux cable which is connected to the power cart/car engine are wired together in parallel when the Aux contactor closes. There is no bypass of the main ships battery ever. M20J Ser. No 237 M20J Ser. No 1256

Following @N204TA highlight of Piper 1 pin vs Cessna/Mooney 3 pin external power adapters: Are you saying that your Mooney has a Piper style single pin receptacle mounted either internally or with a weather proof external door? (Like pic below?) If so it was not installed by Mooney at the factory and it is not the the Mooney Retrofit External Power Receptacle 940115-503 "Installs external power receptacle M20E,F,J,K". Mooney used the Cessna style 3 pin external power adapter. (see below). If you actually have a Piper single pin connector then check your logs to see who/when it was installed. PIPER STYLE ONE (1) PIN CESSNA OR MOONEY THREE (3) PIN ADAPTER

Well it took 50 seconds to drop the initial 1,000 ft from 17,000 to 16,000. After that it was dropping at about 11,500 - 12,000 fpm. Elevation at the crash site, Vinhedo, is about 2,500 ft. So the final descent from 16,000 took about 1 minute and 10 seconds. I am sure it was terrifying. The Juan Browne YouTube above at 3:20 shows video of the descent from 5 different viewpoints. It is amazing that so many people were looking up tracking it in the sky and had time to video it. I suspect Doppler effect caused the screaming prop noise to fluctuate as it spun 360 degrees and caused to people look up.

The plane left Mississippi June 9 and stopped near Las Cruces, New Mexico for a few days and then Sedona, Arizona. Looks like he was on the way back when he landed at Carizzozo on July 21. He was there over a week and a half. There is nothing to do in Carrizozo for that long unless you are going hiking/backpacking in the nearby Lincoln National Forest. I wonder if his plane broke down. You may have noticed that the owner got his Commercial ticket in 6/2022 with Glider privileges. And he had an Instructor MEI rating 8/2021 that expired 8/2023. Interestingly the FAA shows his last Medical was 5/2015 with no BasicMed. He bought the Mooney in July 2021. Knowing about density altitude, leaning and wind should not be a big challenge for a Glider rated MEI if he was flying.

Do you mean this? Some cut a hole - read on.

Except that you’re using an altimeter setting/barometric pressure (26.48) that is lower than has ever been recorded anywhere on earth. I used Standard. The Prelim report says that at Ruidoso/Sierra Blanca it was 30.5 at the time which means the actual density altitude might’ve even been another 5 to 600 feet lower and closer to 8300 feet. The barometric pressure reading at Roswell must’ve been an error. Hey it’s New Mexico – things don’t always work right. Garbage in gives you garbage out. “The lowest barometric pressure ever recorded in the continental United States (CONUS) for a non-tropical system at sea level is 28.20 inHg (955.0 millibars), which occurred twice in US history:”

Perhaps the hype of the "benefits of GA" that drew some new potential owners has worn off with our segment of the GA market. I think that there are basically 2 GA markets. One in which money is no object. A new $ million plane is no problem. And a plane with more comfort options like air conditioning. This is a market where the owner/pilot is not likely going to get his hands dirty (if he can help it). Everything is under warranty. And if not under warranty then "Someone else" is going to fix and care for it. It will always be hangared. Someone else is going to pull it in and out of the hangar. It will always be ready to go. The other is one which survives on a much smaller budget. It comprises the majority of the market which is made up of 20- 60 year old planes. It is more hands on - with the extreme being home built and virtually all hands on. Something is always breaking or wearing out. Parts availability, depending on make/model can be questionable or if available they are still a long expensive wait. Repair of our old planes are not like going to AutoZone and getting a standardized part to plug in. As time goes on our old planes become more bespoke - look all the topics on mix/match interiors, rare to find two pre 2005 planes with the same panel, tons of modifications - firewall forward changes, fuselage speed mods, changes to landing gear, etc. And there are the topics on the plane being AOG. In summer the planes are generally uncomfortably hot until up high. Let's face it, the second market segment has a following but it is not for everyone. It doesn't take too many scrubbed trips because the battery is dead due to a bum baggage light switch, the wings are leaking fuel, etc or bouncing flights in turbulence or even long holds for release on a sweltering day to sour a family on the "benefits of GA." And then the bills come in - sometimes unexpected for the $14K fuel tank reseal or the $50K overhaul or the $15K new Eaton landing gear actuator.....

Not sure where this is coming from. The accident happened in Carrizozo, New Mexico at the Municipal Airport, F37. Field elevation is 5,373 ft. The weather in the prelim report is from 22 naut. miles away at Rudioso Airport (Sierra Blanca KSRR) which is at a higher elevation, 6,810 ft. Like a lot of New Mexico, desolate Carrizozo (population 973) is in the middle of nowhere. There is no online weather from Carrizozo - look closely, they all report outside Ruidoso at KSRR - even the National Weather Service and ForeFlight. There is no METAR from F37. Since it happened at about 1 PM, it was probably about 90-95 degrees F and like most of New Mexico dry as hell with low dew point. I would estimate that density altitude was about 8,800 ft. Winds at Carrizozo that day? Who knows - the reporting at KSRR, located on a mountain valley north east of Ruidoso, is separated from Carrizozo by the Sierra Blanca Mountains, 11,981 ft. It is questionable if the wind conditions at KSRR were anything like Carrizozo at that time. The area around Carrizozo Airport is barren and flat - It is not like Sierra Blanca (Ruidoso) KSRR which is more rugged surrounded by drop offs and valleys- and more prone to shifting wind drafts. This might be a case of a Mississippi based flatlander getting messed up by density altitude. However 2 weeks before he had flown in and out of Sedona without incident. - granted not in the middle of the hot afternoon.

Same plane was for sale on Barnstormers a bit over a month ago for $10K more. Apparently no takers. Something wrong with it? Maybe the market is turning.... https://barnstormers.s3.amazonaws.com/media/docs/doc_SPECIFICATION_1916789_1719724910.pdf https://www.trade-a-plane.com/search?category_level1=Single+Engine+Piston&make=MOONEY&model=M20E&listing_id=2433570&s-type=aircraft

This is probably the most overlooked factor when anyone tries to compare an air cooled aircraft engine to a liquid cooled solid block automobile street engine. Rarely would your old Ford 302 be running WOT -it might be measured in mere seconds - hardly even for one minute for an automobile. Maybe in a truck application, usually derated, it might run WOT for longer periods. But our aircraft engines run WOT for hours on end. Why does that matter? Manifold pressure. A car cruising at 60 mph on a level road, no wind, might have the throttle open 1/3 or about 30-35 degrees. Engine vacuum might be 16-18 inches HG which is about 12 - 14 inches HG Manifold Pressure in our aviation lingo at SL (that is only 6-7 psi). A Lycoming IO-360 at SL WOT might be 26 inches HG Manifold Pressure at 2,500 RPM dropping to 18 inches at 10,000 ft. (that is about 13 psi at SL and 9 psi at 10,000). If the pressure is double, then the air density (number of molecules is double) and since the air/fuel ratio is in a narrow range, the number of hydrocarbon molecules is double burning with double the energy. So with the same or similar Compression Ratio to the Ford 302, the Peak dynamic cylinder pressure of our aviation engines are much much higher than typical car engines - double at SL. Yes the manifold pressure drops on a NA engine as altitude rises but even at 10,000 ft cruise we still have more peak cylinder pressure than a car cruising a level freeway at SL. - probably 30-50% more. More cylinder pressure. See the Savvy graph below. A 20% increase in manifold pressure resulting in a 49% increase in measured peak cylinder pressure. The TN engines that are at 30 inches HG all the time or turbocharged with over boost hitting 40 inches. Yes they have slightly lower static Compression Ratios in order to manage peak cylinder pressure but the turbocharged engines with 1/3 greater boost will hit the highest pressure of all. In addition to higher pressure, the air cooled engine has more hot spots - a solid liquid cooled block has better and more stable heat transfer. As @Shadrach and @A64Pilot said other variables that affect this are ignition timing, valve timing, mixture. This is a good read - https://www.savvyaviation.com/controlling-the-combustion-event/

I am not sure how familiar you are with Mooney Service Centers (MSC). Don Maxwell, located 190 nm away in Longview, TX, is premier. You probably saw that he hosts the annual MooneyMax. Maxwell is also qualified and will undertake major airframe repair that others cannot handle. https://www.donmaxwell.com/ I don't know where you are located and that may seem like a long distance to your or the Seller, but if you get a Pre-Buy from Maxwell there will be little unknown to debate regarding condition of the plane.

Other direction towards the northeast part of Arkansas.

Maxwell in Longview is a heck of a lot closer…

That is after getting about $30K for your old engine. If you have no core then the cost of a new Lycoming IO-360 is $129,000 - But none are in stock so you will likely pay more when/if you can find one. That is why the DeltaHawk is looking competitive for OEM new sales in currently manufactured airframes. Hence no interest in Mooney applications. When considering it as an engine swap on a legacy aircraft, it is competing with Overhauled and Rebuilt engines at much, much lower cost. The economics don't work. And don't forget all the extra cost for new engine mount frame, new cowling, new prop, some changes to engine instrumentation/recalibration and then you need some kind of heater modification. Costs which you would not have with an overhauled Lycoming (maybe some over haul cost for prop and repaint for engine mount frame but no cost related to the cowl or instrumentation or heater). I bet those things easily add another $30,000 on top of the engine - probably more. Hence no interest in Mooney applications.

You are both correct in your assessments. I should’ve been more clear. I agree with. @EricJ that there is no leak in the tubing between the and the ASI. And I agree with you that the only other thing that could have failed is the sensing mechanism (springs, microswitch). If the diaphragm in the switch had failed, there would be a continuous leak, which would give you a low speed reading in the ASI. I have the old style sensor, which screws directly into the back of the ASI. The diaphragm in that looks like some kind of rubberized fabric. Over time and heat mine got brittle which affected its ability to flex and therefore the speed at which it tripped. My diaphragm also eventually developed a leak The newer switch looks like it’s made out of something much more durable.

WTF. That is two (2) owners ago. That owner (now 71 years old) sold it in 2019 and let his Medical expire in 2020. I am surprised that his wife, whom he acknowledged to ATC was on board, allowed him to continue flying a few years and didn’t make him immediately sell it in 2016.

I think @EricJ is right. If there was a leak in the pitot line then the pressure would be low on BOTH the landing gear switch and the ASI. In that case the continuity test on the switch would trip at a normal approx 60 KIAS shown on the connected ASI. - but because of the leak, the plane would need to travel faster than 60 KIAS to create the same pressure in the pitot system. But that is not the case.

That’s the other thing. How many months are you whiling to have your plane down?

You bought a nice-looking plane. But one would need to know more about your goals. Like everything in aviation "its complicated" You can get "modern GPS" with limited modifications But do you want to get rid of your vacuum system? I see you have stand-by vac, Do you want all digital or a hybrid of steam gauge and some digital? Do you want a large flat screen panel? You asked about engine instruments - do you just want redundant digital display or do you want to get rid of you current instrumentation? If so you need a "primary" EDM like a JPI EDM 900 or larger 930 Do you want it all integrated with a modern autopilot? I see you have a WX950 stormscope - do you want storm/lightening on your MDF? - perhaps a WX-500 How much do you want to spend? You really need to look at other panels, find out how much they spent, Also talk to an avionics shop and get estimates. https://www.aircraft.com/aircraft/222336491/n97dm-1997-mooney-m20j-mse Avionics King KMA24 Audio Panel King KLN89B GPS King KX165 Digital Nav/Com with Glideslope King KX155 Digital Nav/Com King KN64 DME with Remote Switch King KCS55A Slaved HSI King KAP150 Fully Coupling Autopilot with CWS Appareo Stratus ESG Transponder with Stratus ADS-B in Equipment WX950 Stormscope Shadin Digital Fuel Flow Electric Pitch Trim Symphony 468 Intercom System LED Wing Tip Strobes & Recon Lights Yoke Ident Button

High cylinder head temperature can be caused by many things unrelated to fuel octane, pre-ignition or knock. You could have high temperature in only one cylinder. You could have an errant temp probe. But you are right that a system could be designed which makes changes or takes action without command by the pilot in order to "save something". And when the pilot realizes why he is losing power, speed or climb he can over-ride it. There is precedent for it in GA with good intentions (automatic action that can be over-ridden by the pilot when (if) he figures it out)- Piper did this with the "Automatic Landing Gear" on the Arrow. I am sure it saved a few gear-ups and retracted the gear many times when the pilot forgot. It also caused many accidents when it happened just as the pilot needed the opposite and the pilot did not realize in time.

Not from the ability to change advance. There is no way for the e mag to know if the engine is beginning to enter knock/detonate conditions due to fuel quality issue, load, mixture, etc. There is no knock/detonation sensor. You are thinking of a liquid cooled automobile engine with a feedback loop that monitors engine noise and can discern a knock or detonation sound signature. No knock/detonation sensor works reliably on an air cooled aircraft engine. Too much other mechanical noise. "In an auto engine, the common cylinders and head make a more metallic or audible sound that is transferred to the entire block assembly. That is why they can use only one knock sensor to control knock in an auto engine." https://generalaviationnews.com/2015/05/27/visser-for-10/ If you have an e mag that blindly retards the engine based on something than actual detonation then you could suffer reduced power just when you need it most. https://generalaviationnews.com/2011/08/29/knock-free/ The e mag might have a hotter spark but I doubt that will help much with low octane knock.