PT20J

Wow, this is really interesting. I must admit, I never thought that much about spark plugs. As I mentioned earlier, my experience with fine wire plugs is mainly with radials (R-985 on Beavers I fly for a seaplane company, R-1830 on a DC-3 I help maintain and sometimes fly for a museum, and an R-2600 on a B-25). On my personal aircraft, I've always used massives. Lot's of comments about improved performance from those who have switched to fine wires made me wonder if I'm missing something. I did some research and here's what I've found. 1. No manufacturer of fine wires touts a specific, measurable benefit beyond longer life. 2. Recommendations are to remove, clean, check gap, and rotate every 100 hrs regardless of plug type, so the maintenance is the same. 3. The only strong recommendation I could find was from RAM with a claimed measured 2% drop in SFC on a specific turbocharged engine. As an engineer, 2% seems within the margin of measurement error and I would want to see the data. http://www.ramaircraft.com/Maintenance-Tips/Spark Plugs-Fine-Wire-vs-Massive.htm 4. Many have stated that the fine wires are 3X cost with 3X life, so the operating cost is about a wash. 5. It's clear that fine wires may help with engines near needing a top overhaul that have an issue fouling plugs. For me, I think it's a wash. I note that my previous study of behavioral finance makes be suspicious of expectation bias and confirmation bias in the anecdotal reports. That does not mean that I do not believe that these reports are sincere -- it just means that I await hard data which even the manufacturers of these spark plugs seem unable to provide. Skip

I’ve got a recent factory rebuilt A3B6 with massives. Starts, idles, cruises fine. Never fouls. Wonder if the fine wires help mostly when cylinders wear and more oil gets past rings? On the radials, we put fine wires in back and massives in the front since rear is harder to access and we don’t want to service them as often. We have to pull the fronts out for compression check so it’s no problem to gap them. They both seem to work fine.

Been waiting for someone to test asymmetric deployment at takeoff. Thanks for the pirep Speed brakes work by increasing the parasite drag. Parasite drag predominates at higher airspeeds. At best glide speed (L/Dmax) parasite drag and induced drag are equal, and below this speed induced drag predominates. So, adding additional parasite drag from the speed brakes has less effect at lower speeds. Skip

Don't make this complicated . If you are going to do a full stall, in any normal category certificated airplane (no Mooneys aren't really different) do it by maintaining level flight, decelerating about one knot per second until you either reach full up elevator or the nose drops - then promptly recover. Most any airplane will drop a wing if you delay recovery (well, except the Cherokees that just oscillate in pitch while descending). Remember that in a stall, your primary roll control is the rudder. If you are aggressive with the rudders you can correct any wing drop before it gets out of hand. If you wait too long you will have to reduce the angle of attack to get the wing flying again to correct the roll. If you are apprehensive about stalls two common mistakes are to either recover too soon (before it actually stalls fully), or to hold the elevator back fixating on the roll and forgetting the rudder while trying to wrestle it with the ailerons which often just aggravates the rolling tendency. Forty-five or sixty degrees of roll may look scary, but you are not really in a spin (by definition) until after you complete one full turn and the airplane had to be recoverable from one turn for certification. (It has to do much more to be certified for intentional spins). The way to get comfortable with stalls is practicing with an instructor who is very comfortable with stalls. Best is a DPE 'cause I guarantee you he or she has seen a LOT of odd stall recoveries and is very comfortable with stalls, spins and recoveries in a variety of airplanes. Skip (CFII, MEI)

Stall avoidance training is better for real life situations. Lot's of people are afraid of full stalls though, and the value of doing them is to lose the fear. Even if it rolls off, you still have plenty of control authority to recover - it just seems scary at first.

Hmmm. Lots of interesting comments. Let's see if we can sort this out... Mooneys are hand built and it is true that they are all a little different. Back around 1992, Rob McDonnell (VP of Engineering at the time) told me that they flight tested each airplane with the stall strips duct taped on and moved them around until the wing drop was "about" equal at stall and then riveted them in place. So, some are probably better than others, but none should roll off greatly. Assuming a wings level, ball centered entry, the stall characteristics will vary with power on or power off, and also the rate of deceleration. To avoid dynamic effects, a power off deceleration in level flight of about 1 knot per second is a good target. Pull up more than that and it will get more exciting. If it still falls off, the first thing to check is that the airplane is rigged correctly, of course. Here's an excellent article on flight checking the rigging. Don't forget the flaps! http://www.knr-inc.com/shoptalk-articles/25-shoptalk/75-201407-control-rigging. Also, you can check if any wing repairs may have altered one wing slightly. Even so... My '78 J always rolled at stall. There was no damage history, but the stall strips were in noticeably different positions on the "nose" of the wing, one being quite a bit higher than the other. My '94 J stalls without noticeable roll, the stall strips are about even, and the right wingtip had a rib and skin replaced due to a hangar door incident by the previous owner (Maxwell did a very nice repair) and there is some bondo on the leading edge from an earlier ding. So, I wouldn't lose sleep over some roll off. Every one is going to be different. If you are uncomfortable with it, go up with an instructor and do stalls until it's second nature so you aren't afraid of it and then focus on stall avoidance. That's important because good landings in Mooneys come at slow speeds. Skip

I used to own a '78 J that didn't have them, and never felt I was missing anything. It took a few hours to learn how to manage the energy effectively, but after that I could easily slip into the SJC 30L ILS between two jets in the conga line from LA and "keep the speed up to the middle marker", sidestep to 30R and make the first exit after landing -- all with reasonable maneuvers and power reductions. Recently, I purchased a '94 J with electric speed brakes and I find that, on occasion, they are handy. But after reading some threads, on speed brake maintenance, and noting that the previous two owners of my airplane had sent them back to Precise Flight for overhaul twice in 1150 hours, I've decided that it may be most cost effective to reserve them for cases where I truly have a need. I remember reading this somewhere: Controller: Cross XYZ at 10,000 Airline pilot: That's going to be pretty difficult from our present position and altitude Controller: Don't you have speed brakes on that thing? Airline pilot: Yes, but those are for my mistakes, not yours. Skip

Bet you won't make that mistake again Lot's of good suggestions and observations in this thread. But, after 44 years, I've learned how fallible human working memory is -- a little distraction, or change of routine, and stuff slips through the cracks. So, don't be too hard on yourself -- you're human and we all do stuff like this on occasion. The checklists and mnemonics and SOPs help, but you will never be perfect. One aspect of airmanship is recognizing and effectively dealing with this fact of life.

Altimeters have a setting knob, VSIs have a zeroing adjustment screw.

The ignition switch only grounds out the right mag (when the jumper is installed) in the Start position. Bendix_Ignition_Switch_Maintenance.pdf sim20-59a.pdf

Let's wait for a pirep from the Bonanza crowd -- they'll try anything

I've always liked King autopilots, but I recently went through several month's effort resolving an intermittent problem with the computer for a KAP 150. All the King autopilots are getting old, some parts are scarce, and there are fewer options for repair. I would look for a plane with an S-TEC, even though I agree with many that the rate-based autopilots don't fly nearly as precisely as the attitude based autopilots. Why? Because there are more upgrade options on the horizon (namely the S-TEC 3100 and the Avidyne DFC90) to upgrade the installation to a modern, digital, attitude-based autopilot without ripping out all the servos and wiring. Some interesting history: Ed King took the best engineers from Collins to form King Radio. Years later, the best engineers left King to start Garmin. EDO morphed into Century after an employee buyout. A group of engineers left Century to form S-TEC to exploit the idea of rate-based autopilots. The idea was that the vacuum system/gyros were the most failure prone system and the fatal accident rate after an IMC vacuum failure was very high. On the other hand, turn coordinators had low failure rates. So, after a vacuum failure, the S-TEC would be able to bring you home safely. Not a bad idea, but they just never were as responsive as the attitude based autopilots. Skip

I'm a retired electrical engineer. The only aviation project I worked on during my career was a flight simulator back in the early '90's. I owned a 1978 J at the time and we used it as a test bed. I got to know the VP of Engineering and a couple of engineers at Mooney at the time and we shared some data. I also had several consultants working on the project. I learned a lot on that project and it and started a fascination with aerodynamics and flight dynamics.

I think certified version of TruTrak doesn’t have trim.

I believe the impulse coupling spins the common mechanism that turns both mags.

OK, so at 2500 lb GW, that’s a ROC decrease of 3.7 * (550/2500) * 60 = 48.8 ft/min. At 100 kts that’s about 30 ft/nm.

Actually, it depends on whether you have the jumper on the ignition switch or not. No jumper = both mags for start.

One mag except Bendix dual mag engines that start on both.

If it doesn’t start after a couple of attempts, prime enough so you are sure it’s flooded and do a flooded start procedure. Works every time. When priming an engine with a RSA injector, it’s important to open the throttle about an inch or so. Idle mixture is controlled by the idle valve connected to the throttle. If the throttle is set too low, the valve limits the fuel flow and you will get an inconsistent amount of prime depending on the throttle position. Skip

Hey, thanks, Clarence. I didn’t know that. Now I know better. Skip

Search youtube for Don Maxwell hot start.

You probably mean the oil suction screen. If you have an oil filter, most mechanics only pull it if metal is found in the filter. It’s a pain to get to and it’s a pretty coarse screen, so if there’s no metal in the filter, it’s pretty rare to find anything in the screen. Continentals have one too, but it’s internal and you can’t get to it.

What melted at what EGT?

Try this: https://youtu.be/jbRYqS-fRo0

I used a Tempest oil filter for the first time recently and it’s supposed to go on dry. Has anyone run into any problems with that? Now, what am I going to do with that half tube of DC-4 that I’ve had for 25 years?