PT20J

Sand to remove corrosion and feather paint edges. Prime with etch primer (better adhesion than zinc phosphate). Take the access panel from the tailcone to an auto paint shop and they can color match it and put it in a spray can.

There's an old saying: A man with one watch knows what time it is. A man with two watches is never sure. In my plane I got the following voltage measurements (engine stopped, master and avionics ON): Aspen PFD: 23.6V EDM 700: 24.9V Mooney voltmeter: 25V (best guess - not enough graduations to read accurately) Fluke DVM at main bus: 24.35V Fluke DVM at battery terminals: 24.4V The DVM is, of course, the most accurate. So, be careful where and how you measure your voltage.

Just curious... what incorrect basic aerodynamic concept did an instructor teach you?

Check on insurance costs. Turbos may be a challenge to insure economically without an instrument rating.

Jimmy Garrison @ All American is a straight shooter. They’ve been around since 1991 - can’t last that long if you don’t treat people right. I have both sold and bought planes there and was treated honestly and fairly on both transactions. The PPI is important, but don’t expect it to catch more than deal breaker defects. Budget for lots of deferred maintenance surprises at your first annual. I think a lot of folks put too much faith in MSCs. I have used both well known MSCs and non-MSC shops. Some of the things MSCs have missed or screwed up were surprising. It really comes down to the knowledge and experience of the mechanic that works on your plane Find a good Mooney mechanic - MSC or not - and stick with him. Best is to be directly involved (owner assist) during any major maintenance. Good luck, it’s a great adventure. Skip

I think you are saying that the gear down light on the annunciator panel did not illuminate, but the floor indicator was in alignment and the floor indicator light was on. I don't have a wiring diagram for an M, but the gear system is likely the same as my J. The down limit switch in the belly is a double pole switch. One pole shuts off the actuator motor when the gear is down and the other pole controls the light. It could be a loose connection between the switch and the annunciator panel, or a bad switch. It's probably not a switch adjustment since the motor apparently shuts off OK. Also, the annunciator light dims when the NAV lights are on and this can make it hard to see in the daytime. Skip

Actually, Lycoming will still overhaul or rebuild the dual mag engines. I discussed this with Lycoming when I recently replaced an IO-360-A3B6D with a -A3B6. You will get an overhauled mag since the dual mags are no longer in production. Since Continental bought the Bendix magneto line, Lycoming has switched to Slicks wherever possible. There are a lot of internal dufferences between the A3B6D and the A3B6 - its not just the mags - and Lycoming will make it worth your while to switch. Skip

On my ‘78 J it was a switch for the Davtron clock flight time function.

Good idea to check the aiming when you replace the bulb.

Thanks. Any idea what rpm it’s calibrated for?

According to the wiring diagram, the hour meter is fed from the electric tachometer on my M20J. Does anyone know how this works? Is there a cut-in rpm below which it doesn’t record, or does the tach pilse modulate to simulate the hour meter on a mechanical tach? Skip

Should be possible to determine if the flaps are closing by noting CHTs.

Here's what I got from Mooney - they told me this is all they have. Skip Mooney Service Manuel M20J Vol. 2 of 2.pdf

Well, best glide is the speed that, power off, gives the minimum descent angle. Any speed, higher or lower, will result in a steeper descent. Low power isn't much different than power off.

Best glide is CL/CD max speed. To get truly on the backside of the power curve, you have to be below the minimum power required speed where CL3/2/CD is maximum, which works out to 76% of the best glide speed (for a derivation of this, see Anderson, Aircraft Performance and Design, Chapter 5). That turns out to be pretty slow. For a Mooney (and most piston powered GA airplanes) the backside of the power curve isn't the big deal that it's been made out to be. Skip

There's nothing particularly special about trimming a Mooney. It's a matter of nailing the attitude and taking the care to get it properly in trim. With a lower performance airplane like a C-172 or a PA28, the airplane doesn't gain or lose altitude very quickly with small pitch changes, so if they are slightly out of trim you don't notice the excursions as much. With a higher performance airplane, it will quickly gain or lose altitude with very small pitch changes. In other words, it is more sensitive to being slightly out of trim. Also, the nose attitude in level flight is relatively low in a Mooney compared to some other airplanes and this can cause a tendency to trim it too nose up. Cross checking with the attitude indicator will help with this. Another way to get the feel for proper trim if you have a 2-axis autopilot is to set power and put the autopilot in altitude hold and let it trim. Then disconnect the autopilot and manually move the trim wheel slightly each way to get the feel for finding the perfect trim again.

I gererally have run Lycoming O-360 and IO-360 engines between 6 and 7 qts. Probably have a couple thousand hours behind them and never saw oil pressure fluctuations as you describe. Last summer I ferried a M20J that was burning about a quart every 2 hrs and saw the oil pressure decrease to the top of the yellow (60 psi). Checked the oil level after landing and it was 4 qts. Added three qts and it was fine. I’d try running it between 6 and 7 qts, and if everything is OK, just operate it that way and don’t worry about it. If you do go tightening bolts, check the torques in the Lycoming manual. Some engine bolt torques are different than general bolt torques. Skip

Turned the lights on in a dark hangar today. The mirrors reflect the taxi light outboard and slightly ahead of the wing I suppose so you can see better to turn. The old lights were so dim that I never noticed, but the LEDs are bright enough that it may be helpful.

I’ve never received an 8130 from Mooney for any part so It’s probably a special request to get one. Lately Mooney lead time have been longer (for me anyway). I think they’re keeping inventory down and building a lot of parts to order. Zinc Chromate isn’t the best corrosion protection for steel. Mooney switched to epoxy primer at some point, which is much better. Your new parts should be epoxy primed.

Yep, that's the one. Drawing from the IPC shows the K-Mart mirror in the right wing, inboard of the taxi light.

The first annual is usually painful, in my experience. You get to find all the little things that the previous owner deferred, and they add up. Sounds like this annual was pretty thorough, so next year it should be much better. Hang in there and think of all the fun you’ll have when you get it out of the shop.

Anyone know the purpose of the little convex mirror inboard of the taxi lights on the M20Js with wing-mounted taxi and landing lights? Also, thought it funny that the IPC lists K-Mart as a source for replacement. Mine are fine; just can't figure out what they do. I never noticed it until I was replacing landing/taxi lights with LEDs today. Skip

Agree with Don. Chandelles and Lazy Eights are coordination maneuvers that are very graceful once you get the feel for the airplane at constantly changing airspeeds. One sure way to screw them up is to muck around with the power setting which puts you out of trim. Skip

Tire manufacturers recommend replacing on condition, not age. Tubes are frequently replaced along with tires as they stretch and grow in service and may be difficult to reassemble without pinching. If tubes leak significantly, the tube and valve should be leak checked in a tub of water. Taxiing and takeoff also wear tires. It’s not worth altering landing technique to save wear. A Michlen rep once told me that airline tires wear most an takeoff because the weight is greatest (fuel load).

The cylinders of a radial engine are arranged in a vertical plane and gravity causes oil to flow down to the bottom cylinders after shutdown. It can get past the rings, but mostly it fills up the lower rocker boxes and seeps into the cylinders through the valve guides. The starters on radials have a friction clutch that's supposed to slip before any damage is done, but we never trust it and always pull the props through a couple of engine revolutions before starting if it's been sitting a while. Also, when you observe someone starting a radial, you might notice the prop turning a long time before it starts. That's because we count 12 blades before turning on the mags -- just to be sure. It's unlikely that a horizontally opposed engine would have a hydraulic lock from just sitting around. However, if an engine is preserved using Lycoming's procedure in SL 180B, you will have added 2 oz. of preservative to each cylinder and this could certainly cause a problem if it were not removed. If the engine has been sitting a long time, it might be a good idea to pre-oil it as Lycoming recommends before starting a new, overhauled or rebuilt engine. This can be done by removing the spark plugs and spinning the prop either by hand or with the starter until oil pressure is indicated. This will also ensure that there is no chance of a hydraulic lock. Skip