PT20J

Huh?

I've quit on VFR flight plans except when crossing the border. Last time I had FSS fail to activate one and another FSS fail to close another one. I contacted each FSS in the air by radio. Instead I get flight following. I figure with flight following, ADS-B, and a 406 ELT that the VFR flight plan doesn't offer much -- and given my latest experience, it seems unreliable. Skip

Equipment code should be S GTX 335 surveillance code is EB1 Skip

Agree. The Aspen AFM Supplement Limitations section mentions that the RSM GPS is for emergency use only, but you have enough other instruments that you don't need the PFD anyway. There are no limitations in the STC related to a functioning GPS.

How do you get to use a 2 degree tolerance? The engine data plate data sent show one. Clarence I assume you are confusing the common practice of some mechanics of not adjusting the timing if the mags are with two degrees of the timing mark with purposely adjusting the setting on the advanced side. There's no "legal" basis for that that I'm aware of. Note if you install a SureFly to replace the mag with the impulse coupling, it will take care of the lag angle and you can set an IO-360 to 25 deg and change the data plate.

It's 38 deg max. From the SureFly website: "For non-turbocharged engines, SureFly controls spark advance up to 38º before TDC as determined by manifold pressure and RPM (engine power setting). Each engine's base timing advance is read off the data plate and set into the SureFly Ignition Module or, "SIM" at installation. The timing advance schedule is hard set at the factory, when the SIM is manufactured, to provide the highest possible combustion efficiency." Skip

The SureFly (missing) advance curve has been bugging me, so I spoke with Jason Hutchison at SureFly. He confirmed that they removed it from the website. He said it was an oversimplification and technically incorrect. He also said that they decided for reasons he declined to elaborate on not to publish the corrected curve(s). He was pretty forthright and I didn't get the sense they are trying to hide anything. I suspect that they are tired of "experts" opining on the details of their design. OK, I get that -- I probably wouldn't get too far trying to get Subaru to send me advance curves for my Outback. Here is what I did learn: The primary design goal of the advance is to adjust timing so that the peak pressure point (PPP) is about 13 degrees ATDC which they found to be close to the Maximum Brake Torque (MBT) angle for most engines in cruise operation. Operating at MBT gives the greatest efficiency. The use of MAP and rpm is analogous to the old auto distributors that had centrifugal and vacuum advances. At 24" MAP and above, the SureFly will be at base timing. Below 21" it will be fully advanced. Skip

Well, actually, I don't think this is the best way to do it. The instrument panel is mounted on rubber LORD mounts for vibration isolation. There should be a ground strap to connect the panel to the frame for continuity, but Mooney doesn't use the panel for primary ground. The best way is to connect it according to the schematic in the Service Manual. But failing that, I'd connect it to a good ground on the tubular structure somewhere. Be sure to use aircraft-approved wire. The clock is required equipment for IFR (91.205). Skip

If you need the pump, you might consider replacing it. If it gets any oil contamination, it won't last long. From Rapco's website: Q: With my engine at idle, the vacuum gauge reads zero, but as the engine RPM is increased, the gauge will indicate vacuum. What causes this? A: The cause for this symptom is most likely the carbon vanes sticking in the rotor slots due to an oil or solvent entering the pump. A leaking (Garlock) oil seal in the accessory drive case can cause this as well as the engine being washed with an oil based solvent without having the pump completely covered. Both of these fluids will work their way into the pump, mix with the carbon dust, and turn into a paste like substance. Dry Air Pumps MUST remain DRY or their life expectancy will be cut extremely short. Inside each pump is a carbon rotor with vanes inside its slots. Centrifugal force slings these vanes out and against the Mil-Spec coated cavity walls moving air and creating vacuum or pressure. During this process, graphite dust is created as the vanes wear and helps keep everything in the pump moving freely. That is until the graphite dust is introduced to a fluid or moisture that creates the paste like substance, sticks the vanes in the slots and does not allow them to move freely and push or pull air until higher RPMS puts greater force on them to do so.

According to Bob Kromer, Mooney sets the demonstrated crosswind low due to concern that "average pilot technique" will be strained by greater crosswinds due to the airplane's tendency to float in ground effect if speed is a little high at flare. Bob's personal limit was 18 kts, but that was when he was flying every day and very proficient. Keep in mind that crosswinds are frequently gusty and may be turbulent due to airflow over obstructions along the sides of the runway. Gustiness and turbulence require somewhat higher speeds and that exacerbates the floating problem. In my experience, when landing with a strong crosswind with gusts or turbulence, you need to really "work" the flare with pitch AND power to prevent the plane from touching down until it is nose high and straight with no side drift. That requires a certain amount of patience, and some touchdowns may still not be pretty. Under FAR Part 25, even transport category airplanes do not have to show a crosswind capability greater than 25 kts. Skip

Anyone know why Mooney does not recommend using a tail weight? They don’t say you can’t do it; it’s just not recommended. BTW, I ran across a Service Instruction that says you’re not supposed to fly with the tie down rings installed. Strange recommendations. Skip

Interesting question. Since neither manual has operating limitations specific to your airplane that are not included in the AFM, you don’t need them in the plane. The reason you need 50 lbs of avionics manuals is that the Limitations section of the AFM supplements frequently require the full manuals to be a available. Any Limitation listed in the AFM is legally binding Skip

The 70/50 rule of thumb (70% of takeoff speed by 50% of runway) turns out to not be very conservative. Theoretically, it gets you to takeoff speed at 100% of the runway and doesn’t allow for any obstacles. But, it’s a good start. Maybe 80/50 would be better. Skip 50-70_20190704_0002.pdf

Don, the certification requirement is 0.2 x Vso which is about 11 kts. However, we know that the test pilots work really hard to get the shortest takeoff roll, best rate of climb, and highest cruise speed numbers possible for the handbook, so it seems odd to me that they wouldn't work a bit to get the highest possible demonstrated crosswind, too. This number has been in the J POH since 1977. The test pilots did a lot of test flights over the years: other numbers have changed, but not that one. Maybe the wind never blows more than 11 kts in Kerrville. Skip

My '94 J came with a WX-900 from the factory. The LCD display on mine was dead when I bought the plane. I just purchased a replacement panel unit on eBay for $365 which was cheaper than having the old one repaired. Skip

Good for you for getting out the POH and thinking this through. An abort point is an excellent idea for any takeoff, but especially in critical situations. A useful rule of thumb is that a 1% gradient is about equal to a 10% addition (down hill) or reduction (uphill) in runway length. Using this and the POH takeoff charts for headwind or tailwind will help you decide what to do. Some mountain airports are one way in and out due to obstacles/terrain. Skip

Ignore the cold idle speed. With the engine warm, set the idle speed and mixture to spec (I don't have a C S&M manual, but it should be about 650 rpm and 25-50 rpm rise when slowly pulling mixture back just before ICO). Skip

A quart per flight (you didn't mention how long your flights are) is a lot of oil. I used to fly a turbo Arrow with an IO360 and turboplus intercooler and it didn't do this.

Mike, Some oil is always carried out the breather (that's why they quit putting them on cars). If you changed something and it causes more oil to come out the breather, then it might be best to figure out how the change precipitated this rather than put a bandaid on it. Excess oil out the breather generally comes from blowby past the piston rings that pressurizes the crankcase.

You're right -- I got it backwards (funny, since I've owned one of each!) I've thought about removing the ramp on #4. Still can't figure out why my #2 is the hottest though - everything looks right. Skip

Ram air was in the center below the spinner. From various postings, there seems to be a lot of CHT variations in Js. The left cowl flap on the early Js had the big opening similar to the right (exhaust side) cowl flap. At S/N 24-1616 it was changed to the flush fit design. Skip

The elevator springs are the trim assist bungees used through the J models. They bias the elevator neutral position as the trim is moved in order to reduce the amount of tail incidence change required. Aileron-rudder interconnects are frequently used to correct some stability or control issue in the lateral axis. The Mooney has rather long (spanwise) flaps. This leaves less wing for the ailerons and the Mooney has rather short ailerons of wide chord. A certain area is needed for effectiveness. They couldn't be much wider in chord as the control forces are already high enough that the trailing edge was beveled (an aerodynamic trick to reduce hinge moment). The roll rate of the Mooney is not too snappy and the interconnect likely improves it over what it otherwise would be. Skip

I replaced my M20J engine with a factory rebuilt IO-360-A3B6 last October. I reused the baffles (they were in good shape) but replaced the baffle seals with GeeBee seals that fit great. At 75% cruise I generally see CHTs about 1- 360F, 2-380F, 3-360F, 4-375F. (These are at peak EGT; CHTs are a little cooler LOP with less spread). Though these are in a good range and the spread isn't bad, I found it interesting that the hottest cylinders are on the left side. Perhaps the air filter and oil cooler which are on that side may be robbing some air from the cylinders. I also noticed the big hole in the baffle in front of the alternator and covered it with aluminum tape as an experiment. That made absolutely no difference in CHTs, so I removed the tape figuring Mooney must have had a reason for putting a big hole in the baffle in front of the alternator. At MooneyMAX Bob Kromer recommended rigging cowl flaps open about 1 inch. He said it cruises a couple of knots faster. I tried it and it lowers CHTs but I didn't notice any speed increase (or decrease). So, if your CHTs are a bit high, this might be the easiest fix. Skip

From POH, demonstrated x-wind velocity: M20J 11 kts C-152 12 kts C-172N 15 kts C-182Q 20 kts(takeoff) 15 kts (landing) PA-28-181 17 kts

25 degrees timing is approved for the IO-360-A3B6. To make it legal you just need to set the timing to 25 degrees, change the lag angle on the impulse-coupled mag, and change the data plate.