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PT20J last won the day on June 3

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About PT20J

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    1994 M20J

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  1. Just show your AI the service bulletin. He’s supposed to follow processes specified by the manufacturer when available.
  2. I’ve had this problem ever since I purchased the airplane two years ago. The door seal was original and very compressed. I pulled it off and verified that the door was not quite flush at the top before I replaced the seal with the Brown Aircraft T-9088 called out in the IPC. With the new seal, it is worse. I screwed the “bullet” latch at the top of the fuselage out a couple of turns and that improved the latching force, but it’s still not right. Based on the description in the service manual, I wonder if the doors were all hand fitted to shape at the factory. Skip
  3. Don, Mid Continent is an authorized BK shop and repairs their stuff. I've found them very reasonable. Fixed my KAP 150 autopilot controller and bench checked a Garmin nav indicator that turned out to be OK and only charged me return shipping. Regal Air in Everett WA has a fleet of Cessna 172s with KX 155s and they send everything to Bevan Aviation. Display retrofit is expensive, but the radios are still solid and repairable. Skip
  4. I hangar it if there is a risk of hail but leave it outside with my Bruce's cover otherwise when away from home. The cover was purchased by the first owner (it's a '94 J and I'm owner #3). The cover is in great shape -- I don't think it was used much. But the second owner installed a 406 MHz ELT and the antenna wasn't accommodated for by the cover. I contacted Bruce's and they took it back and added a provision for the antenna at no charge. That's pretty good customer service. As a side note, I used to enjoy flying down to Morgan Hill, CA for dinner at the Flying Lady restaurant owned by Irv Perch, Bruce's father, and named for Bruce's mother who was an avid pilot. Irv had quite a collection of old airplanes and cars in a barn and would gladly show you around. Irv's property included an adjoining golf course and Irv had one fairway made long and straight enough to serve as a grass runway. They would use it to fly his Ford Trimotor out to the Watsonville airshow every year. Fun times. Skip
  5. The servo just meters total fuel flow according to air flow and mixture control setting. There is one hose that goes from the servo to the flow divider. The flow divider serves two functions: 1) divide flow evenly to the nozzles, and 2) it contains a valve that closes off fuel to all nozzles to insure a smooth shutdown. If the fuel flow is not the same to all cylinders, the problem has to be either something clogging the internal passages in the divider, clogged or unequal diameter lines to the nozzles, or the nozzles. Unlike the servo, the flow divider can be disassembled in the field for inspection and cleaning. The nozzles contain a restrictor and these are matched sets with the nozzle body and care must be exercised when cleaning to not interchange restrictors between nozzles. Also, don't poke anything in the nozzle bores to clean them as this may affect calibration -- just soak them in Hoppes No. 9. You can tell a lot about the nozzle condition by comparing the spray patterns in addition the the baby bottle test. Don't worry about wearing out the boost pump; as long as it is pumping fuel it can run continuously. See Precision Airmotive RSA manuals attached... Skip 15-338E.pdf 15-812_B.pdf
  6. I'm doing the same to my 1994 M20J and I'm almost done putting it back together. I didn't mess with the overhead vents. Unless they are not working properly, don't mess with them because Mooney glued everything together. Starting somewhere in the mid '80's Mooney began using epoxy primer (off white) on the tubing rather than zinc chromate (green or yellow). Your's looks like it has a combination of both, but it's hard to tell from the picture. Zinc chromate is a hazmat and not nearly so good a corrosion barrier as epoxy. I'd clean up everything and use an epoxy primer. Check the areas behind all the gussets for missed primer from the factory. The plastic panels are ABS and cracks can be patched with fiberglass cloth and ABS glue. Don't put it on too thick or it softens the plastic. They will look like new if you paint them with SEM. I used Phantom White which is a close match for then beige instrument panels used in later models. Skip
  7. I never tried laser engraving. An avionics shop made a bunch of placards for the museum DC-3 using traditional mechanical engraving. They looked great. But then we discovered that the glare makes the legends unreadable under some lighting conditions.
  8. The cabin door on my J has about a 1/4 inch gap at the top when the door is closed but not latched. This makes it take a fair amount of extra force to latch as the clamshell at the top latch has to spring the door top inward before the mechanism goes over center. The service manual says, "NOTE Door contour can be altered slightly to conform with cabin contour, if needed, for proper fit and sealing." Has @M20Doc or anyone else done this? Any tips on how to do it.? The door is pretty stiff. Thanks, Skip
  9. This is a great point. When I purchased my J with a little ole' Lycoming IO-360-A3B6D, the EDM 700 spark plug thermocouple for cyl 3 had been put on cyl 1 apparently by mistake. So, I had two thermocouples on the same cylinder that allowed direct comparison. The spark plug thermocouple consistently read 40 deg C higher than the bayonet thermocouple. When I replaced the engine, I got a new thermocouple for cyl 3 that mounts under the factory thermocouple and I now get readings consistent with the factory gauge and the other cylinders. The spark plug thermocouple was accurate. The temperature is higher at the spark plug boss than at the bayonet thermocouple location. So, cylinder head temperature depends on where you measure it. I think we stress out way too much over CHTs. I remember when everyone was stressed about shock cooling. Don't reduce MP more than 1" per fortnight or whatever. Now, the generation that doesn't remember that stresses over the dreaded RED BOX. Don't do this, don't do that, you'll destroy your engine. I get it. These things are expensive and we don't want harm them. But, I think Mike Busch has it right. Understand how these things work. Develop some conservative SOPs that minimize workload and have fun flying. Now if you want to do something more radical like cruise at 80% power deeply LOP, then you need to be more circumspect. Skip
  10. I agree with Ross. This is a statement often made by the APS folks and it is an over simplification. It arises from the observation that the brake specific fuel consumption curve is very nearly linear for the first 50 deg. F or so LOP. So, you can approximate the percent power if you know the fuel flow which is easily set by the mixture control. The APS formulas that everyone uses for this calculation are also approximations and the compression ratio that enters into the formula is only a proxy for thermal efficiency of different engines. Skip
  11. Agree — mostly. Ground resonance is a hazard with articulated rotor systems having three or more blades. It can occur during start up or with a somewhat hard touchdown which upsets the lead/lag balance of one or more blades causing the CG of the rotor system to go off center and setting up the oscillation. Normally, the dampers in the landing gear will damp out the coupled motion to the airframe and the rotor system rebalances and the oscillation quickly subsides. If one or more of the landing gear dampers is defective, the oscillation can build exponentially with positive feedback between the airframe and the rotor system unless the helicopter is immediately lifted clear of ground contact whereupon the rotor system will rebalance. Skip
  12. Dynamic balancing corrects the prop/spinner combination for a condition where the center of mass is not in line with with the center of rotation. Balancing may or may not produce a discernible improvement in perceived vibration, but it’s still a good idea as it may increase the life of accessories and other components. An extreme example of a dynamically unbalanced propeller is ground resonance in a helicopter. An airplane propeller would not become this unbalanced (unless it lost part of a blade), but it is illustrative of how the propeller vibration transmits to the airframe. Skip
  13. All aircraft have unusable fuel. The fuel pickup in each tank is slightly above the lowest point to avoid picking up contaminants. For the M20K, the TCDS lists unusable fuel as 48.59 lbs. or about 8 gal. Remember that the ‘E’ on the fuel gauge doesn’t mean ‘Enough’. Skip
  14. Same for me. The E uses an IO-360-A1A so dynamic counterweights can’t be an issue. Skip