PT20J

The Liberty ships were pretty amazing. Spearheaded by HJ Kaiser and based on a modified British design, over 2700 were built in American shipyards during the war; some constructed in just 5 days. Contributing to their speedy construction was the innovation of welded steel hulls saving time, cost and weight over the then current practice of riveting. There was a learning process with this method and several did suffer catastrophic hull cracking failures. (Remember that when suggesting new cheaper, faster ideas for aircraft production). If you’re in San Francisco, visit the Jeremiah O’Brien, one of only two remaining seaworthy Liberty ships. I’ve taken excursions on it around San Francisco Bay and it’s a kick to go down to the engine room and watch the triple expansion (3 cylinder) steam engine at work. https://www.ssjeremiahobrien.org Skip

Just take it to a reputable repair station and they’ll know how to do the test properly without damaging anything. If you’re really worried about, tell them about your concern and have them explain how they do the test. Skip

Something doesn’t make sense here. I’m not sure what you mean that the dynamic prop balance came out “perfect.” Are you saying that it was 0.0 ips? That would be hard to believe. The balance test uses an accelerometer bolted (temporarily) to the engine to measure vibration. If the prop balance showed low vibration, then how can you be getting the vibration you describe? What rpm did you optimize during the prop balance?

I keep hearing that Mooney flaps are ineffective. Flaps are used to lower stall speed which allows shorter runways to be used. If you compare Vso and Vs1 calibrated stall speeds from various GA singles (I’ve done that in other threads) you find that Mooney has one of the largest spreads. Perhaps we are more used to Cessnas and Pipers that have flaps that don’t decrease stall speed much but do create a lot more drag making steeper approaches easier. Maybe this makes them seem more effective. Skip

Instruments do not need to removed from the aircraft for the test unless faulty. Pitot/static test sets have connections for both pitot and static. The test procedure calls for maintaining small positive pitot pressure throughout the test to avoid damage to the airspeed indicator. Tests run down to -1000 feet static pressure. The airspeed switch is no more likely to be damaged than the airspeed indicator and neither will be damaged if the test is performed correctly. Skip

FAA Weight & Balance Handbook lists standard weight for Avgas at 6.01 lbs/gal @ 59F. You could use that if you want since it’s an FAA reference. Really, the only way to know for sure is weigh it empty. I suppose you could fill it up and drain a carefully measured gallon and weight that. Skip

Thanks, Jerry, for pointing that out. We still run across CFIIs that are unaware of this. Hal Shevers (Sporty’s Pilot Shop) started petitioning the FAA for this around 1992. Took awhile. A second AI is worth 5 TCs (actually 4.895, but I rounded). OK, I’m kidding, but really everyone, if you only have an AI and a TC, you should seriously consider replacing the TC with an AI if you fly much IMC (unless of course you have a rate-based autopilot). Look up the accident rate for partial panel IMC. There are only two reasons for standard rate turns: 1. It avoids banking too steeply with risk of loss of control. This problem is negated if you have a second AI. 2. It allows timed turns in case the HI fails. But now days, it’s easier just to use GPS track. Skip

I’ve had excellent work done and fair pricing at Crown at KPAE. Skip

If you look in the Service Manual you will see that only some of the covers need to be removed for inspection and lubrication.

One of the problems today is that there is a shortage of good mechanics/technicians. Even good shops with good reputations are victims of the people that they can hire. When I got my GTX345 installed I checked the recommendations on the shop and the technician. Shops would do much better at keeping their good reputations intact if they would have someone inspect the work done, but I find that rare to non-existent. Don Maxwell has a good reputation. I've consulted with him and find him honest and helpful and I would use his shop if it were closer. But still, his mechanic that did the last annual inspection on my airplane for the previous owner left a hose clamp off the vacuum filter, reinstalled the spark plug CHT probe on the #1 cylinder instead of the #3 and "fixed" a broken governor adjustment screw by wrapping it in safety wire (didn't hold), and a few other small things. Skip

I hear ya. One idea I got from Mike Busch that I really like is to set written boundaries ahead of time (he suggests this for annual inspections, but I use it for all maintenance). In other words, if you find something unexpected or it's going to be more expensive, or take longer, than the estimate, you must contact me for approval before proceeding. I never found a good shop that would refuse such an arrangement -- in fact they seem comforted by it because it avoids any arguments over the invoice. Skip

Here's a description from McCauley: Static Run-Up - What is Normal? There has been some confusion in the field concerning propeller low blade angle setting, the governor setting and how it relates to static run-up and take-off RPM. As a general rule, engine redline RPM cannot be reached during a full power static run-up. Contrary to popular belief, the governor is not controlling the propeller at this time, the propeller is against its low pitch stop. Attempting to increase propeller static run-up RPM by adjusting the governor high RPM screw will have no effect and will probably result in a propeller overspeed during the take-off roll. On a single engine aircraft several considerations determine both the low and high blade angle settings. Normally 25 to 100 RPM below rated take-off RPM is desirable and acceptable during a static run-up. McCauley's practice is to set the low blade angle so that rated take-off RPM is not reached until the aircraft has reached some significant groundspeed during roll out. At this time, and only this time, the propeller is controlled by the governor. There are two advantages to this practice. First, the maximum static RPM can be used as a check on developed horsepower as with a fixed pitch propeller. Any loss of maximum power over time is readily apparent during a preflight check. Second, if the propeller remains in a flat pitch after take-off due to some malfunction, the higher angle low pitch setting will permit more thrust to be developed to fly the aircraft without overspeeding the engine.

Did you mean 2675 static?

Sorry, I hit Submit too soon. I meant that you might need to call them if you just looked on the website. The factory is shipping parts and perhaps they can order it from the factory. They just got me a couple of placards for the baggage compartment. Skip

LASAR

Here is what has worked well for me: 1. Choose a shop with a good reputation and experience with the work you need done. Write out for them exactly what you want done and get a written estimate. Do not start the work until you and the shop agree in writing to the scope and cost. 2. Do not seek out a shop with a significantly lower price than others. They will cut corners in the installation that will cause problems later. Expect to pay a fair price. 3. Make sure that the shop is a dealer for the avionics you are having installed and buy the avionics from them. This will be beneficial if there are any warranty issues. Also, the markup on avionics is part of their profit and if they don't get that, they have to make it up somewhere else. Edit: A couple of additional ideas: 4. Keep in physical contact with the shop during the work. Most technicians do not want to work with you looking over their shoulder. BUT, I've found that dropping in for a few minutes once a day to see how things are going and to have a friendly chat with the technician can work well. Inevitably, questions arise, and the technician likes getting input (I can do this or I can do that, which would you prefer?). It also gives the technician an opportunity to point out issues he or she may be having (the last shop didn't leave enough extra cable and I had to spend a couple of hours fixing that). At the same time, it gives you an opportunity to make sure everything is going as you expect. Just don't wear out your welcome -- the technician gets paid by the hour! 5. Make sure you get configuration settings and wiring diagrams for any work done. It makes maintenance a lot easier later. Skip

I have messed with my factory-installed Floscan 201B connected to a Shadin Miniflo-L on my '94 J more than makes sense. Here is all I know: 1. The original transducer was intermittent when I purchased the airplane. I tried soaking it in Hoppes No. 9 and this fixed it -- for about a month -- after which I replaced it. 2. The K-factor marked on the original 201B was 29.0. The new one (purchased directly from JPI that now owns Floscan) came with a calibration tag marked 28.989. The Shadin K-factor was set at 33.06. I'm pretty sure this is the way the Mooney factory set it because it was metal stamped on the foil label on the unit. I set it to 28.99 and the fuel flow was way off. I confirmed that the Shadin was good by swapping with a borrowed unit. The results were identical. 3. With the new transducer and the Shadin K-factor set to 33.06, I get fuel burns that vary from correct (compared to the pump meter) to 3.5% low over many tanks of gas. I'm going to adjust the K-factor to center the error, but it's a pain on the Shadin because it cannot be done entirely from the front panel -- it requires removing the unit to set a dip switch. 4. Mooney's installation violates Floscan recommendations: It is mounted upside down and it has an elbow directly attached to the transducer inlet. I corrected both of these issues by making a new mounting bracket in the same location as the original. None of these changes made any difference in the fuel burn variability. So, even though these transducers are specified as being accurate to half a percent on the flow bench at 16.0 gph, I cannot get mine to read accurately at my typical 8.5-9.5 gph unless I adjust the K-factor to be much different than the transducer K-factor and then the variation is within +/- 2% which may be within the measurement error of topping off the tanks. Attached are some Floscan docs of interest. It would appear that a 201A would be a better match for my fuel flow, but I ordered a 201B because that's what Mooney originally used. Skip FloScan Instrument Co. Inc_.pdf Series_200_FlowTransducer_Installation_Comments_201_052_00E.pdf

Is that GAMI tag loose enough to cause vibration damage or slide around on the line? The is an AD on the lines for recurrent inspection.

North American Aviation is long gone. Probably no one at Cal Pacific Airmotive was alive when the last P-51 rolled off the assembly line. Yet Cal Pacific owns the P-51 type certificate and has parts production approval and can pretty much build one from a data plate. I'm pretty sure that the P-51 was about as labor intensive to build as a Mooney. (If you are ever in Salinas, CA, stop by and ask Lori Atkinson to show you around -- it's a fascinating operation).

Don't feel bad. We've been told for years that high CHTs are bad, the red box will destroy your engine, running deeply LOP is better for your engine, and the engine manufacturers don't know how to operate their products. These engines are expensive and we want to do whatever we can to increase their longevity. Not until recently has anyone told us that too much of a good thing is bad. I took the APS course in Ada a few years ago and I don't remember anything about low CHTs causing valve sticking. Since Mike Busch credited Ed Kollin, I looked on Gamguard's website and found this more length dissertation: Camguard-Parts-1-to-3.pdf

It's colloquially called the "rope trick."

The flow divider is pretty simple and it’s hard to see how it would cause a problem with one cylinder. An injector would affect its cylinder only. At idle, the pressure at the injectors is really low - the gas just dribbles out. I’d try cleaning the injectors before spending money on parts and labor. It may not be the problem, but it can’t hurt. 300 hours is pretty low time for a stuck valve unless the clearances were too tight to begin with which seems unlikely for a new cylinder. Mike Busch has an interesting column in the July AOPA Pilot explaining how running CHTs in the low 300s can cause lead deposits that stick valves especially on Lycomings with sodium cooled valves that run cooler by design. Skip

Lee, do you remember the length? I ordered the same part from Sky Geek but sent them back. I seem to recall that they were 6" long and most of the ones on my 94 J are 4". I ended up buying some from LASAR. Skip

Interesting question. My '78 J did not have them. I recall flying IMC through precip one night and putting my fingers up against the windshield and seeing a St. Elmos discharge outside in the vicinity of each finger tip. Eerie. My '94 J has them. The IPC gives no clue as to when Mooney began using them. Skip

According to the IPC, the M20Js starting with S/N 24-0378 had the inside lever mechanism. So, yours is probably original and more likely someone just replaced some parts. I notice that the color of the cover appears different than the color of the door panel. It could be that the cover is a Plane Plastics part which has to be trimmed and drilled. Skip