PT20J

+1 for PHT. Ashley Wilson was very helpful. OEM style hoses have 5 yr. life. I got PTFE hoses with crimped stainless fittings and molded on firesleves that have unlimited life. Just under $1K for complete set for M20J. The molded firesleves look nice and are smaller overall diameter, but are stiffer and a bit more difficult to install when you have a bend in the hose. I believe Guy @GEE-BEE also makes the same style hoses. Compare prices.

Interesting question. A few points to consider: 1. Propeller efficiency varies as both TAS and RPM, and propeller efficiency is generally plotted as a function of advance ratio J = V/nD, where V is TAS, n is RPM and D is diameter. So, the optimum rpm varies with airspeed. Generally, lower rpms for lower airspeeds and higher rpms for higher airspeeds should yield the greatest efficiency. 2. The purpose of a constant speed propeller is to broaden the peak of the efficiency curve over a wider range of advance ratios. This means that at normal cruise speed, the efficiency isn't overly sensitive to rpm. 3. Any rpm/map combination that is in the engine manual is okay to use. For the Lycoming IO-360A, the range at sea level is 1800/25" to 2700/28.5" depending on power output desired. 4. When comparing different rpm/map settings, it is important that the airspeed be the same for both. This is the only way to know that the power output is the same. 5. As noted, rpm/map combinations affect engine power and efficiency as well as the propeller. 6. Often it comes down to finding a rpm/map combination where the engine runs smoothest. A lot of Lycoming four-bangers don't run as smoothly at lower rpms. 7. On a normally aspirated engine, as you climb you will run out of manifold pressure at WOT and then will have to increase rpm to maintain power.

I'd get a good DVM and check the bus voltage to verify that the JPI is reading right. You mentioned that pulling the alt CB didn't affect the headsets. Did you pull the alt FIELD CB? That will turn off the alternator. Check if that changes the headset noise or has any effect on the voltage. With the alternator off, you are just measuring the battery voltage. If that fluctuates, you have a bad gauge or a bad connection somewhere. Check all that before digging into the alternator/regulator.

I've been doing some research and I've decided that the Mooney transducer mounting is all wrong. It's difficult to get any good technical support now since JPI bought Floscan. I can't find anyone at JPI that knows anything about the transducers, and the Floscan phone number just rings a salesman. Shadin tech support just defers to Floscan. There is actually some pretty good info on Floscan's website for the marine versions (most of their business). The marine version is essentially the same design but it's cast from zinc instead of aluminum and they don't come with calibration data according to the Floscan salesman. So, combining information from the marine installation instructions and the aviation installation instructions and some installation instructions from Van's, here's where I think Mooney got it wrong: Per Floscan marine installation instructions: "Flow Sensors must be placed in a horizontal section of fuel line at a low point in the fuel system. Fuel should travel, “Up-hill” when exiting the sensor. Its outlet should be at least 1 or 2 inches lower than the fuel pump inlet." This is, I believe, why it's supposed to be mounted with the wires coming out the top. The outlet is slightly higher than the inlet when mounted this way. Mooney mounts it upside down. The Mooney location also puts the transducer outlet at about the same height as the injector inlet. The instructions that come with the aviation version say this is OK, but I think lower would probably be better. Other less severe mounting issues with the Mooney design are that it is mounted to the engine whereas the instructions that come with the transducer suggest not mounting it to the engine to reduce vibration. Also, it's a good idea to mount it in a straight section of fuel line - Van's suggests at least 6" of straight line on either side - and Mooney puts a 45 degree fitting on the input. Speaking of fittings, Mooney IPC calls out aluminum fittings. Bad idea to put aluminum NPT fittings into an aluminum casting as it can gall. Steel fittings are specified by Floscan and should be used. All Floscan installation instructions (marine and aviation) say not to use Teflon tape which certainly is appropriate since you don't want strands of tape clogging the transducer and injector inlet screen. However, the marine instructions say to use a fuel proof sealant on the NPT threads whereas the aviation instructions say not to use any sealant or you will void the warranty. This makes no sense. Pipe threads aren't designed to seal without some sort of sealer as there's a spiral channel between the mating threads. I'll take a voided warranty over a fuel leak under the cowling any day. Byron did a very nice installation that seems to meet all the Floscan requirements. Look toward the end of this thread: Skip

Great test. I can’t do that in my J because the KAP 150 has autotrim and I can’t fly it precisely enough when it’s that far out of trim to note any airspeed change. It’s kind of interesting that the bungees align the elevator at the takeoff trim setting rather than cruise. As @carusoam noted, we never run out of nose up trim.

Knots2U bought out Aircraft Door Seals so they are the same thing.

A lot of folks on BeechTalk recommend it with no ill effects, so I thought I'd give it a try. Since the transducer wasn't working reliably anyway, I didn't have much to lose. As one of the BeechTalk guys pointed out, Hoppes comes in a plastic bottle .

Here's an interesting paper I ran across. It explains a few things I never understood, especially the mechanism that causes the "vertical" scratches in new cylinders. Skip 10.1.1.851.7750.pdf

Certainly the tail down force is a function of weight, CG and TAS, and if you didn't adjust the trim, the elevator position would vary with these parameters also. However, when you trim, you're changing the angle of incidence of the stabilizer. If there were no trim assist bungees, the stabilizer angle would trim the airplane and the elevator would trail in its neutral position. However, the trim assist bungees on the J and previous models bias the elevator to move along with the stabilizer to reduce the amount of stabilizer travel required to effect the full trim range (that's likely why Mooney called them trim assist bungees). This spring pressure causes the elevator to be slightly out of trail when trimmed at cruise speed.

Yep, that’s the down spring that started with the K.

Here’s a link where someone took one apart. Forgot one more thing: Instructions that came with transducer said not to mount it to the engine. I might try removing it from the engine mounting and rotating it 180 degrees. Still interested if others have run into this problem with the Mooney design. https://www.euroga.org/forums/maintenance-avionics/3929-shadin-floscan-201-fuel-flow-transducer-internals

Interesting. Do you know if this is a factory installation? It doesn't match the IPC which shows wires down.

Soaked mine in Hoppes No. 9 and it worked better but still would sometimes hang up. FWIW, a tech at Shadin said that although Floscan claims 10,000 hours on the transducers, he's regularly seen them get flaky after about 20 years.

The '94 J I purchased last summer is equipped with a factory installed Miniflo-L. The fuel flow would intermittently drop to zero when I bought it. The previous owner had sent the panel unit back to Shadin and it checked out OK and has the latest software version. I replaced the transducer with a new Floscan 201B from JPI (which now owns Floscan) and set the Miniflo-L K-factor to 28.9 to match the new transducer. It seems to read about 6% high, which surprised me as the transducer is rated at 0.5% at 16 gph with 1% linearity. I note that the Mooney factory installation varies from Floscan mounting requirements. Floscan says to mount with the wires facing up; Mooney mounts with the wires facing down. Floscan says no sharp bends within 6 inches; Mooney uses a 45-deg elbow at the inlet side. Of course, I can easily tweak the Miniflo-L K-factor setting to match actual fuel use. But, I'm suspicious of a digital system being so far off and I wonder if others have experienced this with the factory setup. Skip

Seems like everywhere I go, the FBOs have the nose wheel scooper upper tugs. I fly mostly on the west coast, but have some trips planned east later this year. I'm wondering if tugs that grab the nose gear are more prevalent in other parts of the country.

My '94 M20J has some rubbing, especially on the rivet heads. I thought about tape and researched various types but this seemed like a band-aid. And, since most of the rubbing is on the rivet heads, I was unsure how long the tape would hold up and how difficult it would be to periodically replace. My rivet damage is minor, but I saw an Ovation on the ramp the other day and it was so bad that nearly ALL the rivet heads on the top of the flap were worn down to about half their original thickness. I'm not even sure that was airworthy. Don Maxwell suggested an idea that I tried and it worked really well. Lower the flaps slightly. Put a wooden paint stirrer on top of the flap and use a stiff putty knife between the paint stirrer and the trailing edge of the wing to gently flex the wing skin upward deforming it very slightly. After carefully doing this along the length of the flap, I am now able to slide a piece of cardboard from the back of pad of paper between the flap and the wing trailing edge with the flaps up with only a slight drag on the cardboard as it passes the rivets. Before, I couldn't even slip a piece of paper between. Before doing any of this, I checked the hinge play, rigging, flap stops and flap twist , and all were within spec. Skip

1/32” per M20J service manual 32-50-01. S/N 24-1464 on have stops which should be checked/adjusted at annual.

Interesting question. I doubt it makes much difference. Trim drag is primarily the incremental induced drag caused by the wing flying at a higher angle of attack to support the tail down force, and, to a lesser extent, the induced drag of the tailplane creating the tail down force. Near the trim point, any small elevator deflection necessary to generate the tail down force should cause negligible parasite drag. Anyone know why the K and later models switched from the trim assist bungees to a variable downspring? I'm guessing that as the speeds increased, the stick force gradient with airspeed was insufficient to give good stick "feel" around the trim point at higher airspeeds which would be the usual reason for adding a downspring, but I don't know for certain. From Bryan's picture, this change seems to have caused the elevator trim position to shift from slightly nose down to slightly nose up.

Nice picture. Looks like the elevator is aligned pretty well with the stabilizer as expected.

Always nice to have the thunderstorms behind you . This looks like the elevator is deflected up maybe 8-10 degrees. IIRC the K has a variable downspring like the long bodies. So, I wonder if all the models with the downspring trim in cruise with the elevator up.

There are some interesting comments in your post that might help your mechanic find the solution. I note that you stated that you "had" these installed so I'm assuming that you had an A&P do it. Since the problem happened as a result of that work, I'd go back to the mechanic with it. However, a lot of mechanics are not good troubleshooters -- especially with electrical problems. You said that you had "wiring reconfigured." Do you know exactly what was done? If the the JPI and factory gauges use separate probes, it would be a good troubleshooting technique to switch the probes and see if the problem follows the probe. The LED lights draw less current than the incandescents and usually grounding problems are worse with more current, not less, since the poor grounding increases the resistance somewhere and the voltage drop across a resistance is proportional to the current flow. However, LED lights can be a source of high frequency noise which could be finding it's way into the gauge somehow. Are there any funny noises in the intercom or radio audio - especially the ADF if you still have one - associated with the operation of the lights? You said it happens in flight. If it doesn't happen on the ground, that's a clue. What's different in flight? Engine running? Other loads on the electrical system? Alternator charging? Higher bus voltage? Until you find a way to reproduce it on the ground, it will be difficult to troubleshoot. You said that there is a delay of ten to fifteen seconds before the gauge needle rises briskly. Pretty much everything electrical in the airplane goes on instantaneously when power is applied. Do the lights go on immediately when you flip the switch, or are they delayed also? A delay is very unusual and probably a good clue. Maybe something heats up somewhere and changes resistance. The problem is probably easy to fix, but it will take a methodical approach to troubleshooting to find it. A good mechanic or radio shop technician should be able to figure this out. Skip

I have an EFD 1000 and I like it. It has GPSS built in which is nice. Aspen takes care of their past customers and they try to play nice with all the other avionics vendors so you don't find yourself painted into a corner. I find their technical support folks very knowledgeable and helpful and easily reachable by phone.

My 1994 J had electric Precise Flight speed brakes installed at the factory. They’ve been sent back to Precise Flight for overhaul a couple of times by previous owners. They are painted red and the paint looks original. Seems like most of you have red anodized. Does anyone know why mine might be painted instead of anodized? Skip

I think the FAA is going to consider installation of a back seat bladder to be a major alteration since you have to connect to the existing certified fuel system, strap it down somehow to existing structure, and maybe install a transfer pump. That’s going to require a 337, engineering data and a field approval. Not saying it can’t be done, but there are hoops to jump through. The original question was about adding an extra fuel tank in the baggage compartment which, due to weight limitations in that area, would be limited to something less than 20 gallons. IMHO, a better option would be to see if an STC is availble to intall long range tanks. Skip

I was thinking of people who use ferry tanks for ferrying. How do the world travelers make the installation legal?