pmccand

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pmccand last won the day on November 7 2012

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  1. Ok, ok... you'll probably like this story... I had the same question about what cover to use in the desert Southwest so I contacted a manufacturer of really nice custom fitted plane covers with the question...His answer surprised me. He told me that if it was his plane, he would ditch the fabric plane covers altogether and take some of that stretchy plastic stuff used to wrap wrecked cars during flat bed transport on the Interstate. He told me that since he was retiring from making covers, he had no problem confessing that ANY and ALL covers used in windy desert areas will ALL sandblast, and grind your paint and windshield to pieces and he would not buy one of his own products if he lived in the desert. His suggestion was use wal-mart sun visors in the windows and wrap the plane doors and windows tightly with stretchable automotive cellowrap. (I bet this gets some comments from the locals.) This method keeps the rain AND dust out and comes on spools so you can take it anywhere with you. So I went to the local shipping supply store and got a roll of the cheap clear stuff to give it a try. I have to admit, it did NOT work very well on my B model, as the windshield is unmodified old-school (steep) and did not hold the plastic over the door at that angle very well. I found you had to criss-cross above and below the belly and wings, making it kind of a hassle to get started and anchor without a friend. However, the suggestion did seem viable on paper, but you have to use a LOT of it each time you fly. I just have to figure how to make it work . Phil
  2. Haven't had a problem with Rapco. Considerably less expensive than the Tempest, and you can get one overhauled for about $250. I do like Tempest products, but they are really pricey for the dry air vacuums.
  3. Back in the day when I was teaching industrial noise control in grad school, there was three methods to reduce noise in a room. If the noise is outside the room the control methods are generally 1) reduce vibration at the source, 2) add mass between the source and the room. Reducing noise at the source would imply using a better muffler, better engine mounts, reducing vibration through cables, Adel clamps, wires, controls etc. Adding mass is not an option for us, as the amount of mass needed to make a substantial difference is rather great and not conducive to flying. If the source of the noise is inside the same room such as heavy machinery inside a cement-walled room, the methods best control the noise are generally to 1) reduce vibration at the source and 2) deaden the reflections by adding absorptive and/ or diffusive control means such as foams, blankets, diffusers etc. Absorptive means such as foams and fiberglass are not very efficient, as they generally quiet direct reflections only the higher frequencies and by only a few dB. Treating automotive and aircraft noise is not quite the same as quieting in rooms, but techniques used for room treatments stubbornly cling to aviation forums. Neither adding mass or adding damping is particularly effective at quieting an aircraft. Large factories often employ massive HVAC ducts attached to large blower fans and motors and are often sources of objectionable noise. An aircraft is essentally a large HVAC “duct” where high velocity air is flowing through (around) a tube made out of very thin sheet of metal. Similar to industrial units, the thin sheetmetal duct of an aircraft is attached intimately with the motor/ vibration source and has a large airflow around the “duct”. The thin metal panels vibrate usually at resonance with the external stimulus (engine, prop, muffler, wind) and the best way to deal with that is 1) reduce vibration at the source (which isolating the engine in a plane is difficult to do), 2) reinforce (stiffen) large unsupported resonant panels by adding bulkheads, ribs, or stringers (impractical), and 3) add new-fangled damping materials to the large unsupported panels as Bob865 stated above. There are peel-and-stick versions of these damping pads available commercially, but are rather expensive and do have some mass. Several posters on youtube have demonstrated that these Polymer sheets do not have to cover the entire metal panel to be effective. I have seen where only a few dampers of only a few square inches placed near the center of panels effectively dampen the “ringing” of unsupported panels. I have tried this technique in one of my cars, but was not particularly impressed; but in theory, I can’t see why this should not work in an airplane. If I were to try to quiet my bird I would try the new-fangled peel and stick damping on larger panels, add a bit of damping material such as acoustic foams or fiberglass here and there. This should be as good as you can get without altering the vibration at the source. Don’t expect miracles.
  4. New oil tube time. wrap the new one with cloth friction tape. I have also used a bit of vacuum line or fuel hose held on with ty wraps. Either works fine.
  5. I think we need your EGT data. CHT on cyl #1 is only about 250 degrees and significantly lower than the other cyl’s in the second graph, suggesting it isn’t producing power. Oil pressure doesn’t seem that far off as it is pretty consistent in the second graph throughout the flight.
  6. Since it worked for a while after replacing the cylinders, look at them again. What do the spark plugs and compression look like? Also, how black is the oil? I would drain the oil and Have it analyzed. Also cut open the filter and also check your oil pick-up screen for debris.
  7. As a side note to my earlier story of having to make an impossible turn on my first unsupervised solo, when practicing the turn around in a Cessna 150, we found we could execute the 180 degree turn and lose only 50 feet (yeah, FIFTY) vertical feet in the process. Using exactly the same procedures, ( and using only my memory as a reference) the best we could do in the short body Mooney was 250 - 300 feet loss of vertical. The other factors to consider is that the Mooney has travelled much farther from the airport, as it is going much faster than a 150 on climb and the turn radius is many times larger. So when I limit myself to “never turn around under 500”, that is based on allowance for things to go wrong or fudge factors such as decision making times added into the mix. One other thing why it is important to learn about rate of descents in power-off turns is knowing what to do if you lose power at high altitudes directly above the airport. Here, you are not trying to squeeze the maximum glide distance out of your bird, rather you want to know how many more “spiraling” turns you can make in order to be at the correct altitude when lining up for final with no engine. In a Cessna, its no big deal as it looses only a hundred feet or so per turn, whereas a Mooney looses 2 or 3 x that, AND the radius of that turn will be much greater. I find it difficult to instinctively know how to plan for a successful landing at altitude directly over an airport with the Mooney. Maybe someone can enlighten me on how to make power-off descent controlled turn decisions to successfully make it back to the airport when at cruise altitude feet directly ABOVE the runway. How do you know if you have enough altitude as you approach the airport that you need to add that ONE EXTRA TURN ... or not? I really DON’T want that final turn to become an IMPOSSIBLE TURN because I am too low when I get there.
  8. I can’t believe that I missed posting this thread earlier, but I have personally performed the “Impossible Turn” as a result of total engine failure on my FIRST UNSUPERVISED SOLO! I was at 500 feet AGL just after take off in a Cessna 150. It was just the day before, my instructor showed me a procedure that “might save my life some day”. Turned out to be the VERY NEXT DAY! BANG! No engine just after rotation and climbing through 500 feet after take off. Declared an emergency, pushed the nose over, simultaneously dropped 10 degrees of flaps continued turn at best glide speed. After getting the Mooney, I tried to duplicate the turn at altitude. Take it from someone experienced at this...There is NO way in hell that the Mooney could have successfully made that maneuver at 500 feet. NO WAY at all. The turn can be made, but you need a LOT more altitude with the Mooney, so now when I am close to the ground, I look for something soft, flat and inexpensive straight ahead. I still do practice the maneuver, but my decision height to turn around is now much higher than with a Cessna.
  9. My trusty service manual has all the schematics for the early M20’s EXCEPT for the B’s. The B has a master switch that is operated by a mechanical pull cable that runs through the firewall and physically connected to two separate toggle switches on the other side of the firewall. I believe this is the Fred Flintstone version of the solenoid of which you speak on the B models. I don't see that master switch pull cable on the C and later models.
  10. Do a search for "low voltage" on this and any web forum, and invariably you get recommendations to check the voltage regulator, battery, alternator or generator. Today, I found that this is not necessarily the case, and I bet a lot of expensive parts have been replaced when it turns out it could be something as simple as the master switch! (Note: My plane is an 1961 M20B which incorporates a slightly different schematic than subsequent C and later models....so my experiences may or may not hold to your plane) For quite a while, I have been watching my voltage on my JPI EDM900 slowly drop voltage. At first, the JPI indicated 13 volts with the engine off, but recently, I have seen 12, 11, and now 10.1. Running showed similar voltages. Each time we adjusted the Plane Power voltage regulator to compensate to a higher voltage, but little increase was seen when running leading us to believe that one of those expensive units listed above were at fault. What is funny is that the alternator failure light never came on when the engine is spinning and seemed to act normally. When we turned the VR adjustment all the way to minimum (fully clock-wise) the warning light did indeed light up indicating a low voltage, and went out when turned fully counter-clockwise to maximum. Funny thing is that the JPI indicated lower than normal voltage no matter where the VR adjustment was set. So, I pulled out my trusty $10 volt meter and measured the bus voltage. With the engine off, the voltage was sure enough 10.1 volts. However, placing the voltmeter directly on the battery terminals, I found the battery voltage at 12.6 volts! So what's up with that?! Somewhere in the power line the voltage was dropping 2.5 volts. Three minutes of searching, the culprit was found to be the master switch. 12.6 volts was on the battery side of the switch, and 10.1 volts on the bus side. Dirty contacts in the switch. Replaced the switch. Now voltage is 12.6 volts on both sides of the switch. JPI indicates 12.6 volts. Everything is fine. I will have to check the schematic for the 1961 M20B, but I believe that the charging circuit is exclusively on the battery side of the master switch and was probably always working just fine. However, the JPI could not see the actual charging voltage because of the voltage drop across the master switch. Lesson learned is that we should be checking the charging of the alternator at the BATTERY, and not to rely on the instruments inside the cockpit for diagnostics.
  11. I have been trying to find a window of opportunity to fly VFR from Mississippi to Utah for the past 4 MONTHS without any break in the weather. Family tells me that it is better to stay put, as they are busy shoveling snow in Utah this past weekend! It has been CRAZY with the weather patterns, super-saturated ground, low temperatures, low clouds, high winds, and low pressure after low pressure forming in Southern California and dumping on Utah, Arizona, New Mexico and Colorado. Seems as if this pattern is highly unusual for this time of year. I need three or four days clear weather, but the plane has been sitting in the Hangar in 95 degree weather in Mississippi for months. Anyone else feeling like they are not able to fly in the Western USA. or is it just the "weather chicken" in me?
  12. Thicker aluminum skin added a considerable amount of weight to the empty aircraft as compared to the thin-skin C models. Probably has something to do with it
  13. Of course, you are correct that smaller airports do not have secondary radar and transponder coverage. We have three class G airports (MBO, HKS and JVW) surrounding a larger class C airport (JAN) that pick up transponder interrogations ON THE GROUND from JAN (I have verified this through phone calls to field mechanics at the three airports). Conversely, the airport I fly out of is 40nm away (08M) and cannot pick up any radar or interrogations until the aircraft is airborne for several minutes, at 2500 AGL and within a 30 mile radius from JAN. Tech support told me that the Skybeacon cannot access the transponder codes directly without first receiving a transponder interrogation "ping". It is not "triggering" the Skybeacon as you say, because it is not hard-wired to the transponder as other ADS-B units are, and simply doesn't know what the transponder is doing without the interrogation. That "missed radar time" of climbing and getting radar service area does not correlate with the ADS-B data received from the SkyBeacon and therefore, the Mode 3A data outnumber the transponder data with a bad Mode 3A code. If I take off from MBO, HKS, or JVW, I don't have that problem, because the SkyBeacon knows all about the transponder status before leaving the ground. I (and others including the original poster of this thread) run the risk of not being in compliance due to the fact that my flight did not originate with low-level access to radar from a remote airport. From my understanding from discussions with uAvionix, it is this exact situation where folks are departing a remote class G airport with their ADS-B and receiving the nasty letters from the FAA. That's the best I can 'splain it with my limited knowledge and a couple phone calls to uAvionix. I don't know any more than that.
  14. Funny you should ask, cuz today I asked the uAvionix guy about how the big G and other maufacturers are dealing with it.. I was told that other manufacurers are hard-wired into the transponder line somewhere in the system and therefore is not an issue. As G is concerned, one of their products pick up their transponder code from an inductive loop around the coax in the transponder and “spoof” codes during periods where flight is outside transponder coverage areas. So, it appears that uAvionix is out there on their own on this one. Hope all works out. I assume it will but then again, it IS the FAA they are dealing with....
  15. Umm. Actually it is correct. Just got off the phone with uAvionix and because the Skybeacon is not hard-wired into the transponder as are other manufacturers’ devices, it can’t interrogate the transponder frequency unless it receives a ping from ATC. Therefore, folks using the Skybeacon are routinely sent registered letters from the FAA that they are not in compliance with the Skybeacon even after they have been test flown and approved, when they make flights out of non-radar service airports. It is definately an issue, and uAvionix is fully aware of thes letters and are in talks with the FAA to rescind their nanny-monitoring of flights that originate outside of radar service areas. UAvionix was very optimistic that the FAA will change their minds because this requirement was not in the design specifications when the Skybeacon was TSO certified. The guy at uAvionix was so optimistic that he said we should be getting resolution from the FAA in a couple weeks time. So, I am holding on to my SkyBeacon for the time being, trusting that they will come to some agreeable resolution.