pkellercfii

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About pkellercfii

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  • Location
    Richland, WA
  • Reg #
    N1031R
  • Model
    M20K

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  1. ROP vs LOP

    Ken Reed wrote: >With a turbo, you shouldn't lose any speed LOP I will because I can't run the power settings as high LOP as ROP due to TIT limitations. I limit my cruise TIT to 1600 F, which limits my power settings to 60-70% power, depending on altitude. >That's a result of running to rich, not too cool. >That's a result of running to rich, not too cool. Please provide your evidence and data to back up this claim. My evidence to support my claim that it's the result of running too cool is that I only see plug fouling in spring, after a winter's worth of low CHT flying. I typically pull & clean the plugs once or twice a year outside of the spring annual, and rarely see much of any lead fouling then. Same engine, set same way, run the same way. Only difference is flying in warmer weather, with resulting warmer CHTs. --Paul Keller
  2. ROP vs LOP

    For most general cross country cruise flight, my preference is LOP largely because I'm a CB. Well, sort of. It'd probably be more accurate to say I'm selective about how I spend money. Spending money enriching the oil companies for avgas isn't exactly my favorite way to spend money. Since I bought a Mooney, and the specific Mooney model I did buy, for altitude performance and economy, in that order, the minor speed loss associated with LOP operation isn't much of an issue. I lose about 15 KTAS out of 155-200 KTAS running LOP, in exchange for about a 3-4 gph reduction in FF, from 13+ down to around 10. That the engine runs cooler and cleaner are added bennies. That said, I sometimes do run ROP when I'm in a hurry, most often because I'm trying to get ahead of weather, and frequently run at peak TIT. I use peak TIT for what I think of as arrival terminal maneuvering, and for instrument practice, since, for my instrument flying, I'm Mr. Militant about staying instrument current & proficient. As a result, I spend a lot of flying time doing instrument practice with a safety pilot, since I'm located in a desert where there are few opportunities to get actual IMC practice. For that sort of flying, I'm typically running 20"/2300 RPM, which is about 50% power, at peak TIT. Peak TIT at that power level is harmless to the engine, and I've found it to be the most economic way of keeping the engine warm, which is a challenge at that low power setting. Contrary to what I've read in numerous places, my operational experience is that it possible to run an engine too cool, which I would define as CHTs below 300 F. Three years ago I was working hard on my CFII in my own Mooney, which meant lots instrument practice, and so lots of flying time at low altitude, and low power settings, during the winter, which resulted in CHTs always below 300 F. At the annual that spring, my bottom spark plugs came out badly lead fouled, which was something my Mooney expert A&P/IA and I got a bit of a giggle out of, coming out of a normally fire-breathing turbo Mooney. Although my understanding is that fouled plugs by themselves are just a nuisance, frequently fouled plugs can lead to valve guide problems. As a result, I don't run LOP down to touchdown, and, instead, once I'm down to 20" & cruise RPM on descent, I'm also up to peak TIT on the mixture to keep the engine warm. Under those conditions, at best I'll see CHTs in the low 300 F range. YMMV. --Paul Keller CFI-IA '89K@RLD
  3. Aspen RSM mount

    Here's the antenna farm that supports dual GTNs, and Aspen 2000 system and an L-3 NGT-9000 on my Mooney. The two fuselage warts in the nearest foreground are the GTN antennae. The next two warts in the background are the Aspen RSMs. The far wart is the NGT-9000 antenna. The Aspen RSM, obviously, are over the hat rack. No problem with that--the shop simply had some interior disassembly & then reassembly to do. Yes, there are 14 rivets securing doublers under the RSMs,. Again, the #2 comm antenna was moved to the bottom, and, obviously, I have some paint touch up work to do. I only got this back from the avionics shop about six weeks ago. Your proposed position for an RSM, next to the dorsal fin, is just about where I have a 406 Mhz ELT antenna. Perhaps something to think about... --Paul Keller
  4. O2 on/off cable broke

    Mine broke about six years ago. At the suggestion of my IA at the time, we replaced it with stainless steel piano wire. I *think* we used 0.060" wire, which is a slightly larger diameter than the existing wire. Obviously, any piano repair shop can sell you some. It takes about 10'. Save yourself some time doing the replacement--DO NOT remove or disassemble ANYTHING, aside from what's needed to access the knob in the cockpit, It's possible to simply push the wire through the existing casing, with the casing still in place. When we replaced mine, we spent (wasted) a bunch of time doing a lot of interior disassembly to straighten the casing to make it easier to push the new wire through. It turned out, the wire can be pushed through the casing without moving the casing at all from its installed routing. --Paul Keller '89K @ RLD
  5. Dual Alternator usage

    Start the engine with both alternator field switches in OFF. After engine start, the important part: Turn the #2 alternator field switch to ON FIRST. The #2 Alternator is the belt-driven alternator, which doesn't much mind the jolt which comes from suddenly picking up the load of an at least partly discharged battery. Even if it does develop problems, the #2 alternator is a relatively inexpensive & common 24V belt-driven alternator which isn't as expensive to repair or replace as the #1. The #1 alternator of a 252 is another of those rare, expensive bits living forward of the firewall in a 252. In addition to being expensive itself, about $800.00 to replace as of five years ago, the #1 alternator, being gear driven off of the engine back case gearing, also has an extremely expensive coupler, about 1 amu+, that you don't want to jolt with the startup load. After the #2 output has stabilized, usually just a few seconds, then turn the #1 field switch to ON, and then fly with both in ON. If your charging system is setup correctly, you should observe that most of the load is carried by the #2 under nearly all load conditions, even with both alternators online. The #1 is pretty much just a backup. This said, something I do at runup which I'd recommend to other 252 owners is to check the pickup of each alternator separately during the runup. To do this, at runup RPM, with the engine monitor on bus voltage, turn off each alternator separately, and check that each alternator alone maintains the expected bus voltage of about 28.5-29.0 volts. Return both alternators to on before takeoff, and then leave them there the remainder of the flight. If you don't check the alternators separately at runup, it's real easy to miss a dead #1 alternator, since it normally doesn't carry much, if any load. Enjoy the 252--one of the best Mooneys built. --Paul Keller CFI-IA '89 M20K @ RLD
  6. 262 -MB engine operation

    My experience with my '89K, a factory 252 powered by a TSIO-360-MB engine, is that it appears that the turbo wastegate does seem to come full open below 5000' MSL at 20" or so on MP. Below that, yes, it does behave like a normally aspirated engine in that the MP will creep up in descent. Above 10,000' MSL, MP is rock solid on descent. --Paul Keller '89K @ RLD
  7. Battery Voltage Question

    Given the behavior of my 252 on the #1 alternator alone, which is the 252 analog to the single alternator on the 231, this behavior is about what I'd expect, with the exception of the high engine RPM voltage. Because of the low RPMs of the Continental gear-driven alternators, their low RPM voltage pickup is awful. It takes 1300 RPM on the engine to get 28V out of my #1 alternator alone. This said, 13.8-13.9V at high RPM does seem a bit low, and something you might want to have checked with an known accurate voltmeter. I'd suggest checking that at an engine RPM of at least 1700 RPM so that you're not mislead by the poor voltage pickup of the gear driven alternator. --Paul Keller '89 K
  8. "Non Linear" Fuel Flow

    I had this problem with my '89 K model (252, TSIO-360-MB engine) when I purchased it. Fuel flow was fine for takeoff, & at idle. At cruise power settings, full rich was just 20-30F ROP at all altitudes I specifically observed it at. The problem turned out to be that the idle fuel pressure was set too low. Be aware that it seemed like the takeoff fuel presssure looked like it was the sum of the idle and full power fuel settings, and so changing the idle fuel pressure will affect the takeoff fuel pressure & thus TO fuel flow. --Paul Keller '89K @ RLD