RobertE

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About RobertE

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    Lives Here
  • Birthday 07/28/1951

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  • Gender
    Male
  • Location
    St. Helena, CA
  • Model
    M20J

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  1. You know, that’s an interesting and very thoughtful analysis. But (hey, you knew the “but” was coming!) it presumes a manufacturer needs a product line that allows people to transition from one model to the other. Yet the used market does that really well. The fact is, though, that manufacturers address just a small sliver of the market. They live or die on the 350 people (in Cirrus’ case) or 12 people (in Mooney’s or Beachcraft’s case) who decide each year they need a new vs used aircraft. And those manufacturers have learned that someone who is prepared to pay hundreds of thousands more for a new vs 95% as good used aircraft are most likely interested in the higher end of the line. The manufacturing cost doesn’t vary all that much for a bigger engine, turbocharging,.... So it’s really tough for manufacturers to build a business on anything but the top of the line. In my opinion, of course.
  2. I just dropped a Tempest fine wire and have already ordered an $87 replacement. But what’s the worst that could happen had I not replaced it?
  3. I think my photo didn’t properly display the problem. All other plugs have insulators that have a flat surface from the edge to the center electrode. This one has a concave surface (wasn’t this way when new) that has the effect of exposing more of the electrode than it should. In fact, if you looke very closely you will see the wider part of the electrode at the base of the insulator, whereas only the narrow portion should be exposed. To answer some of the questions, I’ve had no problem with the engine, all plugs are firing,.....basically zero observed problems. The only oddity is the eroded electrode.
  4. Anyone know what might have caused this erosion? Anyone else suffer this problem? The plug has 350 hours on it. All others are normal.
  5. Well, I don’t happen to have the heat problem ( yet, legal or not, my A3B6 engine is timed at 25 BTDC) but my overall suspicion is that the % of HP is a practical but flawed approach to figuring out how to avoid detonation.
  6. I reran the GAMI test for the first time in a couple of years today which got me thinking about where, exactly, that red box resides. I know that Mike Busch tends to express it as a % of power (basically no red box at 60 or 65% power, then it gets progressively bigger the higher the power setting). I’m wondering if % of power isn’t just imprecise shorthand for where it actually resides? I know if I set the timing too advanced on my old Corvair it used to knock like crazy when lugging along but would disappear at higher rpm. And that engine advanced it’s timing with rpm which should have mitigated that effect. In our fixed timing engines the problem should be greater, no? Specifically, in my normally aspirated IO360 70% power is achieved at around 23 inches MP and 2500 RPM but at the same 23 inches and, say, 2300 RPM I’m down to somewhere between 60 & 65%. Does that mean I’m generally safe to run at peak EGT at 2300 RPM but not 2500? This seems wrong, at least if I’m going to trust my Corvair experience. Anyone know the truth?
  7. For what it’s worth, I’ve got nitrided cylinders.
  8. To answer both questions, as to break in, I got the normal indications - elevated CHTs in all cylinders initially then declining to normal, accompanied by plugs that showed no oil. As to oil usage after break in, it was never all that low - probably about 7 or 8 hours per quart. It is now down to about 5 and it seems to have gotten there slowly. As I’m replaying all of this I’m wondering if, in fact, I didn’t do a completely thorough job of break in and am now, slowly, seeing the consequences. I plan to make a couple of long-planned trips then have the two offending cylinders pulled to take a close look. I’m going to feel mighty stupid if this was a self-inflicted wound. I’ll report back with findings in about a month.
  9. I’m burning oil in a couple of cylinders despite only 300 hours SMOH. I properly broke in the engine. But here I am with a couple of cylinders with a problem. I routinely run LOP and have cylinder temps around 320F. Might that have produced the problem?
  10. Hey folks. I’ve been following this topic but, honestly, haven’t read every one of the posts in this now 9 page long discussion, which means I might have missed something important. Someone reasonably observed that roughly 10,000 aircraft have arrived annually for many, many years at a cost of what is thus far just one midair, whereas the caravan, with far, far fewer numbers of participants, now also has experienced one midair. That’s a fair point. Let me toss in one little factoid that I find interesting and, perhaps, relevant. Years ago I attended an air show at which the Thunderbirds performed. The evening after that show there was a small cocktail party in which they were the guests of honor (I drank, they didn’t, even though their only flying would be to depart the next day). Anyway, I asked one of the pilots what was something about the Thunderbirds I would be surprised to learn. His answer? He said, “well, you know, we usually have about one midair per year. It’s very minor, but we do touch”.
  11. Scott: I took your skew t course so I know how deeply you understand these things. Let me pose a question to you that I posed to Mooneyspace with only a couple of answers that directly addressed the question. While In Bozeman, MT recently I noticed that many afternoons the towering cumulus clouds form most afternoons around noon on the ridges surrounding the city that, by 3 pm are thunderstorms. My question concerned how one decides whether or not to fly beneath those TCs at noon. If there are, say, 3K feet between the mountain peaks and the bases of those TCs at noon how much vertical development is too much to fly beneath? No rain shafts, no lightning strikes, just very tall clouds. How big is too big? Any other ways to make the judgement call?
  12. I think it’s a no brainer if you’re going to keep the airplane. The higher purchase price will be offset by longer life and slightly better performance (I.e., lower fuel consumption).
  13. Well, I’ve found the source of the problem - a defective ELT (121.5). The radios are back to normal - no static, no odd sounds - when the ELT battery is removed and become defective again when reinstalled. Now there remain some mysteries, such as if that ELT was activated (and I’m told the transmission from that antenna can bleed into the com radio antennas) why didn’t someone report hearing a signal over 1k miles of flight and how come the static varied with RPM? But I’ll take this victory and call it a day. Thought I should close the loop on this.
  14. I’m sure I have old coax. I can, of course, repack the radios but this is a problem that presented itself simultaneously to both radios so I should think any problem would have to have a single, common source. Headed out soon to do more troubleshooting.
  15. I've got radio noise that, I'm sure, is like many have had before (found lots of examples searching the archives) but my symptoms, along with what I've learned so far by troubleshooting, are sufficiently unique that I need help from what is the very big collective brain of Mooneyspace. Here goes. Symptoms - When receiving any signal but the very strongest (in other words, pretty much everything except a tower controller 10 miles out or a approach or center controller when near an antenna) I get staccato-type, high frequency static in receive mode that is loud enough to make it very hard to hear a transmission. This is a crackling sound, not a whine. This happens in both radios (a Garmin 430 and KX155). The static registers only when receiving a signal. When not receiving there is no noise although, occasionally my 430 blinks that it is receiving something and opens the receive circuit when there is no one broadcasting. I'm guessing that whatever is going on is producing enough noise that the radio thinks there is a signal to receive. Troubleshooting so far - Turning off the field to the alternator doesn't stop the static, nor does turning off power to every circuit in the panel. The static persists when running on both mags, the left alone or the right alone. The static does change with RPM. At my normal cruise setting of 2,500 it is loudest, the pitch grows when I go to 2,700 and, oddly, it disappears entirely when I slow to 2,300 or below (maybe the squelch filter is strong enough to block the noise at that frequency?) Tomorrow I'll run the RPM test with the squelch disabled and will also turn off both mags (at altitude) to see if that stops the static. Other than those two tests I don't know what to do and neither does my A&P or Avionics guy. Does anyone have a guess as to root cause or what other troubleshooting steps I ought to take? Oh. One final oddity. I suffered with this problem during about 8 hours of a 10 hour return from Oshkosh. In the last two minutes of those 8 hours when in the traffic pattern at home the radio continually had an open receive circuit with lots of static and, briefly, a sound that sounded a bit like an ELT signal. Tomorrow I'll pull the battery out of that ELT to see if that solves it. But if the ELT is the problem why would the static change with RPM? Odd. Again, any comments would be appreciated.