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jlunseth last won the day on February 18

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    M20K 231

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  1. Mine is on the right only, I did check it. It also is different in appearance than the photo you posted. There is a fairing coming out on the right side below the elevator that covers the rod. The one in the photo 1980mooney posted is also on the right. I would not think it was a cost reduction, there were changes to the elevator for the longer bodies.
  2. I scanned mine and printed it out in two books years ago. One I keep in my office and one at home. The original is required equipment, that stays in the aircraft and never leaves. I could have put it on an iPad, I suppose, but what I found more useful was to create my own checklist and put that on a pdf that is in Foreflight Documents. I use it every flight, all the time. The landing, takeoff and power charts are all to scale so it is not very useful to put them in another format where the scale changes.
  3. The 930 gives you CDT in a bar graph and with a number, which you can see in the photos above near the right side of the unit. It can also give you IAT (you have to order it that way), which you would see in a succession of numbers displayed near the bottom. There are quite a few numbers that are not in the graphics display that show up in that part, such as fuel USD, fuel remaining, etc. There are two modes of operation for that line. Either the unit will step through the numbers in a set sequence, and that would include such things as cylinder EGT's, CHT's, and on through IAT. Or you can manually step through, find a particular number, and pause the line display on that number. The unit does not directly display differential temp, but it displays CDT in the graphical part, and IAT in that line I described, and you do the math. CDT - IAT = DT. As an aside, I have had the unit display CDTs over 280 on some occasions, typical would be a summer climb to the flight levels out west somewhere, perhaps fully loaded. I might get a redline warning somewhere around 17-19k during the climb. I ignore it. The IAT is well under CDT. CDT might be 290 and IAT might be 190. CDT is not to protect the turbo, but to protect the engine from hot induction air. TIT protects the turbo. I don't see how the original GB engine without an intercooler could get above 17k except on cold days, you would definitely see that redline and it would be real. The one number the JPI 930 does not display, which would be nice, is vacuum. I still have a vacuum gauge. All the rest are gone. One sobering thought is that if you lose the alternator and must turn the Master off you have no engine readouts at all with the JPI not even the Remote Alert Display (RAD) will work. But the same would be true of all the electric factory gauges if you did not have the JPI. Whether an EIS with a battery backup would still display anything, I don't know, the unit would have to power the sensors from the backup source. However, if you are at cruise with a stable, known power setting, there is no cause for alarm. You leave the mixture and RPMs at the known good setting you were operating at and limit yourself to only reducing throttle if you touch it at all, that way the temps will all be the same or lower than what you had before the power went out. When you land you don't need full throttle, keep the throttle low. Emergency procedures I have only had to use once, but they got me and the aircraft home and unharmed. The 930 is a very good unit. I find the LOP lean function less than useful in the 231, I just ignore it and use my own numbers. But the unit itself has been very durable and if there is any problem in your engine at all you will see it right away. Also, figure out whether you want an EIS that works with CiES senders in case you want to install them someday. Much better than factory but a different signal to the EIS. The old JPIs can be converted, mine was. The newer ones might work with either factory senders or CiES. Same question for the Garmin EIS.
  4. It occurred to me there is an issue unique to the 231 if you intend the new instrument to be primary for the engine gauges, that is, you would be removing the factory gauges in favor of the new instrument. The 231 is unique among the turbo Mooneys as far as I know, in that it has a Compressor Discharge Temperature redline limitation. The redline is 280 dF. The reason for the limitation is to prevent overly hot induction air, which would cause detonation. The 231 is unique because it is the only turbo Mooney, at least that I can think of, that comes from the factory without an intercooler. Where you would see CDT approach or exceed redline is usually during a long climb or at cruise in high altitudes where cooling is poor. The intercooler will drop the induction temperature by somewhere between 75 to 125 dF, making CDT and Induction Air Temperature essentially irrelevant, the IAT will be so low that there is virtually no danger of exceeding the 280 dF limit. Not sure, but for that reason I don't think the intercooler-certified aircraft such as the 252 and on up have either a CDT or an IAT redline. A 231 is required to have a CDT gauge that is certified, which means the redline has to be marked on it. This is true even if your particular aircraft has an aftermarket intercooler, because the CDT is part of the certification for the aircraft. One could probably go to a FSDO and get 337 approval to substitute an IAT readout for the CDT readout, but it is dubious whether they would allow a readout for induction air temperature to be removed altogether. To my point, if you intend to substitute an EIS of some kind as primary for your 231's instruments, either that EIS would need to be certified as primary for CDT and would be marked with the redline, or you would need to retain the factory CDT gauge. You should verify that the Garmin EIS can display CDT and is certified as primary for CDT. I raise the issue because I doubt it, most turbo aircraft are like the post-231 Mooneys, they don't have a CDT limitation because they were certified with at least one intercooler and therefore the instrument manufacturers don't put one in. The JPI 930 is certified for CDT. Other than the legal issue - that there needs to be an installed and primary CDT in the aircraft - induction air temperature is a non-issue if you have the intercooler. The IAT is never in danger of getting to the redline limit of 280 because the intercooler cools the induction air so well, but the requirement is nevertheless there.
  5. PS found the bigger picture. Here it is. This is before the GTN was added.
  6. I can’t tell you about the G3, but I have a 930 and all those readouts and more are displayed on the 930 both graphically and as a number. The 930 can also display CDT and differential temp (the difference between CDT and Induction Air Temp). Whether you have an intercooler or not, CDT is a required temp in the 231, and if you have an intercooler you need differential temp to use the adjustment table that comes with the intercooler, to make your power settings. I don’t use that table, but you need it anyway, I believe, to comply with the STC for the intercooler. The 930 fits very well on the pilot side, that is where mine is. That puts it in the pilot’s scan. I would not put it anywhere else. Here is a picture of it sitting just right of the six pack instruments. I wouldn’t put it anywhere else, it has saved my bacon sitting there instead of over on the co-pilot side. Sorry, I don’t have a pic of the right side panel, there was one in the albums but appears it was lost during the website conversion. That’s a little bit of the VSI just left of the 930, and a little bit of a GTN750Xi to the right. Ignore the %HP readout, the JPI is computing that as if the engine is operating ROP and it is not, it is LOP. Its at about 74% HP.
  7. angelflightcentral.org will have the information you need. Contact information is on the site. Call them. They vet the passenger for need and post the flight to an internet bulletin board, where an Angel Flight Command Pilot will pick it up. There is no charge for the flight. Passengers are required to sign a waiver which limits both the pilot and organization’s liability. Angel Flight will want medical assurance that the patient can safely fly. There are seven Command Pilots based in ND, and many Minnesota pilots and pilots from elsewhere also serve the state. I have flown many Angel Flights to and from points in ND. However, I would not fly someone I do not know unless they sign the waiver and have been cleared through Angel Flight.
  8. These aren’t ANR muffs. The muffs themselves block the sound. The electronics let you hear despite the muffs. They might let you hear the cars around you. Most of them had wind noise problems though, although in the last few years some have been developed that are not as bad.
  9. I shot sporting clays for years and competed quite a bit. If you wear ear plugs alone you still risk some hearing loss because sound is conducted through the bones behind your ear. If you want the best hearing protection bar none, that would be a good set of shooting ear muffs worn with foam plugs underneath. The problem is that you would hear practically nothing and in shooting, or on a bike, you need to hear. There are muffs made for shooting that have built in electronics, so they suppress high decibel sound. You would have to try them out to see if they work for engine noise. Not quite as good in terms of protection are electronic ear plugs that completely fill the ear canal so not much sound gets in, but they have electronics that let sound through with a high decibel cutoff. Again, you would have to try them out to see if they work. The early versions suffered from wind noise problems, they were useful on a sporting clay range but not so much out in the open fields. Lots of squeal. The best and cheapest solution are foam plugs, they keep out most sound. However, aren’t muffs and plugs illegal to use on a bike, they are in some states. I ride a road bicycle quite a bit, I need to be able to hear, it is a life saver.
  10. That control attachment point in your photo exists only on the right side of the aircraft, there is no such control attachment on the left, and the left and right elevators are separate assemblies other than the control rod that runs through the tail and connects them. They are not a single panel like the stabilator on a Piper. The drawing appears to be the right stabilizer, not the left. Since the left and right are separate elevator panels it does not make sense that flutter in the right side would affect the left severely enough to cause the left to tear off but not the right. Also, the left elevator tore roughly in half. Flutter is generally more severe in the least rigid and most unsupported part of a structure, in this case the outer end of the left elevator. That appears to have torn off first, followed shortly by the destabilized and torn inner half of the left elevator. There is no indication or evidence that the control attachment to the right elevator was severed at all or that the right elevator left the aircraft prior to impact. The NTSB may have more information, but they have not said anything about departure of the right side assembly, either the elevator or stabilizer, prior to impact.
  11. That is an interesting thought. Possible the plane flipped, the wings failed in the negative, and then it continued to tumble so the wings were failed in the positive direction when it impacted. That would square with the prior two incidents, the J and the Rocket, where the failure was negative.
  12. That is the video I saw a week or so ago but could not find any longer. That’s great. I see the counterweight is there. But that begs the question why it is not in the longer video. Looking at the elevator in the Channel 9 video, the outboard end has the same half moon shape as the piece that does not have the counterweight, so it appears that the elevator in the Ch 9 video is the inboard half. But as far as the departure of the counterweight is concerned, that just puts the issue back where it was. When the counterweight departed it took a piece of the elevator with it. Why did the outboard end with the counterweight tear off? And why is the left elevator in two pieces?
  13. It’s in the video that I posted a couple of times, of the stabilizer and elevator on the ground where they were found. https://www.fox9.com/news/neighbors-ran-to-help-after-plane-crash-in-victoria-minn The elevator and stabilizer footage starts at 2:15. I found the video controls a little quirky, it may take a few tries to get the video to stop where you want it. The notch for the counterweight is still present in the end of the stabilizer but the counterweight is gone from the elevator. I also found video that I cannot find any longer, showing what I assume is an NTSB workman carrying the elevator, where it is in two pieces, broken or maybe folded to carry in one hand. However, it does not appear to be broken in the above video.
  14. Why? At least two others broke by that mechanism except they happened to be in an attitude that caused abrupt negative lift rather than positive.
  15. Yes to what Eric said. The classic analysis that the elevator pushes down to keep the nose up just is not applicable in this situation. For one thing, that analysis assumes a low speed flight regime - the closer the aircraft is to stall the more the elevator/stabilizer is needed to increase the angle of attack of the wing. However, that analysis, for one thing, forgets that the elevator on a Mooney is a movable flight surface. As we all know, the Mooney tail looks forward on the ground. That is because we just landed, and in doing that, we trimmed back (up) to generate low speed lift. But at cruise we look like a Cherokee, the empennage has been trimmed so that the tail is back and the angle of attack of the elevator has decreased dramatically, or even gone negative to keep the plane level as airspeed and therefore wing lift increases. Combine that with the fact that the attached elevator can be used to pitch the aircraft down, even dramatically down, and you have an adjustable airfoil that can generate lift in either direction, not just down to keep the nose up, but up to put the nose down. Then you have regime of flight questions. If an aircraft does into a steepening dive it begins an outside loop. In an outside loop, what keeps the aircraft in the loop? A centripetal force. What is that force? It is wing lift that varies from neutral to negative (lift toward the belly of the aircraft). We don’t at this point know exactly what the attitude of the aircraft was when it began to come apart, but it is a good bet that it was in an accelerating dive or steep downward spiral. The wing would have failed in whatever direction it happened to be making lift when the departure of the stabilizer ceased to counterbalance that lift. If the wing lift was positive the result would have been a very abrupt, almost explosive, positive change in the angle of attack, possibly even to the point where the wing was flying more like a flat piece of plywood into winds well over 200 mph. That will crack the wing spar on any normal category aircraft and probably would even challenge an aerobatic wing. It’s possible the pilot created this accident with a sharp pull up, maybe. But. How does that explain the departure of the counterweight from the left elevator. Flutter, and tearing of the elevator explains the departure of the counterweight, followed quickly by the departure of the left elevator itself, then the stabilizer, and the aircraft simply ceases to fly.
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