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Petehdgs

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Everything posted by Petehdgs

  1. I own a 1964 Super21 that has an OEM Nav-O-Matic 300 autopilot. It has been working but I noticed it did not work in cold temperatures. When I started having the same problems with my AI and DG I concluded the grease or oil in the instruments was getting old, so I pulled both instruments and the AP Gyro and sent them out for repair. After repairs My Autopilot does not stabalize the aircraft and tends to roll. This is possibly a bad pickup inside the Gyro. I intend to send it back to Mid-continent Avionics and ask them to re-examine it, but because of the age it may not be possible to get parts or expertise to resolve it. Has anyone here had and OEM Nav-O-Matic replaced with a more modern unit? Were you happy with the results? What kind of $$ was involved? I am basically looking for options here. I don't use the AP all that much, but if possible I would still like it to be available if possible. Thank you all in advance.
  2. Eric Your points are well taken. I'll take it down and consider your points.
  3. I do not recommend going against manufacturers recommendations, or recommendations printed in the POH. I encourage you to follow them.
  4. The RFFA chart does suggest that, yes, based on the parameters of the RED BOX and RED FIN. That is a guideline as a starting point. As long as CHT are good you can lean more. The Lycoming FA Ratio chart recommends running 100ROP to 150ROP for best power. I don't know about 25ROP. I haven't read that in my manual.
  5. Ok. Consider me properly admonished. Perhaps the word livid was too strong a word. I apologize for that. Perhaps I really don't know what I am doing when it comes to writing. "The figures are a mess" doesn't really give me very much to go on. They look a lot better than a hand drawn sketch on the back of a cardboard box. That's what most of my working drawings look like. It is clear that I don't understand what it is that he is trying to impart. So I think we should discuss this in real time. Email me and we can set it up.
  6. Never say never. Engines can fail at any time. But the RED BOX disappears below 60% load, all my initial recommendations are below that, and I recommend monitoring CHT at all times during operations. So, yes. Following instructions presented here, based on the work of the giants who came before me, should not harm your engine in any way.
  7. Eric, I apologize for my tardiness in this reply. There are reasons I have for doing things the way I have. I am assuming you have printed this and have the 10 pages there to look at and scroll through. The figures introduced with paragraphs 10, 15, 24, 26, and 39 are not precise. They are to look at not to measure from. They are just pictures to illustrate a point. All you need to know about 10 (75%) and 15 (65%) is that they illustrate the RED BOX, the bottom of the box is 400F CHT, and the width of the box is less at 65% than at 75% load. All of this information is in the text. ROP is on the left LOP is on the right and the dotted line is Peak EGT. In paragraph 15 I tell you to look at the 75% load box. In the next paragraph 16 I tell you to look at 65% load, which is right there to look at. Paragraphs 9 and 10 are the first discussions of the RED BOX, and there is a the 75% load RED BOX on the page to look at. The RED FIN is first discussed in Paragraph 23, and the first picture of it is at paragraph 24, then a different one at paragraph 26. The figures introduced in paragraphs 4, 18, 21, 34, 39, and after 45 are precision figures. You can print them, measure them with an architect's scale and apply a little calculation and you will have precise measurements that are repeatable. That's what I did. The figure in paragraph 39 is a re-work of the RED FIN shown in Figure 26, corrected to follow the fuel and air curves more precisely. Everything you need to know is in the text, but you can print it, measure it, and get precise readings. I am not a scholar. I am a diesel mechanic and a private pilot. This paper is not for scholars, it is for internet distribution for people who are curious about this subject and want to learn more without spending any money. In other words airplane pilots. Airplane pilots who are notoriously CHEAP. Like me. Not all internet people are willing to take this at face value. Some of them want to make it their own. Some internet people are likely to pick and choose what they want and discard the rest, and then re-post it somewhere else. I'm ok with that to a point. The problem is when someone starts re-wording the document and then posting it in its altered form. For some reason people love to re-edit everything. You, yourself, are livid with me because I have not re-written or re-organized the document to meet your expectations. Within this document I have made specific recommendations for engine operations that put the reader at a point of understanding by using the paragraphs that came before as building blocks of knowledge. What do I want? I want the reader to fully understand paragraph 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, and 44. For most of the audience this means reading and understanding paragraphs 1-32 in sequential order. Every paragraph is important! Every paragraph builds on the previous paragraph! And changing anything, in any of the previous paragraphs, could change the reader's understanding of some key element that could affect engine operation in a negative way. That means possibly, as a result of tampering with this document, engine damage or engine destruction could occur. Which if it did during critical flight operations could lead to loss of life. I take that responsibility seriously, and you should too. Weather you agree with what I am doing or not, you have to understand the potential liability if a loss of life should occur. To that end, every page has a copyright notice and the name of the document, and my email address. Anyone can email me about this document and ask any question they want to ask. Anyone can search the internet for the key words LOP, ROP, RED BOX, RED FIN, BIG MIXTURE PULL and pull up most of the documents I used as research when creating this paper. They can't pull up any information about the RFFA chart without emailing me directly. That is because recreation of this chart is a difficult process that exceeds the confines of the principles presented here. I will say that I puzzled and puzzled over the first version of the RFFA chart trying to figure out how to make it readily adaptable to any engine, as requested last year by a poster in POA. I have finally done that! So here is the paper to give everyone the same level of understanding that I had when I was willing to start experimenting with the operations of my own engine. So, you could say this entire paper is about paragraphs 34 and 35. If you don't get them, you haven't learned anything new. Everything they say about me is TRUE. Good or BAD. One Miracle at a time.
  8. To the best my knowledge what Skip says is all true. The object of the paper is to teach an understanding of the subject matter. It is rather complex. The origin of this knowledge comes from advanced pilot seminars and the gami-injector people. Who did what I couldn't say, because I don't really know. I do know that the writing and organization is my own, and I designed the RFFA chart towards the end, but my basic understanding of this subject comes from the advanced pilot traing class that I took about 18 months ago, followed by hours of research and analysis and experience with my own airplane to create the RFFA chart that can be tailored to any engine. The material is copyrighted to ensure it is not altered, insuring the reader receives a pure dialog. I am receiving no compensation, and am not asking for any. If you feel I have acted improperly, and want me to take this post down, I will. If you want me to add an addendum that properly credits the people that created understanding that we now consider to be fact, I can do that too, but I'll need help doing that.
  9. The easiest way to get the answers you seek is to take the advanced pilot class at https://www.advancedpilot.com/ . I took their class about 18 months ago. It cost me about $500 then. I think it is less now. The class is way longer than my 45 paragraphs in 10 pages, and I think it is worth it. It was for me anyway. The information presented is not theoretical, but confirmed in practice with advanced engine monitoring and dynamometer testing.
  10. Your questions are addressed in paragraph 3, 9, & 10.
  11. I believe you are incorrect about that. The first page opens up with a FA Ratio chart with 4 curves, with clear scales on 3 sides.
  12. >>>How would you explain that the M20R POH and Continental has the IO-550G running best power at 75% at 50 ROP? >>> Based on the research I did, I would tend to disagree. It is clear that when your POH was written they figured that 50ROP was the place to run. The FA Ratio chart that I used in UESP&FMM is a Lycoming chart, and it clearly shows best power is 100-150ROP with increased stress and CHT at 50ROP compared to 100ROP. The Advanced Dynomometer Testing that identified the RED BOX concept puts 50ROP near the center of the RED BOX and identifies it as likely to be an undesirable area to run the engine. The concept is that engine stress increases as a result of fast burning fuel mixtures generating Peak Internal Pressures too close to TDC, and that 40-50ROP is near the center of the maximum stress area, and that is an undesirable place to run depending on the load. Having said all of that, if your POH says you can run there, then you can... but running richer, or leaner, should reduce engine stress and drop CHT. As long as the engine is maintaining operating temperatures, lower CHT and engine stress should mean longer engine service life. That's what you want isn't it? >>>Second, where does induction efficiency figure into engine stress? >>> Increased induction efficiency, increases volumetric efficiency, and increases total load available. This should make things heat up more and make the RED BOX larger unless the designers offset the power increase with increased cooling capacity, or oversized the components such that higher CHT can be tolerated while the strength of the engine structure has been reduced. The RED BOX is based on internal engine stress and loads that make it likely to have 400F CHT because that is the point that alumimum loses half its strength. >>>Would a more efficient induction system allow running closer to peak at 75% power?>>> I don't think running closer to Peak EGT is the desirable goal here. Running with reduced engine stress is, and so is better fuel economy when doing so prolongs engine life as well. To this end you can run above or below the RED FIN. According to the RFFA chart paragraph 34 , 185ROP at 75% load or 50LOP are both completely out of the RED FIN. Of course, while monitoring CHT you could lean closer to Peak EGT, but the best fuel economy will be 75% load at about 50LOP with 51MR, saving 25% of your fuel at 185ROP, or saving 16% at 100ROP, and run 30F cooler CHT while doing it.
  13. I must admit that never in a million years would I have thought the first question to be asked about UESP&FMM would be which settings would give you the most CABIN HEAT!!! LOL! SMH! To be truthful I have never really thought about it... until now. Assuming that this IS a serious question, I will do my best to answer it so long as you understand that this is far from where my mind has been in writing it, and my answer is just an educated guess. So, It is worth what you paid for it. ZIP. Based on my research I would not recommend running at 50ROP at any time for any reason unless the total load is less than 60%. Why? Because the peak cylinder pressure will be too close to TDC which builds more internal stress instead of producing more useful power. IMHO 50ROP uses some energy to create stress that could otherwise be driving the airplane forward. This is undesirable at best, damaging at worst. If the load is low enough, then not damaging, but not as good a use of the fuel either. I would also not run 50ROP at all during the break in period. NEVER! (but, I have not studied this specifically) 100 ROP or more is acceptable as is 15-100LOP. Be sure to stay out of the RED FIN. IMHO. YMMV. In making useful cabin heat you are running cold air around an exhaust fed heat ex-changer and the design of this device has a lot to do with how well it works. Temperature and mass flow both affect how fast it heats up and heats the cold air it is warming. Mass Flow varies with MR number and load, with ROP having slightly more Mass Flow than LOP. Once the heat ex-changer is hot, it is not likely to cool off rapidly unless it has been optimized for minimum weight (likely in an airplane) so again mass flow and temperature both affect it. Having said all of this, 50ROP has slightly more mass flow than Peak EGT or 50LOP. 50LOP will definitely will produce less heat than either of the others, but it depends on how much mass flow is involved between the other two options. If the mass flow is small, then Peak EGT will win out over 50ROP, but if the mass flow is higher then maybe not. It might be a toss up at 50ROP vs Peak, but peak should win at 100ROP vs Peak EGT. 100LOP will be less than either of the other two. IMHO> So I have now answered a question I never thought I would be asked. One Miracle at a time!
  14. Understanding Engine Stress, Power, and Fuel Mixture Management (UESP&FMM Rev7) has been removed, for review. I ask that all existing copies be deleted. I further request that Mooneyspace.com delete this thread and related materials associated with it. Have FUN! Fly SAFE! Pete
  15. I sent you a detailed IM. Call me anytime 8am-6pm eastern
  16. Blue on Top, if the VG folks aren't getting their approval based on performance, what are they getting it on? What are the STOL folks doing when they add leading edge cuffs, stall fences and VGs? I mean, this type of stuff is done on Cessnas all the time. What is the catch that they use?
  17. If the VG mfrs don't get FAA approval for their equipment then how do they leave them on the wing and how do they get approval for others to install them?
  18. How do I intend to proceed going forward? That is, if there is a forward place to go to from here. I have thought about that a lot. It appears from my research that there are airfoil errors that can be corrected and that those corrections can improve the stall characteristics (and safety) of our birds in flight. ( I understand most of you do not agree) It also appears crystal clear from this discussion that the only person interested in pursuing this improvement is me. If I had 10 or 15 other people who might be interested in improving the low speed handling of their birds then I might consider applying for an STC for multiple aircraft, but since it is only me that changes things quite a bit. The first step is to determine how the cuff will be applied. I think I have a good plan for that so the next step is to discuss this with my AI and seek his advice about securing a 337 modification approval. That discussion will be a rather lengthy on and based on the outcome of that discussion with my AI and the FAA, that may put the stops on the project right there. If approval is given and the scope of testing is understood and acceptable then I would proceed to fabricate a LE cuff out of Epoxy resin, fiberglass, and 2lb foam core. I have a plan for that. Once completed and inspected a flight test will be performed based on the FAA requirements for the 337. That would leave me with a one-off modification and improvement to my bird. On the plus side, there would then be one Mooney with an improved airfoil in the fleet. At least then real numbers can be obtained as to weather the process warrants further investigation by other MSers. Of course, in the mean time I am going to do my best to fly what I have as well as I possibly can. One Miracle at a time.
  19. In 1988 Harry Riblett wrote: "In my studies I have identified a critical airfoil parameter that I call the Initial camber angle", or initial slope of the mean line, that is, perhaps the most important feature of the airfoil affecting stall performance. Unfortunately, in the NACA airfoils, the mean lines (-2xx, -4xx, -6xx) are all exact multiples of each other, and the initial camber angles are uncontrolled, and usually too small (flat). For instance, this angle in the 64-212 is only 3 degrees, whereas I have identified the optimum angle to be about 12 degrees for a typical 12% thick laminar flow airfoil, up to about 15 degrees for thicker and urbulent airfoils. If the angle exceeds these values, there will be excessive drag at high speed; less than this, and the stall performance is not optimized. It is more than a coincidence that this angle approximates the stall angle of attack for the airfoil. When this angle is correct, stall performance is optimized, with no performance penalty at high speed. In effect, this puts an optimum "leading edge cuff on the airfoil, and it also improves performance with flaps." I wanted to see what that actually looks like on a wing, but I have been unable to find a description of how to measure it. So I drew the 64-412 airfoil used on the outer portion of our Mooneys by using the leading edge circle and forming the upper and lower curves from the ordinate tables for the first 10% of wing chord. I used the NACA slope and radius method as described by HR in a 1992 article of Sport Aviation. This method has the undesirable effect of raising the true leading edge and de-cambering airfoil from the intended camber line, but this should be the way the airfoil was constructed at the factory. To determine the LE droop angle I chose to connect a line between the upper and lower surfaces where they intersect the LE circle, then measure that angle by taking the inverse SIN of the rise/run. Obviously I could be off by a bit but I confirmed 3 degrees (or less) on the 64-412 airfoil. I then added the LE Cuff by dropping the nose 0.70% of Chord from the actual raised nose position, then moving that point forward by 0.50% Chord. I then drew the LE Circle and the upper and lower surface curves. This puts the LE Cuff angle at about 12 degrees, exactly where HR recommends that it be for optimum soft stall and cruise. I also added the perpendicular thickness of the proposed GA cuff. It will be less than 5/8 thick at the thickest point (Chord=67 inches). That makes it very light indeed, less than 8 lbs total weight, maybe as low as 6. Riblett 1992_12_20_.pdf
  20. This is not ridiculous at all if you have read Stick and Rudder. WL discusses this reaction at length and explains why it is the wrong thing to do.
  21. Based on the research I have done, the softness of the stall will not be positively improved by changing the flaps system. According to the performance curves in TOWS the stall is sharper with flaps applied, changing the flap system is not likely to improve that. I am not interested in changing the flaps.
  22. I missed that Riblett put a performance curve for the GA cuff on the next page. I think I got it confused with the evolution of GA airfoils, which looks similar. See attached. 1. There is an improvement in climb performance and extension of the laminar bucket. 2. The stall is softened considerably and extended. 3. There is indeed a drag penalty at high speed cruise of about 2% drag, or about 2 at 200. 4. There is no drag penalty at economy cruise. 5. The estimated weight addition is only 6 lbs based on .050" skin over 2lb density foam. I still think this bears further investigation, even if I am the only one. Mooney 64 wing cuff performance .pdf
  23. Yes the stall strips are installed and I found a really interesting article about how the factory tests and installs them during post production testing. The purpose of the stall strips are to make sure the airplane stalls straight ahead without rolling more than 15 degrees. They got that dead on on my bird! But there is no perception of shudder or buffering at all. I also watched a video of a Mooney pilot who suggests landing in the flare by pulling back until the horn just blows and keeping the yoke in that position until touchdown. That will be leaving some low speed performance on the table but I think it is a good starting point for training. I am coming down final 1 tick above best angle of climb AOA and that is a sweet spot for good semi-short landings, and managing obstacle clearance. I can easily slip down and have a really good feel of the aircraft especially if I reduce flaps by about 1/3 or so at treetop level. It is much easier to make a good smooth landing that way, but again that means leaving some low speed performance on the table. I have not done much experimentation with adding power at the bottom of the flair. I read some good suggestions about that and that is another area I am looking at. Hope that answers your questions
  24. I hear what you are saying but if you look at page 19, the minimum drag of the laminar flow bucket is virtually identical in all 4 airfoils presented. The laminar bucket actually expands as the airfoil is modified.
  25. I disagree that VGs don't impact top speed or cruise speed fuel economy. I admit I don't have direct experience with them. The people that I have talked to that have them say there is a drag penalty, but the improved low speed performance is worth it to them. I'd like to hear from a Mooney owner that has them installed. To me VGs are a band-aid and are unclean to the airflow, but they do have a proven track record of effectiveness. To me the slight modification to the leading edge is a lot cleaner to the airflow, but it is too bad it is more time consuming to get built and installed.
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