MooneyCFII

Cool Joe. But wouldn't you rather have your Acclaim rather than a C182T? I am working with them to get a Mooney sim, including the Acclaim.

Thank you. I'm adding it to the list of panels. Nice panel. The new panel I am doing for my K won't be far off from yours.

Thanks. I will send this along. I suspect we will get a more-or-less generic 6-pack panel with typical nav/comms, add an HSI, add a 430/530, Aspen or G500, etc. But switches and controls will appear in their proper places and will behave as they do in the plane. It should be a good way to learn the new avionics before you plunk down your bucks for a new panel.

More info. The TouchTrainer from FlyThisSim is based on the X-Plane flight dynamics engine. It is much more true-to-life than the Microsoft Flight Sim model. You can tune the model by changing power-to-weight, prop efficiency, airfoil, coefficient of drag, change in Cd with gear and flap deployment, change in center-of-pressure with gear and flap deployment (so you get the correct pitch change), etc. This means that the model is easily tuned to match the real airplane. Take-off roll, distance to clear obstacles, climb rate, landing roll, etc., will behave properly for changes in load, CG, and density altitude. One of the cool things that I plan to use in my training is that the TouchTrainer is compatible with PilotEdge. PilotEdge is a live air traffic control service. You fly the sim and you can talk to a live controller. He/she sees you and other sim users on her "scope" and can provide vectors, clearances, traffic calls, or just suggestions for bettering your radio procedure. You can fly realistic VFR and IFR scenarios, and then the controller can tell you how you did and help you do better. What a boon for new (or "seasoned") pilots with mic fright. Sorry for waxing ecstatic. I am *really* impressed with this product and look forward to using it with my students.

I am working with the folks at FlyThisSim (FTS) to develop a set of Mooney simulations for their TouchTrainer. Since I wanted a Mooney sim to use with my students (I hope to use the sim as a procedures trainer for new Mooney pilots as well as for getting an instrument rating) this seemed like the best route. After looking at a number of sim manufacturers I decided to work with FTS because they are willing to customize their sim to match the panel in a specific aircraft and then get it certified as a BATD for initial training and currency. (Once done you could use the Mooney Sim in the TouchTrainer to do your recurring IFR currency and the panel would look and behave like YOUR aircraft.) Of course, it makes sense for the first sim to be an M20J since that seems to be the most popular of all the M20 series. (Please correct me if I am wrong.) And, of course, since I am footing part of the bill for its development, it is going to be an M20K sim too. (Not too much different from the M20J.) But the nice thing about the Mooney is that the airframe behavior just hasn't changed that much thus allowing the creation of a sim for nearly any of the M20 series in relatively short order. It should be possible to have a family of simulations that covers from the M20A through the Acclaim. I am pretty excited about the idea. In speaking with FTS today they asked me if I could provide some examples of common instrument panel layouts so they can match them. Seems like we have three main panel sizes, several with the basic 6-pack of steam gauges, various nav/com and GPS combos, with and without HSI, and some of the new glass panels. (They have G1000, G500, and Aspen glass to use to build new panel layouts.) So I am soliciting pictures of peoples' panels. I want to get a good cross-section of early, mid, and late model panels to use as templates for the sims. They already have a good library of instruments, radios, GPS's, and autopilots. About the only thing they don't have is the pneumatic wing-leveler. (Is anyone still using the pneumatic wing leveler AP anymore?) So, if you have a good panel shot that you think is representative of a substantial number of aircraft, please send it to me or directly to FTS. Disclaimer: Just so everyone understands, I have no formal relationship with FTS other than I am going to become a customer. I do not receive any compensation from FTS. I like their product and have ordered one to use in training. Because I do Mooney training I am working with FTS to help them develop a Mooney sim I can use but I can imagine a number of Mooney pilots wanting their own sim to use to maintain log-able IFR currency or to use to earn their instrument rating.

On a related note, Garmin has just weighed in with their AoA indicator. It is a differential-pressure unit but, lo and behold, it is a three port device that senses dynamic (pitot) pressure too, making it a true AoA instrument ... for one flap position. <sigh> Nope, no flap position sensing or calibration. Poop. But, hey, we are getting closer! (I prefer differential pressure instruments to moving vane type because there are no moving parts to break. But we still need to solve the problem of calibration for flap position.)

Well, close. First, the question is, "what are we measuring?" Start by drawing a line from the leading edge of the airfoil to the trailing edge of the airfoil. This is the chord line. AoA is the angle that the relative wind makes to the chord line of the wing. Now extend the flaps. You have changed the location of the trailing edge of the wing and hence the chord line. Now it is possible that the wing still stalls at the same AoA but since the chord line has changed, critical AoA will likely occur at a different angle relative to the longitudinal axis of the aircraft. Our perception is that the wing stalls at a "lower" AoA when, in fact, the wing still stalls at the same (or very similar) AoA. This is why we need our AoA indicators to be calibrated for flap deflection. I have heard a couple of AoA manufacturers say, "well, if you calibrate it clean you will have a "buffer" when you put the flaps down." I'm sorry, I don't want an unknown buffer. I want to know where approach reference AoA is and I want to know where critical AoA is REGARDLESS of where my flaps are set. (Oh, and I really want to know zero-lift AoA too but ... I'm abnormal. :-)

Sorry, I tried to figure out how to interleave my responses with the quoted text but couldn't figure out how. And the message that came in email had all the quote levels stripped out. So I am just sending out a straight-forward reply. The system that I had in my Nanchang CJ6A was from Advanced Flight Systems. See: http://www.advanced-flight-systems.com/Products/AOA/aoa.html The problem with the systems that use a differential pressure probe (like the Bendix/King or Alpha Systems units) is that they don't actually measure AoA. A differential probe *can* be used to measure AoA but only if the differential pressure is corrected for dynamic (pitot) pressure. That means the calibration will be correct at only one flap position AND only one aircraft loading, or only one AoA. The Advanced Flight Systems unit has the static/dynamic pressure correction which is why it gives proper indications at all speeds and loadings. (Like I said, it was dead-nuts accurate from 0.5G to 5G.) But because it connects to the pitot/static system and doesn't carry the FAA Seal of Approval, you can't install one in an aircraft with a standard AC. I have heard of this unit being granted a field approval if the owner mounts a second pitot tube on the aircraft just for the the AFS AoA indicator. Given that many of the low-cost, easy-to-install system are differential pressure only (the most popular was the Lift Reserve Indicator) you really don't know what they are telling you other than some kind of relative sort-of, kind-of, AoA-like-but-not-really indication. They will give accurate information over a wide range, but only at one loading. IF you adjust the probe position correctly you can get it to tell you one particular AoA at any dynamic pressure (airspeed). I believe that the original Lift Reserver Indicator (LRI) had you adjust the angle of the differential probe to show critical AoA so it did show critical AoA at any speed or loading. It was just that the scale was compressed at higher airspeeds and wing loadings. But don't take my word for it. Here is a very interesting paper that describes how all this works: http://www.nar-associates.com/technical-flying/angle_of_attack/DeltaPAOA_wide_screen.pdf I believe this paper is actually addressing the errors specifically in the Alpha Systems unit. (I am guessing at this based on the photos.) Vane-type sensors, if properly placed, do read AoA for whatever configuration they are calibrated for or, if they have some way to sense flap position, can be calibrated for all flap positions. This is pretty straight forward. Personally I just don't like having a vane out there where it can ice up or get damaged. (OTOH, if your wing is iced up, your AoA isn't going to help you at all because your wing now has a completely different airfoil making the AoA indicator useless. So maybe a vane isn't so bad after all.) But a vane does respond to incident wind independent of airspeed and so can provide accurate relative AoA indications across a wide range of airspeeds. Add correction for flap position and you have a useful AoA sensor. BTW, the unit that will be adding flap correction is from RiteAngle. I'm sorry if I appear negative. I just find it so frustrating that the FAA inhibits technology that really could make our flying safer. When I went looking at AoA 15 years ago, the unit from Advanced Flight System (then Precision Flight Controls if I recall correctly) was the hands-down winner. Today it still appears that way. I would have one on every one of my airplanes if I could get away with it. But a differential pressure unit without dynamic pressure correction just doesn't really tell you what you want to know no matter how fancy the display is. So it looks to me like the vane-type indicator is the best we are going to get in the near term.

Having lived with AoA on other aircraft I thought I would make a comment. The problem with ASI is that it lags, it has installation error, and marked stall speeds are only valid for steady state flight at one weight (max gross). You can invoke a sudden change in AoA to stall the wing without a corresponding change in AS. Also, stall "speed" changes with loading. Stall speed is increased in a level turn and can result in an accelerated stall. (I like to take my students up, configure the airplane for landing, and demonstrate how one can invoke a stall at speeds well above the indicated stall speed in the base-to-final turn.) So an AoA indicator is really useful because it gives instantaneous indication of the state of the wing relative to stall. An airspeed indicator doesn't even come close. (But every airplane has an ASI so you still have to know how to use it and what its limitations are.) On my last AoA equipped aircraft I had it configured to indicate from zero-lift (zero alpha) to critical AoA for both "clean" (gear and flaps up) and "dirty" (gear and flaps down) configurations. it was calibrated for both and therefore I always knew how far I was from stall and how far I was from best L/D, always useful in an engine-out situation. (I tested it from 0.5G all the way up to 5G and it was dead-nuts on.) It was even useful in a botched aerobatic maneuver as I could just pitch to zero alpha and then recover without having the airplane depart in an undesired snap-roll or spin regardless of whatever airspeed I was flying at. (It is really useful to be able to fly the airplane well below "stall speed" without stalling.) So, yes, I am a CONFIRMED believer in AoA indicators in aircraft. Everyone here should have one in his or her aircraft. Now for the problem: the current crop of "easy-to-install" AoA indicators that have been approved for aircraft flying with a standard airworthiness certificate have no way of automatically adjusting themselves for flap deployment. (The FAA would not approve them if they had any connection to the flight controls.) Extending the flaps changes the effective AoA of the wing and produces erroneous readings. So you have a choice: configure the AoA indicator to read correctly flaps-up, or configure the AoA indicator to read correctly flaps down. If you are like Phil and are specifically addressing the issue of the infamous base-to-final stall-spin event, configuring the unit in the landing configuration is probably the better approach. If you want a more general indication then you probably want to configure with the airplane "clean" and then re-mark the instrument to show the error when "dirty". That seems like a kludge to me so I have decided to wait for the availability of an AoA indicator like the one I used to have, which worked in all configurations. I know of one AoA manufacturer who has an AoA indicator that takes in flap position information to correct the AoA readings, making the unit usable and accurate in all flap configurations. The only problem is that he is still awaiting FAA approval for his new device. Once he gets approval I will probably purchase his units for all my airplanes. Brian "Pinky" Lloyd

Lovely Bob. Well done! So many variables, so little time. :-) I find it helps to remember that MAP dominates when it comes to controlling ICP.

Every aircraft manufacturer does different things. And people add things to their airplanes. Mooney does have a fuel pressure gauge that is different than the fuel flow gauge I was alluding to. The gauge I was talking about is typically a 3.25" analog "steam" gauge with a pointer that rotates and is calibrated in GPH. Every *injected* Lycoming engine I have flown behind has had this analog fuel-flow gauge on the panel somewhere. It does indeed sense fuel pressure in the flow divider and translate than into a fuel flow indication. And it is possible that Mooney never put this gauge on some models with injected engines, instead deciding to put in a vane-type fuel-flow indicator, e.g. Shadin. After all, manufacturers get to make changes and the certify the aircraft that way. BTW, this does not apply to Continental engines with fuel injection. The Continental fuel injection system is VERY different from the Bendix RSA fuel injection system used on the Lycoming engines. (I am a fan of the Bendix RSA system myself.) I like the Bendix RSA system because it is a true fuel servo system that controls fuel flow by mass airflow.

Lycoming normally provides/specifies an analog gauge for fuel flow. If you follow the plumbing you will find that it connects to the flow divider that sits on top of the engine and feeds fuel to each of the injectors. The gauge is just a pressure gauge. When you have an orifice, i.e. the injectors, fluid (fuel) flow through the orifice is going to be proportional to the pressure. So if you know what the fluid is (its viscosity is the key here) and the size of the orifice, you can calibrate the gauge to read flow as a function of pressure. More pressure, more fuel flow. Less pressure, less fuel flow. It is that simple. Is this accurate? For the most part it is pretty accurate. OTOH if the orifice(s) are dirty or partially blocked, the gauge will no longer be accurate. A partially-blocked injector will require higher pressure to flow the same amount of fuel. A partially-blocked injector will result in low fuel flow and a leaner mixture for that cylinder. If you have a multi-port EGT and/or CHT you can see that the EGT and/or CHT values no longer read the same as they did for the desired fuel flow. (Knowing what your EGTs and CHTs normally read for a give power setting and altitude is quite useful for keeping track of how the engine is working.) If you have added a vane-type fuel-flow gauge (shadin, JPI, whatever) then the two gauges will no longer agree. That is a hint you need to do maintenance on the injectors.

Talk about thread drift! This started out with: I tried to answer but got caught up in the "why" rather than just focusing on the "how". I did throw in a fair bit of "how" but I think it got lost in all the other stuff flying around. So, the first answer is, "don't push your engine too hard." The first and easiest way to stay out of the red box with a normally-aspirated engine is to climb to 10,000' or above. If you do that, there is nothing you can do with the throttle, prop, or mixture that will hurt your engine. If you are down lower you just need to set a lower power setting or use a richer (ROP) or leaner (LOP) mixture setting. Here is the logic behind that and it applies to ALL normally-aspirated engines: at 10,000 feet your MAP will be down to about 20"Hg. That is 2/3 of sea-level pressure. That means that no matter what you do with the controls, maximum power available is 2/3 of sea-level or 66%. If you reduce RPM at all you are going to reduce power from 66% to something lower. (At 7500' max available power is about 75% and reducing RPM will select lower power from that.) So for the guy flying behind a carbureted Lycoming engine power management is easy: Take off full-power with a full-rich mixture. IF you have an EGT of any sort, lean during climb to maintain whatever EGT value you had at take-off. Climb to 7500' or higher and level off. Reduce RPM (yes, this is the first power reduction) to your desired cruise RPM. Lean the mixture until the engine stumbles. Richen the mixture until the engine runs smoothly again. You are done. Set cruise cowl flaps (if you have cowl flaps). Monitor CHT. If you have normal CHTs all is good. If CHT is high, reduce RPM and/or MAP, relean, and check CHT again. At 7500'-8500' I would set 2400 RPM. I would use higher RPM values at higher altitudes to get more power but I wouldn't do anything with the MAP. Let altitude set your MAP for you. If you have an injected Lycoming engine you have a fuel flow indicator that is actually a fuel-pressure gauge. On the face of that gauge you will likely have full-power fuel-flow values for different altitudes. As you climb, lean to the marks for the different altitudes as you climb through those altitudes. In essence, you substitute those indications for step 2 in the above climb procedure. While it is technically possible to get a carbureted engine to run LoP smoothly it is not likely. I know of two tricks to vary mixture distribution with a carbureted engine: close the throttle from wide-open and turn on carb heat. By closing the throttle just a tiny bit so that there is only the barest reduction in MAP, the throttle valve now introduces turbulence in the flow and this aids in fuel vaporization which helps mix the fuel and air. If you have a multi-probe EGT you will probable notice a shift in EGT on one or more cylinders. And carb heat raises the induction temperature which helps with fuel vaporization. I can go on here but I think that addressed the original question.

I do seem to have annoyed people and I apologize. If anyone is interested I will be happy to describe what I teach for setting power and mixture for a carbureted engine, a normally-aspirated injected engine, and my 231 (which has no automation in the turbocharger control). These techniques have served me well for 45 years and I have taken several 4 and 6 cylinder Lycoming engines past TBO. I normally operate lean-of-peak where possible. I fly with aircraft with no engine instrumentation to speak of (oil pressure and temperature only) and with aircraft with SOTA engine monitoring.

No, I did not contradict myself. I probably should not have posted the anecdote from yesterday at the Mooney factory because that was confusing. Percent of power is based on the rated power of your engine in your airplane, period. If the POH says your engine produces 280hp then your engine produces 280hp regardless of what a similar engine in another installation produces even if you think they are the same engine. That is my conservative answer. (You know, the one you give to the examiner when you are doing an oral.) That having been said, after I read the POH I read the engine manufacturer's manual. After examining that data I may choose to deviate from the POH. And, no, your engine manufacturer doesn't talk about the red box. Some engine manufacturers say don't run LoP and yet we do and we know it is safe to do so. It is not unusual for airframe manufacturers to derate an engine, usually by limiting max RPM. In that case the red-box would remain approximately the same because ICPs are more dependent on MAP and induction air temperature (the density of the induction charge) than they are on changes in RPM. (And yes, I am aware that, with fixed ignition timing and at lower RPM the combustion event will complete at an earlier crank angle and that may lead to a difference in ICP due to the volume of the combustion chamber being slightly less but, by and large, MAP *is* the more dominant parameter.) So an engine that is derated by RPM should still have its %power calculated relative to the rated power in the installation. (Which is what I said at the beginning of this message.) So all of this is a guideline. The "red-box" is not absolute. We do know that if you are going to push your engine harder and run at a higher percentage of power, you have to be more conservative about mixture manage and run it more rich on the RoP side or more lean on the LoP side than if you are running at lower power. Conversely, you can climb higher or pull back the MAP and not worry about the details.

I have not checked mine over the entire range. The engine manufacturer only provides data for RoP. I checked some data points there and it seems pretty accurate. The caveat here is that JPI has you calibrate the monitor based on actual numbers and temperature (as I recall; I did it about 1.5 years ago) during initial set-up and if you don't, it will likely be way off. Also LoP seems reasonable given the expected power reduction for a given MAP and RPM when operating LoP vs. RoP but I can't say for sure. But it seems like it is right within about 3%. I started to write about using rate-of-climb to determine available HP but figured that might be more than people want to read right now.

Apropos to this, yesterday I was on the tour of the Mooney factory as part of the MAPA fly-in. The gentleman from Mooney who was leading our tour group gave a comment on this that was quite interesting. We were looking at a nearly-completed Acclaim when he mentioned that the engine was derated to 280 hp. Someone asked why it was derated and he said that the engine has been made to produce anything up to 400hp with just tuning. He also said that the maximum continuous rated power of ANY of the engines regardless of maximum power output is 265hp. How does this map to the desired percent-of-power? Frankly, I don't know but it seems telling that, no matter how much they are rated for in take-off configuration, they all have the same METO (maximum except take-off) power. What this tells me is that the REAL answers are in the engine manufacturer's documentation. Once again I recommend getting the engine manual and studying that for more in-depth information.

When I was young and flying my father's 182, we had a fancy new Alcor EGT. Wow! High tech! (And in 1968 it was high-tech.) Alcor said, "Best power, 75F rich of peak EGT; normal operation 50F rich of peak EGT; best economy 25F rich of peak EGT." I believed it. I ran that airplane at 50F rich of peak EGT. Of course, if I leaned it the traditional way, i.e. pulled back on the mixture until it got rough and then enriched until it was running smoothly again, I also ended up at 50F rich of peak EGT, so that seemed like the right thing to do. Probably the thing that really saved me was that I lived on the west coast and to go anywhere I had to get up above 10,000' no matter what. Frankly the fact that most normally-aspirated engines have no trouble making it to TBO suggests that it really isn't as critical as I think people are now making it out to be. Where it becomes more critical is with the turbocharged engines. Flying the earlier Mooneys was about economy more than speed. Then the 201 came along and suddenly we kicked-butt on the Comanches and Skylane RGs. We were neck-and-neck with the Bonanza crowd. The 231 came along and suddenly Mooney was SERIOUSLY in the speed biz. (And there were a lot of blown-up TSIO-360-GB1s along the way too -- shame on Continental for that.) The way to eke out that last 5 knots in order to have the fastest airplane in the air is to run the engine at high power in cruise. That means 75%-80% power. And turbocharging will let you do that at altitude. Now the whole red-box/red-fin thing becomes really important. If you don't pay attention to the mixture you can and WILL shorten the life of your engine. And it doesn't help that the PoH encourages high-power engine operation to achieve the high speeds. After all, the manufacturer wants you to be happy with the lightning-fast speed of your fancy new airplane. Of course, the warrantee is going to run out long before the engine needs to be overhauled at what would ordinarily be mid-TBO so what do they care? (OK, maybe they aren't that callous but their motivation IS different than the owner's.) (I would love to see a paragraph in a POH that tells the truth about lower power settings, engine longevity, and reduced maintenance costs.) Now we know more about engine operation and we have better tools. We know that operating these high-powered engines to get max performance CAN shorten the life of the engine. But now we have ways to see what is really going on in order to prolong life. We should use them. But, in the end, it really does come down to this: reduce the power and your engine will last longer. You will pay less for fuel and maintenance. Period. I was thinking about launching into how TAS doesn't change a lot from 8000'-12000' at wide-open throttle (WOT) with a normally aspirated engine but Norm's articles are good. Read those.

Oh, I forgot to add a link to this useful article: http://www.oshkosh365.org/saarchive/eaa_articles/2012_12_08.pdf

You'd think that, after doing email on mailing lists for 35 years I would learn that it is not possible to make a joke without someone assuming I am trying to give offense. I wasn't and I am sorry. My comment was tongue in cheek. I assumed that since you were here and asking, you would understand that I understand you are seeking assistance. It was not intended as a cheap shot at you ... unless you are a politician too. That being said, there is some onus on you to seek more information if you feel the PoH is not complete. The quality of information in the PoH is all over the map even with different years of the same airplane. My Piper PA-16 "Clipper" came to me with a "PoH" that was nothing more than 3 sheets of single-sided paper stapled together, most of that having to do with W&B and nothing on the engine other than maximum HP spec at red-line. Other airplanes had quite adequate engine operation charts and diagrams in their PoH. But none of them were what I would call complete. When I buy an airplane almost the first thing I do is go get the engine manufacturer's manual for the engine in the plane. There is a wealth of information that the engine manufacturer gives to the airframe manufacturer that the airframe manufacturer leaves out of the PoH. (After all, the engine manual may be bigger than the aircraft's PoH!) One of the most useful, if not understandable, is a nomograph that lets you calculate percent of power and fuel burn from OAT, pressure altitude, MAP, RPM, and mixture setting. I usually take that and make myself a table to use in the plane for common altitudes and power settings. (I do this for common weight-and-balance conditions too.) And I don't expect you to have fancy instrumentation. In fact, I have found that when operating my 231, I primarily set the mixture using two things: fuel flow and the seat of my pants. I get up to altitude, set my MAP and RPM to yield 62% power, then do the Big Pull on the mixture control until I feel the sudden deceleration that comes with getting on the lean-side of peak EGT and then fine-tune the fuel flow. I then cross check with TIT to ensure that I went past peak EGT by the expected amount. I find the "Lean Find" of my fancy engine monitor to be of questionable usefulness. (Actually it is useful for finding the GAMI spread when determining if I need GAMI-jectors for that particular engine but after that, not so much.) After that I should see my CHT quickly settle to expected values. If they are lower than usual, I have probably over-leaned and am too far LoP. If they are a bit high, I need to lean some more. For this I check using TIT and approach peak TIT from the lean side. Other than the TIT, I don't think I have paid attention to an actual EGT value in a long time, except for trying to troubleshoot a problem like a fouled plug, bad mag, or induction leak. So I am not assuming anything in the way of special hardware. I do think your airplane should have some sort of EGT indication and probably should have CHT for all cylinders but beyond that, the fancy stuff only really helps with trouble-shooting. Of course, having a fancy engine monitor gives you more information about what is happening. But people have been flying their airplanes successfully for over a century without a lot more information than oil pressure, oil temp, and their ears. Perhaps the best way to ensure you are not going to hurt your engine is to fly it such that it runs at 65% power or less most of the time. Then mixture, red-box, red-fin, etc., just doesn't matter. And for someone flying behind a normally aspirated engine, the easiest way to do that is to fly high. Fly above 10,000' behind a normally-aspirated engine and you just aren't going to have to worry about damaging it through mixture mismanagement. And if you are going to fly low, pull back on the go-knobs and save fuel. Fuel burn decreases faster than TAS does. About the only time it matters is when you are fighting a headwind and need to fly down low.

Different versions of the "same" engine that produce different maximum power really are different engines. There are usually differences in compression, valve timing, crankshaft and rod "beefiness", etc. So use the rated power for YOUR engine, not other versions that you think are the same engine.

I don't know. I don't have your engine manual or PoH in front of me and I can't see your EGT. You really should take out your POH or engine manual and do the numbers. Given that you have a pilot's license, learned to navigate, know how to work W&B problems, etc., I know you can pull out your manual and figure out percent-of-power and then figure out where your mixture is relative to the Red-Box/Red-Fin. But if you insist on someone pulling numbers out of the air, here are my guesses. (Disclaimer -- if you fry your engine based on what I write here pulling numbers out of the air you are on your own.) Your engine is running between 75% - 65% power depending on the altitude you select, at 6500' you are closer to 75% power and should run no leaner than 150F degrees RoP or richer than 40F degrees LoP. At 10,500' where power is closer to 65% you should run no leaner than 100F RoP or leaner than 20F LoP. So look at your EGT and figure out what where you should put your mixture control. Now, as to figuring out percent-of-power, if you are running rich of peak (RoP), percent of power is a function of available air. After all, when running RoP, you have excess fuel and only those fuel molecules that can match up with oxygen molecules can burn to produce power. Once you use up all the oxygen, no more fuel burns even if you add more fuel by running a richer mixture. MAP and RPM determine how much air gets into the engine so they determine percent-of-power when operating RoP. So, What does the POH or engine manual tell you about percent-of-power for your power settings? When running LoP you have excess air/oxygen and more (all) of the fuel molecules burn. So when you are running LoP the percent of power correlates more closely with fuel flow. So the process is pretty straight forward: Find your percent of power from the book or maybe use the percent-of-power function from your engine monitor. (I discovered by accident that my EDM930 knows the difference between RoP and LoP percent-of-power and changes the percent-of-power display depending on whether I have selected ROP or LOP operation in the lean-find function.) Now find the red box that goes with that percent of power. Figure out the width of the EGT danger-zone for that percent of power. Adjust your mixture to keep the EGT outside the danger-zone. Cross check with CHT to be sure the engine is keeping its cool. I know, I didn't give you an easy answer. Sorry. I know it can seem confusing initially but it is pretty straight forward if you tackle the concepts head-on. OTOH, if you aren't willing to think and learn, you probably should take up something other than flying -- politics maybe.

Back from my first MAPA fly-in. (I suspect I met some of you.) It was great. Norman, I read more. Excellent! Great work. I have been doing this in a slightly less analytical fashion for many airplanes for quite some time. Climbing high, allowing the aircraft to operate below Carson's speed and closer to CAFE speed, will often result in shorter flights because it will allow me to skip a fuel stop. Not having to descend, land, fuel, and take-off again, makes up a LOT of time for the slower TAS. Here is the thing: when it comes to airplanes, fast almost always means efficient. So I don't see the Mooney as a particularly fast airplane, but rather as a particularly EFFICIENT airplane. Horsepower doesn't buy you speed because IAS varies as the cube-root of excess horsepower. Want to go twice as fast using horsepower? You need 8 times the power! In reality speed comes from aerodynamics, primarily from reducing parasite drag. The Mooneys, and especially Roy Lopresti, knew this. So you can slow down, overfly a fuel stop, and get there sooner, burning a LOT less fuel. Using these techniques I discovered I could operate my Aztec, a not-particularly-efficient twin, substantially more efficiently. I used to fly between Puerto Rico and Florida regularly and learning to operate most efficiently allowed me to do the trip non-stop. Not only did I not have to buy expensive fuel in the Bahamas, I was also able to avoid having to deal with Bahamian and US Customs. Talk about saving time and money! So my engine settings almost always end up to be 60%-65% power, 40F LoP, and then picking the altitude that results in the greatest average ground speed (including climb). It means my 231 isn't going nearly as fast as it can but I usually save enough money in a day of flying to pay for my dinner and motel. OK, on longer trips you have to pee in a bottle. Sorry.

How true. And iron gyros are only as reliable as the #$%^ vacuum pump that feeds them. Given the choice, I'll bet my butt on the switch, the circuit breaker, and the battery before I will bet my butt on the vacuum pump. Give me an all-electric panel with two alternators over a half-electric/half-vacuum panel any day of the week.

I guess it is an occupational hazard.