nickmatic Posted January 16, 2014 Report Share Posted January 16, 2014 Getting used to flying my new Encore (conversion) and loving it. But as a newbie to the plane and high performance engines in general I'd like to hear some best practices. First question is about descent... My instructor, quoting an old rule of thumb for turbocharged engines, says reduce MP by 1" per minute to avoid shock cooling. My mechanic, still being conservative, says maybe 2" per minute is ok. Either way, the thing just wants to fly so you've gotta wait forever to slow down and start descending. But this MAPA article, written by one of Mooney's test pilots, says just chop it to 20" all at once if needed and don't worry about shock cooling: http://www.mooneypilots.com/mapalog/M20K252_evaluation_report.htm I've read other articles as well that say shock cooling isn't as big a deal as it's made out to be in the 252/Encore, as long as you avoid going below 20" right away and 15" on initial approach. What do encore/252 drivers out there do? I also notice the article says I should see 2700rpm on takeoff full power setting but I see just below 2600. I think my prop governor needs adjustment but I also noticed my Encore POH says 2600. Did they reduce this speed from the 252 to the Encore? Lastly, how do people feel about this article? It's seems pretty sensible to me. Cheers, Nicholas Quote Link to comment Share on other sites More sharing options...
chrisk Posted January 16, 2014 Report Share Posted January 16, 2014 From my perspective, 1" per minute seems a bit conservative, especially as I go from a full power take off of 40" to 36" for climb. Having said that, I can see the logic of always having the exhaust driving the turbo (instead of momentum). I suspect 1" every few seconds is sufficient to accomplish this. I'm sure others can contribute more than an old wives tale. (like over squared operation) As for shock cooling, its a huge debate. I'll just say you should ensure your engine is within operating temperature in case you need a go around. And it might not be if you make a power off (idle) decent from FL20. Quote Link to comment Share on other sites More sharing options...
nickmatic Posted January 16, 2014 Author Report Share Posted January 16, 2014 Thanks Chris- Good point about keeping the engine within operating temps for a go-around. I hadn't thought of that. I always make throttle movements smoothly and slowly and that's another thing to look out for. Quote Link to comment Share on other sites More sharing options...
Parker_Woodruff Posted January 16, 2014 Report Share Posted January 16, 2014 I owned an Encore conversion as well. Typically cruised between 29" and 31". No problem bringing it straight back to 25" or even 20" when starting the approach. Whoever came up with these supposed linear relationships between 1" and 1 minute & also 1" and 100 RPM (for the "don't fly oversquare types) is perpetuating terrible flying technique. You are pilot in command, not your engine. Too many pilots put themselves in a bind while trying to make approaches and have difficulty flying in a logical fashion because they're caught up on these blanket rules of thumb. There's my rant. 5 Quote Link to comment Share on other sites More sharing options...
chrisk Posted January 16, 2014 Report Share Posted January 16, 2014 Whoever came up with these supposed linear relationships between 1" and 1 minute & also 1" and 100 RPM (for the "don't fly oversquare types) is perpetuating terrible flying technique. There's my rant. And to add more opinions. http://www.taturbo.com/turbooperation.html They are in complete agreement with Parker. 1 Quote Link to comment Share on other sites More sharing options...
WardHolbrook Posted January 16, 2014 Report Share Posted January 16, 2014 Educate yourself on how to fly YOUR airplane. Find out for yourself whether or not those old rules of thumb may or may not apply to YOUR airplane (or any airplane for that matter). Have an EDUCATED reason why you do whatever it is you do in YOUR airplane. 2600 or 2700 RPM on takeoff? There is a correct answer. Which is it for YOUR airplane? Is it your governor or is your tach off? When it comes to shock cooling, again there is a correct answer backed up by facts, not opinions. Do your due diligence, educate yourself don't just throw it out to a bunch of nameless entities on an internet website that may or may not really know what they're talking about. Just saying... Quote Link to comment Share on other sites More sharing options...
nickmatic Posted January 16, 2014 Author Report Share Posted January 16, 2014 Educate yourself on how to fly YOUR airplane. Find out for yourself whether or not those old rules of thumb may or may not apply to YOUR airplane (or any airplane for that matter). Have an EDUCATED reason why you do whatever it is you do in YOUR airplane. 2600 or 2700 RPM on takeoff? There is a correct answer. Which is it for YOUR airplane? Is it your governor or is your tach off? When it comes to shock cooling, again there is a correct answer backed up by facts, not opinions. Do your due diligence, educate yourself don't just throw it out to a bunch of nameless entities on an internet website that may or may not really know what they're talking about. Just saying... f Umm, this is exactly what I'm trying to do. I've found the collective wisdom available on this forum to be immensely valuable when corroborated with experience, observation, and the manuals, as I indicated in my OP. Quote Link to comment Share on other sites More sharing options...
Parker_Woodruff Posted January 16, 2014 Report Share Posted January 16, 2014 You should advise us in what region you live and then we can maybe point you to a CFI that will have expertise in your make/model airframe and engine. Think really hard about this. Would you want to spend 10 minutes going from 30" to 20" of manifold pressure to set up an approach? 5 minutes? That's quite a long time... I don't hold myself out for giving initial training in certain airframes, though I might give a flight review or IPC. Why? Because that person needs to learn the correct habits for his/her new plane from someone with expertise in that airframe. Your initial training should be based on facts, not rules of thumb. Why? Because you need to get the most out of YOUR plane! 2 Quote Link to comment Share on other sites More sharing options...
WardHolbrook Posted January 16, 2014 Report Share Posted January 16, 2014 Umm, this is exactly what I'm trying to do. I've found the collective wisdom available on this forum to be immensely valuable when corroborated with experience, observation, and the manuals, as I indicated in my OP. I'm not trying to be flippant, but you're really talking to the wrong crowd. For starters, I'd be going to the POH and any pertinent supplements. (Which you've done.) Then I'd take a look at your actual engine manual; after that, I'd get a hold of a Continental Tech Rep. For giggles I'd back that up with the available information out there written by former Mooney test pilots. If any of the above leaves you with any questions then I'd be talking to someone at advancedpilot.com for additional educated info. The problem with educated guys like us is that often, we're not all that educated as evidenced by all of that "so many inches per minute" stuff. Quote Link to comment Share on other sites More sharing options...
nickmatic Posted January 16, 2014 Author Report Share Posted January 16, 2014 You should advise us in what region you live and then we can maybe point you to a CFI that will have expertise in your make/model airframe and engine. Think really hard about this. Would you want to spend 10 minutes going from 30" to 20" of manifold pressure to set up an approach? 5 minutes? That's quite a long time... I don't hold myself out for giving initial training in certain airframes, though I might give a flight review or IPC. Why? Because that person needs to learn the correct habits for his/her new plane from someone with expertise in that airframe. Your initial training should be based on facts, not rules of thumb. Why? Because you need to get the most out of YOUR plane! Indeed. I'm in the NYC area. I've connected with John Pallante who is one of the local Mooney experts, but we have yet to make our schedules match. But honestly everyone I speak with has a different answer, which is why I wanted to broaden the net and see what real Mooney drivers are doing. I know exactly none other than myself. Shock cooling is something you can't really observe and establish a procedure around, so I'm trying other angles. Quote Link to comment Share on other sites More sharing options...
Z W Posted January 16, 2014 Report Share Posted January 16, 2014 I do slowly back out the throttle before starting my descent, in that I spin out the vernier kind of slowly to avoid making big sudden power changes. I do that partly to go easy on the engine, and partly to avoid scaring passengers. They don't really like sudden changes in the sound of the engine. I used to do 1" per minute as the POH recommends, but I noticed that as long as you keep the cowl flaps closed, the engine does not "shock cool" in any sense of the term. I can verify that with my 6-cylinder engine monitor. As long as you leave the engine properly leaned, the temps stay up in the green operating range, which is where you want them for a go-around. I find 2500 RPM and 20" of MP, with the cowl flaps closed, is a great power setting for sustained descents of 500 to 1000 FPM. According to Wikipedia, your TSIO-360-SB (Encore) engine should have a maximum RPM of 2600, and a maximum MP of 39". This is different from your stock TSIO-360-MB (252) engine, which is 2700 RPM and 36" MP. http://en.wikipedia.org/wiki/Continental_IO-360#TSIO-360 And I think you asked your question in the right place. There are very few people flying your airframe and engine in the world. A high percentage of them are here. If you can find a CFI with a lot of M20K time, great. I never could. Quote Link to comment Share on other sites More sharing options...
chrisk Posted January 16, 2014 Report Share Posted January 16, 2014 Do your due diligence, educate yourself don't just throw it out to a bunch of nameless entities on an internet website that may or may not really know what they're talking about. Just saying... I'm not trying to be flippant, but you're really talking to the wrong crowd. For starters, I'd be going to the POH and any pertinent supplements. (Which you've done.) Then I'd take a look at your actual engine manual; after that, I'd get a hold of a Continental Tech Rep. For giggles I'd back that up with the available information out there written by former Mooney test pilots. If any of the above leaves you with any questions then I'd be talking to someone at advancedpilot.com for additional educated info. Excellent advice. I hope Nickmatic reports back with his findings. Quote Link to comment Share on other sites More sharing options...
nickmatic Posted January 16, 2014 Author Report Share Posted January 16, 2014 I'm not trying to be flippant, but you're really talking to the wrong crowd. For starters, I'd be going to the POH and any pertinent supplements. (Which you've done.) Then I'd take a look at your actual engine manual; after that, I'd get a hold of a Continental Tech Rep. For giggles I'd back that up with the available information out there written by former Mooney test pilots. If any of the above leaves you with any questions then I'd be talking to someone at advancedpilot.com for additional educated info. The problem with educated guys like us is that often, we're not all that educated as evidenced by all of that "so many inches per minute" stuff. Ok sorry, it sounded like criticism since there were no constructive pointers. Finding the engine manual, speaking with Continental, etc. seem like good things to try as well. Quote Link to comment Share on other sites More sharing options...
nickmatic Posted January 16, 2014 Author Report Share Posted January 16, 2014 I do slowly back out the throttle before starting my descent, in that I spin out the vernier kind of slowly to avoid making big sudden power changes. I do that partly to go easy on the engine, and partly to avoid scaring passengers. They don't really like sudden changes in the sound of the engine. I used to do 1" per minute as the POH recommends, but I noticed that as long as you keep the cowl flaps closed, the engine does not "shock cool" in any sense of the term. I can verify that with my 6-cylinder engine monitor. As long as you leave the engine properly leaned, the temps stay up in the green operating range, which is where you want them for a go-around. I find 2500 RPM and 20" of MP, with the cowl flaps closed, is a great power setting for sustained descents of 500 to 1000 FPM. According to Wikipedia, your TSIO-360-SB (Encore) engine should have a maximum RPM of 2600, and a maximum MP of 39". This is different from your stock TSIO-360-MB (252) engine, which is 2700 RPM and 36" MP. http://en.wikipedia.org/wiki/Continental_IO-360#TSIO-360 And I think you asked your question in the right place. There are very few people flying your airframe and engine in the world. A high percentage of them are here. If you can find a CFI with a lot of M20K time, great. I never could. Thanks Zane. This is what I'm doing for the moment as well. And good find with Wikipedia! That confirms what my POH says. My POH is a bit of a hodgepodge given that the plane is a conversion. But now I know it's correct. Quote Link to comment Share on other sites More sharing options...
John Pleisse Posted January 16, 2014 Report Share Posted January 16, 2014 Ignore all manufacturer's limitations and operating procedures, read 5 or 6 Avweb articles, read two or three Mooneyspace LOP threads, loosely throw around the term "Old Wives Tales" and then proceed to do all aviating with the mixture control. 2 Quote Link to comment Share on other sites More sharing options...
kmyfm20s Posted January 16, 2014 Report Share Posted January 16, 2014 Ok sorry, it sounded like criticism since there were no constructive pointers. Finding the engine manual, speaking with Continental, etc. seem like good things to try as well. Even thought their intensions are good, I agree with you. I'm not flying a turbo but I would want to hear how people fly their plane the way they do and why. They obviuosly came to some conclusion with some sort of an education either right or wrong. There many topics discuussed on this forum that maufacturers, CFI, engine companies recommmend that are considered to be rediculus. Lets hear how you fly your planes and why then nickmatic is armed with many question to ask "The Pro's" to come up with his method. Quote Link to comment Share on other sites More sharing options...
nickmatic Posted January 16, 2014 Author Report Share Posted January 16, 2014 Ignore all manufacturer's limitations and operating procedures, read 5 or 6 Avweb articles, read two or three Mooneyspace LOP threads, loosely throw around the term "Old Waves Tales" and then proceed to do all aviating with the mixture control. Is that the red one or the blue one? I can never remember Quote Link to comment Share on other sites More sharing options...
John Pleisse Posted January 16, 2014 Report Share Posted January 16, 2014 :) Quote Link to comment Share on other sites More sharing options...
carusoam Posted January 16, 2014 Report Share Posted January 16, 2014 You'll like John P... This is probably true of anyone that has there name in the MAPA book.... I've had the good fortune of spending a few hours training with him. Best regards, -a- 1 Quote Link to comment Share on other sites More sharing options...
jackn Posted January 16, 2014 Report Share Posted January 16, 2014 1" / min is not going to hurt anything. But, is 59 or 30 seconds. Most likely no. Use common sense, I wouldn't yank power and drop. These engines aren't prone to shock cooling. They run pretty cool. I would be much more worried about a high speed/ low power decent., where the prop is driving the engine. To get back to your question, just slowly and reasonably reduce power. You have speed brakes. I use mine. Quote Link to comment Share on other sites More sharing options...
Danb Posted January 16, 2014 Report Share Posted January 16, 2014 John pall. Is definitely a great source of info and mooney expert trainer lots of info from him and rest of Mapa safety guys. You will be pleased 1 Quote Link to comment Share on other sites More sharing options...
nickmatic Posted January 16, 2014 Author Report Share Posted January 16, 2014 You have speed brakes. I use mine. I'm using mine a LOT. Darn thing just doesn't want to come out of the sky. Love it. Slowly learning to think more ahead. Quote Link to comment Share on other sites More sharing options...
jackn Posted January 17, 2014 Report Share Posted January 17, 2014 Thinking ahead is key to flying and maintaining a Mooney. 1 Quote Link to comment Share on other sites More sharing options...
KSMooniac Posted January 17, 2014 Report Share Posted January 17, 2014 Thought experiment... throttling-up for takeoff (no matter how fast you feed in the throttle, certainly faster than 1" per minute) or flying from dry conditions into rain (especially cold rain) will change your CHT's faster than reducing MP at any rate you try. Why would you not shock cool or shock heat in the first two scenarios but shock cool by reducing MP? www.advancedpilot.com is the best place to learn all about engine management as they teach you what is going on inside the engine during all phases of flight and mixture setting. You'll learn how to use an engine monitor, and how to diagnose and troubleshoot maladies. Then you will have the knowledge to operate your engine smartly and efficiently. That kind of knowledge goes a lot further than a recipe from the internet or a Mooney instructor (or test pilot) that doesn't have that knowledge. It is a shame that we can get licensed knowing so little about what the engines are doing in my opinion. 1 Quote Link to comment Share on other sites More sharing options...
carusoam Posted January 17, 2014 Report Share Posted January 17, 2014 Let's meet in Ada, OK in a few months..... If we get enough interest, we can have a Mooney specific training, or mostly Mooney specific.... http://www.advancedpilot.com/ Shock heating would imply uncontrolled expansion, and OWTs aren't factual, detailed or specific enough to handle expansion.... Best regards, -a- 1 Quote Link to comment Share on other sites More sharing options...
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