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m20J cruising altitude


teethdoc

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6000-8000 works best for a combination of speed/economy. Economy cause you're LOP and speed cause you can make 60-70% power. Higher, LOP you're stuck operating at possibly too low a power or you have to go ROP and you're spending more gas than if you were lower LOP.

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My 201 likes 6000 to 8000 feet MSL.

 

The problem that I would like some input on is that In FL I like to fly as high as I can even if O2 is required to get above buildups that are around for a good portion of the year. The problem is that my 201 does not climb well above 8000 or 9000 feet; you can maybe get 300 FPM @ 70-80 KIAS with OATs in the 55-65 (f) range and to get more FPM, you have to really increase the AOA and lower airspeed even more which I don't like to do. I cant find a Service Ceiling in the POA and I know other 201 owners fly higher. Any thoughts?

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I'm in California, and there are a lot of mountains if you go any distance. If I could pick the altitude, I would pick 6000 to 9000 to get good speed/economy and no O2. However, I often fly in the 12,000 range. I've been as high as 17,500. At about 250lb under gross I am climbing around 350fpm at 12,000, give or take.

 

Larry

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One of the great things about our birds is that wing, which loves thin air.  Our NA engines run out of steam though, but I have climbed - patiently - to FL170 to take advantage of winds.  But FL080-120 is obviously the sweet spot.  For me the Powerflow exhaust made a noticeable difference, more in climb than cruise.  I rarely fly at altitudes at which I have to throttle back to achieve 75% power, but we have mountains in and around SoCal.  I am sure were I midwest or east-coast based that would be different.

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My 201 likes 6000 to 8000 feet MSL.

The problem that I would like some input on is that In FL I like to fly as high as I can even if O2 is required to get above buildups that are around for a good portion of the year. The problem is that my 201 does not climb well above 8000 or 9000 feet; you can maybe get 300 FPM @ 70-80 KIAS with OATs in the 55-65 (f) range and to get more FPM, you have to really increase the AOA and lower airspeed even more which I don't like to do. I cant find a Service Ceiling in the POA and I know other 201 owners fly higher. Any thoughts?

I think you need to increase your IAS. Vy for my F is ~91KIAS at those altitudes. I would guess that Vy in a J might be even higher. In any case, once obstacles are cleared I would consider Vy a minimum climb speed, and instead usually settle at around 105KIAS for better cooling, visibility, and forward speed while sacrificing little in climb rate.

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On my way to the Caribbean I cruise at 13,000ft and coming back at 14,000ft. Mostly due to get radio/radar range. As you go higher the plane gets pretty quiet to the point that you can easily talk with passengers without wearing headsets. I found best climbing speed to be around 110kts IAS. I just trim to 120kts IAS on initial climb and let the speed drop down as it climbs. Cruising altitude is also a function of the distance to be flown. From FXE to ORL (150nm) I normally cruise 6 to 7Kft. Highest I ever got on my 201 was 19,000ft by my self with 40gals onboard. For practical flying I would not recommend above 15Kft. It is a waste of time and fuel with no added performance.

 

José 

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I think you need to increase your IAS. Vy for my F is ~91KIAS at those altitudes. I would guess that Vy in a J might be even higher. In any case, once obstacles are cleared I would consider Vy a minimum climb speed, and instead usually settle at around 105KIAS for better cooling, visibility, and forward speed while sacrificing little in climb rate.

Thanks for the input. Airspeed was my first thought but I need 70-80 KIAS just to maintain 300 FPM climb rate. 

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Thanks for the input. Airspeed was my first thought but I need 70-80 KIAS just to maintain 300 FPM climb rate.

Climbing at an airspeed lower than Vy is only hurting your climb rate. The definition of Vy is the BEST RATE of CLIMB airspeed. Pitching up to a lower airspeed may appear to increase climb rate, but this is only temporary. Once the airplane settles down at it's new lower airspeed, climb rate will be lower than if it had been left at Vy all along.

Next time you go flying, try maintaining an airspeed no lower than Vy all the way up to 8000' and I think you will find your climb rate is significantly better than 300FPM.

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Climbing at an airspeed lower than Vy is only hurting your climb rate. The definition of Vy is the BEST RATE of CLIMB airspeed. Pitching up to a lower airspeed may appear to increase climb rate, but this is only temporary. Once the airplane settles down at it's new lower airspeed, climb rate will be lower than if it had been left at Vy all along.

Next time you go flying, try maintaining an airspeed no lower than Vy all the way up to 8000' and I think you will find your climb rate is significantly better than 300FPM.

That is correct. At a given power setting, you increase your angle of attack past best rate of climb and you end up on the back side of the power curve.... Greater increases in AOA will only lead to LESS rate of climb at that point (until the airfoil stalls/ ie you fly through critical AOA).

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According to my poh Vy decreases the higher you go.

That is also true. Until Vy intercepts Vx, at which point you're pretty much at the service ceiling of the aircraft. Vy decreases in speed per altitude, Vx increases in speed per altitude. Factory defined service ceiling is a function of the intercept of those two 'speeds'. Realize, though, that all the speeds in your POH assume max gross weight: weight being a factor in speed change as a function of stall speed. If you use AOA, though, it's 100% independent of weight and ultimately what your airspeed indicator reads. L/Dmax and stall speed both occur at their own respective AOA's: regardless of bank angle, weight, etc. The AOA remains the same... Just the IAS changes.

Lots of speeds to remember... Lots of inaccuracies that come with those speeds and the assumptions they are built off of: aerodynamics is much simpler when you abandon speed and think in the "native language" of AOA......

Of course, we don't have AOA gauges, unless we installed them aftermarket, so we're stuck cutting butter with a chainsaw (ie using an airspeed indicator to calculate... Well.... Everything... And have a list of numbers to memorize, interpolate across and guesstimate from).

Rant complete... Again...

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6000-8000 works best for a combination of speed/economy. Economy cause you're LOP and speed cause you can make 60-70% power. Higher, LOP you're stuck operating at possibly too low a power or you have to go ROP and you're spending more gas than if you were lower LOP.

If you have 25 degrees of timing 9000 works well to if you put the prop at 2600rpm and run it peak or just a few degrees rop or lop as your high enough where you can put the mix anywhere you want it. At that power setting I think peak is at about 9.6gph and yields 155kts.

If I'm in a big hurry at 9k it's 2700rpm mixture at peak and it's about 10.2 ish gph and that's 159kts. If I'm in a super big hurry ill set the mixture at 30rop which will burn 10.6gph and yield 160-162kts. Going 80rop might be worth another 1-2kts but it uses another 1.5 gallons per hour. If the OAT is moderately cool at 9k, let's say 7c or lower I can run 2700rpm 30rop all day long and not bust 365cht.

If peak egt won't get me enough speed I keep increasing the prop speed until I go as fast as I want.

All these numbers are just me on board with 1/2 fuel so if at gross subtract 3-5kts

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  • 3 years later...

Thought I would revive this thread from 2013. I don't have O2 but curious how many of us M20J guys have oxygen at their disposal? Have you guys climbed just to see how high it will go and what performance do you guys see when there? I'm typically a below 10,000 feet flyer but just curious.  I want to try the limits of the J at some point. 

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I fly my Executive at FL250 the J doesn't even have a cool name.  201 what is that compared to Super, Ranger, Master, or the all powerful Executive.  Don't bring a knife to a gun fight!

image.thumb.jpeg.0a6948a51ce4c18cd5605e2f3f8d8c92.jpeg

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