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I want to make a pitch and power table for C172s based on calculation, just like I attached above.

I picked up this table on internet, but I'm not sure where it comes from.

Do you have any ideas how to get these values?

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  • $\begingroup$ I don't completely understand your question. In the example you included, which columns do you want to calculate? What values do you intend to use as input to the calculations? $\endgroup$ – Pondlife Nov 11 '18 at 21:56
  • $\begingroup$ Well, let's say we want to fly C172S in cruise level flight, 100KT. In that case, the values, pitch and power, will be only one in theory, right? My question is how to get these values, pitch and power, based on calculations. $\endgroup$ – Avenue2Aviator Nov 13 '18 at 7:09
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I got the answer from cessna company, as below.

The pitch/power table you have provided is not a product of Textron Aviation and has been developed outside of our flight testing and engineering. We have no formula available for calculating required pitch attitudes, The table shown appears to be developed by a flight school based on actual flight test observations.

In general terms, pitch relates to angle of attack. Angle of attack required for certain climb and descent rates are dependent on variables such as gross weight, C.G. location and indicated airspeed. In relation to the quote “pitch + power = performance”, a more accurate approach for developing a quick reference chart assuming the aircraft gross weight and C.G. remains constant is to match indicated airspeed with power settings. Pitch + power can approximate an airspeed, but more accurately power + airspeed = pitch. Flying an aircraft “by the numbers” relies on power settings and airspeeds, which consequently will produce a certain pitch attitude. Conversely, to facilitate a desired climb or descent rate we set power and approximate a pitch attitude to arrive at the desired airspeed.

The interrelation between pitch and airspeed is for the most part interchangeable, but most accurate is thinking of pitch attitude being a consequential product of power and airspeed in the context of normal flight maneuvers.

Well, nothing new here. But I found that there are no exact formula to deal with power and pitch table. I'll try to collect actual data.

Thank you guys.

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When you are flying you will be looking at airspeed. Pitch, throttle setting (and trim) will depend on this and whether you are climbing, descending, or in level flight. Data can be gained from experience, or one can go on a flight dedicated to gathering this information all at once. Fill in the blanks one at a time!

A chart such as this could be a useful part of the POH in the event of an emergency, such a malfunction of the airspeed indicator.

A scenario pointed out in comments would be a pitot tube icing event. Rpm settings for pitch would be useful for maintaining straight and level flight, giving valuable time for problem solving. Possible solutions mentioned were use of GPS to get ground speed, then land into the wind so airspeed at least is as much or more than ground speed. Also on the list would be to ask ground radar for your speed and fly a straight in landing pattern factoring in the wind.

But under normal conditions, your eyes belong either out the window or on your instruments.

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    $\begingroup$ I disagree. The knowledge contained in table is important e.g. as a tool to cross check airspeed indicator. Pilots should have at the very least a rough feel for which pitch & power combinations are normal, preferably even by flight phase, and which are not. In the absence of aerodynamic and propulsive calculation model, I would probably try to fly the aircraft, trim meticulously and take notes in various flight phases, maybe from a couple of different flights, in order to build the table from real aircraft data. Cross validate with a sister ship, if possible at all. $\endgroup$ – Cpt Reynolds Nov 11 '18 at 12:24
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    $\begingroup$ Yes sir, anything that helps familiarize one with the operation of any machine is helpful. I just did not think it was practical to be reading such things while flying. I would be more on full throttle and Vy on climb out, controlling speed with elevator. And flying with a good instructor helps too! $\endgroup$ – Robert DiGiovanni Nov 11 '18 at 12:29
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    $\begingroup$ BTW, trimming meticulously and taking notes (as a retired researcher) would certainly impress me, particularly in the testing and development stages. This data would be useful in writing the POH. $\endgroup$ – Robert DiGiovanni Nov 11 '18 at 12:53
  • $\begingroup$ Agreed. This should probably be memory item rather than having to rummage through the POH for it while trying to not lose control with the other hand while encountering pitot icing in IMC. $\endgroup$ – Cpt Reynolds Nov 11 '18 at 12:56
  • $\begingroup$ That is a great point, as reliability of airspeed indicators is critical. These days, I wonder if GPS can tell? Kudos to those who must fly in all weather. $\endgroup$ – Robert DiGiovanni Nov 11 '18 at 13:02

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