Cessna 172 Performance Analysis Part 1 - Climb Rate

So after reading so much conflicting information about the performance of the 172 from people with a variety of backgrounds, I decided the best thing to do was compare it straight to the source. I started with climb performance as it was the quickest one to come up with a repeatable scenario. I do intended on doing other areas as time permits.

Testing Method:

Configured the aircraft for 2550lbs and take off from CYTZ RWY 26. Set FD for Alt hold for 300’ MSL and HDG hold 262 degrees. After establishing trimmed flight at 300’ and 74KIAS, set altitude target for 15,000’, engaged FLC and applied full throttle. At 3000’ lean for max RPM and repeat every 1000’ thereafter. All values taken from SimVarWatcher.

I considered anything within a 5% margin of error to be a reasonable variance.

Overall the results fell somewhat where I expected, above 0C and below 5000’ Pressure Altitude the plane behaves more or less as expected. But once you go outside those parameters, things start to go off the rails so to speak. I’m no expert in FDE editing/creation so I can’t give a lot of insight into why this happens, but I thought being able to see it like this may help with some of these discussions.

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I have to say, I have never ever flown an aircraft in real life which hit the POH benchmarks. Especially climb performance wise :sweat_smile:.

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True, but in my experience normally the real thing fell short of the book numbers, not significantly above. I suppose maybe a 5% variance is a bit on the harsh side.

Falling short of the POH data indeed, ok thats an interesting find :sweat_smile:.

I am not sure that percentage deviation would be the right choice to measure this. It worth noting that a variance of 100 fpm can be explained by any number of variables. When we get to 10000 ft, to be within that 100 or so range is to be expected.

The big variance at the lower temperatures would suggest this is not a 172 thing but more likely the way the sim is calculating density altitude or maybe even the lapse rate in the sim.

I commend the test and other than the presentation of the data as a % margin, it is a valuable test. I would suggest that if at all possible this should be repeated with other aircraft to see if the variance based on temp is consistent with being a sim variance rather than an aircraft variance.

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