Wow ! 32 C, 40 felt! That means it will be hot and humid. Do you know the impact of this kind of temperature on the performance of your device? If not, you should !
It is easy to imagine the pilot who flies his Cessna 172 every weekend, normally alone, in typical summer conditions and decides to take his two brothers-in-law and his sister for a ride; just a little ride around the airport. If this pilot does not take the time to do small calculations, he may be surprised. And it won't be a good surprise!
The performance of your aircraft depends not only on the engine, but also, and above all, on the altitude of the airport, temperature and humidity. If these parameters increase, the lift, the rate of climb as well as the power of your engine will be less. The only thing that increases… is your stall speed. So in hot and humid weather you lose out on everything.
What does density altitude mean to you? This is the pressure altitude corrected for temperature. Take for example, a Cessna 172R in Thedford Mines (elevation 1408 feet), a pressure of 29.75 ”Hg and a temperature of 32 °C, the density altitude will be 3,842 feet. So this plane will behave as if it is at 3,842 feet. The take-off distance will be approximately 1,550 feet instead of 1,100 feet if the temperature was 20 °C and the distance to clear a 50-foot obstacle will be nearly 2,600 feet rather than approximately 2,850 feet. The Thedford Mines runway is 4,500 and there will be no problem to take off, but in the event of an engine failure, there won't be much room to spare. On a shorter runway under the same conditions with a 100-foot obstacle to overcome, it might not work.
So take the time to think about how your plane will behave before pushing the throttle.
Here is a link to a video which shows a situation where the pilot narrowly escaped such a situation.
https://youtu.be/ZmEVwyMRYIY
It is with sadness that we learned of the recent death of Roland Brassard. Several of our readers will have known Roland personally or for others by his benevolent and reassuring voice on the HF frequency 5.275 MHz - XKV918.
