Cessna 182 Checkout
For the past 13 years that I’ve had my private pilot licence, I’ve flown relatively basic airplanes; Cessna 150, 152, 172 and Piper Warriors. They were all made in large numbers and all have characteristics that make them good trainers; low stall speed, very stable in a stall, good flight envelope, low fuel burn and fixed-pitch propellors. That means that you’ll find these airplanes at almost all flying schools or clubs you go to, though that’s starting to change as Diamond Star and others make low-end planes with similar characteristics.
But the problem with all these planes is that they’re slow and have a small useful load. So, because of that, and because I want to expand my horizons, I started getting checked out in the Calgary Flying Club’s Cessna 182. The Club’s 182 has a 230HP Continental engine connected to a variable-pitch contant speed propellor. For me, given how much I’ve flown and flown recently, that means two flights; one to do upper air work and one to do circuits.
Since today we did the upper air work, I did all the flying, with my instructor Jason simply explaining any subtleties briefing before I did stalls, steep turns, slow flight and foced approaches. The plane is absolutely amazing. The engine has a distinctive sound that almost purrs. The extra horsepower and fine pitch on takeoff gets the aircraft moving rapidly such that you are almost pushed back in your seat. And unlike the Warrior, the 182 wants to climb from the airport height of 3937 feet, even in the heat of a mid-summer day. Overall the upper air performance of the 182 is similar to that of the 182 except that everything happens faster. The one exception worth noting is that in slow flight the 182 appears to just “hang” suspended in place in the air; it’s amazing.
The constant speed propellor wasn’t nearly as complex as I had expected. The problem with reading about variable pitch propellors, either in books or on the web, is that everyone starts talking about how it works without explaining how it works for normal people. Aviatrix has a good explanation on her blog, employing some good analogies. One thing that I never really understood (I am a programmer afterall not a mechanic) is the relationship between horsepower and speed. I just assumed that more horsepower meant more speed. So if you changed the Warrior’s 160HP engine to 230HP that it would go that much faster. Then, while doing some research I came across an article that stated the (now blatently) obvious: two engines turning the same pitch propellor at the same RPM will produce the exact same thrust, even if one engine has 160HP and the other 230HP. That’s where variable pitch comes in; in a nutshell a variable pitch propeller lets the engine make use of that extra horsepower. I’ll have to search around for the article again because it’s worth a read for anyone who just didn’t understand.
Update: I found an article titled Engines & Propellors which does a pretty good job of explaining about variable pitch propellors and why a pilot would desire a constant speed propellor, which is a special type of variable pitch propellor.
Mon, 04 Jul 2005 14:04 Posted in Flying
