"...Is/would a supercharger be more compatible? Or is it pretty much the same thing?
A turbocharger and supercharger are pretty much the same thing. The proper name for a turbocharger is a turbosupercharger. The primary difference is that a supercharger is (in most aircraft installations) gear driven and a turbosupercharger is exhaust driven. For simplicity, it's pretty hard to beat a turbo.
"...Other than speed, the only advantage I could see for having a turbo is the family has property in the mountains of Colorado, and there is an airport there at nearly 9'000' ASL..."
As I wrote in my earlier post, there are basically two reasons (well, maybe three) where a turbo is economically justified. "The real question is do you need the turbo? Is the airplane operated out of high density altitude airports or do you really need the high altitude capability that the turbo provides?"
Those are the big two reasons, the other reason is power related - some designs, for whatever the reasons, need the power that you can presently only obtain from turbocharged engines or turbines. If the designer / builders elects to go with pistons and the power is needed, well, that's the other time they're justified.
You mentioned speed. That's correct, typically, at altitude they are faster. The reason for that is that turbocharged aircraft are able to maintain a higher percentage of their rated power at higher altitudes. Typically a normally aspirated aircraft engine loses about 2% of its power for every 1,000 feet it is above sea level. Additionally, your true airspeed increased about 2% for every 1,000 feet above sea level as well. That, of course, is a good thing; but with a normally aspirated engine it doesn't take long to run out of power in a climb.
Again, loss of power is the primary culprit. Normally aspirated aircraft lose power with altitude. An aircraft's climb ability is directly proportional to the amount of "excess" power that it has available vs. what is needed to maintain level flight. For example, if a 200 HP
normally aspirated airplane requires 100 HP
to maintain level flight it would (at SL
, ISA day) has 100 "excess" HP
to use for climb. At 10,000' MSL
, the engine might only be able to produce 160 HP
, leaving it with a 60 HP
surplus. This is the reason why turbocharged aircraft perform so well - you are able to maintain SL
power up until you reached the "critical altitude" for your particular installation. In some cases this is as high as 18,000' MSL
. This performance comes at a price - Heat, and heat is the primary culprit for the higher maintenance bills.
(Note: This is also why light twins typically perform so poorly on one engine. Take, as an example, a Twin Comanche with two 160 HP
engines. If that airplane required, say, 150 HP
to maintain level flight it would have 170 "excess" HP
to climb with. If it lost an engine, it would have lost 50% of its available power, but with just 10 "excess" HP
, it may have lost 95% of its ability to climb. Light twins have two engines because they need two engines, not because it's cool!)
One final comment, turbocharged airplanes have a speed advantage at altitude - not necessarily down low. The equipment that give them their power advantage at altitude increases backpressure and adds weight. For most, otherwise comparable aircraft, the point where having turbos really "kick in" is around 10,000 feet. A case in point was the Baron 56TC that I used flew for a mining company 25 years ago. That airplane was a beast, it was basically a flying test bed for the 380 hp engines that Beech installed on the Duke. Originally, the Beech Travelair / Baron airframe was certified with 180 hp engines. The 56TC had 380 hp on each wing! It was the closest thing that you'll ever come to flying a jet with pistons. However, below 8,000 feet the lowly 260 hp B55 Baron would out run it. (At altitude, it was a different beast entirely - I used to be mistaken for King Airs all of the time.) The same thing applies to the Mooney 201 and 231, and just about any other pair of similiar aircraft that I can think of.
Oh well, got to go.