Why are there so few small pressurised aircraft?

I knew a guy who had a few years with a Cessna 421C which had a similar capability – as would any pressurised plane with a turbo. He spent hundreds of k doing it up. He got out of flying years ago – as have most pilots in that “class” who I knew 10+ years ago.

lionel wrote:

This Extra 400 situation shows there is demand for a “small” pressurised plane. There is so little choice…

Very much agree.

This is true. But I feel the concept of the piston pressurized plane is simply wrong. The thin air is not a very good match for such an engine because of engine cooling, ignition and in general an operational profile which is very unforgiving regarding failures. So what we probably need is a smaller affordable generation of turbines and then fit those into a 4 seater airframe. Currently the closest ist probably the Evolution but as we know not certified and maybe the engine should still be a bit smaller.

Sebastian_G wrote:

Evolution but as we know not certified and maybe the engine should still be a bit smaller.

Allison Model 250?

Flyingfish wrote:

For this, we need a RR/Allison 250 on steroids AND a reasonable price – I heard that they cost 800 K (!)

Years ago I did some research regarding the repair of a damaged Silver Eagle. As is written above the prices for this quite small engine are just crazy. I also did similar research on the much bigger PT6 on another occasion and that seemed cheap in comparison.

There is quite some development work for “small turbine for aviation”, but the years pass and they never exactly come out certificated and installed in certified planes. I think I remember a Czech manufacturer, but cannot remember their name, and then now I find an Australian one and I remember a French one that Robin was going to put in their planes… and another Czech one (or maybe a renaming / purchase of the one I remember…)

Sebastian_G wrote:

But I feel the concept of the piston pressurized plane is simply wrong. The thin air is not a very good match for such an engine because of engine cooling, ignition and in general an operational profile which is very unforgiving regarding failures

Agree to this. My engine’s also not actually really happy above FL160, for the very reasons. You can either add a lot of fuel to cool down the engine or throttle back so much that there’s only an advantage if you have a lot of wind that pushes you in the right direction. So I only go up there if it’s for the weather. I get about the same MPG regardless the altitude, but due to the lack of cooling its getting slightly worse above FL160.

lionel wrote:

There is quite some development work for “small turbine for aviation

I’m also monitoring this development, but it takes ages for steps even in microlight or uncertified developments. They show promising results, much more efficient and can burn practically any fuel and mixtures thereof.

Why are there so few small pressurised aircraft?

Costs? To make use of pressurization a lot more has to come into the equation, like de-icing capabilities and engine. So if you go that route you can just make more steps at once and there you have the TBM series.

Search here for the grob 140.

Lots of hopes, for a high quality small turboprop plane, but not pressurised.

Marketing always kills this. By the time Socata were listing a CD player enclosure (just the box) for €4000, you may as well throw in the kitchen sink, and you get a TBM. Great for the dealer ecosystem; no invoice under 5k or so

Sebastian_G wrote:

So what we probably need is a smaller affordable generation of turbines and then fit those into a 4 seater airframe.

I think electric engines could also fill this gap in the future (when batteries are good enough), since they should produce basically the same power regardless of altitude.