Comment by sidlls | Hacker News Reader

Comment by sidlls | Hacker News Reader

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What's amusing to me is the juxtaposition of this old tech in the engines vs. the sophisticated avionics and surface controls in these aircraft. The Cirrus aircraft I fly have advanced garmin avionics, including terrain maps, airspace maps, ADS-B integrations, GPS navigation, autopilot, etc. Yet there I sit, fiddling with mixture, ensuring alternate/backup inputs are available in case something goes awry, and dealing with dumb non-linear responses in the throttle because the engine is using tech that's literally decades old and hasn't changed (much) in the last 50 years. There's an upside to this, I guess: I have a number of levers (literally) to pull if something is out of whack, and it creates a kind of weird redundancy/safeguard system to manage various failures. On the other hand, because all these things have to work together, it's entirely possible for weird failure modes to occur that cascade/build on each other unrecoverably.

I can't wait to get my hands on the new jet powered plane coming to the club I fly with.

My litmus test is this: in 1960/70/80, it wasn't uncommon for a car to break down in the middle of a road trip, and to hear horror stories of people stuck in the middle of nowhere. Cars were more hackable but they also weren't reliable at all. Nowadays cars just work, for the most part. GA engines should be the same.

My experience is that GA engines also “just work”, particularly if you reference them back to the automobile equivalent of total motive energy produced per mid-trip breakdown.

My airplane makes about 225 horsepower during cruise flight, for 3-4 hours on a typical leg. My car makes 25-30 horsepower in cruise.

Take the airplane engine that has done 1950 hours of weight-off-wheels time so far (including some takeoff/climb, but also some descent), turn that into x8 the auto hours and give an average speed of 40 mph and you get an implied 600K miles worth of total cumulative motive energy produced.

Most cars will need significant maintenance on the road to 600K miles or on their way to 2000 hours of operation at 75% of rated power (as do airplanes on their way to 2000+ hours of operation, of course).

Airplane engines are quite reliable. As easy to operate as a modern auto? No, but I’m not sure they need to be that easy, since pilot training and certification is quite a bit more rigorous than it is for autos.

The GA engines in the aircraft I've flown (all Cirrus) do "just work". I have had trouble starting one once, but it was already hot and I had to fiddle with the mixture and throttle during and immediately after turnover. I have yet to encounter engine issues in-flight (but I don't have a ton of flying hours, either).

Cars and planes took different paths to reliable engines. Cars made new, better, reliable engines. Planes took the old engines and made them super reliable. The plane approach does require a lot more maintenance and certification.

Also, planes use engines differently. They basically run flat out for hours, while cars only use peak power when accelerating.

>Also, planes use engines differently. They basically run flat out for hours, while cars only use peak power when accelerating.

This is often said but isn't really all that true if you dig in. Most planes have a cruise power setting that is below that used for takeoff, often 65-80%. Further, engine are often de-rated so that max throttle means something like 80% of the engine's max horsepower. Those two factors along with variable pitch props on some planes which act like gears, mean that even planes often cruise at closer to 60% rated engine horse-power rather than 100%.

Which is still quite different from a car that may be cruising on the highway at 20-25 horsepower which is often under 10% of rated power.

Diesel engines in boats and gensets run at 80% load continuously, and are most happy there. Diamond makes nice planes, I wish there were more like it.

What flying club are you in that’s getting a jet? That’s something that I’d never expected to see (mostly from an insurance angle).

Cirrus is producing a new single-engine jet aircraft. Looks pretty slick!

There are two SF50s based on my home field. I’ve talked with all three owners (one is sole owned and one in a two-person partnership) and all are thrilled with their choice. One had upgraded from two different Eclipses and the other from a 340 then a C90.

Price is about 3 million dollars, new.

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