[pdonis]

> all those regulations must have something to do with how few people die in airplane crashes

Many of them do, but that certainly doesn't mean all of them do.

It's really hard to see how using decades old engine designs with leaded gas is necessary to prevent crashes, or how updating a proven airframe to newer engine designs that have a lot of operating time in cars needs to be an extremely onerous process to avoid crashes.

[ceejayoz]

Cars and planes have significantly different impacts on the engine.

https://www.flyingmag.com/aircraft-do-car-engines-make-good-...

> Car engines are designed to provide quick bursts of relatively high power output for acceleration, and then only modest power output for steady-state cruising. It’s unusual for an auto engine to operate anywhere near its redline rpm or max-rated power output. Airplanes, on the other hand, usually take off and climb near 100 percent power output, followed by steady-state cruise often at 75 percent power. Aircraft engines are designed to sustain this punishment reliably over a typical 2,000-hour service life. Try running your car’s engine at or near redline rpm all the time and see what happens. Of course, we don’t know what will happen, and in an airplane we can’t pull over to the side of the road when it does.

[cduzz]

The story suggests they used a marine engine, which in turn is an automotive engine modified to run under marine conditions, which among other things includes "run at full load for hours" or "run at partial load for hours".

Typically, of course, you're not seeing a lot of elevation changes in a marine application, but with modern fuel injection that's probably not such a big deal.

[dsfyu404ed]

So de-rate and conservatively tune the engine to a peak HP that can be sustained indefinitely. This is SOP when putting automotive engines in industrial uses. Just because you don't know of it doesn't mean it's not dirt common and well practiced in industry.

2000hr equates to, generously, like really generously, a 150-200k service life. It really drives me up the wall to see you acting like this is a big number when in any other context you'd be happy to pop in and tell us about how your you're so smart because you bought a Toyota and it's guaranteed to make it that far.

[ceejayoz]

> So de-rate and conservatively tune the engine to a peak HP that can be sustained indefinitely. This is SOP when putting automotive engines in industrial uses.

Those industrial uses don't crash into a random person's house if they fail, and "conservatively tune" means you've changed the engine's behavior. The FAA likes you to demonstrate safety when you change safety-critical things.

> 2000hr equates to, generously, a 150-200k service life.

At a much higher cruising RPM, which is the entire point of the article.

[xyzzyz]

> Those industrial uses don't crash into a random person's house if they fail,

It is highly unlikely to crash into a random person’s home due to engine failure. Planes don’t drop out of the sky like stones when their engines fail. You can still fly them and pick a spot to attempt emergency landing or controlled crash.

For comparison, cars crash into people’s homes all the time, but i don’t believe it is ever a result of car engine failure. No reason to expect plane engine failures to cause these.

[p_l]

Considerable amount of plane crashes, including deadly ones, involve engine failure - often due to things that aren't present at all in automotive (or marine or industrial) use.

[xyzzyz]

Sure, but this doesn’t mean that private pilots need or want FAA to “helpfully” force them to use older tech.

The argument I responded to was about negative externalities of potentially less safe new levels plane engines for third parties. I claim that these are negligible, because the risk of the worse engines is entirely internalized among the plane occupants: with less safe engines, more people will die, but these will almost certainly be plane occupants, not third parties. Third parties do die in plane crashes sometimes, but this is either caused by pilot error, or technical failure causing the plane to be uncontrollable, not failure of the engine. On piston GA planes, control is entirely independent of the engine.

[Sebb767]

> At a much higher cruising RPM, which is the entire point of the article.

Looking at their demo videos, they seem to be running the engine at something like 3000 RPM, which is not that far from cruising RPM on a car.

[aeternum]

This is often achieve by simply derating the engine. You redefine redline to be 75% of what the engine was designed to produce. Then your takeoff becomes 75% power and cruise is more like 56%.

[bischofs]

the 24 hours of Le Mans, and tens of thousands of runabout marine applications with automotive engines disagree with you. The real question is would you prefer a 1950s Lycoming engine with a mechanical fueling system, or a modern car engine that has been proven in millions of vehicles?

[ceejayoz]

https://en.wikipedia.org/wiki/24_Hours_of_Le_Mans says "Racing teams must balance the demands of speed with the cars' ability to run for 24 hours without mechanical failure", which implies a slightly shorter lifespan than you'd want in a plane.

[aredox]

As if running an engine for 24 hours was good enough for a plane!

And le Mans is not an oval track: engines don't run at 100% all the time.

And how many le Mans cars break down during the race?

[voldacar]

Hence why they used a marine engine.

[moremetadata]

Its a little more complex than that. Vehicles (cars, trucks) can rely on the engine power being transferred to a high friction surface (the road) with help from gravity with immediate effect. Where as boats and aircraft are transferring engine power to a low friction medium (air and water) where gravity is important for aircraft otherwise you die when you hit the ground unless you can auto rotate in a helicopter or glide in a plane, but where gravity is not so important in the scheme of things, if those extreme risk situations are catered for.

I bet they could have got the costs down more if they had used a Toroidal Propeller.

Here (already cued for you) https://youtu.be/s_J1OYcCPms?t=23 the footage shows less vortices generated with the Toroidal propeller seen in the top half of the frame of the two boat propeller underwater.

Its these vortices in water which generate cavitation on a traditional style propeller, which leave little pits on the surface of the propeller eventually leading to its replacement as its surface contributes to more friction and thus less fuel economy.

If the friction from the pitted surface is ignored, then it can lead to parts of a blade becoming more like swiss cheese with holes that results in parts of the blade breaking off.

Wind Turbines could generate more electricity if they used toroidal blades, but currently the engineering skill does not exists to scale these blades up in size, and have the ability to "detune" a blade in gale force/storm force winds to minimise damage to the generators and the unit itself.

However the use of these wind turbines also means, the state have a stealth population control mechanism as these wind turbine blades can also be altered to generate plenty of infrasound which can be used to make large parts of the population in the vicinity feel anxious, something that's documented in the Disney sound engineering labs in the 40's/50's when the sound engineers inadvertently made themselves all feel very ill for a few days. Ergo you will probably see less people striking in future!

[stenius]

I personally don't know what will happen, but I figure that type of test is easy to do in a lab environment.

[ceejayoz]

Easy, but quite expensive to have a meaningful sample size.

[aeternum]

The problem is that regulations are often a knee-jerk reaction without consideration to the second order effects.

When a crash happens, add a rule to prevent it from happening again.

Eventually however you have so many onerous rules that it becomes incredibly expensive to design a new aircraft engine and thus are suck with decades old tech that lacks modern innovation and safety features.

It's very rare to do a pass over regulations to try to simplify them. From a regulatory POV, there is little glory in that and lots of risk.

[xyzzyz]

Exactly. This is similar to medical context, where it is found that decreasing regulations typically improves safety, both because it is easier to innovate and bring better products to market, but also because it increases liability of manufacturers: in a highly regulated market, they can say “sure, our device have caused you harm, but it operated exactly as FDA (or FAA) required, so take it up with them”.

See https://marginalrevolution.com/marginalrevolution/2022/11/fd... for example.

FAA overall has done a lot of good for the safety of the flyers (and I respect it much more than other regulatory agencies tasked with protecting us). The problem is that very often there is a trade off between safety and other things, and regulatory framework prohibits the people it is meant to serve from deciding on their own where exactly they want to be in terms of this trade off. For example, if motorcycles were invented today, they would almost certainly be banned as way too unsafe to operate. That would suck, because I love riding motorcycles.

[ryandrake]

Almost all of the innovation that's going on in light, piston airplanes today is happening in the experimental category. I've got newer, better, and safer avionics, sensors, lighting, and engine systems in the E/A-B category airplane I built in my garage than I would on a 1970's Cessna. The richness of inputs I have in the cabin, including a big moving map GPS, ADS-B traffic, satellite weather, carbon monoxide detection, a vast array of engine monitoring signals, AOA, and so on provide so much more in terms of safety and situational awareness. Pilots in the USA are truly lucky that we have this option.

[gocartStatue]

Ha! Classic Theory of Constraints: most constraints come from rules that used to accomodate for some limitations. Most of those limitations are long gone, but we’ve come to not question the rules; we mistake them with reality.