So when talking about airliners, we're mostly talking about jet engines, which, by the way, are a subclass of turbines.

And your aircraft type had the limitation, but I would guess most modern airliners would not have 100LL as an available alternative fuel at all. Did the airplane you flew have T56 engines?

[removed]

Think of the dangers that batteries pose in aircraft today. Those with a memory may recall the Dreamliner fleet being grounded due to battery fires. Then think of how dangerous they can be with twice the energy in the same volume.
Batteries are like rocket engines, in that they are a chemical reaction that has its oxidizer built into it. Unlike automobiles, there's generally no convenient way to immediately pull over and get out.

[removed]

[removed]

Turbines can even run on natural gas (peak electrical generation). It all has to do with how the combustor is designed along with the compressor delivering the air and the injectors delivering the fuel.. whatever it is. The efficiency and power you get out of the turbine also is optimized for the fuel its using, so running Avgas in a turbine designed for JetA might not have enough power to get you off the ground or burn too hot to damage the Stage One High Pressure Turbine Blades.

[removed]

[removed]

[removed]

That and lives are on the line. No one wants to be the refiner who sells new, lead free fuel only you have airplanes crash and then be involved in massive lawsuits for wrongful death. Maybe the new fuel causes premature engine wear under some unforeseen circumstances like in cycles of hot and cold weather that were difficult to test for. Or maybe the hypothetical crash had nothing to do with the fuel but the lawyers smell a settlement. Either way there’s a lot more risk when compared to a car where the worst case is you may need to pull off the road. Also most cars are not 50 years old and have engines designed for newer fuel formulations.

[removed]

Totally, like many of them can't even hold their necks up. We're expecting our second in a few months, and I can't even imagine how much easier it would be (lol as a parent, not as a pregnant mother) if the baby was 5 months older when it was born. You'd avoid the first sleep regression - I do wonder if the first sleep regression happening around 4 months means they're "supposed" to have gone through it before they're born.

The evolution of communities and culture may be related to this - since our babies are helpless potatoes, we need help keeping them alive.

Small, light AND SIMPLE. No liquid cooling, no knock sensor, no computer controlled fuel injection, no O2 monitoring or exhaust gas recirculation, no transmission. Often the pilot controls the air/fuel mixture manually watching rpm and exhaust temp. Very primitive, but not a lot can go wrong as long as you don't have detonation which tear up an engine pretty quickly.

[removed]

[removed]

Yeah, they’re definitely still helpless. But anyone who’s been around a newborn can attest to how shockingly fragile and vulnerable they are. At 6-7 months babies can crawl, sleep through the night, have more weight on their bones, etc.

No system is perfect, and it's practically impossible to entirely prevent bad actors from circumnavigating safety precautions. However, researchers are aware that maintaining the double blind nature of the study is necessary to properly evaluate medical outcomes, and we do everything possible to ensure the quality of our research is unadulterated. Think of it this way: why would we want to invalidate years of work?

> The sensory fibers are the outside of the nerve(insulative portion of the cable) and the motor fibers are the inside(copper wire).

Can you cite a source to support this? I can't find one, and I did find a paper where they attempted to image the fibers (https://translational-medicine.biomedcentral.com/articles/10.1186/s12967-021-02871-w). Their images seem to me to show them all mixed together.

[removed]

On a soft surface is not a big deal.

However on a hard surface it can lead to necrosis on muscle tissue due to hypoxia, which then needs to be surgically removed, which causes permanent lose of functions. (This is common on people who pass out on concrete and sleep on their arm, due to alcohol or drugs)

[removed]

[removed]

[removed]

So modern piston aircraft have things like fuel injection. ECUs no. It's mainly because there hasn't been a reason to innovate. Piper and cessna (the two largest general aviation manufacturers) haven't had a reason to innovate. The engine suppliers of which there are 2 main ones, haven't had a reason to innovate on anything. Diamond and cirrus are changing this. Diamond is using modified Mercedes diesel engines so they burn JETA (jet fuel is similar in a lot of ways to diesel fuel) their planes also are FADEC controlled. Meaning they do have an ECU that manages the engine. So no controlling fuel flow with a mixture lever, no adjusting the propeller with a lever. The system handles all of that. Add in that it's very expensive to certify a new engine and with little demand for anything new means manufacturers have been able to roll out the same airframe and construction for 50-60 years.

Long story short. Expensive to not on design and engine plus certify it and all its components for flight with little demand for innovation means companies won't bother.