Mentally disturbed? I think not. I've met Sophie Wilson who is about the most level-headed person I have met. If you don't know who she is, she designed the ARM instruction set (and still is in processor design today), recognised as one of the best instruction set architectures around. But she was born as Roger Wilson.

If you're really that spiteful towards intelligent people who have contributed more to society in a week than you probably have in your entire lifetime, then go do without anything with an ARM CPU inside of it.

Transgender haters should also stop using their phones and other mobile devices. Sophie Wilson, designer of the ARM instruction set (and still a CPU designer today, working on processors for carrier grade communication equipment) is transgender.

The problem is people think it's a "choice", when gender dysphoria is actually a recognised clinical condition (and many people with it suffer in silence and end up committing suicide). The alternative to suffering in silence is to go ahead with gender reassignment which gains you huge numbers of haters. Frankly I'm surprised at the attitude of some slashdotters to this, virtually all my friends in nerdy/geeky circles are very tolerant and treat LGBT people with respect (in particular, the couple of transgendered people I know have been accepted as their new gender rather than people screaming "If you were born a man then you're still a man" like a lot of people in this conversation).

I know one or two very "boyish" looking women. Should they have to be classified as a man on (say) the drivers license database because if they happen to be (for example) wearing overalls they might be mistaken for a young man?

Malthus will eventually be right. Growth (population, economics, any growth) cannot continue infinitely. At some point there is a certain amount of people and a certain amount of energy use that the Earth can sustain. The current population is not sustainable with current technology because we require depleting, non renewable resources to keep everyone going. It's probable that the current population can be sustained renewably, but even so, eventually there is an upper bound on what the earth can sustainably support. Indeed, there is an upper bound on what the entire solar system can support (which is very, very large) but we have to get to the point where we have the technology to do that BEFORE we exceed what the earth can support.

Learn how to make electronic devices. It's never been easier to get started with this stuff than today. Start out with a breadboard, some transistors/resistors/capacitors/common IC types like the venerable 555, work with AVR or PIC microcontrollers, and perhaps work up to designing digital circuits in CPLD and FPGAs. You can even get four layer PCBs made in a factory for your projects in small runs.

Aircraft engines don't need the lead to protect the valves. Aircraft engines aren't the cast iron lumps used by Detroit, they've always been aluminium with valve seat inserts. Many very very old aviation engines are being run today, right now, on normal unleaded mogas (well, mogas with no ethanol). In the context of aviation, lead is purely there as an octane booster. For the aircraft engines that don't need the high octane, the lead is actually harmful to the engine (from nuisances such as spark plug fouling to deposit build ups on valve stems and guides, causing valves to stick which is not fun) and unleaded avgas can't come too soon. The problem is certification - it's not enough the engine is approved to run on 91UL avgas, the engine+airframe combination has to be approved for each subtype - for instance, for a Cessna 172, there are about 20 odd different models for just one aircraft and each will need approval which is a slow and expensive process.

Many aircraft have STC (supplimentary type certificates) - which in many cases is merely a paperwork exercise - to run on unleaded (but ethanol-free) mogas.

That said, this move would permanently ground the WW2 display fleet that is currently flyable and a bunch of old Piper Cubs and Ercoupes.

It won't ground Cubs and Ercoupes, most of them will already run happily on mogas and actually do so (so long as it's ethanol-free. unleaded mogas sold at an airport is ethanol free but not many airports sell it). The engines in Ercoupes and Cubs are low power, low compression and just don't need the lead - in fact the lead is actually harmful to them (spark plug fouling, lead deposits etc).

Unleaded fuel won't harm most aviation engines, even ones designed before WW2. Aircraft engines have been aluminium since well before the war, and have always had hardened valve seats. Unlike car engines where the idea is "make it cheap, doesn't matter if it's heavy", aircraft engines have to be both durable and light and this has always been a requirement, so aircraft engines have been all aluminium for as long as living memory. Valve seats is not the reason that lead is in avgas, that's an old wives tale. The TEL is in there purely as an antiknock agent, nothing more and nothing less. The vast majority of aircraft piston engines will run happily all the way to rated TBO (time before overhaul) and long beyond on unleaded fuel, and many are already approved to run on 91UL (91 octane unleaded) avgas at least in Europe. It's the large (and more modern) turbosupercharged aviation engines that have a problem with unleaded fuel, and the problem is detonation.

It's not necessarily the high octane. If the vehicle wasn't driven much, then normal automotive fuel tends to "go off" and varnish up the carburettor, fuel lines, fuel tank etc. Avgas on the other hand stores a lot better since the usage pattern of many aircraft that run on avgas is to perhaps be flown once or twice a month and maybe not at all during the winter. You can keep avgas for an extended period of time without it "going off". For an old, occasional use vehicle then it may just run a lot better on avgas because basically while it's parked up the fuel system doesn't get varnished.

That's an old wives tale. Read this: http:/// www.avweb.com/news/pelican/182149-1.html

Aviation engines don't need the lead for valves and seats - that's an old wives tale. All the lead is for is to increase knock margins, nothing more nothing less. Virtually all of the engines fitted to the fleet will make their rated lifetime on the new 91UL unleaded avgas. The problem engines are really the larger turbosupercharged engines fitted to larger piston powered aircraft.

The majority of the general aviation piston fleet could all run on unleaded fuel tomorrow if:

- a: it was available
- b: the regulator allowed it

Over here in Europe 91UL (unleaded avgas) is now available and has been for a couple of years, but the process to approve every airframe+engine combination (it's not enough that a Lycoming O-320-B2B is approved, the combination of Lycoming O-320-B2B and every single type of aircraft it is fitted to must be approved, except in the case of Permit-to-Fly aircraft (i.e. antiques and homebuilts) where just the engine needs to be approved. Unleaded avgas can't come soon enough, leaded avgas is actually BAD for most of the fleet, it causes spark plug fouling and other unwanted effects (as well as being very toxic). Unfortunately 91UL isn't very widespread yet, I've yet to see it for sale anywhere despite the list of engines and airframes approved to use it getting longer each month.

Nope, turboprops are less efficient than piston engines (especially the small turbines, which are very inefficient especially at low altitude). They are just much lighter and much simpler and MUCH more reliable (but a lot more expensive to overhaul). For instance, compare one of those huge "corncob" radial engines with a turboprop that produces the same shaft horsepower in terms of complexity and reliability - horrific compared to a turbine. But the old 1940s radial will have a better brake specific fuel consumption by quite a margin compared to a turbine of the same power.

Aviation engines (with the exception of the turbosupercharged ones) just are not high compression at all. We have an O-320-B2B in ours (which is a "high compression" engine according to Lycoming). They aren't high compression by modern standards at all, ours is something like 8.5:1. However, a BMW K1200S motorcycle has a compression ratio of 13:1 and runs on unleaded fuel you buy at an ordinary gas station. Indeed, the workhorses of the GA fleet (normally aspirated 4 and 6 cylinder Lycontisaurus engines) will all run fine on the new 91UL that's becoming available here, but each engine/airframe combination (or just engine, in the case of antiques and homebuilts) must be tested and approved before you can use it. Lycoming about a month ago approved our version of the O-320, and it couldn't have come soon enough as leaded fuel gives us spark plug fouling problems if we have extended ground runs.

Diseconomies of scale and extreme certification requirements. Very few are made. The fixed costs of car engines can be spread over millions of units, but the fixed cost of aviation engines only over a few hundred to low thousands per model.

In aircraft engines, the lead is only an octane booster. It's not there to lubricate the valve seats. The thing about valve seats is a myth, at least in the case of aviation engines. Certainly the workhorse engines of most the GA fleet (4 and 6 cylinder normally aspirated opposed piston engines) don't need the lead at all, not even as an octane booster. Since I have a Lycoming engine, I've been following it, and they've been steadily adding more engine types to the list approved to run on the new 91UL unleaded avgas (our engine, an O-320-B2B was approved many many years ago to run on a 91 unleaded used by some militaries, but they only just approved it for the new 91UL standard). The O-320 series has been around for decades.

See: http://www.avweb.com/news/pelican/182149-1.html - on some of the old wives' tales about lead.