I've passed next to an Autobahn segment in construction, and it looks nothing like road construction in the U.S. The construction is a multi-stage, 24/7 operated front, moving at a fixed speed. The machine that lays down the road is pretty much a continuous operation reinforced concrete layer, with GPS-referenced tooling. With a effing huge spools of rebar fed into it. You have prepared roadbed on the front, and a concrete runway out back. That's what I made of it, anyway. Highway construction in the U.S. looks, unfortunately, like something from a 50 year old dusty Encyclopaedia.
The main problem is that you have already assumed that we somehow need to be other people's nannies. Accident != accident. If someone kills/wounds only themselves due to speeding, who cares. The law should allow their health insurance to go through the roof, just like auto insurance would, though.
What everyone is talking about is E=0.5*m*v^2. When you hit something, the energy to be dissipated goes up as square of the velocity. Increasing your speed to 90mph from 60mph more than doubles your kinetic energy. Unfortunately, when crumpled fast enough, typical structures dissipate energy while providing some force that's only a function of displacement. IOW, your car may well be too short to protect anyone inside when hitting a wall at 90mph, but at 60mph your kid in the backseat could perhaps just be an orphan. I'm not the one to say which is better; the "speed kills" screamers have already made the decision for everyone else.
Unless you can cope with the weight of a thermoelectric pile, the only other way of generating electricity is by running a thermal engine of some sort. And those are notoriously inefficient. Add to that inefficiencies in power conversion and transmitter system (no matter what the wavelength), and you'll never be able to get rid of more than perhaps 25% of the heat.
That's nowhere near good enough to warrant all the trouble in the first place. If reduce the amount of heat to radiate using passive radiators is merely 25%, you may as well go all the way and radiate all 100% of it.
So yes, thermodynamics says that if you have no cold plate, the passive radiator is all you get to dissipate heat in a system with no mass flow (materially isolated, but not thermally isolated).
Thermodynamics fail. Energy conversion isn't just a concept, there are natural limits as to what you can do. Running a laser as a way of dumping heat is just a surefire way of having to dump a good 80-90% of said heat as, well, waste heat.
As for electronic device operation: don't worry. They are designed for automotive temperature range. I own a plain old Jane ICE car, and the radio, the ECU, and everything else, works just fine in -20C as well as in +100C (the latter is how hot some power devices get after a heat soak).
The electronic modules are inefficient enough that they will heat up plenty fast enough. Batteries heat up while you charge the car, so that shouldn't be much of a problem either. Motor heating: LOL. The drivetrain's efficiency is pretty low in sub-freezing temperatures since all the oils/greases are thick, so it'll heat itself up just fine. Brushless motors are no more than say 98% efficient, so that's a nice couple-hunded-watt heater right there. Of course the brushless motors really like being cold, since the winding resistance is lowest then, so you'd wish they stayed cold.
I think that the the headphone cable would be a good enough approximation for an AM and FM antenna. Car radios don't have a ferrite bar antenna and they work just fine picking AM off the whip antenna.
The inertial reference + GPS augmentation is there for a reason. Even in VFR, it's good airmanship to periodically verify that the artificial horizon matches up with real horizon. If you're over water or desert, then even in VFR I'd tend to trust artificial horizon first.
If you lost air data, then in cruise you can periodically do a full turn, and use the ground track to estimate wind vector (speed+direction), and your true airspeed. Of course things get trickier when you're trying to land. Even then if you get mean wind speed and direction from local weather report, you can figure out an offset to ground track speed to get back airspeed. Ideally you'd chose an airfield where you can do a long straight-in approach to a looong runway. Then you err on coming in fast, and hope there's enough runway to stop;)
Pitot ice is not an issue in cruise, as long as you recognize it as such. You look up a table or a nomogram in the aircraft manual, where the inputs are loading, altitude and maybe temperature, and the output is a throttle setting. Unless the aircraft is structurally damaged or iced, you'll fly within 10-20 knots of what you want. Heck, there is a first-hand account somewhere of doing just that by a pilot who flew same equipment, and lost air data. Of course if you get confused and try funky things, you're in for a world of hurt.
1. The pilots must be trained how to specifically deal with taking over a system with unknown state.
2. Since #1 is prone to all sorts of problems, it's better to avoid. Thus pilots must be trained to oversee and keep current their mental image of the aircraft's status.
3. Since #2 breaks down, #1 is still important.
IIRC, in AF447 there were strong indications that the air data system was failing. A known problem. I think that weather only added to the airframe stresses, but primarily the pilots overstressed it.
Methinks that pilots need to be routinely reviewing airworthiness directives and similar documents, even foreign ones if they understand the language. Yes, I know, the poor chaps and gals barely have time enough to rest... At least that would give them a chance of thinking "hey, what if that's this problem".
In high stress situations, you don't have much in the leeway to think of unlikely scenarios like total failure of air data. Yet total air data system failures routinely seem to kill people:(
I agree that everything with safety implications should be subject of scrutiny. It's just that human factors are very widely misunderstood. You have mechanics who can inspect any flying hardware, but good luck finding a "mechanic" who can examine a pilot to determine if he/she is fit for flying that day.
Please don't twist my words. I don't claim there are no non-human-factor caused crashes, I just claim that a vast majority is human factors, and mostly cockpit human factors at that.
AF447 is, to the best of my knowledge, a case of the pilots getting confused by a single point of failure in the air data instrumentation. If you look around, you will find posts by pilots who faced similar issues, had similar ACARS messages sent out, and they recovered without problems as long as they followed procedures. Surely it did fall apart in the sky, but it didn't "just" fall apart, at least there is no reason to think this way so far. To me, that's not unlike China Air 006 but with a different ending.
USAIR 1549, the famous Hudson water landing -- well duh, it was not a human nor a mechanical problem. Force majeure. One example of it, so what.
Emirates 407 -- well thank you, because that was a classic case of human error. Funny coincidence of you mentioning it -- just see yesterday's TDWTF story about Command 696.;)
I agree wholeheartedly. But still the human usually fails -- not always the pilot. Of course you need to draw a line somewhere, lest you classify, say structural engineering failures as human errors too. When we reduce controlled flights into terrain (CFITs) by an order of magnitude or two, then I can come back to revise my skewed worldview;)
I didn't say anything about how the RAT works. I only said that as long as (some of) your hydraulic systems are operable, and you have RAT, you can fly a fly-by-wire plane. So we agree here.
I never said that RAT provides academic benefits. I merely said that the GP's claim about all subsystems being out is pretty much made up. Theoretically possible, but didn't happen just yet.
When engines, generators, hydraulics and pneumatics (are there any?) have failed on a fly-by-wire plane, there's no point in recording anything anymore. Well, there is a point if you want to see how a plane behaves with unactuated control surfaces, but that's of academic interest and beside the point of determining why it crashed. Because crash it will.
Loss of engine power does not imply that a fly-by-wire plane is unflyable. As long as you have hydraulics and ram-air turbine, you can still fly it. Won't do much in the way of aerobatics, but you can, say, land it in a river. I don't think that there was any incident with a fly-by-wire plane where, without significant loss of structure (think engines falling off), the engines were out and the hydraulic/ram-air system was out as well.
Umm, no. You're almost a century out of touch with reality. What you say was true in 1930s.
Today, when an airplane crashes, the human has failed. Pretty much always. Technical issues that lead to crashes are very, very rare. If you were to place monetary bets, a winning strategy is to bet for human failure.
As long as the hardware would be FCC certified, and they could obtain base station licensing, that is. I figure that's another $100k per year amortized over 10 years. If you're lucky. Or am I off base here?
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I agree. As for ice, the speed limit then is useless anyway, since a 35mph road covered in ice may be barely useable at 12mph. BTDT.
I've passed next to an Autobahn segment in construction, and it looks nothing like road construction in the U.S. The construction is a multi-stage, 24/7 operated front, moving at a fixed speed. The machine that lays down the road is pretty much a continuous operation reinforced concrete layer, with GPS-referenced tooling. With a effing huge spools of rebar fed into it. You have prepared roadbed on the front, and a concrete runway out back. That's what I made of it, anyway. Highway construction in the U.S. looks, unfortunately, like something from a 50 year old dusty Encyclopaedia.
On a Volvo S80 2.9, the sweet spot seems to be 50mph. 600+ miles on one tank IIRC.
The main problem is that you have already assumed that we somehow need to be other people's nannies. Accident != accident. If someone kills/wounds only themselves due to speeding, who cares. The law should allow their health insurance to go through the roof, just like auto insurance would, though.
What everyone is talking about is E=0.5*m*v^2. When you hit something, the energy to be dissipated goes up as square of the velocity. Increasing your speed to 90mph from 60mph more than doubles your kinetic energy. Unfortunately, when crumpled fast enough, typical structures dissipate energy while providing some force that's only a function of displacement. IOW, your car may well be too short to protect anyone inside when hitting a wall at 90mph, but at 60mph your kid in the backseat could perhaps just be an orphan. I'm not the one to say which is better; the "speed kills" screamers have already made the decision for everyone else.
Unless you can cope with the weight of a thermoelectric pile, the only other way of generating electricity is by running a thermal engine of some sort. And those are notoriously inefficient. Add to that inefficiencies in power conversion and transmitter system (no matter what the wavelength), and you'll never be able to get rid of more than perhaps 25% of the heat.
That's nowhere near good enough to warrant all the trouble in the first place. If reduce the amount of heat to radiate using passive radiators is merely 25%, you may as well go all the way and radiate all 100% of it.
So yes, thermodynamics says that if you have no cold plate, the passive radiator is all you get to dissipate heat in a system with no mass flow (materially isolated, but not thermally isolated).
Thermodynamics fail. Energy conversion isn't just a concept, there are natural limits as to what you can do. Running a laser as a way of dumping heat is just a surefire way of having to dump a good 80-90% of said heat as, well, waste heat.
Mod parent up. That's the real insight.
As for electronic device operation: don't worry. They are designed for automotive temperature range. I own a plain old Jane ICE car, and the radio, the ECU, and everything else, works just fine in -20C as well as in +100C (the latter is how hot some power devices get after a heat soak).
The electronic modules are inefficient enough that they will heat up plenty fast enough. Batteries heat up while you charge the car, so that shouldn't be much of a problem either. Motor heating: LOL. The drivetrain's efficiency is pretty low in sub-freezing temperatures since all the oils/greases are thick, so it'll heat itself up just fine. Brushless motors are no more than say 98% efficient, so that's a nice couple-hunded-watt heater right there. Of course the brushless motors really like being cold, since the winding resistance is lowest then, so you'd wish they stayed cold.
OK, so somehow it measures the magnetic component only, as that's only what can pass through the shielded case of the radio. Hmm, I didn't know that.
I think that the the headphone cable would be a good enough approximation for an AM and FM antenna. Car radios don't have a ferrite bar antenna and they work just fine picking AM off the whip antenna.
Fsck AM, but does the FM tuner include digital demod for HD radio? Now that would be something. FM radio by itself: meh.
The inertial reference + GPS augmentation is there for a reason. Even in VFR, it's good airmanship to periodically verify that the artificial horizon matches up with real horizon. If you're over water or desert, then even in VFR I'd tend to trust artificial horizon first.
If you lost air data, then in cruise you can periodically do a full turn, and use the ground track to estimate wind vector (speed+direction), and your true airspeed. Of course things get trickier when you're trying to land. Even then if you get mean wind speed and direction from local weather report, you can figure out an offset to ground track speed to get back airspeed. Ideally you'd chose an airfield where you can do a long straight-in approach to a looong runway. Then you err on coming in fast, and hope there's enough runway to stop ;)
I don't say that if a human has failed, it is only his/her fault.
Pitot ice is not an issue in cruise, as long as you recognize it as such. You look up a table or a nomogram in the aircraft manual, where the inputs are loading, altitude and maybe temperature, and the output is a throttle setting. Unless the aircraft is structurally damaged or iced, you'll fly within 10-20 knots of what you want. Heck, there is a first-hand account somewhere of doing just that by a pilot who flew same equipment, and lost air data. Of course if you get confused and try funky things, you're in for a world of hurt.
OK, one learns something every day. So a RAT supplies electric actuators, and not simply a hydraulic pump? Good to know.
1. The pilots must be trained how to specifically deal with taking over a system with unknown state.
2. Since #1 is prone to all sorts of problems, it's better to avoid. Thus pilots must be trained to oversee and keep current their mental image of the aircraft's status.
3. Since #2 breaks down, #1 is still important.
IIRC, in AF447 there were strong indications that the air data system was failing. A known problem. I think that weather only added to the airframe stresses, but primarily the pilots overstressed it.
Methinks that pilots need to be routinely reviewing airworthiness directives and similar documents, even foreign ones if they understand the language. Yes, I know, the poor chaps and gals barely have time enough to rest... At least that would give them a chance of thinking "hey, what if that's this problem".
In high stress situations, you don't have much in the leeway to think of unlikely scenarios like total failure of air data. Yet total air data system failures routinely seem to kill people :(
I agree that everything with safety implications should be subject of scrutiny. It's just that human factors are very widely misunderstood. You have mechanics who can inspect any flying hardware, but good luck finding a "mechanic" who can examine a pilot to determine if he/she is fit for flying that day.
Please don't twist my words. I don't claim there are no non-human-factor caused crashes, I just claim that a vast majority is human factors, and mostly cockpit human factors at that.
AF447 is, to the best of my knowledge, a case of the pilots getting confused by a single point of failure in the air data instrumentation. If you look around, you will find posts by pilots who faced similar issues, had similar ACARS messages sent out, and they recovered without problems as long as they followed procedures. Surely it did fall apart in the sky, but it didn't "just" fall apart, at least there is no reason to think this way so far. To me, that's not unlike China Air 006 but with a different ending.
USAIR 1549, the famous Hudson water landing -- well duh, it was not a human nor a mechanical problem. Force majeure. One example of it, so what.
Emirates 407 -- well thank you, because that was a classic case of human error. Funny coincidence of you mentioning it -- just see yesterday's TDWTF story about Command 696. ;)
WTF didn't they put an interlock of some sort? FAIL.
I agree wholeheartedly. But still the human usually fails -- not always the pilot. Of course you need to draw a line somewhere, lest you classify, say structural engineering failures as human errors too. When we reduce controlled flights into terrain (CFITs) by an order of magnitude or two, then I can come back to revise my skewed worldview ;)
I didn't say anything about how the RAT works. I only said that as long as (some of) your hydraulic systems are operable, and you have RAT, you can fly a fly-by-wire plane. So we agree here.
I never said that RAT provides academic benefits. I merely said that the GP's claim about all subsystems being out is pretty much made up. Theoretically possible, but didn't happen just yet.
When engines, generators, hydraulics and pneumatics (are there any?) have failed on a fly-by-wire plane, there's no point in recording anything anymore. Well, there is a point if you want to see how a plane behaves with unactuated control surfaces, but that's of academic interest and beside the point of determining why it crashed. Because crash it will.
Loss of engine power does not imply that a fly-by-wire plane is unflyable. As long as you have hydraulics and ram-air turbine, you can still fly it. Won't do much in the way of aerobatics, but you can, say, land it in a river. I don't think that there was any incident with a fly-by-wire plane where, without significant loss of structure (think engines falling off), the engines were out and the hydraulic/ram-air system was out as well.
Umm, no. You're almost a century out of touch with reality. What you say was true in 1930s.
Today, when an airplane crashes, the human has failed. Pretty much always. Technical issues that lead to crashes are very, very rare. If you were to place monetary bets, a winning strategy is to bet for human failure.
As long as the hardware would be FCC certified, and they could obtain base station licensing, that is. I figure that's another $100k per year amortized over 10 years. If you're lucky. Or am I off base here?