PakledHostage

Admittedly it is a bit of an extreme example, but Vancouver's 99 B-line bus route has ridership in excess of Nibb's numbers. They are as high as 60k per day. Articulated double buses similar to the one shown in Phoenix_ca's photo serve the route, running in a restricted bus lane and making only limited stops. If I am not mistaken, they are natural gas powered diesel buses rather than electric trolley buses. This is because they have to be able to pass the electric trolley buses that are connected to the overhead power lines along the same route. Overcrowding on that bus route's transportation corridor is one of the strongest arguments in support of building a new metro line. I agree. A new bridge was built in the greater Vancouver regional district over the past few years or so at a cost of ~2.5 billion CAD. The major aspects of the project did nothing more than replace an existing bridge and upgrade an existing highway interchange. A metro line to replace the bus route I just mentioned above would cost less than 1/2 that and serve far more commuters.

I have three options when commuting to work: public transit (a train and a bus), driving and cycling. Driving takes the same amount of time as public transit by the time I park and walk to my office. Cycling takes about 5-10 minutes longer than the other two options. When the weather's nice, I ride my bike. It is cheaper, good for me and it doesn't feel like commuting; I am doing something I enjoy. When it rains, I take the train/bus. I don't have to fight traffic and I can entertain myself by reading these forums on my phone...

Citation needed. Without it, your post is nothing more than right-wing rhetoric...

Good guess, but it was actually the Kennicott for the leg between Whittier and Juneau and the Matanuska for the Juneau to Bellingham segment of the trip. The Kennicott is new enough that it has active roll stabilization but I guess they still strap the cars down as a precaution. Yakutat Bay, on the Gulf of Alaska, is one of the top cold water surfing destinations in the world for a reason...

This seems properly off-topic for the Science labs, but I have to chime in that I agree. I took a winter trip aboard the Alaska ferry from Whittier, Alaska to Bellingham, Washington a few years ago... It took 10 days (including a 4 day layover in Juneau), but it was a far greater adventure than any flight I've ever been on. They strap the cars down for the Gulf of Alaska portion of the trip. Don't want them sliding around and banging into each other in the big waves...

Thanks! Yes, the streaks were airplanes. I shot the video in Canyonlands National Park near Moab, UT. The planes were heading to/from the general direction of LA and Vegas. That probably explains why there were so many of them. Each frame in the video was a 30 second exposure. I shot about 330 frames and compiled them to play back at 15 FPS. 30FPS is more standard for video but everything seemed to move too fast at that rate so I slowed it down to 1/2 speed. I quit shooting at 330 frames because the battery in my camera ran out. I had another battery but I wouldn't have been able to change it without moving the camera so I didn't bother. Instead, I used the second battery to get some still shots of the milky way, etc. If I go down to the desert again, I'll have to get a higher mAh battery grip for my camera so that I can let it run longer. I'd also change some settings in the camera and maybe point it at a more interesting part of the sky... Live and learn. For anyone who hasn't been there, Canyonlands National Park in Utah is a great place for star gazing! If you ever go, bring a camera and tripod. Better yet, bring a telescope.

I know that I am reviving a bit of an old thread, but there is some great work in here and I doubt anyone will mind. This is my own latest attempt at photographing the night sky. The frames in the time lapse video were shot over four hours in Canyonlands National Park in Utah. I wish I had more frames to work with so I could make a longer video, but the batteries in the camera ran out of power.

That may yet change. I recently heard an interesting story about organic flow batteries on the CBC's "Quirks and Quarks" science magazine radio program. It seems that a research group at Harvard University has made significant progress in using quinones in flow batteries. And since increasing the storage capacity of flow batteries is simply a matter of increasing the size of the electrolyte storage tanks, we may yet see a day where such batteries are an integral part of windmills and large solar arrays. Indeed, the state of California has mandated that utility companies build energy storage capability into their networks. This will inevitably fuel the market for batteries and drive additional research into battery technologies.

As others have pointed out already, the throttle on a jet engine controls the fuel flow. On the turbofan engines used on commercial airliners, the piece of hardware that controls the fuel flow is typically called a hydro-mechanical unit (HMU) or Fuel Control Unit (FCU). Depending on how modern the engine is, the throttle will be connected directly to the HMU/FCU or to a computer which is in turn connected to the HMU/FCU. The most sophisticated engine control computers are called FADEC systems. FADEC stands for "Fully Automatic Digital Engine Control". The FADEC computer manages fuel flow in response from throttle inputs and to keep engine parameters within operating limits. Throttle response on turbofan engines is slow due to the engine's spool up time. Turboprop powered aircraft typically have variable pitch props and their throttle response is quicker, despite the fact that the core of the engine is really no different than that of a turbofan. Propellers on turboprop aircraft like Dash 8s are constant speed propellers. They are governed to turn at a fixed RPM, regardless of throttle setting. You don't have to wait for them to spool up and spool down. As an interesting side note, you can actually hear the governors on turboprop airliners like Dash 8s working during takeoff if you pay attention. During initial climb, you will often hear an annoying "wow-wow-wow" sound that fades to a uniform droning of the propellers once you're climbing comfortably. The annoying sound is called beating. It is caused by the difference in RPM between the two props. The governors are synchronized to each other during normal flight to eliminate the beating sound, but the system is normally turned off during takeoff because you don't want the slave engine's RPM to follow the master's down if the master quits.

Thank you.

But the point Nibb made that you may have missed is: Perhaps the experts here can explain to the rest of us how it would be ensured that the reaction would not START as a result of a catastrophic failure of the rocket? How would it be ensured that the parts of the engine that control the rate of reaction in the core would not be damaged in some way that would affect their ability to function following a launch failure? As has been mentioned several times in this thread, there is a difference between energy and power. But any reactor capable of powering a NERVA engine would have to have a very high reaction rate, presumably generating dangerous reaction products at an equally high rate. Can someone please explain how that reaction rate would be safely controlled following a catastrophic launch failure or pad explosion, given that the damage the engine sustains is difficult or impossible to quantify?

Also on Fox:

For anyone who's interested, Slooh is hosting live coverage of the Antarctic annular eclipse, starting in about an hour from the time of this writing. Supposedly it will also be visible as a partial eclipse from parts of Australia. Maybe someone from down that way will post pictures here?

I thought some here might enjoy this story about a reporter who intentionally submitted a plagiarized paper to certain online journals1. He created the paper by combining text from a geology and a haematology paper. Several of the journals agreed to publish the paper. I wonder how many times publications like this are exploited to give questionable science an air of credibility? I'd like to think that such papers wouldn't withstand scrutiny of the scientific community, but they might be cited by people arguing one position or another on forums such as ours... 1There's a link to the full radio interview on the web page that I linked to above.

I fail to see how choosing to cut/break your own arm off is a value judgment?

But even people will act irrationally when confronted with seemingly futile situations. It is a rare individual who'll try something daring when really stuck. Consider Aron Ralston of "127 hours" fame. If your choice is "die" or "risk dying", why not choose "risk dying"? Yet how many people could have done what Aron Ralston did to save himself? And some bugs are "smarter" than others. Bees, for example, have language that allows them to communicate between individuals and problem solving. I have also personally witnessed problem solving behavior in yellow jackets. Social insects like bees, wasps and ants are amazing creatures, and probably far more sophisticated than most people give them credit for.

That density seems a bit low. After all, water has a density of 1000 kg per cubic meter, near as makes no difference. Maybe have a look at Purdue University's Impact Earth website for some representative numbers?

I mean no disrespect, but can I ask you to elaborate on an earlier "back of the envelope" calculation that you did in light of the above? You calculated the L/D performance of a B747 based on climb performance information that you found in a manual for a flight simulator program. You determined that the aircraft, when loaded to maximum takeoff weight and in the early part of its climb, has an L/D of 5.5. You extrapolated this number to predict that the aircraft's L/D in landing configuration was about 4, while your new data above suggests that the L/D may be as high as 12 in normal cruise. Fair enough, but could you please speak to how calculations similar to your earlier calculation (but using early climb performance for a fully loaded B767-200), would predict the likelihood of pilots being able to successfully land a B767 after both engines flame out? The question is relevant because The Gimli Glider was a B767-233 (where the "33" means that it was a variant built to Air Canada's specifications) powered by two P&W JT9D-7R4 engines and it was landed successfully in just such a situation. We started this discussion with you arguing that it is not possible to land a B747 deadstick. Notwithstanding your efforts to justify your position, I think your analysis is oversimplified and it is pointless to draw such conclusions from it. I suspect that the same oversimplified analysis that you applied to the B747 would predict equally bad glide performance for the B767. But clearly it is possible to glide a B767 over 100 NM and land safely (if you start at 41000 feet) because it has been done in real life. If your numbers work out the way I anticipate they will, then I would argue that the empirical data invalidates your analysis.

For what it is worth, most B747s don't have a RAT. Only the newest B747 type (the B747-8) has a RAT. What's more, the APU on the most common B747 model currently in service, the B747-400, cannot even be started in flight. The aircraft type relies on windmilling engines to provide limited hydraulics and batteries to provide electrical power in the event that all four engines flame out. The B747-8 only has a RAT because of its increased reliance on electrical power.

You've given a "high level" description of the physical mechanism of induced drag, but I still take issue with your final sentence. As you've explained, increased circulation about a 3D wing results in increased induced drag, and circulation about a wing at high angle of attack with flaps deployed is a lot higher than it is about a clean wing at a low angle of attack. Fair enough, but it is an apples and oranges comparison. To focus on the relatively poor glide performance of a B747 (or any other aircraft) in landing configuration in comparison to another aircraft type in clean configuration is pointless.

[citation needed] While a B777 is not an A330 or a B767, this contrasts sharply with two well known dead stick landings carried out in those two aircraft types. Aerodynamically, the twin engined B777 isn't that much different than the twin engined B767 and A330. The B767 dead stick landing was, of course, the Gimli Glider. I wasn't able to find the official accident report online but the Wikipedia article and many other sources describe the engines flaming out at 41000 feet over Red Lake, Ontario. Red Lake to Gimli is 122 nautical miles. Even so, the flight crew arrived at Gimli with TOO MUCH energy and famously had to side slip the aircraft to scrub speed before landing. Similarly, page 8 of the official Portuguese GABINETE DE PREVENÇÃO E INVESTIGAÇÃO DE ACIDENTES COM AERONAVES report into the dead stick landing of Air Transat flight 236 in Terceira describes the flight crew performing a 360 degree turn to bleed excess altitude during their approach, despite having to glide for 65 nautical miles from where the second engine flamed out to Lajes airforce base in the Azores. You may be thinking of the glide performance of British Airway's flight 38 (a B777-200ER) following the failure of both engines while on approach to Heathrow airport, but that isn't a fair comparison because the aircraft was flying slowly, close to the ground and in landing configuration when the engines quit.

A lot of people say that, but talk about the ultimate "glass is half empty" perspective... Michael Collins flew to the bloody moon! Heck, according to his own words in his book "Carrying the Fire", he would likely have commanded Apollo 17 had he stayed in the astronaut program. He chose to retire instead. Clearly he was satisfied with his achievements as an astronaut.

I'm not really sure. I haven't paid much attention to how the game has changed since about v0.18 because I haven't really played it since then [gasp!]. In the early days of modding, parts and plugins were required to go into those directories for security. The game limited a mod's access to things like the internet and storage on people's computers outside of the game installation directory. I was aware that some of that had changed but didn't realise that some mods are now installed elsewhere. In short, it is a throwback to the old way of doing it. I don't think it causes any problems, does it? Indeed the installation instruction template in Spaceport that I use still shows the old way of doing it.

UPDATE I have rebuilt the plugin for v0.23.5 of the game. It has already been posted to Spaceport. I have not yet implemented support for SBAS satellites although it is on my list of things to do. The time displayed in the UT field is now shown in Kerbin days, hours and minutes. I haven't had a chance to figure out how to read whether the "Earth Time" setting is set in a user's game, so I have only implemented a work around for those who want to use Earth time. Change the "EarthTime" in the FigaroReceiver part's Part.cfg file to "TRUE" if you would rather have the receiver display times in 24 hour days.