YouTube description:

According to the pilot-in-command (PIC), he was performing autorotations at the lower part of the main rotor rpm green arc in part due to weight considerations. Upon entering the accident autorotation, he maintained an airspeed between 85-90 knots in the hope that extra speed would allow a more aggressive deceleration flare prior to touchdown, which should in turn further slow the rate of descent and forward speed. The helicopter's rate of descent was high, and as the PIC turned the helicopter onto the runway heading it was apparent to him that the rate of descent was excessive and that he was too low to execute either a proper deceleration flare or perform a power recovery. He attempted to level the helicopter as much as possible prior to impact to minimize the damage to the helicopter and prevent injury. The helicopter landed hard with the left skid contacting the runway first. The left skid collapsed, damaging the outboard landing gear damper attachment structure. The helicopter slid about 100 yards before coming to a stop. According to the manufacturer, the main rotor rpm range is 90 percent to 106.4 percent. At the helicopter's weight and the density altitude on the day of the accident, the main rotor rpm during the autorotation should have been above the 106.4 percent limit (red line), requiring the pilot to increase collective pitch to maintain the rotor rpm within limits. Performing autorotations at the lower part of the green arc provides less availability of rotor energy to perform an autorotation landing. The pilot should have recognized that he was not achieving the required main rotor rpm for the autorotations and terminated the maneuvers. The helicopter was within weight and balance limits.

The National Transportation Safety Board determines the probable cause(s) of this accident as follows:

The pilot's failure to maintain adequate main rotor rpm during an autorotation, which resulted in a hard landing.

If it doesn't make the Star Wars laser cannon sound every time it fires, we have failed as a species.

Alternatively, if this is mounted on planes, I expected the announcement of this technology to be shown off better. I mean, where is the house full of unpopped popcorn that we can cook from high altitude? That would've been impressive.

1.8 gigapixel ARGUS-IS. World's highest resolution video surviellience platform by DARPA.
1 million terabytes a day saved forever.

The ARGUS array is made up of several cameras and other types of imaging systems. The output of the imaging system is used to create extremely large, 1.8GP high-resolution mosaic images and video.

The U.S. Army, along with
Boeing, has developed and is preparing to deploy a new unmanned aircraft
called the “Hummingbird.” It’s is a VTOL-UAS (vertical take-off and
landing unmanned aerial system). Three of them are being deployed to
Afghanistan for a full year to survey and spy on Afghanistan from an
altitude of 20,000 feet with the ability to scan 25 square miles of
ground surface.

http://www.liveleak.com/view?i=e95_1359267780

the equivalent of 100 predator drones looking at one place AT ONCE ... hahah they stole my idea

I thought you were having some fun but I still felt it needed to be addressed, it's an oft repeated prejudice. Anyways I still contend that Ultramarathoners are tougher than anyone. Running 24 hours at a time...sometimes in high altitude with little oxygen or in 120 degrees through death valley. They're the toughest people on the planet in my view. It's one thing to play through pain, it's another to do it for hours upon hours. That's just my opinion, the voice in my head is the only thing that holds me back.

The mission generally dictates the engineering and design of a mechanical system. The Buran and the Shuttle are prime examples. The new X-37 resembles both in general shape because a reusable "space plane" needs certain specific physical characteristics.

The Mig-25 looks like the F-15 because both were originally designed as high altitude, high mach interceptors. The demand placed on the system by the overly large engines dictates the shape.

The basic principles of radar "stealth" dictate certain shapes to be effective. The Have-Blue shape was effective against high frequency radar through deflection. As materials technology advanced, e.g. radio absorbing materials, more aerodynamic shapes could be implemented and still retain "stealthy" characteristics, if not improve upon them.

All the F-22 vs Pak50, M1a1 Abrams vs T80 videos are funny. The 1 versus 1 advantages are fun to debate, but its the entire system that wins or loses the fight. In the same vein, its common knowledge that German armor in WW2 was vastly superior to American armor in every technical way. Similarly, German fighter aircraft were more maneuverable than the P-47s and P-51s that they fought. Unfortunately for the Luftwaffe, this superiority was not enough to defeat the allied system as it rolled east across Europe.

The term 5th generation does not define the aircraft themselves, but the system they belong to. If you read wikipedia, this does not mesh, but the wiki values maneuverability (which is inherently limited by the pilot), stealth features (limited by current materials and design), advanced avionics (what does this mean?) and multi-role capabilities (we have had this since the 1980's). The key to 5th generation fighters and its defining characteristic is the ability to integrate the new fighters with every other piece of war equipment in the theatre, not just in tactical use, but the total meshing of sensors and 2-way data links. Its the difference between a war of attrition and a war of "look first, shoot first".

The Russians appear to be building an excellent stealth fighter that looks sexy as hell. The Chinese are doing the same. What they both lack at the current time is the "backend" systems to make these new 5th generation-esque vehicles fully capable. The Pak50 and the J20 won't be sharing targeting data with their Navy or other ground forces anytime soon.

I'm a pilot, I know the rules and regulations. I thought I'd put that in my last reply, but it looks like I didn't. The PC-6 is designed to do this maneuver, and if it were dangerous it wouldn't be certified to do it.

The posted video and the one I linked to are doing the same thing, a rapid descent (also called emergency descent). Generally rapid descents call for slowing down to the safest operating speed with which the aircraft can fly with flaps and landing gear extended (it's usually marked on the airspeed indicator), bank into a 45° or greater turn and use pitch to keep the speed right at the max allowed speed. This is the fastest way to lose altitude without gaining excessive airspeed. Instead of using steep turns, the PC-6 uses its prop as a brake and can just descend at a steep angle without having to watch airspeed to avoid damaging flaps or gear by accidentally going too fast.

What's "not cool" about it? The plane is designed to fly in and out of remote airports with short unpaved runways. It's basically using the propeller as an air brake which allows for a near vertical descent without building up excessive airspeed. Sky diving operators use it because it can make it back to the airport before the sky divers hit the ground and be ready to go up again. Other planes would take several minutes to safely descend from high altitudes, using more fuel and time.

Noting about moving targets. How about adjusting for wind, distance, barometric pressure and altitude?

Nah, its clearly Seige Tanks and Science Vessel

Ok, so they use different frequencies in the electromagnetic spectrum to select different robots. I was doing that when I was 12 years old. My brother and
I both had remote control cars. If we wanted to use them at the same time we had to use different frequency crystals. Planes are equipped with a transponder which broadcasts an identification and sometimes altitude so ground radar can tag them more effectively. Couldn't you basically do the same thing with these robots, or just use the same process as in this video only instead of using the visible spectrum just use a lower frequency wave and all its advantages.

Or, you could actually use the advantages of high frequency and "point" at the robots you wanted to select rather than broadcasting to all of them and selecting through a process of elimination (which could take a while if you wanted to select multiple robots out of a large group).

So yah, I agree with everybody else. Unless they have some very specific design contraints this doesn't seem like a very elegant solution (although it does utilise the hardware they already have - cameras and lights).>> ^Payback:

Seige Tanks and a Banshee? Better hope you're playing against a total noob Zerg.

Doesn't seem like a falling satellite to me, but it's hard to tell with video so blurry and shaky. It looks more like the contrail from a commercial airliner at cruising altitude lit by the post-sunset (or pre-sunrise) sun. At first it's flying away with a vector to the left. Later when it's going "straight down), it's just flying directly away.

>> ^joedirt:
It isn't science or new or even interesting. It's been done and proven. USAF did exactly this in 1960. This just added a few hundred feet to their altitude.


A few hundred feet? Try an extra 30000.

>> ^kymbos:

To me, it's like those hotwheels loop-de-loop videos, except less visually arresting. Even with those you can get some 'Science!' out of it, but it's still a marketing activity.

Less visually interesting? Are you on crack? Look at that view. I would kill for the opportunity to do something like this.

I don't really believe there's an awful lot of science going on, but that's fine, it's not really about science.

Personally, if this is how Red Bull want to spend their marketing dollars, I say good on them. They sponsor a lot of cool and interesting stuff around the globe. I'm still not buying their product, but it's a lot better than being told that red bull gives you wings.

>> ^Deano:

>> ^kymbos:
Am I the only person who does not give a shit?

It's a human being doing something incredible and breaking boundaries. Isn't that worth something?
What if this had happened before the Columbia disaster and the data about how you can bail out in the upper atmosphere had been used to save those lives (i.e they bailed out just before the ship tore apart)?
I think it's a wonderful and worthy stunt and funded out of all those Red Bull drinks


No, it's a stupid advertising gimmick. It isn't science or new or even interesting. It's been done and proven. USAF did exactly this in 1960. This just added a few hundred feet to their altitude. Russian probably did it sooner.

So no it's not a human breaking any boundaries or any thing novel. It is just advertising paid for by product sales. No different from a TV commercial expect it tricked you into talking about their product.

"At high speeds this precooler cools the hot, ram compressed air leading to an unusually high pressure ratio within the engine. The compressed air is subsequently fed into the rocket combustion chamber where it is ignited with stored liquid hydrogen. The high pressure ratio allows the engine to continue to provide high thrust at very high speeds and altitudes. The low temperature of the air permits light alloy construction to be employed which gives a very lightweight engine — essential for reaching orbit." —WikiPedia

>> ^deathcow:

They must be talking about using space to get from Europe to Australia, as friction is a real bitch otherwise.

Possibly, although I think its somewhat more likely they'd just be flying at very high altitudes where the atmosphere is very thin.


From what I read on wiki it seems the engine is basically rocket/turbine hybrid. They use liquid hydrogen as fuel but instead of storing oxygen they suck it out of the air. The problem the cooling fixes seems to be related to supersonic airflow. Turbine engines need subsonic airflow to work properly so they use a ram, a cone on the front of the turbine, to slow the airflow before it enters the engine. This heats the air entering the engine up a lot, hot air takes up more space and so its difficult to get enough oxygen to the hydrogen fuel. Cooling the air after it passes over the ram lowers the air pressure and allows more air to pass through the engine. Scramjets approach this problem a different way in that they can operate with supersonic airflow, although they have the limitation of not working subsonic.

Anyway. Its quite fascinating. I don't think we'll be seeing commercial aircraft using this technology anytime soon though. I'd be pretty nervous about flying on something that is basically rocket powered. Space tourism maybe? If it can fly to high altitudes with the turbine and then switch seamlessly to using onboard oxygen it could be a much more efficient way of getting into space without using onboard oxygen the whole way up.

Oh, and RIP Concorde. I used to go to school under their flightpath out of Heathrow. 11am on Wednesdays they used to rattle the windows passing over.

I did a little amateur investigation, a bit of reading and some numbers but you can skip to the bottom for a summary.

The plane is a Stinson 108-3, 16500 foot service ceiling, 2400 pound gross weight limit (1300 empty weight), 50 gallon fuel capacity. Thats about 1100 of useful weight (2400-1300), with full fuel that lowers it to 800 (6lbs per gallon*50 gallons=300lbs), I saw 3 men in there the 4th passenger I'm gonna assume male, so lets say 180lbs for each (200 for the pilot) that comes to 740lbs for passenger weight. That leaves 60lbs for cargo. Although I couldn't see the cargo, they were still close to the weight limit but still could have been within normal limits.

The airport Bruce Meadows (U63) has a field elevation of 6370 feet. I couldnt find the airport temperature for that day but I did find nearby Stanley Airport 23 Miles southeast of Bruce Meadows. Their METAR history shows a high of 27 Celsius/81 Fahrenheit for June 30, 2012. Definitely a hot day but was it too hot? The closest I could find on performance data shows a 675 Feet per Minute climb at 75 Fahrenheit at sea level. Thats pretty close to what many small planes of that nature can do, so I took those numbers and transposed them over what a Cessna 172N could do. The 172N has a slighty higher climb performance about 750 for sea level and 75 Fahrenheit, a difference of 75 feet ill subtract out. At 6000 feet at 27C/81F the 172N climbs at 420FPM. Taking out the 75 feet brings it to 345 FPM, now I know this isn't perfect but I'm going with what I have. The plane began its climb out at 1:13 and crashed at 2:55, that leaves 1 minute and 42 seconds in between or 1.7 minutes. 1.7*345 means about 590 feet possible gain. But the plane isn't climbing at its best the entire video, at 2:35 it is apparent something is giving it trouble, that brings it down to about 1.58 minutes climb time which is 545 feet. Theres still another factor to consider and thats how consistent the altitude at the ground was.

The runway at Bruce meadows faces at 05/23 (Northeast/Southwest) but most likely he took runway 23 (Southwest) as immediately to the north east theres a wildlife preserve (Gotta fly at least 2000 feet over it) and he flew straight for quite some time. Although the ground increases in the direction he flew, by how much is difficult using the sectional charts. That means that although he may have been able to climb to about 545 feet higher than his original ground altitude, the ground rose with him and his absolute altitude over the ground would be less than that maximum possible 545. The passenger in the rear reported the plane could only climb to about 60-70 feet above the trees. The trees looked to be around 75-100 but thats still difficult to tell. That would mean according to the passenger they might have only been about 170 feet off the ground. It could still be wildly off as we cant exactly see the altimeter.

Finally theres that disturbance at 2:35 described as a downdraft. It could have been windshear, or a wind effect from the mountains. I don't have too much hands on knowledge of mountain flying so I cant say. If it was windshear he might have suddenly lost a headwind and got a tailwind, screwing up his performance. It could have been a downdraft effect. The actual effect on the aircraft may not have been much (lets say 50 feet) but near obstacles it was definitely enough to have a negative impact.



Summary:

Yes he was flying pretty heavy but he may not have been over the weight limit

The temperature in the area was definitely hotter than standard and the altitude was high, but he still had climbing capabilities within service limits. However he didn't give himself much of a safety threshold.

He might have been able to climb about 545 feet higher than the runway elevation, but the terrain altitude rose in the direction he flew, so his actual altitude over the ground was probably smaller than that.

The disturbance at 2:35 might have been some form of windshear which has the capacity to reduce airplane performance, and with his margins of safety so low already, that could have been the final factor.

Basically he may very well have been flying within the service limits of the aircraft, but the margins of safety he left himself were very low and the decision to fly over obstacles like those trees in that mountain enviroment could be the reason this would be declared pilot error.

Other notes:

The takeoff looks pretty rough but he trying to get off the ground as quickly as he can and ride ground effect until he gets up to speed.

I cant find anything resembling a proper PoH for this aircraft but I did find some data that looks pretty close to it. However this aircraft was a model from the late 40s, so the standards of performance may not be the same as now, and the transcribing I did to the 172N could be thrown off more.

On that note, I do realize that a 172 would have different aerobatic effects with altutude and temperature than a Stinson 108, but its the closest data I could use.

I also couldnt not find balance information to get a rough idea of how the plane was balanced. The type of balance on a plane does have effects on performance.

http://www.airport-data.com/aircraft/N773C.html (The aircraft)

http://www.aopa.org/airports/U63 (The airport)

http://www.ntsb.gov/aviationquery/brief.aspx?ev_id=20120701X65804&key=1 (The NTSB link posted earlier)

http://personalpages.tdstelme.net/~westin/avtext/stn-108.txt (Closest thing I could find to performance data, the actual numbers are at the bottom)

http://vortex.plymouth.edu/cgi-bin/gen_statlog-u.cgi?ident=KSNT&pl=none2&yy=12&mm=06&dd=30 (Weather data at nearby Stanley)

http://skyvector.com (sectional chart data, type U63 into the search at the upper left, then make sure that "Salt Lake City" is selected in the upper right for the sectional chart)