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Post by the light works on Nov 8, 2015 2:34:14 GMT
Just watched the movie, and oh, heck yeah. AMPLE movie myths.
let's start - in the opening scene, the fly a helicopter into a canyon with an overhang by "tipping the hat" - tilting the entire helicopter and rotor disc to sideslip under an overhang, into a canyon barely wide enough for the helicopter rotor. so: possible to get there, possible to remain airborne in the canyon? then they use a Huey to support a compact SUV (on a winch line) while rescuing the driver. wikipedia says 5000 pounds - so, hey, maybe possible.
any input, anyone got anything else? I've dubbed it the backdraft of disaster movies.
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Post by silverdragon on Nov 8, 2015 8:31:31 GMT
No a helicopter can not fly in such a confined space. Or WOULD not fly... unless the pilot has "them" the size of wrecking balls.... they are taught to avoid confined spaces. Depends on the gap to the sides of the canyon, but general rule, three times the width of the blades minimum?... I know the Chinook display team main pilot has said he wont even land next to a building unless there "is enough space", and he can tip the Chinook to something like 70degree nose down.
Confined spaces cause many vortexes, This is due to the wash being forced down, having nowhere to go, so going up past the blades, then being sucked back into the blades.... it will create a vortex that will suck the craft down. That would create a vortex ring. It would be a stall....
This was all covered in principals of flight for me back in the last century before internets, so I have the books here, but not any internets links, and I'll be (censored) if I can find anything like that?.. I didnt do rotatory wing much in my time, so I aint no expert on this, just enough knowledge to say if it cant swing round 360 without the tail hitting something, it wont go there.... Rescue pilots wont even land next to a tree if they dont have to, and will use the winch.
Depending on the Huey... which one?.. some can lift, others, well, you would need the flying banana Chinook to lift something as heavy as a typical American heavyweight SUV?...armoured as well, thats a big ask in confined spaces. (Thinking if its a Humvee on a Bell Huey Cobra, no way?...) so size matters there. Weight issues, maybe they can strip down the insides of the heli to loose weight... was that covered?... Fuel weight as well, a full tank can weigh in at more than a small car.... dependant on heli of course.
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Post by the light works on Nov 8, 2015 16:25:07 GMT
No a helicopter can not fly in such a confined space. Or WOULD not fly... unless the pilot has "them" the size of wrecking balls.... they are taught to avoid confined spaces. Depends on the gap to the sides of the canyon, but general rule, three times the width of the blades minimum?... I know the Chinook display team main pilot has said he wont even land next to a building unless there "is enough space", and he can tip the Chinook to something like 70degree nose down. Confined spaces cause many vortexes, This is due to the wash being forced down, having nowhere to go, so going up past the blades, then being sucked back into the blades.... it will create a vortex that will suck the craft down. That would create a vortex ring. It would be a stall.... This was all covered in principals of flight for me back in the last century before internets, so I have the books here, but not any internets links, and I'll be (censored) if I can find anything like that?.. I didnt do rotatory wing much in my time, so I aint no expert on this, just enough knowledge to say if it cant swing round 360 without the tail hitting something, it wont go there.... Rescue pilots wont even land next to a tree if they dont have to, and will use the winch. Depending on the Huey... which one?.. some can lift, others, well, you would need the flying banana Chinook to lift something as heavy as a typical American heavyweight SUV?...armoured as well, thats a big ask in confined spaces. (Thinking if its a Humvee on a Bell Huey Cobra, no way?...) so size matters there. Weight issues, maybe they can strip down the insides of the heli to loose weight... was that covered?... Fuel weight as well, a full tank can weigh in at more than a small car.... dependant on heli of course. in the movie, this was a modern version of the Huey "Hog" the SUV was what we would call small - the size of the ones tested in the top gear caravannist episode. it was also about 5 minutes past out of fuel, just to add more tension - but as you say, it adds more carrying capacity. and I believe the term you would search on the internet to explain the problem is "settling with power" which as I recall the explanation from when it happened on the Bin Ladin raid the air currents around the helicopter shift such that it is essentially sucking its own air cushion out from under itself to feed the rotors. www.copters.com/aero/settling.html
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Post by oscardeuce on Apr 11, 2017 4:52:06 GMT
I miss my days flying our Huey (UH-1H model). Don't miss the fuel and maintenance bills though. Delivering SEALs for an airshow routine in this photo. Another view of our second restored aircraft.
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Post by the light works on Apr 11, 2017 5:58:53 GMT
I miss my days flying our Huey (UH-1H model). Don't miss the fuel and maintenance bills though. Delivering SEALs for an airshow routine in this photo. Another view of our second restored aircraft. one of my goals for my rescue career is to get a helo ride out of it. considering we are in negotiation to train the local coasties, there's a better chance of it than ever. my usual partner for my friday duty shifts got to spend a day doing ridealongs with the air ambulance service.
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Post by silverdragon on Apr 11, 2017 9:54:06 GMT
If you get to a "door open" experience, dont be shy, look out.... First the overpowering aroma of fuel being burnt at high velocity will always let you know where you are and whats making all the noise. Second, having a vice-like grip on something solid is natural. Seeing the crew, although tethered up as a matter of operational procedure, but seeing the crew of a C130 "skip" about the ramp on an open back door whilst air-dropping cargo, "was not natural" to me, how the hell did they do that without crawling about on all fours hanging on for dear life?.. seeing chopper crew on the bigger ones like the flying banana do the same... erm?.. excuse me?.. why the HELL aint you screaming in fear?... I know they get used to it and know instinctively when to look for something to hang on, as they can "Feel" the thing make a turn before it actually does the turn, and all of that, its their office space, they know what to do, but not me... I dont get vertigo, but watching them gave me vertigo?.. I got air-lifted by the training exercise Mountain Rescue one time, before my RAF days, maybe its that that made me sign up?.. I dont remember.. but anyway, it was my turn to "play the injured", so it was me in the stretcher, and they winched me up. Being winched towards a BIG NOISY FAN.... erm?.. "Change of underwear please"?.. terrifying but exciting at the same time?.. And BLOODY NOISY.. I say Bloody Noisy... can you turn it down a bit some of us are trying to sleep?..
It was only about a five mile ride, felt like 500 yds, very quick. And the landing?.. I only knew we had landed when the engine slowed down. Very soft. Then over the intercom "Please return seats and tables to upright position if you have enjoyed the flight, the RAF say thankyou, if you didnt, we were the Navy..." They "stretchered" me over to a waiting rescue 4x4 "ambulance", and then they all had a quick chat with senior officers and away they went. I didnt even get the pilots name... I wonder if he remembers that day?..[approx '83 IIRC?...]
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Post by the light works on Apr 11, 2017 14:09:13 GMT
If you get to a "door open" experience, dont be shy, look out.... First the overpowering aroma of fuel being burnt at high velocity will always let you know where you are and whats making all the noise. Second, having a vice-like grip on something solid is natural. Seeing the crew, although tethered up as a matter of operational procedure, but seeing the crew of a C130 "skip" about the ramp on an open back door whilst air-dropping cargo, "was not natural" to me, how the hell did they do that without crawling about on all fours hanging on for dear life?.. seeing chopper crew on the bigger ones like the flying banana do the same... erm?.. excuse me?.. why the HELL aint you screaming in fear?... I know they get used to it and know instinctively when to look for something to hang on, as they can "Feel" the thing make a turn before it actually does the turn, and all of that, its their office space, they know what to do, but not me... I dont get vertigo, but watching them gave me vertigo?.. I got air-lifted by the training exercise Mountain Rescue one time, before my RAF days, maybe its that that made me sign up?.. I dont remember.. but anyway, it was my turn to "play the injured", so it was me in the stretcher, and they winched me up. Being winched towards a BIG NOISY FAN.... erm?.. "Change of underwear please"?.. terrifying but exciting at the same time?.. And BLOODY NOISY.. I say Bloody Noisy... can you turn it down a bit some of us are trying to sleep?..It was only about a five mile ride, felt like 500 yds, very quick. And the landing?.. I only knew we had landed when the engine slowed down. Very soft. Then over the intercom "Please return seats and tables to upright position if you have enjoyed the flight, the RAF say thankyou, if you didnt, we were the Navy..." They "stretchered" me over to a waiting rescue 4x4 "ambulance", and then they all had a quick chat with senior officers and away they went. I didnt even get the pilots name... I wonder if he remembers that day?..[approx '83 IIRC?...] probably not. another day on the job, you know. I've recieved packages from the helo. noisy, smelly, and windy. not airmailed, mind you - that is a specific term for something very different, and we're not allowed to do that with victims.
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Post by silverdragon on Apr 13, 2017 10:02:06 GMT
If you get to a "door open" experience, dont be shy, look out.... First the overpowering aroma of fuel being burnt at high velocity will always let you know where you are and whats making all the noise. Second, having a vice-like grip on something solid is natural. Seeing the crew, although tethered up as a matter of operational procedure, but seeing the crew of a C130 "skip" about the ramp on an open back door whilst air-dropping cargo, "was not natural" to me, how the hell did they do that without crawling about on all fours hanging on for dear life?.. seeing chopper crew on the bigger ones like the flying banana do the same... erm?.. excuse me?.. why the HELL aint you screaming in fear?... I know they get used to it and know instinctively when to look for something to hang on, as they can "Feel" the thing make a turn before it actually does the turn, and all of that, its their office space, they know what to do, but not me... I dont get vertigo, but watching them gave me vertigo?.. I got air-lifted by the training exercise Mountain Rescue one time, before my RAF days, maybe its that that made me sign up?.. I dont remember.. but anyway, it was my turn to "play the injured", so it was me in the stretcher, and they winched me up. Being winched towards a BIG NOISY FAN.... erm?.. "Change of underwear please"?.. terrifying but exciting at the same time?.. And BLOODY NOISY.. I say Bloody Noisy... can you turn it down a bit some of us are trying to sleep?..It was only about a five mile ride, felt like 500 yds, very quick. And the landing?.. I only knew we had landed when the engine slowed down. Very soft. Then over the intercom "Please return seats and tables to upright position if you have enjoyed the flight, the RAF say thankyou, if you didnt, we were the Navy..." They "stretchered" me over to a waiting rescue 4x4 "ambulance", and then they all had a quick chat with senior officers and away they went. I didnt even get the pilots name... I wonder if he remembers that day?..[approx '83 IIRC?...] probably not. another day on the job, you know. I've recieved packages from the helo. noisy, smelly, and windy. not airmailed, mind you - that is a specific term for something very different, and we're not allowed to do that with victims. Hmm... I got a talking to from a pilot one who had to fly a certain personage guilty of something serious, he may argue about the status of "Airmail", in that he wanted to fly over the prison and save ground transportation times with just chuck him out with a chute. [C130 Herky-bird pilot...] I asked why that was a problem?.. His reply was that it didnt mean he had to tell him how to use a chute first did it?.. Or that they had to attach the long-line for auto-deployment either. "And no reserve chute either" This is the same pilot that during his training did some work as the person who works the ramp when they are doing parachute training, who used to delight in a little wind up, and was the "Legend" who just as you were about to jump would hand you a pull-ring not attached to anything with a "You might need this!" and a heafty push... Either that or would hand them the long-line hook that is supposed to be attached to the inside of the aircraft with a short cut off 3ft line with "Is it supposed to be like that?" as they jumped?.. Problem was he was good at his job. But opening your door and finding he had been there first and booby trapped it with a spring loaded glitter bomb?.. Or he was the one who would slide a newspaper under your door fully loaded with talcum power and deploying a leaf blower to ensure it covered everything?.. He was also one of my teachers, in that he was the first one to look at a roll of wallpaper that had a design that replicated bricks and start laughing. I found out why... He grabs a trestle table, and wallpapers the table, which at that time, is exactly the same size as the dormitory doors, if not slighly larger... it may have been a door in its previous life?.. He then knocks on a door, shoves it into place and waits... Someone answers to see a brick wall outside their door?.. with some mild graffiti that gets added now and again. Even the RSM was in fits of laughter at that one. That table was kept, and every year, as we got "newbs", one of them was treated to greenhorn treatment with it. Every year, door opens, "WTF?... how?.. " even more fun if its done during fire alarm drill. One recruit has gone down in legend as taking one look and then jumping out the window instead of further investigation... From then, it was decreed, only for use on ground floors?.
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