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#31
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RANS S-9 Chaos loses a wing
At least one type suspends the aircraft tail down when the chute is
deployed. This is probably the optimum energy absorbing method, with abvious benefits in crushing the tail first, and keeping a high wing from dropping into the cabin. The disadvantage is the possibility of whiplash on the neck. Brian W On 8/19/2010 10:09 PM, a wrote: On Aug 19, 10:56 pm, wrote: It would seem like it would be a big advantage to come down level, for the aircraft and the passengers. To heck with the aircraft. At that point it has already done something to let me down, so to speak. Now it's only purpose in life is to absorb as much of the impact energy as it can and keep that energy from me and my passengers. Which is why I put the "and the passengers" in there. You can't beat all the ways a level aircraft can protect the passengers. The gear gives and holds, or collapses and absorbs energy, protecting the passengers. The seats give and hold, or collapse and absorb energy, protecting the passengers. The cushions (if it has them) absorbes a little energy. The seats hopefully are contoured to support the passengers, thus spreading the remaining energy throughout the body rather than making one part of the body take all of the punishment. If the seats are nicely reclined, they help protect the back even more. The fact that you are not moving forward, like a nose first impact, will keep the engine from ending up in your lap, and if it has a header fuel tank, it will be less likely to rupture and burn. Also, your body will be less likely to smash into the instrument panel and other forward structures. So yes, the heck with the aircraft. Level is good. It just so happens that if the aircraft comes to rest level and on even, forgiving terrain, well designed landing gear and energy absorbing seats might be about the only thing that has to be replaced. Someone mentioned it is like dropping from 15 feet, at 23 MPH. Shoot, most of the time a person will survive a fall of that distance without anything to protect them. Having a plane and a seat to take some impact should be gravy. -- Jim in NC It pays to remember to open the doors before impact, there's a chance airframe bending would otherwise jam them. Interesting though, jammed doors were not mentioned as a factor in the cases where people talked about deployed rescue parachutes, although in one case I think someone had to break open a window |
#32
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RANS S-9 Chaos loses a wing
On Aug 19, 10:56*pm, "Morgans" wrote:
It would seem like it would be a big advantage to come down level, for the aircraft and the passengers. *To heck with the aircraft. *At that point it has already done something to let me down, so to speak. *Now it's only purpose in life is to absorb as much of the impact energy as it can and keep that energy from me and my passengers. Which is why I put the "and the passengers" in there. *You can't beat all the ways a level aircraft can protect the passengers. *The gear gives and holds, or collapses and absorbs energy, protecting the passengers. *The seats give and hold, or collapse and absorb energy, protecting the passengers. *The cushions (if it has them) absorbes a little energy. *The seats hopefully are contoured to support the passengers, thus spreading the remaining energy throughout the body rather than making one part of the body take all of the punishment. *If the seats are nicely reclined, they help protect the back even more. *The fact that you are not moving forward, like a nose first impact, will keep the engine from ending up in your lap, and if it has a header fuel tank, it will be less likely to rupture and burn. Also, your body will be less likely to smash into the instrument panel and other forward structures. So yes, the heck with the aircraft. *Level is good. *It just so happens that if the aircraft comes to rest level and on even, forgiving terrain, well designed landing gear and energy absorbing seats might be about the only thing that has to be replaced. Someone mentioned it is like dropping from 15 feet, at 23 MPH. *Shoot, most of the time a person will survive a fall of that distance without anything to protect them. *Having a plane and a seat to take some impact should be gravy. -- Jim in NC Jim, a 15 foot fall -- think of falling from the roof of a two story building -- does real damage, but in the case of a rescue parachute you're in a metal cage. Level impact in something like a 182 has the fixed gear that have a lot of flex -- a few inches of spring yield would reduce the G forces a lot, and the history shown in one of the urls I posted has the people walking away from the crash. A Mooney might be a different story. the gear is fairly stiff, they connect right to the wing spar which is not attached to the fuselage but goes right through it -- one piece, end to end. I think a 15 foot pancake drop in my airplane would hurt a lot more than in a Cirrus or a Cessna. So you've had an engine failure or the like, you're at best endurance glide, in a perfectly fine airplane except the fan stopped turning, it's IMC, and that red handle is right there. If you pull it you're probably going to inflict several hundred thousand dollars on the airplane, if you get under the cloud deck just maybe you can land. . . You really want to have thought about all of that beforehand, and have programmed yourself to pull the handle in a circumstance like that. I am thinking the prudent pilot would say "Dammit" and deploy the parachute. I had best write a decision tree and do some calculations, I'm starting to talk myself in this thing. I've got a couple of thousand hours PIC, never had to do an off field landing (the airplane and the pilot are both well maintained), but things do happen. . . |
#33
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RANS S-9 Chaos loses a wing
On 2010-08-20, brian whatcott wrote:
At least one type suspends the aircraft tail down when the chute is deployed. This is probably the optimum energy absorbing method, with abvious benefits in crushing the tail first, and keeping a high wing from dropping into the cabin. The disadvantage is the possibility of whiplash on the neck. Brian W I get having that distance from the tail to crush, like a crumple zone, but wouldn't that add some significant dangers, such as: If the plane is 20' long, and only crushes 5', wont you then be ~15' in the air when it tips, w/o the benefit of the parachute? Also, landing on the tail, wont you also have the engine, which is most of the airplane weight, still above you? That's a lot of potential energy that could cause it to collapse more, and put an engine in your lap. I'm still relatively new - 15hr Student Pilot, so there may be some things I'm overlooking; but those things sorta jumped out at me as potential additional hazards. Regards, Scott |
#34
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RANS S-9 Chaos loses a wing
"brian whatcott" wrote in message ... At least one type suspends the aircraft tail down when the chute is deployed. This is probably the optimum energy absorbing method, with abvious benefits in crushing the tail first, and keeping a high wing from dropping into the cabin. The disadvantage is the possibility of whiplash on the neck. If there was a nearly upright sitting position, it would be good back support, but... If the design had a regular nose mounted engine, that would mean a sudden stop could allow the engine to keep going and end up on your lap. -- Jim in NC |
#35
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RANS S-9 Chaos loses a wing
On 8/20/2010 11:59 AM, Gemini wrote:
On 2010-08-20, brian wrote: At least one type suspends the aircraft tail down when the chute is deployed. This is probably the optimum energy absorbing method, with abvious benefits in crushing the tail first, and keeping a high wing from dropping into the cabin. The disadvantage is the possibility of whiplash on the neck. Brian W I get having that distance from the tail to crush, like a crumple zone, but wouldn't that add some significant dangers, such as: If the plane is 20' long, and only crushes 5', wont you then be ~15' in the air when it tips, w/o the benefit of the parachute? Also, landing on the tail, wont you also have the engine, which is most of the airplane weight, still above you? That's a lot of potential energy that could cause it to collapse more, and put an engine in your lap. I'm still relatively new - 15hr Student Pilot, so there may be some things I'm overlooking; but those things sorta jumped out at me as potential additional hazards. Regards, Scott The tail down approach hangs the chute off the engine mount - a hard point in any plane. when the tail touches down, that starts taking some of the load, so the chute slows the remainder better.... Brian W |
#36
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RANS S-9 Chaos loses a wing
"Flaps_50!" wrote in message ... On Aug 19, 8:05 pm, "Morgans" wrote: "Oliver Arend" wrote Even if you have a BRS installed, it is advisable to try an emergency landing in a suitable field, since very likely the structure of the airplane will suffer less damage. As someone pointed out, the airplane comes down nose first, usually with a speed of about 5-6 m/s (15-20 ft/ s). That can break a lot of expensive stuff (prop, engine, fuselage). Some airplanes, like Cirrius, have a harness that supports the aircraft, and the aircraft comes down in a more or less level attitude. Are you saying that your aircraft have the harness attatched to the aircraft so that it always comes down nose first, or just that it will sometimes get tangled and come down nose first? It would seem like it would be a big advantage to come down level, for the aircraft and the passengers. -- When you pancake in the risk is to your spine and you need proper cushions/sear design to take care of that. As far as I know, with some (?most) parachute systems you hit the ground at about 23 mph which is equivalent to dropping the plane from about 15 feet. Such an impact will probably do serious damage to the plane making it a write off. So, I don't rate the planes chances much. Whether the planes structural failure will affect your chances to climb out unaided is moot. I think that a pull on the handle should be considered to be the last resort when you know you are not able to glide to a forced landing. I imagine that in some terrain the chute may be a bad idea compared to a pilot controlled crash. So IMHO the chute is a good device to have as an option but also has some negative features and needs proper training for best use. For example, suppose your engine fails at 500' -should you pull the handle? Which is safer, to land in the tops of trees or fall vertically under parachute and risk cabin penetration? In mountains, do you want to parachute into the sides or crash land on a ridge or valley? I hope you see my point. Cheers One of the themes developing here it the recoverability of the air frame, what a crock!! if the pilot feels that the situation is so far beyond his/her capabilities then I think that any damage to the airframe is the furthest thing from their mind and rather they have taken a course of action designed to make their survivability a priority. honestly do you think someone would pull the chute if they only thought "maybe I can't do this" or when they thought "****!! this is going to hurt" -- [This comment is no longer available due to a copyright claim by Church of Scientology International] "I like your Christ. I do not like your Christians. They are so unlike your Christ" |
#37
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RANS S-9 Chaos loses a wing
Morgans wrote:
Some airplanes, like Cirrius, have a harness that supports the aircraft, and the aircraft comes down in a more or less level attitude. Are you saying that your aircraft have the harness attatched to the aircraft so that it always comes down nose first, or just that it will sometimes get tangled and come down nose first? It would seem like it would be a big advantage to come down level, for the aircraft and the passengers. The chute must be stored somewhere, and its lines have to be attached to the plane in a way which doesn't endanger the occupants when the cute gets deployed. By far the easiest way to do this is to store it in the aft fuselage and to attach the lines behind the cockpit. Which happens to reslt in a nose down attitude when the plane hangs on the chute. I'm sure there are other ways, but they come at a price, moneywise and weightwise, both not desirable in a RANS-9. A Cirrus may be a different story. |
#38
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RANS S-9 Chaos loses a wing
On Aug 22, 9:56*am, John Smith wrote:
Morgans wrote: Some airplanes, like Cirrius, have a harness that supports the aircraft, and the aircraft comes down in a more or less level attitude. *Are you saying that your aircraft have the harness attatched to the aircraft so that it always comes down nose first, or just that it will sometimes get tangled and come down nose first? It would seem like it would be a big advantage to come down level, for the aircraft and the passengers. The chute must be stored somewhere, and its lines have to be attached to the plane in a way which doesn't endanger the occupants when the cute gets deployed. By far the easiest way to do this is to store it in the aft fuselage and to attach the lines behind the cockpit. Which happens to reslt in a nose down attitude when the plane hangs on the chute. I'm sure there are other ways, but they come at a price, moneywise and weightwise, both not desirable in a RANS-9. A Cirrus may be a different story. The aftermarket instillation of a Cirrus like rescue parachute in Cessnas most often has the canister in the luggage compartment, and it appears the harness attaching it to the firewall and aft on the airplane are under a fiberglass fairing that gives way when the parachute is deployed. The airplanes are intended to come down more or less flat. In a significant number of cases (the statistics are cited in references elsewhere in this thread) the airplane was not totaled after being brought down under the parachute. |
#39
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RANS S-9 Chaos loses a wing
"Garry O" wrote One of the themes developing here it the recoverability of the air frame, what a crock!! I don't think that was the thrust in this part of the thread. It perhaps was elsewhere, but here, the level parachute landing vs. tail up or tail down is being discussed. It seemed someone said the ultralight type aircraft they were talking about had the chute rigged from the tail. I was stating that the fuselage, landing gear and seats offered much better crush distance (equating directly to peak G forces experienced by the occupants) that would a tail up landing. I stick by that observation for well designed aircraft. The landing gear will crush, and so will proper seat supports, thus giving maximum protection to the people in the plane. if the pilot feels that the situation is so far beyond his/her capabilities then I think that any damage to the airframe is the furthest thing from their mind and rather they have taken a course of action designed to make their survivability a priority. honestly do you think someone would pull the chute if they only thought "maybe I can't do this" or when they thought "****!! this is going to hurt" I never have been in a position to pull a chute in a plane, but I purposely drove off an inline in a van rather than roll down the incline, and in that case, I most definitely thought "this is going to hurt" in one millisecond during the crash. I made the right choice, because I did not roll, and I most certainly would have if I had not made the conscious choice to drive directly off of the drop-off. If a person decides to pull a chute, they most likely have decided the plane is a write-off. It only could be a bonus if it is not. -- Jim in NC |
#40
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RANS S-9 Chaos loses a wing
Morgans wrote:
"Garry O" wrote One of the themes developing here it the recoverability of the air frame, what a crock!! I don't think that was the thrust in this part of the thread. It perhaps was elsewhere, but here, the level parachute landing vs. tail up or tail down is being discussed. It seemed someone said the ultralight type aircraft they were talking about had the chute rigged from the tail. We don't really KNOW how it was rigged, only how it came down. As much roll as was present, it could well be that part of the harness got wrapped around the tailwheel or something... -- Richard Lamb |
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