wmartin@STL-06SIMA.ARMY.MIL (Will Martin) (02/04/91)
From: Will Martin <wmartin@STL-06SIMA.ARMY.MIL> Regarding aircraft that have braking or drag parachutes that can be deployed during landing: 1) Are they regularly used every landing, or only in exceptional circumstances, such as on runways too short for a chute-less landing? 2) Can they be re-used, or are they destroyed by a single use? (Exhaust melts or ignites lines or fabric, or the strain of one use renders them unsafe for future reliability?) 3) If they are re-used, how are they re-packed? Do any aircraft have a mechanical roll-back-in device that sucks the chute back into the housing without manual intervention, making it reusable automatically? Or do they have to be gathered up and re-packed by ground crew or a rigger? Is that done while the chute is still attached to the aircraft, or is it removed? If the latter, are pre-packed chute packages a standard replacement part, where the crew just grabs one off the shelf and plugs it into the aircraft? Are these then a standard part used on many different models of aircraft, or are such chutes unique to each specific type? 4) Are there many different methods of housing such chutes on aircraft? That is, do some extrude from orifices, while others come out of clamshell-door pods? Are they deployed with explosive mechanisms, or just let fall into the airstream and open by that wind? 5) Where do they fasten to the airframe? It would seem the tip of the tail isn't all that strong, but aircraft with arresting hooks would need some sort of main-structure spar to hang that on, so the chute could be linked to that in those models. Is the existence of such a strongpoint the determining factor in whether an aircraft is equipped with a drag chute? Regards, Will wmartin@stl-06sima.army.mil
henry@zoo.toronto.edu (Henry Spencer) (02/05/91)
From: henry@zoo.toronto.edu (Henry Spencer) >From: Will Martin <wmartin@STL-06SIMA.ARMY.MIL> >1) Are they regularly used every landing, or only in exceptional >circumstances, such as on runways too short for a chute-less landing? Yes. :-) Depends on the aircraft. Historically, it's not uncommon for a drag chute to show up as a retrofit after landing characteristics are found to be marginal, in which case it's used regularly. There are some cases, like the drag chutes on Norwegian F-16s, where it is mostly meant for severe situations like badly-iced-up runways. >2) Can they be re-used, or are they destroyed by a single use? ... In general they are re-usable. >3) If they are re-used, how are they re-packed? Do any aircraft have a >mechanical roll-back-in device ... Not that I know of. They have to be repacked by ground crews. The hassle of doing this, and in some cases the need for special facilities to do it, is one reason why modern aircraft prefer not to use them. >4) Are there many different methods of housing such chutes on aircraft? >That is, do some extrude from orifices, while others come out of >clamshell-door pods? Are they deployed with explosive mechanisms, or >just let fall into the airstream and open by that wind? I believe it's fairly normal practice to house them behind small doors, with a small drogue chute expelled explosively to pull the main chute out aerodynamically. >5) Where do they fasten to the airframe? Unfouled deployment of the chute pretty much demands that they be on the rearward extremities of the aircraft, typically either in the tip of the tail or in a pod on the rear edge of the fin. Mounting the fin and the stabilizer tends to require strong structure in that area anyway. -- "Maybe we should tell the truth?" | Henry Spencer at U of Toronto Zoology "Surely we aren't that desperate yet." | henry@zoo.toronto.edu utzoo!henry
jabishop@uokmax.ecn.uoknor.edu (Jonathan A Bishop) (02/05/91)
From: jabishop@uokmax.ecn.uoknor.edu (Jonathan A Bishop) wmartin@STL-06SIMA.ARMY.MIL (Will Martin) writes: >From: Will Martin <wmartin@STL-06SIMA.ARMY.MIL> >Regarding aircraft that have braking or drag parachutes that can be >deployed during landing: >1) Are they regularly used every landing, or only in exceptional >circumstances, such as on runways too short for a chute-less landing? In the case of the F-4, at least, they only use them when they have to. I live near Tinker AFB in Oklahoma, and we used to have an AFRES squadron of F-4's here (they've since been replaced by F-16's). In all of the years that I watched the planes, I very seldom saw the chutes used. They were usually used only when a fairly heavily loaded plane landed on the short runway. >2) Can they be re-used, or are they destroyed by a single use? (Exhaust >melts or ignites lines or fabric, or the strain of one use renders them >unsafe for future reliability?) Yes. >3) If they are re-used, how are they re-packed? Do any aircraft have a >mechanical roll-back-in device that sucks the chute back into the housing >without manual intervention, making it reusable automatically? Or do they >have to be gathered up and re-packed by ground crew or a rigger? Is that >done while the chute is still attached to the aircraft, or is it removed? >If the latter, are pre-packed chute packages a standard replacement part, >where the crew just grabs one off the shelf and plugs it into the aircraft? >Are these then a standard part used on many different models of aircraft, >or are such chutes unique to each specific type? The base parachute shop re-packs them. They are removed from the plane, sent to the shop, and packed by hand. There are always spares ready, so a new one is plugged into the plane immediately. -------- jabishop@uokmax.ecn.uoknor.edu "I'm with you, LEM, though it's a shame that it had to be you. The mother ship is just a blip from your train made for two. I'm with you, boys, so please employ just a little extra care. It's on my mind, I'm left behind when I should have been there." --Jethro Tull, "For Michael Collins, Jeffrey, and Me"
henry@zoo.toronto.edu (Henry Spencer) (02/06/91)
From: henry@zoo.toronto.edu (Henry Spencer) >From: henry@zoo.toronto.edu (Henry Spencer) >... There are some >cases, like the drag chutes on Norwegian F-16s, where it is mostly meant >for severe situations like badly-iced-up runways. I have to amend this slightly: turns out the Norwegians also use the chute for operations into unusually short runways. -- "Maybe we should tell the truth?" | Henry Spencer at U of Toronto Zoology "Surely we aren't that desperate yet." | henry@zoo.toronto.edu utzoo!henry