Lear drag-chutes
03-03-2010, 12:31 PM
#1
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Lear drag-chutes
This is just a question I wanted to throw on here for any Learjet folks.
I'm just a dumb airline guy that was curious about Learjet drag-chute kits. The other day I was thumbing through a publication that advertises aircraft and noticed that numerous Lears had these kits installed. I actually thought it was sort of interesting. I've never actually seen them in use anywhere, is it typically an emergency-only device? Or was it due to brake-design on the 20-series, etc? Just curious...
I'm just a dumb airline guy that was curious about Learjet drag-chute kits. The other day I was thumbing through a publication that advertises aircraft and noticed that numerous Lears had these kits installed. I actually thought it was sort of interesting. I've never actually seen them in use anywhere, is it typically an emergency-only device? Or was it due to brake-design on the 20-series, etc? Just curious...
03-03-2010, 01:14 PM
#2
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Really designed for emergency use only though there is also an air brake system as well if the hydraulics fail. Many of the 35's I flew had the chute installed.
There has been at least one event where one deployed in flight. It should be hooked up such that even an accidental deployment would just throw out the chute without being attached to the aircraft. There is a hook or riser of sort that is supposed to catch the chute if you purposely use it. The mechanic had installed it incorrectly and the pilots did not catch it on preflight. When the chute deployed it was attached in such a way that they could not jettison it.
There has been at least one event where one deployed in flight. It should be hooked up such that even an accidental deployment would just throw out the chute without being attached to the aircraft. There is a hook or riser of sort that is supposed to catch the chute if you purposely use it. The mechanic had installed it incorrectly and the pilots did not catch it on preflight. When the chute deployed it was attached in such a way that they could not jettison it.
03-03-2010, 03:18 PM
#4
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Must be fairly easy to repack. I helped repack a chute on a F-4S once and it wasn't an easy job and not one that a pilot in a nice shirt and tie would be doing! Interesting though - I never know any corporate type of aircraft had a drag chute. I imagine that a drag chute deployed in flight would be ripped to shreds.
USMCFLYR
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03-03-2010, 03:28 PM
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They are meant to be deployed at low speeds like 100 knots or so. When I worked on test aircraft we had them on all the aircraft, and they had speed limitations around 120 knots. Get in an unrecoverable spin, pull the handle, it would pull the tail up. Some use explosive charges and some just use springs to deploy. The spring and cable systems especially were not all that reliable, I heard recently one of the test aircraft had an accidental deployment without doing anything to ask for it. They jettisoned the chute and all was well, not sure if the chute was damaged. Pilots do not pack them, sent them off to a guy who specializes in that.
03-03-2010, 03:33 PM
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Originally Posted by Cubdriver
They are meant to be deployed at low speeds like 100 knots or so. When I worked on test aircraft we had them on all the aircraft, and they had speed limitations around 120 knots. Get in an unrecoverable spin, pull the handle, it would pull the tail back up for you. Some use explosive charges and some just use springs to deploy. The spring and cable systems especially were not all that reliable, I heard very recently the crew on one of our aicraft had an accidental deployment without doing anything to ask for it. They jettisoned the chute and all was well, not sure if the chute was damaged or not.
USMCFLYR
03-03-2010, 04:31 PM
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The F-4 landing chute could be repacked by most anyone and we used them often to save the brakes. It took a stand and a good wacking with a chock to get all of that JP stinking nylon into the tailcone. It was deployed by a large spring.
Alternate uses included spin recovery. Tapping the burners would cut the chute in less than a second as would hitting the release handle.
The major problem with a chute on rollout is that it increases your sensitivity to crosswinds by a very large factor.
Cubdriver is right as usual, above a certain speed most will be ripped off or blown out. The fighter chutes were good for about 160+ knots or so.
Alternate uses included spin recovery. Tapping the burners would cut the chute in less than a second as would hitting the release handle.
The major problem with a chute on rollout is that it increases your sensitivity to crosswinds by a very large factor.
Cubdriver is right as usual, above a certain speed most will be ripped off or blown out. The fighter chutes were good for about 160+ knots or so.
Last edited by jungle; 03-03-2010 at 04:47 PM.
03-03-2010, 04:58 PM
#8
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The F-4 landing chute could be repacked by most anyone and we used them often to save the brakes. It took a stand and a good wacking with a chock to get all of that JP stinking nylon into the tailcone. It was deployed by a large spring.
USMCFLYR
03-03-2010, 05:01 PM
#9
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Originally Posted by USMCFLYR
Well you didn't *always* need to use a chock as those rascally PCs made me use my fist to punch the last of the chute into that little tailcone - of course racking my knuckles in the process!
USMCFLYR
USMCFLYR
03-03-2010, 05:27 PM
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Originally Posted by Cubdriver
They are meant to be deployed at low speeds like 100 knots or so. When I worked on test aircraft we had them on all the aircraft, and they had speed limitations around 120 knots. Get in an unrecoverable spin, pull the handle, it would pull the tail up. Some use explosive charges and some just use springs to deploy. The spring and cable systems especially were not all that reliable, I heard recently one of the test aircraft had an accidental deployment without doing anything to ask for it. They jettisoned the chute and all was well, not sure if the chute was damaged. Pilots do not pack them, sent them off to a guy who specializes in that.
What everyone says sounds good, but i think the faster you are (up to the limits of the device) the more effective it would be. The Lear 35 maximum drag chute deploy speed is 150kt (demonstrated). Vref is anywhere between 115-130kts. Shouldn't be an issue on the ground, but should separate in flight.
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