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Is wearing a personal chute with a bail-out system acceptably safe compared to an airframe chute?

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SVSUSteve

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The ballistic chute alone is only a partial solution. When the plane hits the ground at 16'/sec, a standard rate, something has to decelerate the plane so that the occupant doesn't suffer a spinal compression fracture. Cirrus have a reinforced landing gear for that purpose. But if you come down over water, the landing gear won't help.
The landing gear is only part of the way the Cirrus manages those impact forces. Admittedly, the Cirrus models have a lot of room for improvement but is still better at managing vertical impact loads than about 95% of GA aircraft. The seats have an energy absorbing module for example. It's better to have a spinal fracture (which most of the sort we are talking about tend to be stable and many don't injure the cord) than to have no chance at survival at all.

There are good images of what this module looks like after an impact, into water no less, available on the docket management system of the NTSB. Look for the fatal crash of N91MB at Indianapolis in 2006 and find the survival factors report. I would provide the file directly but I happen to have been friends with the pilot who died in this crash and would prefer not to have dig it out of my archive for emotional reasons. If you cannot find it, let me know and I will post it.

EDIT: RiggerRob pointed out much the same thing.....sorry Rob, didn't see your post before I commented.
 

deftone

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Mar 24, 2018
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Lafayette, LA
Intereating discussions here. I wear a bailout rig every day as I’m a full time diver driver. Luckily never had to use it, but I have practiced getting from my seat to the door on multiple occasions and it’s not always easy with the rig on, even on the ground. Definitely take the time to practice if you go this route. Also be aware of snagging risks that could deploy your rig in the aircraft. An extremely dangerous event. At our drop zone we had a fatality a few years ago when a ride-along snagged his D-ring and promptly departed the airplane out of the open door. He struck the stab and was killed.

Also have a rigger teach you care and maintenance of the rig, also have them run through safe deployment and landings etc.

I had a BRS in my Rans, it was there when I bought it, so not much in the way of advice, but it was certainly a reassuring feeling knowing it was there.
 

Vigilant1

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I wonder if one of the large "G Series' hobby rocket engines would be enough to pull a pilot chute or even a very light canopy to full extension. Lots of things to go tragically wrong with that idea, but it would fill many Sundays with fun experimentation. It's nice to live in a place with a lot of wilderness . . .
NOT to encourage irresponsible experimentation or the misuse of hobby rocket engines. Just a back-of-the-envelope calculation:
Example parachute: Apco MD28UL: Weight 4.0 KG, max load 340 kg (750 lbs), 64m2 area. With a 750 lb load, Apco says the rate of descent is 6.3 m/s (21 fps, or 14mph). That's the same speed if you'd be at after a 7 foot fall--so good crush space under the butt will be important. (For comparison, the Cirrus SR22 descends at 15-28 fps).

Example rocket motor: F67-4W: 61 N-s total impulse, 69 N avg thrust, 86 N (19 lb force) peak thrust, total thrust duration: 0.95 sec.

If one of these engines were lifting the entire 'chute pack at once, it would accelerate at about 3Gs and at the end of the the .95 sec burn time, the package would be 13 meters (42 feet) from the launch point (assuming a directly vertical launch). Now, in reality, our rocket won't be lifting everything at once. But there will also be the resistance of the unrolling canopy and lines and the air resistance of that nylon. If the rocket/slug drags the pilot chute up first and then the apex of the folded canopy, it seems quite possible that the rocket could get a pilot 'chute and maybe a good portion of the canopy out of the pack, away from the plane and well into the slipstream.

Since this is a "no-fail" project, using two of these engines in parallel would help assure we got at least one timely ignition. If they both ignited, we'd expect the acceleration to be 99 m/s2 (10g's). That's, again, assuming the whole parachute pack is lifted at once rather than spooling it out starting at the apex . If our rocket/"slug" drags our pilot chute+ lines, canopy, shroud lines, and bridle in trail and the whole thing totals 40 meters in length, they would be fully stretched out at 0.9 sec, just before the thrust ends (with the rocket "slug" traveling at 200 mph, in theory) . Again, air resistance, line drag, etc would slow things down in the real world.

The rocket engines come in a 2-pack for $35. The APCO MD28-UL lists for about $1100.

To get everything way from the plane a lot more rapidly, a larger rocket motor is needed. Engines with 5-10 times the thrust shown above are available.

To state the obvious: It would require a lot of work to actually develop a DIY setup that is reliable. Getting the canopy and lines out into the air is just one step in the process (e.g the APCO product has a max tested opening velocity of 90 mph. Anyone wanting more than that will have even more work to do--sliders, etc). Since a life depends on it, it's smarter to invest in a professionally engineered whole-plane parachute. There are a lot of scenarios where a botched 'chute deployment would give results far worse than an attempted landing.
 
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Riggerrob

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How would you quick attach the pilot chute to the whole airplane chute, when rigging/un-rigging? I'm assuming the pilot chute would stay with the wing, and the canopy with the fuselage....
Dear karmarepair,
I am suggesting leaving all of the AAP and pilot-chute semi-permanently bolted to the fuselage. Keep the parachute canopy in the turtledeck, but move the pilot-chute up to the top of the rear cabane struts. Route the pilot-chute bridle/lanyard up a rear cabane strut. Build a small, wedge-shaped fairing for the pilot-chute. To make space for the new fairing, saw a corner off of the left wing panel (inboard, rear corner). This adds zero new bolts or pins to install before flight.
The only pin - to worry about - is the AAP's ground locking pin, which is removed during normal pre-flight walk-arounds ... similar to ejection seat ground locking pins. If the pilot forgets to remove the ground locking pin, a big, red, "remove before flight" flag will sap him/her in the face. I would bolt the AAP deployment handle to a front cabane strut so that it is easy for the pilot to see and pull.

I would also add a shadow-board or tool-roll to simplify pin-count during pre-flight walk-arounds. If your tool roll only holds one pin per slot, it is quickly evident if a pin is missing. The cloth tool roll can substitute for the second-set-of-eyeballs.
A second set of eye-balls is the best inspection tool.
 

SVSUSteve

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The landing gear doesn't help dissipate impact shock in a water landing.
Well aware. I was simply pointing out that the landing gear not the only attenuating mechanism and honestly, as someone (RiggerRob?) pointed out, they are effectively a secondary mechanism due to the normal nose low attitude associated with ground contact.
 
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