New Paradigm in Spacecraft Parachute Design

[ep29030]

This might interest some of you....

https://www.laboratoryequipment.com...=5866807&et_rid=%%subscriberid%%&location=top

 

[XolveJohn]

That looks like a typical normal old school parachute, just new testing techniques.

No parachute works all the time. Just ask the guy in that early Soyuz. Hit the ground at 300 mph.

Don't ever wrap the shroud lines around the chute. Coil them up. There is a trick to packing chutes so they work.

I did think the airbags they used on the one Mars lander were clever.

 

[OverTheTop]

No parachute works all the time. Just ask the guy in that early Soyuz. Hit the ground at 300 mph.

IIRC that was caused by a process sequence issue. Chute was packed in the compartment before the attached cover was given its final bake for hardening. This was to keep schedule I think. Even the entire weight of the capsule pulling on one processed the same way could not unfurl it from the bay. Apparently the conversation with mission controllers on the way down was scathing. I have a recollection that Gagarin might have originally been slated for that flight, but his hero status meant Komarov went first dur to the high risk. There were many problems and concerns about the craft, even before launch.

 

[jazzviper1]

That looks like a typical normal old school parachute, just new testing techniques.

No parachute works all the time. Just ask the guy in that early Soyuz. Hit the ground at 300 mph.

Don't ever wrap the shroud lines around the chute. Coil them up. There is a trick to packing chutes so they work.

I did think the airbags they used on the one Mars lander were clever.

There is nothing wrong with wrapping the lines around the folded or rolled chute. I do it to slow the deployment of the chute it reduces the opening shock. Never had a problem.

 

[rharshberger]

There is nothing wrong with wrapping the lines around the folded or rolled chute. I do it to slow the deployment of the chute it reduces the opening shock. Never had a problem.

+1, this isn't heavy cargo drops or skydiving, in over 20 years of flying rockets I have yet to see evidence of line burn on my chutes. I have always done Estes chutes the way the recommend and as long as the chute hits air undamaged it deploys, for mid and high power I use a modified version but still make about 2-3 wraps around the canopy, no issues there either. I dont believe the typically short shroud lines we use are in contact with the canopy long enough to damage, most damage seems to come from ejection charges or the chute fouls.

 

[Incongruent]

I have a recollection that Gagarin might have originally been slated for that flight, but his hero status meant Komarov went first due to the high risk. There were many problems and concerns about the craft, even before launch.

Komarov went even though he know it was going to fail and because Gargin was backup and he didn't want to have his friend die.

 

[ksaves2]

Komarov went even though he know it was going to fail and because Gargin was backup and he didn't want to have his friend die.

This account is fraught with inconsistencies. Read the original article here: https://www.npr.org/sections/krulwi...3/cosmonaut-crashed-into-earth-crying-in-rage

Then go to the links with an annotated version. Kurt

 

[XolveJohn]

jazz: I have seen many rocket chutes not deploy due to wrapping lines around them. We found that folding the chute a few times, stuffing in the tube, then coiling the lines, and laying the coil on top works every time.

Plus a trick when there is 2 chutes, one for the nose section, one for the body, put the nose chute on the bottom. That way if they just partially blow out, the nose chute will pull out the other one.

Chutes are not 100% reliable. When I used to jump, beside the jumpmaster forgetting to clip my static line to the pilots seat (I caught it and yelled him before jumping), I had a chute come out with half twisted lines. Watched it for a while before dumping reserve, they did untwist quick enough. Note I quit before the 13th jump, I was sure I was going to die.

One of our scale competitors in the last Internats was first in static judging with a Saturn 1B, flew great, except the chute for a shroud section failed to open. DQ. He did not win.

 

[jazzviper1]

jazz: I have seen many rocket chutes not deploy due to wrapping lines around them. We found that folding the chute a few times, stuffing in the tube, then coiling the lines, and laying the coil on top works every time.
I have never had a failure packing the way I do. Lines first deployment is the preferred method for man rated and cargo chutes. The only practical way to duplicate that with really small chutes is to roll pack them and roll the lines around them. Helps prevent popped lines too.

Plus a trick when there is 2 chutes, one for the nose section, one for the body, put the nose chute on the bottom. That way if they just partially blow out, the nose chute will pull out the other one.
I still do that.

Chutes are not 100% reliable. When I used to jump, beside the jumpmaster forgetting to clip my static line to the pilots seat (I caught it and yelled him before jumping), I had a chute come out with half twisted lines. Watched it for a while before dumping reserve, they did untwist quick enough. Note I quit before the 13th jump, I was sure I was going to die.
Never had the static line issue, but I did have line twists due to an improperly set deployment brake on a chute someone else packed. Left side opening shock was a bit harsh. I had to kick the line twists out because the canopy was in a turn.

One of our scale competitors in the last Internats was first in static judging with a Saturn 1B, flew great, except the chute for a shroud section failed to open. DQ. He did not win.

Sorry I don't know any thing about international scale rules.

 

[Lowpuller]

Coiling lines is asking for a tension knot.

Never coil lines.

I recommend wrapping them around the canopy.

The stacking technic is used in rock climbing and vertical caving, because coiled ropes, coiled lines = tension knots.

Either properly stow lines on a diaper or dbag, or wrap them around the canopy, but I would strongly recommend against coiling. Just my opinion based on experience, 2000+ jumps, a rigger, rock climber and vertical caver.

 

[jazzviper1]

Coiling lines is asking for a tension knot.

Never coil lines.

I recommend wrapping them around the canopy.

The stacking technic is used in rock climbing and vertical caving, because coiled ropes, coiled lines = tension knots.

Either properly stow lines on a diaper or dbag, or wrap them around the canopy, but I would strongly recommend against coiling. Just my opinion based on experience, 2000+ jumps, a rigger, rock climber and vertical caver.

+1 I agree.

 

[XolveJohn]

Everyone has his favorite methods, but on a light rocket, there is not much force pulling on chute to open, wrapping the lines around it just makes it worse. Would make a good R&D project, comparing methods.

Another problem is opening airspeed, too low and it will not open, that is why I like to have it able to just spring open without entangling lines to restrict it.

A long time ago, a kid decided to ride a jet ski off of niagra falls river, then open his parachute. Problem is was going too slow for chute to open and died from the fall.

We should ask that sole cosmonaut who was testing one of the first Soyuz, with an untested chute. Never opened, and he hit the ground at 300mph.

We had a jumper falling on his back, chute had a streamer, he tried to snap open the lines. They tell you never to do that, as you can't judge time that well. They were right, he never got it open. Parachutes to me are like gambling, don't do it with your life, or your rocket. When the chute hits the air, it has to be ready to inflate without any delay. I have never had any problem with laying the coil of lines on top of the chute, hundreds of deployments, plus a lot more of my pals.

Also, techniques that work on real people chutes may not be optimal for small model chutes, the Reynolds # is quite different, as the aerodynamics. Like how little model planes do not fly nearly as well as big real planes.Q

QUIZ TIME. What went wrong here?:

https://www.youtube.com/watch?v=hhwhkwE1nws

[url]https://www.youtube.com/watch?v=6qF_fzEI4wU
[/URL]

 

[jazzviper1]

Everyone has his favorite methods, but on a light rocket, there is not much force pulling on chute to open, wrapping the lines around it just makes it worse. Would make a good R&D project, comparing methods.
My experience speaks or itself I have been flying rockets since 1976.

Another problem is opening airspeed, too low and it will not open, that is why I like to have it able to just spring open without entangling lines to restrict it.
I wrap the lines around all of my hand tossed parachutes and they open just fine.

A long time ago, a kid decided to ride a jet ski off of niagra falls river, then open his parachute. Problem is was going too slow for chute to open and died from the fall.
He was an idiot Niagra isn't that high, even with a stack packed no slider base rig I don't think it would open.

We should ask that sole cosmonaut who was testing one of the first Soyuz, with an untested chute. Never opened, and he hit the ground at 300mph.
The Soyuz parachute failure most likely had nothing to do with packing, but with the unstable tumbling capsule, and possibly a faulty connection to the space craft.

We had a jumper falling on his back, chute had a streamer, he tried to snap open the lines. They tell you never to do that, as you can't judge time that well. They were right, he never got it open. Parachutes to me are like gambling, don't do it with your life, or your rocket. When the chute hits the air, it has to be ready to inflate without any delay. I have never had any problem with laying the coil of lines on top of the chute, hundreds of deployments, plus a lot more of my pals.
Statisticly speaking parachutes are the most reliable form of aircraft ever developed. They will open from almost any packing configuration, some skydivers back in the 60s used to stuff them in paper shopping bags so they could jump faster. Stability of the load at the time of deployment has more to do with malfunctions than packing. If you packing method works for you that is fine keep doing what your doing.

Also, techniques that work on real people chutes may not be optimal for small model chutes, the Reynolds # is quite different, as the aerodynamics. Like how little model planes do not fly nearly as well as big real planes.Q
The basics are still the same.
QUIZ TIME. What went wrong here?:
Pilot chute never opened the pack. Looks like he was using a standard sized pilot chute he should have used at least a 60 inch pilot chute. So poor planning and poor equipment choice/knowledge and definitely poor body position were the cause of this accident. Also he should just not have done it. This is apples and oranges to our discussion .

https://www.youtube.com/watch?v=hhwhkwE1nws

[url]https://www.youtube.com/watch?v=6qF_fzEI4wU
[/URL]

...

 

[XolveJohn]

Someone said his pulling line could have been rigged wrong, and the flip was bad, I don't know.

I don't consider parachutes the most reliable item in recovery, not like a streamer. I do not think there is a computer

simulation program for parachutes, that works. Note nasa always tests theirs in a wind tunnel, I saw a Mars one rip into
shreds.

Parachutes don't like to open too slow or too fast. I am trying to get one to open from ejecting the engine from a glider pod, like in the old days, but it will be going pretty fast. Do you have any suggestions? I will try wrapping the lines around it in this app, to slow it down.

The second vid everything went well, but we were all on edge seeing on TV in real time. Nervous. The network did not insist on a reserve chute at first, then the day before demanded it. He did not want it, did not train with one, affected maneuvering. And he had to land on his back to avoid getting paralyzed, as bent in half. For some reason it was a back reserve, I had used front ones, dunno. But then when ready to jump they called him and said he could take it off!

That was a very special net setup on 4 cranes with a complex tension releasing control system, read about the project, was on TV about a year ago. Good jumping.

Another question. The Apollo capsule had 3 chutes. Was this for redundancy? They could have used one big one.
Wasn't there a possibility of the 3 tangling together? The shroud lines were all the same length.

 

[XolveJohn]

Here are some comments from a guy who has been flying model rockets and high power since the late 1960's.

Wrapping your shroud lines around the parachute itself, whether it is plastic or
fabric (such as rip-stop) is generally not a good idea, although I believe that
companies like Estes tell you to do this in their instructions. It takes longer for
the parachute to open after deployment, and this may allow the rocket to build up
downward airspeed so that when the parachute canopy does open the high speed opening
shock could blow out the chute, tear shroud lines off the canopy or zipper the
airframe, or all three. This may not be a big problem in a model rocket that weights
only a few ounces, but a high power rocket is another story. There are several
different techniques you can use that work better. If you are using a deployment
bag, the D-bag will have canopy line stows on its outside. Problem solved. Some
people will lay the canopy out and run the lines up and down on top of the canopy
fabric and then fold the canopy on top of the lines. The method I prefer is to wrap
the lines around my hand and then use one rubber band to secure them. I do the same
with the shock cord. The rubber band will pop off when the lines are extended.
Both the parachute lines and shock cord are placed on top of the folded canopy,
which is protected by a nomex flame blanket.

 

[jazzviper1]

Here are some comments from a guy who has been flying model rockets and high power since the late 1960's.

Wrapping your shroud lines around the parachute itself, whether it is plastic or
fabric (such as rip-stop) is generally not a good idea, although I believe that
companies like Estes tell you to do this in their instructions. It takes longer for
the parachute to open after deployment, and this may allow the rocket to build up
downward airspeed so that when the parachute canopy does open the high speed opening
shock could blow out the chute, tear shroud lines off the canopy or zipper the
airframe, or all three. This may not be a big problem in a model rocket that weights
only a few ounces, but a high power rocket is another story. There are several
different techniques you can use that work better. If you are using a deployment
bag, the D-bag will have canopy line stows on its outside. Problem solved. Some
people will lay the canopy out and run the lines up and down on top of the canopy
fabric and then fold the canopy on top of the lines. The method I prefer is to wrap
the lines around my hand and then use one rubber band to secure them. I do the same
with the shock cord. The rubber band will pop off when the lines are extended.
Both the parachute lines and shock cord are placed on top of the folded canopy,
which is protected by a nomex flame blanket.

I have never seen a rocket accelerate after ejection usually the now broken aerodynamics have a very low terminal velocity.
Take it from a rigger who has spent over 33 years working with and studying parachutes and related technology.
By the way Parks College uses parachute simulation software, and so do several parachute manufacturers.
Like I said before keep doing what works for you but don't tell people that your way is the only way.

 

[georgegassaway]

Here are some comments from a guy who has been flying model rockets and high power since the late 1960's.

Wrapping your shroud lines around the parachute itself, whether it is plastic or
fabric (such as rip-stop) is generally not a good idea, although I believe that
companies like Estes tell you to do this in their instructions. It takes longer for
the parachute to open after deployment, and this may allow the rocket to build up
downward airspeed so that when the parachute canopy does open the high speed opening
shock could blow out the chute, tear shroud lines off the canopy or zipper the
airframe, or all three.

My experience is mostly the opposite. When ejection is late and the rocket is falling fast, the last thing I want is an instant chute deploy (Bene the,re done that, shredded chute, or broken shock cord, or zippered body, or combination of those three).

I do want it to take a little while to unroll and deploy. By then, the rocket has slowed down to a reasonable level.

If I had a rocket that ejected at a slower speed, but with the chute taking a few seconds to deploy the rocket began to fall fast enough for the chute to rip , I have made a totally inadequate weak recovery system which would never have held together for a high speed deploy.

When NASA wants to deploy chuts to slow something down, they don't have it "pop open" right away. For one a drogue help slow some, as well as to stabilize, and often to help yank out the main chutes. When the main chutes are popped out, they are usually reefed. So the vehicle slows more and more. Then the chute disreefs, preferably a slow disreefing, so it slows more before the chute finally is unreefed completely and deployed 100%. On the shuttle SRB's the process was very long, as there was a lot of mass at extreme speeds to slow down. They did not need to slow it all down at once.

See wiki about Shuttle SRB parachute sequencing/reefing: https://en.wikipedia.org/wiki/Space_Shuttle_Solid_Rocket_Booster#Descent_and_recovery

I know it's not very practical to attempt reefing on hobby parachutes, and a shuttle SRB level of reefing would be overkill. But relating how important it is to not go for full 100% deployment in an instant, if there are are better options.

 

[XolveJohn]

OK, will watch that. I guess variety is the spice of life. If everyone did things the same it would be boring.

I know that with real chutes (jumpers), they use some kind of bag or sleeve to control deployment speed, I think.

I have mostly flown model rockets, that is why I asked my friend to comment, who has flown L's, hybrids, etc. Also was
an avid jumper.

 

[XolveJohn]

Never got an answer:

Another question. The Apollo capsule had 3 chutes. Was this for redundancy? They could have used one big one.
Wasn't there a possibility of the 3 tangling together? The shroud lines were all the same length.

COMMENTS FROM MY PAL, who has been flying rockets for 50 years. Dude has a lot of experience, and knowledge.




"I have never seen a rocket accelerate after ejection"

Just because the aerodynamics
of a rocket are broken doesn't necessarily mean that the rocket will slow down.
I've seen plenty of HP rockets blow their nose one and still scream in and impact
the ground at high speed.

Any parachute will "snivel" for a time before it catches air and opens. This time
is determined by the size of the canopy and how it was packed. With the advent of
dual deploy for HP rockets, it is advantageous to open your drogue parachute right
at apogee, which is usually when the airspeed of the rocket is lowest or perhaps
even zero. This gives you the advantage of having the most altitude to open your
drogue and the slowest vehicle velocity to minimize the opening shock on the
recovery system and anything attached to it. Drogue parachutes reduce the descent
velocity of the rocket and give more control as opposed to a drogue-less recovery
system in which the rocket is in free fall with nothing to slow it. Having a drogue
chute will also lessen the opening shock on the main chute because of the slower
speed of descent. Many Estes-type rockets weigh so little that they won't even cause
damage to themselves much less anything they might hit if their recovery systems
doesn't deploy properly. High power rockets are another story.

Probably the most difficult thing is judging the ejection delay on conventional
commercial model and high-power rocket motors that will allow recovery system
ejection at apogee. Too short a delay and the rocket will eject its recovery system
on ascent and too long a delay will allow the rocket to descend at a high speed
before ejection of its recovery system. Both cases can cause airframe zippering and
damage to the recovery system. Electronic ejection systems solved this problem.

SRB analogy is flawed in many ways. First of all, you are never going to
get an "instant chute deploy" in anything other than a small model rocket with a
plastic chute. Of course, the smaller the parachute, the faster it will open.
George is talking about having a rocket accelerating on its downward flight suddenly
opening its parachute. Of course this can cause damage to the rocket and recovery
system. This is where picking the right ejection delay is crucial. I'm sure you
have experienced the plastic parachute in your model rockets "setting", that is,
sticking together. You put talc on the inside of the parachute to prevent this from
happening. By tightly wrapping the plastic parachute with the shroud lines, you will
increase the chance of the parachute sticking together and not deploying correctly.
The low weight of the rocket, coupled with the low descent speed will not get enough
air flowing past the folded up parachute to force it to open.

Now I have seen large rip-stop parachutes blow out panels or break lines, but that
is usually because the canopy was undersized for the rocket or the rocket was
traveling too fast (up or down) when the canopy opened.

Reefing the canopies is a good idea. Skydivers of course have a slider on their
canopy lines which slow the opening of the canopy. One HP rocket company does make
a device to mimic this, but it is large and heavy and meant only for HP rockets.
Having devices to reef the opening of parachutes on low-power model rockets is not
feasible. Besides, we are talking about model rockets here, which usually weigh
less than 3 pounds, not some huge SRB that, according to NASA, weight 193,000 pounds
EMPTY! You really can't compare the two and it is ridiculous to even try.

 

[XolveJohn]

pic

 

[jazzviper1]

Never got an answer:

Another question. The Apollo capsule had 3 chutes. Was this for redundancy? They could have used one big one.
Wasn't there a possibility of the 3 tangling together? The shroud lines were all the same length.

COMMENTS FROM MY PAL, who has been flying rockets for 50 years. Dude has a lot of experience, and knowledge.




"I have never seen a rocket accelerate after ejection"

Just because the aerodynamics
of a rocket are broken doesn't necessarily mean that the rocket will slow down.
I've seen plenty of HP rockets blow their nose one and still scream in and impact
the ground at high speed.

Any parachute will "snivel" for a time before it catches air and opens. This time
is determined by the size of the canopy and how it was packed. With the advent of
dual deploy for HP rockets, it is advantageous to open your drogue parachute right
at apogee, which is usually when the airspeed of the rocket is lowest or perhaps
even zero. This gives you the advantage of having the most altitude to open your
drogue and the slowest vehicle velocity to minimize the opening shock on the
recovery system and anything attached to it. Drogue parachutes reduce the descent
velocity of the rocket and give more control as opposed to a drogue-less recovery
system in which the rocket is in free fall with nothing to slow it. Having a drogue
chute will also lessen the opening shock on the main chute because of the slower
speed of descent. Many Estes-type rockets weigh so little that they won't even cause
damage to themselves much less anything they might hit if their recovery systems
doesn't deploy properly. High power rockets are another story.

Probably the most difficult thing is judging the ejection delay on conventional
commercial model and high-power rocket motors that will allow recovery system
ejection at apogee. Too short a delay and the rocket will eject its recovery system
on ascent and too long a delay will allow the rocket to descend at a high speed
before ejection of its recovery system. Both cases can cause airframe zippering and
damage to the recovery system. Electronic ejection systems solved this problem.

SRB analogy is flawed in many ways. First of all, you are never going to
get an "instant chute deploy" in anything other than a small model rocket with a
plastic chute. Of course, the smaller the parachute, the faster it will open.
George is talking about having a rocket accelerating on its downward flight suddenly
opening its parachute. Of course this can cause damage to the rocket and recovery
system. This is where picking the right ejection delay is crucial. I'm sure you
have experienced the plastic parachute in your model rockets "setting", that is,
sticking together. You put talc on the inside of the parachute to prevent this from
happening. By tightly wrapping the plastic parachute with the shroud lines, you will
increase the chance of the parachute sticking together and not deploying correctly.
The low weight of the rocket, coupled with the low descent speed will not get enough
air flowing past the folded up parachute to force it to open.

Now I have seen large rip-stop parachutes blow out panels or break lines, but that
is usually because the canopy was undersized for the rocket or the rocket was
traveling too fast (up or down) when the canopy opened.

Reefing the canopies is a good idea. Skydivers of course have a slider on their
canopy lines which slow the opening of the canopy. One HP rocket company does make
a device to mimic this, but it is large and heavy and meant only for HP rockets.
Having devices to reef the opening of parachutes on low-power model rockets is not
feasible. Besides, we are talking about model rockets here, which usually weigh
less than 3 pounds, not some huge SRB that, according to NASA, weight 193,000 pounds
EMPTY! You really can't compare the two and it is ridiculous to even try.

The Apollo capsule used three chute but only two were necessary for a safe landing on water. So yes there was redundancy in the system. Both Mercury and Gemini had main and reserve parachutes. There would have been no room to put a single large parachute in the recovery compartment due to its shape.

As to the SRB statement they are decelerating during the entire free fall. There is a really good video that takes you for a ride from launch to splash down, with speed and altitude data included.
What George is talking about I have seen several times when I get a "bonus delay" and the rocket is half way to the ground at ejection. It does not take hardly any speed to open a small plastic parachute talc or no talc. I tie one to a toy roll and wrap it like I usually do, toss it in to the air and it will open just fine, and my toss isn't that fast. Often the chute will open just at apogee (about 15 to 20 feet with my arm) and that is the point at which it is moving the slowest. Back when I started in rocketry the roll and wrap method was all the books and instructions recommended and it has worked well for me and thousands of other rocketeers. By the way I never said to wrap the lines "tightly" around the chute, snugly would be a more apt description.

 

[XolveJohn]

Got it. But I remember that when jumping, if your main chute, and reserve had about the same length of lines, you had to cut away from the main before dumping the reserve, or they could tangle. The 3 Apollo chutes did not seem to have that problem. Maybe you could avoid cutting away when jumping?

 

[georgegassaway]

When jumping, you do not release main and reserve at the same time.

For Apollo and shuttle SRB's, the three chutes were ejected out simultaneously, no opportunities to tangle with one another.

"Project Apollo : Last Five Miles Home" A documentary produced by Northrop Ventura Corporation detailing development and testing of the Apollo Command Module Earth Landing System (ELS) to include the spacecraft's Main Parachutes used to safely recover the crew after returning from the moon. The film includes discussion and footage of parachute production, drop tests, development of the affiliated Earth Landing Sequence Controller, Drogue and Pilot parachutes.

[video=youtube;gDNDQQlx1JE]https://www.youtube.com/watch?v=gDNDQQlx1JE[/video]

So aggravating that the last scene ended so abruptly!

And this video, "Riding the Boosters", is a lot of fun to watch, period. The Main Chute deploy is at about 6:45, showing the slow deploy and disreefing. The Drogue deploy is not shown. Seems to happen around 6:25 or so as that is when the booster seems to start to stabilize tail-down. And a few seconds later the effect of the vertical deceleration apparently dislodges some smoldering stuff from inside the booster (the SRB's did have liners, somewhat like reloadable motors do), to fall out the nozzle and burn more intensely once it gets into the 300 mph blast of fresh air. The event that occurs at about 7:03, smoke and something falling off to splash into the ocean, is the SRB nozzle extension being blown off. That was to reduce the stress on the aft skirt of slamming into the water at 56 mph. The nozzle could not be reused anyway.

[video=youtube;527fb3-UZGo]https://www.youtube.com/watch?v=527fb3-UZGo[/video]

 

[XolveJohn]

The old military surplus chutes we used had lines twice as long as the reserve, it was deemed safe to open the reserve even if the main was out, but failing. There were no capewell fittings to cut-away.

Nice vid on the Apollo chutes. They sure packed down into a small package, and had a huge number of shroud lines.

The opening is still scary to me. Since the whole mess was not rotating, there was no chance of lines entangling. But if there were differences in the 3, or only 2 came out, it might have spun with dire consequences.

Here is a great site if you never heard of it: https://www.apolloarchive.com/

Lots of pics of the moon program. This is the site I send "fake moon landing" people to, telling they could not have faked all those shots. Not even at Walt Disney!

 

[georgegassaway]

The opening is still scary to me. Since the whole mess was not rotating, there was no chance of lines entangling. But if there were differences in the 3, or only 2 came out, it might have spun with dire consequences.

Some of the testing, as in that first video, used two chutes instead of three.

I the case of Apollo 15, one chute did not open properly. I do not know the cause, it was out and partially inflated, almost as though the reefing lines got hung up or were not cut away. I any case, landed safely on two chutes. In the video below, someone on audio mentioned the landing speed on two chutes was 32 ft/sec rather than 28 ft/sec if all three were open.

If only one had opened, possibly injury to the crew but survivable impact . But would probably need to get them out ASAP as the CM pressure shell structure may have cracked, may have begun to take on water. They sure had copters right on scene, that was the closest camera footage I can recall seeing of a splashdown.

[video=youtube;E-Vd75Ptg9I]https://www.youtube.com/watch?v=E-Vd75Ptg9I[/video]

Some more videos. A clip from "Moon Machines", the CM episode.

[video=youtube;gdO151wNPkI]https://www.youtube.com/watch?v=gdO151wNPkI[/video]

And this Orion spacecraft parachute test. One chute was a bit lazy in opening.

[video=youtube;bwdNQoAKBs4]https://www.youtube.com/watch?v=bwdNQoAKBs4[/video]

 

[XolveJohn]

I would love to know how those pencil size reefing cutters worked. No way they were wired to the deployment controller in the capsule, they must have been self contained. Maybe mechanical with baro sensor. Or a squib with electronics in that little pocket. You would want them all to fire at exactly the same time, hard if independent. Maybe were connected with radio modules.

At least we did not need landing rockets like the Soyuz.

Here is a great Little Joe flight, cause it falls apart! Backwards gyro wires. The Chinese did that once on a Long March,
it tipped and flew horiz a couple miles, hitting a town and blowing it to smithereens.

[video=youtube;AqeJzItldSQ]https://www.youtube.com/watch?v=AqeJzItldSQ[/video]

 

[jazzviper1]

I would love to know how those pencil size reefing cutters worked. No way they were wired to the deployment controller in the capsule, they must have been self contained. Maybe mechanical with baro sensor. Or a squib with electronics in that little pocket. You would want them all to fire at exactly the same time, hard if independent. Maybe were connected with radio modules.

At least we did not need landing rockets like the Soyuz.

Here is a great Little Joe flight, cause it falls apart! Backwards gyro wires. The Chinese did that once on a Long March,
it tipped and flew horiz a couple miles, hitting a town and blowing it to smithereens.

[video=youtube;AqeJzItldSQ]https://www.youtube.com/watch?v=AqeJzItldSQ[/video]

A cartridge with a built in time delay. They were armed on line stretch, and when the delay expired the cartridges charge drove a sharp wedge that cut the reefing line. The same system is used on the parachute in the Aces II ejection seat.

 

[jazzviper1]

Some of the testing, as in that first video, used two chutes instead of three.

I the case of Apollo 15, one chute did not open properly. I do not know the cause, it was out and partially inflated, almost as though the reefing lines got hung up or were not cut away. I any case, landed safely on two chutes. In the video below, someone on audio mentioned the landing speed on two chutes was 32 ft/sec rather than 28 ft/sec if all three were open.

Actually the reefing lines were not the problem. The RCS propellant leaked or was incorrectly dumped and ate through one of the risers thus resulting in a partial canopy. If I recall correctly some of it got into the crew compartment as well.

If only one had opened, possibly injury to the crew but survivable impact . But would probably need to get them out ASAP as the CM pressure shell structure may have cracked, may have begun to take on water. They sure had copters right on scene, that was the closest camera footage I can recall seeing of a splashdown.

[video=youtube;E-Vd75Ptg9I]https://www.youtube.com/watch?v=E-Vd75Ptg9I[/video]

Some more videos. A clip from "Moon Machines", the CM episode.

[video=youtube;gdO151wNPkI]https://www.youtube.com/watch?v=gdO151wNPkI[/video]

And this Orion spacecraft parachute test. One chute was a bit lazy in opening.

[video=youtube;bwdNQoAKBs4]https://www.youtube.com/watch?v=bwdNQoAKBs4[/video]

Thanks for posting the videos.

 

[XolveJohn]

Jazzviper: Interesting details on the reefing cartridges, are they mechanical, chemical, or electronic? The size of a pencil is pretty small, just wondering how they jammed that all in such a small package back then. Probably not electronic.

 

[Nytrunner]

I would love to know how those pencil size reefing cutters worked. No way they were wired to the deployment controller in the capsule, they must have been self contained. Maybe mechanical with baro sensor. Or a squib with electronics in that little pocket. You would want them all to fire at exactly the same time, hard if independent. Maybe were connected with radio modules.

At least we did not need landing rockets like the Soyuz.

Here is a great Little Joe flight, cause it falls apart! Backwards gyro wires. The Chinese did that once on a Long March,
it tipped and flew horiz a couple miles, hitting a town and blowing it to smithereens.

[video=youtube;AqeJzItldSQ]https://www.youtube.com/watch?v=AqeJzItldSQ[/video]

That's one way to test a LES. Have an actual accident....