Making Parachutes from Umbrellas?

[BigMacDaddy]

The other day I saw a broken kid's umbrella with a nice American flag design on it. I wondered -- could you turn that into a parachute for a model rocket?

I found this video showing exactly this (although not for rockets) -

Ah and then I even found an Apogee newletter talking about this - https://www.apogeerockets.com/education/downloads/Newsletter487.pdf

I guess I really should have stopped and picked up that umbrella.

Has anyone done this?

 

[Sandy H.]

I have not, but a club member almost exclusively flies modified canopies from umbrellas. Next time I'm there, I'll ask and try to take a few pictures. They recover very nicely and are quite colorful. It might be a lot of work, but once I know more, I'll follow up.

Sandy.

 

[BigMacDaddy]

Some examples...



best one I found so far...



I guess many of these are polyester which seems like it is even more heat resistant than nylon...

 

[mikeyd]

Here is one under recovery on an Estes/NCR bomarc, that was built heavy at over 3lbs. If you Schroll in tight you can see the MCI on the side of the 54in umbrella/parachute.

 

[Hobie1dog]

I guess many of these are polyester which seems like it is even more heat resistant than nylon...

From the Web:

"As they are often used in outdoor gear and apparel made for the outdoors, they are both shrink-and-stretch resistant, and mold, mildew and stain resistant! Another interesting distinguishing comparison is that while both fabrics are flame retardant, polyester is significantly more heat-resistant than its nylon ..."

Will polyester melt in high heat?

Like most synthetic fabrics, Polyester is not highly flammable. Polyester is naturally flame-retardant, but it does melt when it reaches a high temperature. Poly blends like polycotton can both burn and melt, depending on the nature of the fibers and the weave of the fabric.

 

[Scott_650]

Here’s an Apogee Peak of Flight article on the subject https://www.apogeerockets.com/Peak-of-Flight/Newsletter487

 

[BigMacDaddy]

Here’s an Apogee Peak of Flight article on the subject https://www.apogeerockets.com/Peak-of-Flight/Newsletter487

Thanks -- yes, I found that article in my search... definitely going to start looking for old / broken umbrellas.

 

[rocket_troy]

Tried it a coupla times on an L class HPR hybrid. Mind you, I was using a $2 shop cheap Chinese offerings, but it didn't hold up for my attempts. Probably okay for smaller/lighter rockets.

TP

 

[Kelly]

I've done it, on an L1 rocket. It worked fine, it was about a 3'+ chute. The material used is not as thin as the 1.1oz ripstop I normally use to make a chute, so it doesn't pack as well, and wieghs a bit more, though.

 

[Handeman]

I have 4 or 5 chutes made from umbrellas and a few more old umbrella skins waiting. They are small, about 30", to 54" golf umbrellas. Most of them were picked up from old broken and discarded umbrellas. I used them for Level 1 and Level 2 DD rockets up to about 9 lbs. I bought a spool of 150 lbs. dacron line, like you find on the cheap 1" blinds you find at Wal-Mart, years back for $15 for 3000 ft. I use that for shroud lines, so a 53" chute costs me about $0.27 and 30 minutes time.

They don't have spill holes in the top, but that hasn't been an issue so far.

 

[bwayne64]

This would make a cool one, ; )

 

[cwbullet]

The other day I saw a broken kid's umbrella with a nice American flag design on it. I wondered -- could you turn that into a parachute for a model rocket?

I found this video showing exactly this (although not for rockets) -

Ah and then I even found an Apogee newletter talking about this - https://www.apogeerockets.com/education/downloads/Newsletter487.pdf

I guess I really should have stopped and picked up that umbrella.

Has anyone done this?

They work well but might not hold up as well to faster or more powerful deployments. You need to make sure your delay is near perfect.

 

[Handeman]

They work well but might not hold up as well to faster or more powerful deployments. You need to make sure your delay is near perfect.

I have not found that to be the case. All my umbrella chutes have held up just fine to less then nominal deployments. The only one that failed was a early deployment just before motor burnout at about 250 - 300 mph. In that case, I think the chute failure reduced the amount of damage to the rocket.

 

[cwbullet]

I have not found that to be the case. All my umbrella chutes have held up just fine to less then nominal deployments. The only one that failed was a early deployment just before motor burnout at about 250 - 300 mph. In that case, I think the chute failure reduced the amount of damage to the rocke

I have not seen the same results as a flyer or a Prefect. I would be interested in what technique you use that makes your results different.

 

[Handeman]

I have not seen the same results as a flyer or a Prefect. I would be interested in what technique you use that makes your results different.

Nothing special. I use about 2" of zig zag stitch to attach shroud lines that are 1.5 x diameter long, use minimal ejection charges.

 

[cwbullet]

Nothing special. I use about 2" of zig zag stitch to attach shroud lines that are 1.5 x diameter long, use minimal ejection charges.

The failures I have seen fail that would not fix. They failed at the seam of the umbrella and not at the point of attachment of the shroud line.

 

[Banzai88]

The failures I have seen fail that would not fix. They failed at the seam of the umbrella and not at the point of attachment of the shroud line.

In my experience, that's almost always the case with umbrella skins. We use a general rule of thumb about sewing ripstop gores for parachutes of no more than ~8 stitches per inch. I'm sure I could look up where I remember that from, probably Naka or even instructions from ripstopbytheroll.com......and it comes down to many of the unbrella skins that I've looked at to make parachutes from have a tighter stitch than that. Thus, it seems that the skins are more likely to tear at the seams because of that factor alone.

In normal use, an umbrella skin would never encounter the type of forces that an off-nominal deployment would subject it to (maybe short of Jim Cantore doing a hurricane report on live TV)....so we're lulled into a false sense of security about it's integrity.

Every single failure I've seen of an umbrella skin parachute was along the commercial seam line and occurred with an off-nominal deployment. Not saying that if everything goes perfectly as planned that they're not sufficient, but we're supposed to plan for the worst in our safety systems and recovery gear, no?

I stopped even looking at them as source material when I saw one fail and have a delayed opening with some authority that tore out every single stitch in it along the seam lines (but not one single stitch of shroud lines was even stressed when we inspected the wreckage), and the rocket came down with 6 nicely shaped triangle streamers. Opening hit so hard we could hear a loud bang, and watched as the parachute all but exploded into rags. The event was quite impressive, if somewhat dismaying for the ultimate fate of the rocket.

And yes, I think that something commercially available for rocketry would have fared better. I've seen a few similar events where the drouge charge never popped the rocket apart at apogee, and the rocket came in ballistic and deployed the main at the prescribed altitude......and all promptly failed to some degree, but NEVER to the degree that every single stitching seam tore on the canopy like the umbrella skin event.

 

[Handeman]

In my experience, that's almost always the case with umbrella skins. We use a general rule of thumb about sewing ripstop gores for parachutes of no more than ~8 stitches per inch. I'm sure I could look up where I remember that from, probably Naka or even instructions from ripstopbytheroll.com......and it comes down to many of the unbrella skins that I've looked at to make parachutes from have a tighter stitch than that. Thus, it seems that the skins are more likely to tear at the seams because of that factor alone.

In normal use, an umbrella skin would never encounter the type of forces that an off-nominal deployment would subject it to (maybe short of Jim Cantore doing a hurricane report on live TV)....so we're lulled into a false sense of security about it's integrity.

Every single failure I've seen of an umbrella skin parachute was along the commercial seam line and occurred with an off-nominal deployment. Not saying that if everything goes perfectly as planned that they're not sufficient, but we're supposed to plan for the worst in our safety systems and recovery gear, no?

I stopped even looking at them as source material when I saw one fail and have a delayed opening with some authority that tore out every single stitch in it along the seam lines (but not one single stitch of shroud lines was even stressed when we inspected the wreckage), and the rocket came down with 6 nicely shaped triangle streamers. Opening hit so hard we could hear a loud bang, and watched as the parachute all but exploded into rags. The event was quite impressive, if somewhat dismaying for the ultimate fate of the rocket.

And yes, I think that something commercially available for rocketry would have fared better. I've seen a few similar events where the drouge charge never popped the rocket apart at apogee, and the rocket came in ballistic and deployed the main at the prescribed altitude......and all promptly failed to some degree, but NEVER to the degree that every single stitching seam tore on the canopy like the umbrella skin event.

I'm not saying you are wrong to not use umbrella skins for chutes, but I don't agree with your "we're supposed to plan for the worst in our safety systems and recovery gear" statement because most of what is being discussed are not "safety" systems in my opinion, in that they are not there to insure the safety of people, only the undamaged "safe" return of the rocket.

I define safety systems to be systems that insure the safety of people at the launch, not keeping the rocket unbroken. Safe distances, pad setup vs. wind direction, LCO warning procedures and safety codes are the things the ensure personal safety. Anything done to ensure an undamaged (safe) recovery of a rocket is only adding to the personal safety of flyers and spectators by very small decimal points as to be almost negligible. We call it a "safe" landing and "safety systems" because it's convenient to use those terms, but almost all of the time we are talking about making sure the rocket is recovered in a flyable condition, not safety of people.

I don't think we can plan for the worst in "safety"/recovery systems or even outside nominal in many cases. If you do that, you over build, end up over weight, and can seldom meet the intended use of the rocket. Recovery systems, like all the systems of the rocket are managed by risk vs. cost vs. requirements. I'm not using 9/16" Kevlar shock cords and 3/8" u-bolts in what should be a 4 lbs. rocket because the worst case of a failed apogee charge and successful main charge might deploy the main at 300 mph. If that happens, my rocket and most of it's parts are a write off. I'll go build another one.

Sure, a rocket could fall on someone if that rocket's recovery fails, but they could also get struck by lightening. Which is the more likely? With the safety codes, safe distances, etc. I suspect the lightening, certainly being injured in a car accident going to and from the launch. The only really "safe" option would be to not launch at all.

Just my thoughts on this. That's why I don't have a problem using umbrellas skins as chutes. If they fail in an other than nominal flight, so be it. I'll just pick up the pieces and move on.