Parachute options for 45# L3 rocket.

Sorry, I read that into the thread title...

My bad, perhaps. I just meant it will be on an M motor. Not really relevant to the size of parachute ...

Bat-Mite, I think putting L3 in the tile probably did it.

Nathan, I can't remember if you use the deployment bags from Fruity Chutes or not? Just wondered if you had any experience with them as I am looking a a bag with the 60" Iris.

I really like the d-bag that came with my flare parachutes. I ended up sewing elastic to the outside of the bag to stow the lines.

You know, my chute came stuffed in a bag that is attached to a spill hole. Is that a D-Bag? I thought I would have to buy something. I still don't get the concept. What pulls the chute out? What happens to the bag after the chute is out?

There are several ways.
The most reliable is a pilot chute attached to the top of the bag.
This can be the drouge chute if you hold back the main in the bodytube by some device.

This figure from giant leap shows two different setups, one where everything is connected and the freebag method:

Bat-mite said:

You know, my chute came stuffed in a bag that is attached to a spill hole. Is that a D-Bag? I thought I would have to buy something. I still don't get the concept. What pulls the chute out? What happens to the bag after the chute is out?

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That should be a d-bag, d-bags are pulled off the main with a pilot chute attached to the d-bag.

So this assumes a separate chute for the nose cone and two-piece recovery?

I have updated the figure to show how you can do it with everything connected, but the freebag method has less changes of entanglement.

Thanks, Thomas.

I was thinking some more, and the bag that the chute came it is probably not fire-retardant. So I would still need to buy a bag, unless I can wrap the bag/chute in a Nomex blanket. I have a 33" Nomex.

Is there a downside to having the D-Bag inside a wrapper? Or, if I am using a wrapper, is there an upside to still using a D-Bag?

Bat-mite said:

Thanks, Thomas.

I was thinking some more, and the bag that the chute came it is probably not fire-retardant. So I would still need to buy a bag, unless I can wrap the bag/chute in a Nomex blanket. I have a 33" Nomex.

Is there a downside to having the D-Bag inside a wrapper? Or, if I am using a wrapper, is there an upside to still using a D-Bag?

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I wouldn't use a nomex blanket if you are using a D-Bag. The DBag will protect the main chute just fine. I would however wrap the drogue in nomex. The main upsides to a D-Bag are:

1. controls the deployment of the parachute. The shroud lines will always be taut by the time the chute starts inflating. It can also prevent tangling of components.
2. can pack a chute into a smaller space.
3. There is less chance of the chute hanging up in the body tube.

So if my D-Bag is made of plain old cotton cloth, I don't have to worry about it catching fire?

Bat-mite said:

So if my D-Bag is made of plain old cotton cloth, I don't have to worry about it catching fire?

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Can you post a picture? Most of the D-Bags I've dealt with are nomex.

NateLowrie said:

Can you post a picture? Most of the D-Bags I've dealt with are nomex.

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Um, eventually.... It is stuffed in a box at the moment. But remember, this is a military surplus cargo chute. I don't know how they deployed it, but I'm guessing there was no BP involved.

On a related note, even if it is Nomex, what protects the shroud lines on the outside?

Bat-mite said:

Um, eventually.... It is stuffed in a box at the moment. But remember, this is a military surplus cargo chute. I don't know how they deployed it, but I'm guessing there was no BP involved.

On a related note, even if it is Nomex, what protects the shroud lines on the outside?

Click to expand...

The bag should come with a flap that goes over the shroud lines. Giant leap has a good picture: https://giantleaprocketry.com/products/components_recovery.aspx#Tac-Bag

I will look at mine tonight; however, my guess is that it does not have anything such as that, and was never intended for pyrotechnic ejection.

Here are the pics of the bag that the chute came in.


This is the outside.


You can (sort of) see that there are shroud lines coming from the spill hole, and they go into the bag and are attached inside.


Turned inside out, you can see where the shroud lines attach to a loop on the inside of the bag. So the bag is not designed to separate from the chute.


Finally, this is the bottom of the bag. There is nowhere to anchor a pilot chute.

These chutes were used for giant (size of N motor) battlefield illumination flares and were single use. The bag was attached to a line from the deploying aircraft, the flare sent overboard, and the line pulled the bag off. The bags are not fire resistant.
The first time I got these, I got them directly from the company that demilitarized them at $50 for 10. When I tried again, they told me the contract was over.

I would stitch a little attachment loop to the top of the d-bag for a pilot chute. I use a nomex blanket with my d-bag, as it is the same material as yours. I drop the nomex blanket in the tube so that the blanket is between the AV bay and most of the recovery gear. That provides sufficient protection of the recovery gear. Think about it more like wadding than a burrito.\

EDIT: It looks like your d-bag originally had a pilot chute that was cut off. There's no reason for the webbing stitched to the bag if there was no chute. It was originally just like mine.

I used a top flight 120" one for mine which was 42lbs on the pad or about 37lbs recovery weight. No deployment bag, I just flake the gores, z fold everything and fold it neatly into a burrito. Works great and inflates rapidly.

Edit: whoops just saw there was a second page

Please indulge my parachute ignorance. What does "flake the gores" mean?

Gores are the panels of fabric that make up the canopy of the chute. I believe flaking refers to laying each section out neatly, one on top of the other with the shroud line attachment points together, and each panel laid out as flat as possible. This is generally the first step any time a chute is folded by any method other than the infamous ball and stuff method.

OKay. That's what I always do. I just didn't know what it was called.

Like I said earlier, finding a 225 sq. ft. area to lay this thing out w/out getting it filthy is going to be a challenge.

It's going to get dirty. Just do it outside.

Bat-mite said:

OKay. That's what I always do. I just didn't know what it was called.

Like I said earlier, finding a 225 sq. ft. area to lay this thing out w/out getting it filthy is going to be a challenge.

Click to expand...

https://topflightrecoveryllc.homestead.com/Folding.html is a good example of flaking the gores. See the third picture for flaking the gores. Notice how the canopy sections are Z-folded on top of each other. The reason I bring this up is I see a lot of people that fold the chute in 1/2, than in 1/2 again, etc until they get the lines together. That's not the same. It makes a world of difference when the chute deploys.

Yea a big chute is basically impossible to prep indoors unless you've got a rigger's shack or a humongous workshop. I just take mine out in the yard and run around like an idiot until it's fully inflated so that I can untwist the lines, lay it in the grass and do what topflight says. I've had no problems prepping the chute a few days before a launch and just leaving it bundled carefully until actually loading it in the rocket.

Also two problems arise with gigantor chutes upon recovery: when your fincan touches down and the chute is no longer carrying half the weight it was, it can gather a lot of power from the surface winds to drag that sucker across the ground, and when it finally does collapse if you pick it up from the lines it may suddenly inflate if the breeze is blowing. Don't get pulled over!

Keep in mind that if you do use the military d-bag and not an aftermarket one, that it is designed as a stuff sack, not for the chute to be folded up and inserted.

Tonimus said:

Keep in mind that if you do use the military d-bag and not an aftermarket one, that it is designed as a stuff sack, not for the chute to be folded up and inserted.

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+1,,, big...
This is a very important point John...
You have an absolute top D bag man
right at your fingertips...
He flies flight after flight where each flight has two parts
come down separately and both huge chutes are in D bags...
Ask Tom C for his opinion / methods..

Teddy