Deployment bags

[timothyterpsalot]

does anyone know of a good website that describes the use of deployment bags? or does anyone care to explain a little about them?
When is it a good idea to start thinking of using them? depending on the size of the rocket? the weight? size of the chute? Thanks!

 

[quickburst]

Deployment bags or D-Bags are very simple to use and will extend the useable life of your recovery system. Most of the time they are used in 4" airframes or larger.

See: https://www.quickburst.net/qb_d_bags.htm

To order: https://www.quickburst.net/unregulated_products.htm

 

[troj]

Here's a photographic sequence of how to pack a parachute into a bag. This may not be the exact bag or parachute you're using, but the basic ideas are the same.

https://www.rocketryonline.com/modules.php?name=Forums&file=viewtopic&t=94

-Kevin

 

[troj]

In terms of what does a deployment bag do? It keeps your recovery system neat, tidy and organized, aiding in a neat, orderly deployment.

If you look at a lot of altimeter dumps, you can see the recovery system deployment, in the form of a spike that's actually a higher G load than when the motor first hits. This happens when the canopy is allowed to inflate before the lines or riser are taught.

A proper deployment bag helps prevent this by causing the lines to unstow first, then the canopy is allowed to come out and inflate. This means the recovery system is stretched out, and the canopy inflates more slowly (still a matter of seconds), causing it to not snatch the rocket hard. If you see a really hard deployment, you can watch a 20+ pound rocket bounce back on the end of a harness -- NOT a good thing!

The other thing a deployment bag does for you is reduce the risk of an entanglement or an inversion.

They're all about reliability, and it's never too early to start learning about them or using them. I have a friend who uses them on 5lb rockets.

-Kevin

 

[Gus]

Kevin,

Absolutely first rate photo essay. Thanks so much for doing it and providing the link here.

 

[knarfster]

In terms of what does a deployment bag do? It keeps your recovery system neat, tidy and organized, aiding in a neat, orderly deployment.

If you look at a lot of altimeter dumps, you can see the recovery system deployment, in the form of a spike that's actually a higher G load than when the motor first hits. This happens when the canopy is allowed to inflate before the lines or riser are taught.

A proper deployment bag helps prevent this by causing the lines to unstow first, then the canopy is allowed to come out and inflate. This means the recovery system is stretched out, and the canopy inflates more slowly (still a matter of seconds), causing it to not snatch the rocket hard. If you see a really hard deployment, you can watch a 20+ pound rocket bounce back on the end of a harness -- NOT a good thing!

The other thing a deployment bag does for you is reduce the risk of an entanglement or an inversion.

They're all about reliability, and it's never too early to start learning about them or using them. I have a friend who uses them on 5lb rockets.

-Kevin

How do you use a deployment bag on a dual deployment? i do not want the rocket coming down in two seperate halves. I have a 5" rocket with the drogue in the bottom booster section, with the main in the upper payload bay being deployed between 1000-1200 feet. Do I need a "pilot chute" in upper section? the nose cone is not coming out during the deployment. The hard attachment points are in the middle at the ebay coupler.

 

[troj]

How do you use a deployment bag on a dual deployment? i do not want the rocket coming down in two seperate halves. I have a 5" rocket with the drogue in the bottom booster section, with the main in the upper payload bay being deployed between 1000-1200 feet. Do I need a "pilot chute" in upper section? the nose cone is not coming out during the deployment. The hard attachment points are in the middle at the ebay coupler.

There are two types of deployment bags -- free bags, and non-free bags. With a free bag, the bag is not attached to the parachute that it contains, and the bag is pulled up and away. On the other type, there's a short tether that runs from the inside of the bag to the top of the parachute that it contains, keeping them attached.

You can use your drogue to pull the bag up and off, if you use a device such as a Tether. Or, you do more conventional dual deploy, and use a small pilot chute to extract the bagged main.

-Kevin

 

[ClayD]

In terms of what does a deployment bag do? It keeps your recovery system neat, tidy and organized, aiding in a neat, orderly deployment.

If you look at a lot of altimeter dumps, you can see the recovery system deployment, in the form of a spike that's actually a higher G load than when the motor first hits. This happens when the canopy is allowed to inflate before the lines or riser are taught.

A proper deployment bag helps prevent this by causing the lines to unstow first, then the canopy is allowed to come out and inflate. This means the recovery system is stretched out, and the canopy inflates more slowly (still a matter of seconds), causing it to not snatch the rocket hard. If you see a really hard deployment, you can watch a 20+ pound rocket bounce back on the end of a harness -- NOT a good thing!

The other thing a deployment bag does for you is reduce the risk of an entanglement or an inversion.

They're all about reliability, and it's never too early to start learning about them or using them. I have a friend who uses them on 5lb rockets.

-Kevin

yes, but they add a level of things that can go wrong.
Some of us that have seem them cause streaming parachutes.(maybe a user error we saw) but non-the-less, added complexity to deployment.

you can absolutely use deployment bags in dual-deploy, athough its not for me (i dont want the extra fuss, i pack my chute so it unfurls slowly). For the main, just use a pilot chute to drag out the laundry.

Giantleaprocketry.com, has d-bags and shows the dual-deploy all together method.

 

[cjl]

yes, but they add a level of things that can go wrong.
Some of us that have seem them cause streaming parachutes.(maybe a user error we saw) but non-the-less, added complexity to deployment.

you can absolutely use deployment bags in dual-deploy, athough its not for me (i dont want the extra fuss, i pack my chute so it unfurls slowly). For the main, just use a pilot chute to drag out the laundry.

Giantleaprocketry.com, has d-bags and shows the dual-deploy all together method.

Deployment bags significantly decrease the chance of a tangle or a failed deployment when used properly. I've seen failed deployments due to incorrectly used deployment bags, but when used correctly, they pretty much guarantee that the chute will come out, not be tangled, and open smoothly and in a controlled fashion.

 

[eengelgau]

Hi - I have a pictorial how you use our d-bags, which would be similar to most others: https://www.fruitychutes.com/how_to_pack_a_deployment_bag.htm.