Parachute packing and sizing

[lastingk]

Greetings everyone, I'm incredibly new to model rocketry and I lack lots of knowledge and experience. I am part of a project group in my university and we are trying to design a rocket.

Rocket is for a rocket design contest. Our rocket design have 10cm diameter that fits to our expected rocket flight aim. But now we are worried about parachute packing.

For the required parachute that fits to our weight and fall rate, research on internet showed us most of the packings in internet shared packing size between 11cm-20cm in diameter, of course varies in lenght in terms of packing volume. We would like to know if it is possible to pack thinner but longer so that it would fit to our 10cm diameter rocket.

Thank you in advance.

(Note: Sorry if there is any mistakes in my writing, english is not my native language.)

 

[David Schwantz]

You can pack any way you need to. Just insure that it is protected from BP blast. Also might check out Top Flight Chutes, they have many thin mil chutes to choose from. I have several and they are good quality.

 

[Bat-mite]

Some of our parachute vendors sell chutes that are designed to be durable but pack tighter. They are more expensive than standard chutes.

Here's one: https://fruitychutes.com/buyachute/iris-ultra-chutes-30-to-192-c-18/

Here's another: https://the-rocketman.com/ultra-light-annular-parachutes/

Yes, you can pack the chute longer and narrower. This creates more difficulty in protecting the chute from the ejection charge. You would need a longer, narrower chute protector which you would probably have to make yourself. People have done it with denim soaked in some kind of boron solution, but I don't know anything about that.

However, my simplest answer is that most commercial parachutes that are correctly sized for your descent weight will fit nicely in your airframe, unless your airframe is extraordinarily heavy.

A deployment bag is another option to look into.

 

[lastingk]

I am really grateful for your answers, thank you both. Our system consists of a non-pyro ejection system, so we only have the chute to pack. Thanks to you, now we are more confident in our diameter and shape.

 

[David Schwantz]

If you can, I'd love to hear more about your non-pyro system.

 

[lastingk]

It is basically Co2 cannister ejection system, but for the activator, we are using spring power and a piston with a sharp point to release Co2 cannister. Piston consists of a hole suitable for a solenoid. When spring is loaded, the piston will come to the same axis with the solenoid, where solenoid will lock the system with its pin. As the command comes from Arduino, the solenoid will draw its pin and free the piston, which releases the spring. Spring and piston will be cased within a cylinder with holes in desired locations.

Or at least that is what we plan currently. If the system will be a success I am going to make a thread in this forum. I do believe it will be a guide or an example for any other people who is considering a non-pyro system.