Make my parachute!

Hi, I'm from Brazil.
I'm a college student, and my university have plans to compete in 2021 university nationals rocket design league, i'm a member of the recovery system. We all are begginers.
I know the rocket will have about 13kg and 2,4m. I calculated de parachute area (semi elipsoidal) and the diameter i had was 580cm for descendent velocity of 4m/s, and 464cm for a descendent velocity of 5m/s. For the axis a/b=1.4144 ". I tought i did the calculus right but i dont know anymore, the chute is too big i guess... The rocket apogee will 3000m. Can someone tell me if the chute is ok? As I said, I dont Know if I calculated it right... Ah, and how the number of gores can make a difference in the perfomance? What number of gores do you suggest? The material of the chute will be Nylon Ripstop.

Rocket diameter?
Length available for chute?
Given altitude, presume your team is doing dual deploy.

Hi,
The rocket diameter is 13cm and the lenght for the chute is about 30~25cm(maybe a few more or less).

Hi Manoel,

Most people I know aim for a descent rate of about 6 m/s for the main chute (deployed at ~200m altitude) and 25-30 m/s for the drogue. The descent speed is very dependent on the chute design. There is an excellent calculator on the Fruity Chutes site at https://fruitychutes.com/help_for_parachutes/parachute-descent-rate-calculator.htm . If you end up needing the very best performance for a small packing volume, the Fruity Chutes "Iris" line of toroidal chutes is king, but they are expensive.

When you say the length of the chute is 25-30cm, I assume that is the volume of the tube where all of the following need to be packed for flight: parachute, shock cord, shock cord attachment (both ends), deployment charge and chute protection. That is a lot of stuff for a small area.

Zeus-cat said:

When you say the length of the chute is 25-30cm, I assume that is the volume of the tube where all of the following need to be packed for flight: parachute, shock cord, shock cord attachment (both ends), deployment charge and chute protection. That is a lot of stuff for a small area.

Click to expand...

Yes, we Will have only the main chute and a shock cord of course... do you think is really deep?

For the metrically challenged, 25-30cm is 10-12 inches. The smaller parachute you listed is 464cm (15 feet). Unless your rocket is maybe 100cm in diameter you can't put your parachute in 25-30cm long tube.

My confusion. You must mean the diameter of the tube is 25-30cm. I was thinking length. How long is the tube for your recovery system? We need the volume.

The rocket will have about 13 cm diamenter and 30 cm lenght for parachute. the max hight(apogee) of the rocket will be 3000m.

I think the diameter of the rocket is very, very thin!

464cm was the calculus I had for a descent velocity of 4.5 m/s, but now I put on https://www.rocket-simulator.com/descent_calc1.php, and the simulator says about 300cm diamenter. What do you think? I did wrong?

I did another calculus for a 14kg rocket, can you see it and tell me if is that right? plssss

Here! 370cm diameter for a terminal velocity of 4.5 m/s.

And really sorry for so many questions hehe. But i'm a really interested in this subject and I want to be better and better... What volume do you think is necessary for that? The 13 cm of diameter and 30 of lenght is really small?

Here is an experiment. Figure out how many square cm your parachute will be. Take a bed sheet and measure it to determine how many square cm it is. Divide the parachute size by the sheet size to determine the scale factor.

Now fold the sheet to make it fit a tube similar to your rocket. Measure the folded sheet to determine the volume. Multiply the volume of the folded sheet by the scale factor. (optional) Swear in the appropriate language. That is an estimate of how much volume you will need in your rocket.