Homemade parachute - gripe about polypropylene cord for shroud lines

[brockrwood]

First attempt at homemade parachute (12"/13") made out of black plastic garbage bag.

I like the black color - easy to see against a white or blue sky.

The gold, polypropylene shroud line cord was obtained at Walmart. It is strong enough but it unravels like crazy if you don't burn the ends of the cord.



The spill hole is about 2" in diameter. Seems a bit big. I will make it smaller when I create version 2 of the homemade parachute.

 

[MidOH]

Spill hole looks perfect. How heavy is the rocket? Alpha 3, Black Brant 3, types, I run huge holes to keep them from sailing.

I use the innards of paracord for chutes. Save the sleeves though, they are great over Kevlar lines.

 

[neil_w]

The spill hole is about 2" in diameter. Seems a bit big. I will make it smaller when I create version 2 of the homemade parachute.

Disagree, spill hole does not look too big at all. I make mine at least that big, probably bigger.

 

[brockrwood]

Spill hole looks perfect. How heavy is the rocket? Alpha 3, Black Brant 3, types, I run huge holes to keep them from sailing.

I use the innards of paracord for chutes. Save the sleeves though, they are great over Kevlar lines.

The intended rocket is an Estes Bull Pup 12D. The information I googled on the rocket is that it weighs 1.8 ounces without an engine. (I can't just weigh the rocket because it is on a stand with a coat of primer drying on it right now.) I just weighed a spent B6-2 engine on the postal scale. It weighs 8 grams (.28 ounces). So the total weight suspended from the parachute would be about 2.08 ounces.

 

[brockrwood]

For the record, I have never come across an "official" way to measure the size of a hexagonal parachute. If you measure the parachute I made from "flat side to opposite flat side", the size is 12". If you measure it from corner to opposite corner (which is really the diameter of a circle that would perfectly enclose the hexagon), then it is 13". Which way of measuring is correct? Or is there no consensus?

 

[MidOH]

Yeah, I'd keep the spill hole for sure. Run a bead of CA across the bottom edge of the fins maybe.

No consensus. Shape of chute and material can have a bigger effect than minor changes in diameter. I just tune them with the spill hole and line lengths.