Nylon Parachute Modification?

[JamesBenMoore]

Hey Y'all.

I am working on modifying my Wildman Journey 75 for a potential L2 launch. I intend to add a 10" section (above a 2" switch band with 8" coupler) to make room for a standard DSDD setup with a simple AV bay. The kit came with a 30" Top flight nylon chute, which in Openrocket shows a descent rate of about 38ft/s. From what I've gathered that seems to be too slow for drogue and too fast for main. My question is, could I cut a hole in the center of this chute or otherwise modify it to speed up that descent rate and use it as a drogue? If I could do this the plan would be to use a Rocketman 5ft cute as a main to get the ground hit velocity down to right ~14.8ft/s.

This information is coming from Openrocket with a 3" diameter, 56" tall rocket that weighs ~5.5lbs at burnout. Thanks!

 

[Handeman]

You can put the spill hole in the chute, but make sure you cut the hole with a hot knife so the edges are melted and don't fray. Then try to roll the edges and sew a seam around. If the seam around the spill hole can't handle the stresses, the chute could split a seam or tear from the spill hole to the outer edge.

You could also lift the chute from the center, pull it tight, and put a zip tie tight around it about 5 - 6 inched from the tip to reef the chute and make it smaller. You can also do that with the shroud lines, but I've had better luck with the zip tie around the chute itself.

With that size and weight of rocket, you should only need about a 12" drogue so you might want to consider buying another chute rather that trying to reef the 30" chute that much.

 

[JamesBenMoore]

You can put the spill hole in the chute, but make sure you cut the hole with a hot knife so the edges are melted and don't fray. Then try to roll the edges and sew a seam around. If the seam around the spill hole can't handle the stresses, the chute could split a seam or tear from the spill hole to the outer edge.

You could also lift the chute from the center, pull it tight, and put a zip tie tight around it about 5 - 6 inched from the tip to reef the chute and make it smaller. You can also do that with the shroud lines, but I've had better luck with the zip tie around the chute itself.

With that size and weight of rocket, you should only need about a 12" drogue so you might want to consider buying another chute rather that trying to reef the 30" chute that much.

Thanks for the advice, seems like cutting a hole in it might be a bit more complicated to get right than I would like.

 

[OverTheTop]

You might also find that cutting a spill hole does less to the sink rate than you might have thought. Been there, done that.