Nomex modification for use with a cable cutter

I tried using a cable cutter on my 7.5" LOC Door Knob a couple weeks ago. Unfortunately the parachute came out at apogee. Luckily I didn't have to hike too far to recover it.

The rocket has a 58" parachute and a 24"x24" square nomex blanket from Top Flight Recovery. The blanket seemed way too big to me, but that was the recommended size for the airframe. I secured the bundle as tight as I could with the zip tie, but it just wasn't tight enough to keep the chute from unfurling.

I wanted a better way to keep the nomex securely closed until the cable cutter was activated. I remembered the way that racing car parachutes are bundled together, with a loop on one corner of the blanket passing through the other three corners. They are also tightly packed. After playing with it for a while I decided that a much smaller nomex could be used. I tried a 12"x12", but wound up using a 9"x9". I added a pair of grommets to each corner and then passed the zip tie through each pair. It is much more secure and the bundle is much smaller that before. It's only 4.5" x 4.5" x 2.5" now.

Nice tight package Chris . . . kudos. I guess I need to invest in a grommet gun. I pass by one all the time at Home Depot.

That's great. I'm assuming it works just fine? I will have to try that with my setup.

Nice idea.

I just tried it in the garage by cutting the cable tie with diagonal cutters. The chute popped out immediately. Unfortunately I won't be able to try it in the rocket for a couple months. :sigh:

MikeyDSlagle said:

That's great. I'm assuming it works just fine? I will have to try that with my setup.

Click to expand...

What's the specifics on the grommets? Thanks Kurt

They are 1/4" brass grommets. I bought a General branded kit at ACE HW.

I tried out this setup over the weekend. Unfortunately the main chute opened at apogee. The apogee event must be pretty turbulent to have popped that cable tie on the nomex. Maybe I need to use some beefier cable ties and make a bigger cable cutter to suit. The other idea I've been contemplating is putting the main in a separate compartment and using a chute cannon.

I tried a similar setup using a D-bag with grommets as well as a pilot attached to the main in the D-bag. I tried it three times and worked through some of the issues, including adding the grommets and beefier cable ties. On my last attempt with eh grommets the cable tie cut when it was supposed to however the cable tie get caught up in the grommets so if never completely deployed, the main was partially out, enough to slow it down a bit and thankfully it landed in nice soft mud so no damage but mud.

The point is that the cable tie, in my case, got hung up in the grommets, so something to be aware of.