executioner first flight

[3boydad]

e9-4 nice flight. deployed chute which tore right off. strings still attached to swivel. and a nice little 3 inch zipper. with about 15 ft of kevlar. i guess i should have added elastic to the end of that kevlar. now its on the back burner until i complete some of my other projects. i am working on a big dog by quest. i sure hope i dont get these same results. i replaced the tiny kevlar with some thicker and added a few ft to it with the elastic. I need to learn how to make zipper less designs. and chutes that wont just tear off. i have some pro series 24 inch nylon. that chute that broke was a 24 inch estes plastic chute. what a joke.

[DizWolf]

4's a quick delay. Moving that fast at deployment and a rigid shock cord is going to be rough on the chute. I did toss a nylon chute on mine though, and using a fire blanket helps slow things down a bit before the chute "hits". 6 second delays would also give more time to coast and slow down deployment speed

[3boydad]

4's a quick delay. Moving that fast at deployment and a rigid shock cord is going to be rough on the chute. I did toss a nylon chute on mine though, and using a fire blanket helps slow things down a bit before the chute "hits". 6 second delays would also give more time to coast and slow down deployment speed

i went with the recommended motor. i need to fix the zip and add a nylon chute. should i add elestic to the end of the kevlar to help slow it down too? this is my first zipper. and i dont want to zipper any more of my rockets

[DizWolf]

I cut about six inches off mine after a core sample. Still flies fine. I'd just cut off the zippered part. Elastic can't hurt. Another thing you can do is wrap the Kevlar cord where it will hit the body tube. Foam, tape, anything to make it fatter at that point. It'll spread the force, and make it less likely to cut the tube.

[3boydad]

I cut about six inches off mine after a core sample. Still flies fine. I'd just cut off the zippered part. Elastic can't hurt. Another thing you can do is wrap the Kevlar cord where it will hit the body tube. Foam, tape, anything to make it fatter at that point. It'll spread the force, and make it less likely to cut the tube.

its a pretty small zipper. i think i could wood glue it. put some fill n finish and sand her down and repaint. i just want to avoid ay futre zipper. i was under the impression 3x the legnth of the rocket and you would be fine. but im starting to think kevlar jus below the op then elastic kinf of like quest does. I am building a big dog right now and i made the kevlar much longer with the elastic tied on. i dont want to zipper this bird too.

[Rocket86]

E9-4 works well in mine. I use kevlar attached to a baffle, but then have 1/4" elastic about 3 feet long tied to that. The kevlar is below the top of the body tube so only the elastic can contact the tube, which is a big defense against zippering. I think you need to have some form of shock absorbtion, either by elastic or a weave/loop in the kevlar. Without it there can be a lot of shock, especially for a plastic chute.

[awseiger]

I left mine the way it comes with the elastic shock cord. Sure, it'll fail sometime, but the manufacturer must have put it there for a reason, right? I bet the zipper is because of the kevlar. It's kind of like a body tube knife, especially with those thin BT-80's

I gave up on the Estes chutes long ago for rockets bigger than C impulse. A gentle tug can pull the shroud lines right out of the plastic... Go with a nylon chute. I use an 24in chute that puts er' down nice and light every time with mine. If you don't want to do that, reinforce your Estes chutes with the little 3-ring hole re-enforcers. I use these on my Black Plastic Trash Bag chutes that I have used all the way to MPR rockets, and I've never had a fail.

E9-4 is the right motor for this rocket. Mine ejects a little past apogee every time.

[AfterBurners]

do you have any type of program that will give you an estimated speed of deployment? I use ROCKSIM to help with that.

[Daddyisabar]

Good thing your cheap Estes plastic chute tore off or you might even have a longer zipper in the thin walled Estes tube. I say "Yeah - I meant to do that - part of my scientific design parameters." Then my buddy tells me to get a real mid power kit with a thicker tube, nylon chute, nomex blanket and a real AP motor. Yep, if your gonna fly Estes thin wall tubes with a high end Kevlar modification, you better have some anti-zipper method. CA and sand the forward edge of the tube, use some wider underwear elastic from Hobby Lobby, slap pieces of cardstock from the packaging and duct tape together for and anti zipper pad on the lovely Kevlar. With cheap plastic chutes, lots of dog barf, underwear elastic, tri-fold mount and some good clear tape to repair that plastic chute, and you can fly with low end recovery products for a long time, you just have to check them out after every flight and make the necessary repairs. It may be a bit more work, you might not be the coolest or most hip flyer at the launch, but you will have flown cheaply many times and that's all the poor folk can ask for.

[DizWolf]

E9-4 is probably the right engine for the bird. Come to think of it I've darted a couple this size on 6 second delays. No more posting while sleeping.

I still do recommend at least some elastic, something thicker where it means the body tube, or lots of elastic and a fire blanket. I mounted a 48" piece of elastic under the top CR. I also used a nylon chute, but the plastic ones have never failed me. I wrap it tight, wind up the shroud lines, and wrap it in the fire blanket. This series of photos is from a D12-3 launch, but it shows how the fire blanket arrangement slows and turns the tube to avoid a zipper....at least in theory. It also shows the next launch where the blanket jammed because I was lazy loading it up, and thus core sampled it. I used a thick epoxy, and wound up with a final weight a little over 10oz.... thus the crazy low alt. shown on the Alt2. Cutting the tube down 6" after the core sample added a good 75 feet or more

http://gallery.me.com/dbmccann#100753

[Texas Rocketman]

I just finished building my Executioner today. I modified the rocket to run on the Aerotech G80T class motor, added a nylon chute and did a custom paint job on it. It's slick and should perform really well on the G engine. Here's a pic of my completed rocket.

[3boydad]

the thing is. ppl were saying use 3x the length of the rocket to avoid zippers. well that is false. it seems kevlar is goo to righ below the top of the MT then eleastic is your friend. like quest does it. I build my big dog using extra long kevlar with the elastic bu i dont want to zipper that bird too. im confused and a little upset. i have about 10 pro series 24 inch nylon chutes. i will start using those. i thought a brand new plastic 24 inc chute would work but she tore right off and drifted away. no damage to the bir but te very small zipper. but still

[chadrog]

Shock cord length is a factor, but ejection timing is a larger factor. If you eject late, it really doesn't matter how long your cord is, you risk a zipper. I was 2 seconds late on one last week (with about 15 feet of cord) and that resulted in a 10 inch zipper. I've seen very few Estes e's with accurate delay lengths as well.

[DizWolf]

Also the 3x length is a general guide not a rule. It's also mostly used with rockets that have thicker walled tubes. Estes tubing is thin and tears easily. With no give in the shock cord, even a brand new chute is going to shread at that force of ejection.

[[POW]Eagle159]

I just make the estes rockets how they say, and IT WORKS... wow, no mods needed. I really dont get when people say you NEED a kevlar shock cord. I use 1/4 inch ribber band cords in ALL of my rockets, and it all works FINE. The rubber band shock cord has never failed me, never zippered any tube...

I used rubber bands for rockets from 1-12 ounces and from 1-5 feet long. I use a 1x rubber to body length.