Chute Release Setup Options

[Ccolvin968]

So obviously CR is used for a DD style setup on LPR and MPR rockets.
Do you guys include a drogue chute to slow the descent or do you just let it fall then pop?
The reason I'm asking is because the Sims on OR are very unhappy with a chute opening at ~80 ft/s.
Thanks!

 

[Steve Shannon]

So obviously CR is used for a DD style setup on LPR and MPR rockets.
Do you guys include a drogue chute to slow the descent or do you just let it fall then pop?
The reason I'm asking is because the Sims on OR are very unhappy with a chute opening at ~80 ft/s.
Thanks!

OR gives a warning about fast deployment speed, but unless you use a large drogue chute you'll probably get that anyway. I'm reviewing a simulation right not with a 103 fps main deployment. OpenRocket warns about it, but that's the whole purpose of dual deployment, to fall quickly, but not too quickly, between apogee and main to prevent drifting.


Steve Shannon

 

[tim cubbedge]

I've only used chute release with motor ejection and no drogue and have yet to shred a chute nor have I seen anyone else with same configuration. So to answer your question I just let it fall and pop.

 

[dhbarr]

Fall, then pop. Depending on how I reef the main, can get drogue-like performance out of the laundry bundle.

 

[Ccolvin968]

Got it.

So I shouldn't have to worry about shredding a chute then?

 

[The_Lone_Beagle]

Fall, then pop. Depending on how I reef the main, can get drogue-like performance out of the laundry bundle.

Ditto...actually, it doesn't seem to matter how I reef the chute too much, the tied up "laundry bundle" really works well at slowing down the rocket. It is really cool to see it come down and then all of a sudden pop open.

I don't think you have to worry about it.

 

[TangoJuliet]

Ever had a LPR eject the chute and for some reason it doesn't open and your watching it fall closer and closer to the ground, when all of a sudden the chute opens and you're all like, "Woohoo!", and no damage is done to the rocket? It's just like that.

 

[Ccolvin968]

Plenty of times!
Good point!

 

[dhbarr]

Ever had a LPR eject the chute and for some reason it doesn't open and your watching it fall closer and closer to the ground, when all of a sudden the chute opens and you're all like, "Woohoo!", and no damage is done to the rocket? It's just like that.

It's just like that -every single time-consuming. Much gasps / oohs from the onlookers when someone has 100m punched in.

 

[crossfire]

Most of the summer I used drop and pop method. I have only used a drogue with a rocket that I had a lot of nose weight. I wanted the nose and booster to fall at about the same rate.

 

[Ccolvin968]

Drop and pop seems to be the consensus.
Thanks everyone!

 

[ksaves2]

Look at the chute release as a device that gives one a bit more leeway on the apogee event. With the chute contained by the Jolly Logic Chute release, the stresses
on the harness are much less when the package is blown. Sure, one doesn't want a 3 or 4 second longer than necessary charge to blow the package out as the decent rate is going to be rather fast. A second before apogee or a second or two after apogee with a chute release is likely acceptable.

When the rubber band is released, it takes a bit of time for the package to open and the chute to fill. The deployment seems to me to be more gentle than a very
late ballistic decent/deployment. (Which of course we could get away with, with light modrocs that had shock absorbing rubber shockcords.) Kurt

 

[byoungblood]

Most of the damage I've experienced from early/late deployments seems to come from the shock cord or nosecone banging into the body of the rocket because of the sudden shock of deacceleration. With a DD or CR recovery (just have to try mine out now!) you've already split the body and stretched everything out. If you don't attach the 'chute directly to the nosecone it also appears to lessen the shock on the recovery system when the main opens.

 

[Handeman]

I only got 3 successful flights with my JLCR. The fourth flight ejected everything at motor burnout. An Estes Leviathan on a H128W. The speed was so great the chute opened and the shock was so violent the BT zippered down to the CR and tore the BT in half. The JLCR was attached to a chute shroud line. The chute actually came back intact, probably because the JLCR kept it from opening immediately, but the JLCR was gone. I think the knot in the tether pulled loose and it fell by itself. It was never found.

 

[o1d_dude]

FWIW, I replaced the JLCR leash with a heavier and longer loop of kevlar and have had no problems on five flights thus far. Big high power rockets put up over 2k feet, too. Biggest chute thus far has been a Fruity Chutes 48" classic elliptical.