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Yet Another Way to Fail When Flying Rockets November 28, 2017

Posted by rluhman in Rocketry, Technology.
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Jolly Logic Chute Release

Early in 2016 I bought a Jolly Logic Chute Release.  The device is about the size of a small matchbox.  It allows you to turn any rocket (that the device will fit into) into what is essentially a dual-deploy rocket.  I have several 2.5  to 7 inch diameter rockets that deploy their parachutes at apogee (the highest point of the rocket’s flight).  Depending on the altitude the rocket reaches and the wind it can result in a long walk to retrieve the rocket.

Enter the Jolly Logic Chute Release.  This nifty little device uses a rubber band and pin that wraps around the folded parachute preventing it from opening.  Then when the rocket descends to a pre-selected altitude the pin will release and the parachute will unfurl and the rocket will land safely at a distance that is much closer that it would have otherwise.  I used it quite a bit during the 2016 flying season and had only one failure when the rubber band released from the Chute Release, but somehow entangled in the parachute which caused the parachute to fail to open.  I have avoided stretching the rubber band that tight since then and have had no problems.

That is until this last flight in November 2017.  I had missed all the 2017 season due to back problems, but I finally seem to have that managed and I went out fly on the last launch on the year.  I carefully folded the parachute for my LOC Precision Minnie Magg and wrapped the Chute Release rubber band and pin around the parachute and locked in into the other side of the Chute Release.  I then did my usual shake test to be sure the parachute would not slide out from the rubber band and everything was fine.  Out to the pad I went and we launched it on an Aerotech I161 motor.  It boosted beautifully into the clear November sky, arced over popped the nosecone and bundled parachute out at apogee.  It fell down to abour 400 feet when the Chute Release did its job and released the parachute which opened perfectly and it landed a few hundred feet from the pad.  What a great way to end the season.  A perfect flight.

At least it was until I got to the rocket to pack it up and bring it back in.  I went to the Chute Release to remove it and put it in my pocket for the walk back to the car, when I noticed that it did not look quite right.  I picked it up and the case had opened like a clam shell and there was nothing inside the case.  Crap!!  Somewhere out in the sod farm are the expensive electronics that do their magic and all I have is a nice clean empty plastic shell.  After some thought and examination of the rocket, the only thing that I have been able to conclude is that somehow when the rubber band was released the Chute Release recoiled and smacked into the large quick link that holds the parachute to the shock cord.  It must have hit just right to pop the case open and out fell the electronics.

 

Chute Release Protector

Oh well, once again live and learn.  They do now make a Chute Release Protector that attaches with a velcro strap.  If I had used that then the case may have still popped open, but it would not have been possible for the electronics to fall out.  When I buy my new one I will definitely be buying the Protector.

Now that the flying season is over it’s time to work on my winter projects and buy a new Chute Release.

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