SHOCKCORDS.COM

Makers of tubular nylon shock cords for the mid and high power rocketry hobby. All shock cords are stitched with flame resistant Nomex thread and come in several different colors.

WHY TUBULAR NYLON

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1 Inch

2 Inch

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Patrick Carroll

 

 

             Tubular nylon is the best product for shock cords when used for rocketry recovery. There are many factors which make it suitable, some of which are cost, availability, strength, resistance to damage and comes in many different colors. Kevlar is also well suited for shockcords but its high cost can make it prohibitive for smaller projects.

 

             From a strength perspective 9/16^th tubular nylon has an average breaking strength of 1200lbs, one inch 2000lbs and two inch 4000lbs and up. This is largely dependant on the weave i.e. climbing spec or mil spec. Mil spec usually has a coarser weave than climbing spec. Some one inch climbing spec is rated for 4000lbs load rating and has a very smooth texture.

            

             Kevlar shock cords can have a load rating up to 20000 lbs but is impractical for use in the average high power rocket. Reason for this will be revealed later in the article. The main benefit in the use of Kevlar is heat resistance to the recovery charge.

 

             Tubular nylon shock cords have a strength rating that is more than adequate for the average rocketeer because the failure point of the rocket components are below the rating of the tubular nylon. For example the basic construction of a mid and high power rocket is glassine or phenolic tubing with plywood bulkheads and centering rings. The anchor point for the shock cord is usually a steel u-bolt through a plywood bulkhead that is glued to a cardboard body tube. This arrangement although strong enough for recovery, if you happen to stress the shock cord to its maximum you will probably be recovering your rocket with a garbage bag due to a stripped chute or a anchor point that has pulled through a bulkhead. Henceforth this is why 20k Kevlar may sound great as a shock cord material but is impractical for all but the most expensive and complicated projects. It is useful in minimum diameter projects where space and weight are limited.

 

 

 

 

 

 

 

Special note: Shockcords.com is not responsible for loss of property or livelihood due to product malfunction. It is the Sole Responsibility of the end User to determine the safety and suitability of any Shockcords.com product. Furthermore, the end User must inspect these products periodically to determine the ongoing safety and integrity of said products.