A recovery tether is a simple device that allows you to use dual deployment out of the same opening in your rocket. We sell the Tinder Rocketry Tender Descender recovery tethers. Use the tether with a deployment bag to hold the main parachute inside your rocket until you want it to emerge. We feature three tether devices:
The Tender Descender HDPE is 1½”L x ¾”W x ¾”T (without the quick links installed) and weighs in at just over 39 grams (including quick links) yet can take an initial shock load of up to 600 pounds and will deploy with up to 200 pounds attached. This device is intended for rockets weighing up to 25 pounds. Price is just $59.
The Tender Descender L2 has the same dimensions as the HDPE version but is made from heat-treated, copper-toned, anodized aluminum. The L2 weighs just 52 grams with its stainless steel quick links yet can take an initial shock load of as much as 2,000 pounds and will release with up to 500 pounds attached. This device is intended for larger rocket projects of up to around 60 pounds. Price is $85.
The Tender Descender L3 for those REALLY BIG projects. This incredibly strong tether is made from heat-treated, copper-toned, anodized aluminum and measures 2¼”L x ¾”W x 1”T (without the quick links attached). The L3 weighs just 5 ounces including the ¼” stainless steel quick links. This device can take an initial shock load of over 5,000 pounds and smoothly releases with over 1,000 pounds attached. This device is intended for rockets weighing up to 300 pounds or more. Price is $129.
All tethers work via a simple principle. Two quick links are restrained by pins pushed through a machined housing. A small black powder charge is loaded into the housing chamber in the center, just .25G for the smaller units and .35G for the larger one. When fired, the pins are pushed out and the quick links are released. The Kevlar cord keeps the pin assembly and the housing attached to one of the quick links. The other quick link is completely released.
Tether Protector Bag - When used inside a rocket airframe, we also sell a small Nomex bag to place your tether inside. This protects the airframe from the pin assembly when it releases (with some force) and, at the same time, prevents the hot gas from the black powder charge from damaging your recovery gear. Order a bag along with your tether if you plan to use this inside your airframe.
Line Cutters - A line cutter is a very simple device that is used to cut a piece of nylon wire tie in order to allow your parachute to open or to release your parachute or anything else. It can also be used to reef a parachute.