5th June 2011, 08:41 PM
Choosing a Recovery Tether....
I am having a little trouble choosing between the Defy Gravity tether and the L2 Tender Decender tether. Anyone have recommendations for either? The Defy Gravity seems to be very high quality, but I'm not sure I like the fact that the rubber parts have to be periodically replaced. Both pages are here:
I am going to do dual deploy out of a single compartment on a Nike rocket. Electronics are going in the nosecone. Regardless of which one I go with, I am going to do the reefed setup, where the rocket will fall drogue-less and then the tether will release the parachute. Hopefully I will have this ready for next weekends NEFAR launch (i will have to order tonight in order to get it in time). Pictures to come as soon as I start!
NAR #89512 L2
5th June 2011, 09:24 PM
I've flown both a number of times.
I personally prefer the Tender Descender, but with a few caveats:
The defy gravity tether works great out of the box, but can be a bit touchy on the amount of tape and other factors. Out of 10 flights, I've had it separate early once (ie, not enough tape-charge didn't fire early), and not separate at all once (ie, too much tape-charge fired). It is also larger and you have to be more careful about the pieces damaging your airframe. It also can be a pain to fit the igniters in
I've flown a tender descender 5 times. It failed to fire once (electronics issue), and worked the other 4 times. It packs smaller, doesn't require the rubber gasket, doesn't require some variable amount of tape or black powder, and can be used (at least in my experience), within the airframe with little worry of it blowing a hole in the side.
The tender descender isn't perfect, though. Despite how the instructions say it works, I cannot manage to fit a daveyfire or m-tek electric match head in the L2 sized one without damaging the head. This means that you need to find some other kind of igniter. I used Quest Q2G2's, but still had trouble fitting 2 in the device without damaging them, but after enough trouble, can make them work (also ended up damaging quite a few igniters in the process). A single one fits fine. I also messed around with using hot glue to make a small channel on the outside for powder and placing the igniter on the outside and allowing the powder to to burn through the igniter hole and set the device off. I never ended up needing to fly this configuration. Another issue is that the igniter wires can be easily pulled out and thus need to be secured somehow so they don't. This can be done by attaching them to one of the quicklinks.
Tether: has failed me more, difficult to get igniters in, bigger
Tender Descender: impossible to get electric matches in, smaller, has worked for me 100%
5th June 2011, 09:28 PM
The RATTWorks AARD works very nicely.
5th June 2011, 09:44 PM
I will help you decide on the TD. I have the lite weight one and the medium one I will sell to you very cheap. Never used. Email me at TFRLLC@Charter.net for the price.