Tandem drogue

[Hooknswoop 19]

A tandem Instructor that owns his own tandem rig was having bad openings on a brand new canopy. I watched video of one and it looked as if the canopy wasn’t hooked up correctly or that there was something wrong w/ the trim. So I looked the canopy over and finding nothing wrong, jumped it. I had the longest “trap door” sensation at pull time that I have ever had in over 800 tandem jumps. I even had time to wonder what was happening and look over my shoulder in time to watch the canopy come out of the bag.

It opened fine, with a line twist, no big deal. I looked at it hard under canopy and could find nothing wrong with it.

Back on the ground, I looked at the drogue and it was COMPLETELY collapsed, similar to a kill line PC. It shouldn’t have completely collapses, it should have had about 8 inches of center line travel left and stopped collapsing. Well turns out the drogue was incorrectly modified.

Hook

[freeflyswc 0]

Good thing it diddn't end up to be a drogue in tow (if that's possible)

[AggieDave 6]

What was the modification and what was the reasoning behind it?

--"When I die, may I be surrounded by scattered chrome and burning gasoline."

[Hooknswoop 19]

It was a Vector II drogue. The ring in the bridle and the ring at the base of the drogue were removed. It is these two rings that act as stops to stop the drogue from completely collasping. I have no idea why they were removed.

Hook

[rgoper 0]

good catch bro!

--Richard--
"We Will Not Be Shaken By Thugs, And Terroist"

[SkymonkeyONE 3]

No shit. I can think of no reason why someone would do that. I wonder if someone did that because they were getting snapped on opening and were trying to alleviate some of the snatch force. Not too smart, that's for sure.

[alan 1]

Hook, I've watched video of quite a few tandem drogues and they seem to really wander around a lot, maybe even enough to make it more work for the TM to keep the ride nice and smooth. Ever wonder why they don't put a vent at the apex to reduce the oscillations?

alan

[Hooknswoop 19]

There is mesh around the equator of the drogue, i suspect it there is reduce the oscillations. Where the fabric/tape meets the mesh is a big wear point on drogues. The mesh tears easily. So adding more mesh would increase the amount of repairs that has to be done on a continuing basis. I read that some BASE PC's now incorporate a bit of mesh near the top to reduce oscillations. I think because of the massive burble drogues operate in, there isn't much that can be done to stabilize them. I haven't felt the oscillations under a drogue before, so I don't think it is a big deal.

Hook

[riggerrob 563]

Much of the drogue oscillations are caused by turbulent air flowing around the student's legs. Next time you watch a video of a bumpy ride on a tandem Vector, take a good look at the student's legs. Chances are they are extended.