Reserve PC's

[Hooknswoop 19]

I did some testing of a couple of reserve PC's in the wind tunnel recently. The results created more questions than they answered.

I asked myself, what makes for the best reserve PC? I think it the PC that get the bag off the PC at line stretch the quickest in any situation. That is asking a lot of a PC. Low speed or high speed is two very different situations.

I do not think that the PC that produces the most drag is automatically the best PC. Before that becomes a factor, the PC must get clear of the burble and inflate. A PC with more drag may end up deploying a reserve slower if it spends any time at all in the jumpers burble. A PC that orbits can contribute to an off-heading opening or line twists.

I tested drag force at lower speeds (up to about 42 mph), how quickly a PC would inflate and pull from laying on it's side and from up-side-down. The last 2 tests, I tested 2 reserve PC's side-by-side.

With the PC's laying on their sides, one inflated and began to pull, while the second layed there. With the up-side-down test, the PC that layed on it's side inflated and began to pull while the PC that came up off it's side remained inverted on the net.

One PC tended to orbit significantly while the other was much more stable.

It is these results that caused me to re-think what makes a good reserve PC from simply a PC that pulls the hardest to one that inflates and pulls from any angle.

The PC's were about as far apart from a design perspective as you can get.

Derek V

[pchapman 279]

So many factors involved indeed. We haven't even gotten into spring length, spring strength, weight of the PC, weight of the cap,...

Was the one that started to pull while starting on its side, a certain meshless one?

Although the Vector reserve PC has been questioned about its low speed drag, I thought I heard that part of Bill's philosophy was to make it catch air well from different angles, such as on its side.

[skydiverek 63]

Quote

Although the Vector reserve PC has been questioned about its low speed drag, I thought I heard that part of Bill's philosophy was to make it catch air well from different angles, such as on its side.

That is correct.

[riggerrob 643]

Was it a coincidence that Booth introduced the mesh-less Vector 2 reserve pilot-chute around the same time that most round reserves were grounded by acid mesh?????