Pilot chute wind tunnel testing

[pchapman 261]

The performance of pilot chutes has come up from time to time here.

I came across this link - Some pilot pilot chute testing in a horizontal tunnel in Oshawa, Ontario by Matt G, Will Kitto, & Martin Tilley, behind a wingsuit. They used standard, toroidal, and midskirt vented designs. The focus is on BASE but it is interesting testing in any case.

http://base-book.com/pc-extraction-and-inflation

[erdnarob 1]

Hello Peter
Have you tried to test a reserve pilot chute in a vertical wind tunel ? This is what I would like to do. The set up should be quite easy since the wind tunel operator can vary the speed which is seen on a display screen from inside.

This is what I had in mind to do so :
What it takes is somebody recording the speed and force (with a suitable dynamometer measuring up to 200 lbs). 5 points (speed and force) should be enough to draw a graph.

This set up would be near the reality of the free fall.

The pilot chute can be attached to the bottom screen. I have talked to SkyVenture officials in Montreal. Their fear is to get something giving up and hit the fan propeller at the top. They told me that even a 25 cents loose coin can badly damage the fan. Maybe if I show them a set up well designed, they would let me do it.
The problem is to borrow a suitable dynamometer.

Personally I think there will be less chance in such a set up to get something loose than what can happen having several people flying inside with shoes, googles, helmet, piece of clothes...etc

What do you think ?

Learn from others mistakes, you will never live long enough to make them all.

[Hooknswoop 19]

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Have you tried to test a reserve pilot chute in a vertical wind tunel ?

I have. About a dozen of them. Changed the way i think about reserve pilot chutes. Initially, I agreed with your idea, the Pc that pulls the hardest wins. After watching the wind speed come up with 2 PC's attached to the net, I completely changed my thinking. The first PC to inflate wins. I have video somewhere.

Derek V

[erdnarob 1]

Hello Hooknswoop

Thanks for your message. Of course you need a fast PC inflation but you also need enough force to extract your reserve from its tray.

1) Do you have any figure about speed versus force for a specific PC ?
2) What is the highest PC force you have seen at 120 mph ?

Thanks

Learn from others mistakes, you will never live long enough to make them all.

[JerryBaumchen 1,046]

Hi Derek,

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About a dozen of them.

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The first PC to inflate wins.

Since my pilot chute was one of those tested and I have a copy of the results, my belief is that total pulling power is also very important.

While you may give 'first to inflate' your best consideration, I believe that both are very important as regards total deployment times.

PIA did some testing recently of pilot chutes & extraction forces. I have seen one video that shows the bag beginning to come up & out of the container before the pilot chute is completely inflated & before the bridle is taut. My conclusion is that the drag on the two items was enough to get the bag out of the container.

Just my $0.02 on this,

Jerry Baumchen

ETA: This is a dumb statement: 'My conclusion is that the drag on the two items was enough to get the bag out of the container.'

Of course, there is enough drag. What I meant to say is: 'My conclusion is that there was sufficient drag, without the pilot chute being totally inflated, to get the bag out of the container.'

Sorry.