Question: Venting holes in parachute shade structure

sunnay · Post by **sunnay** » Tue Jun 06, 2006 5:35 pm

We bought a freaking huge parachute (100 ft) for our camp and we are concerned about it trapping air since our center pole is only 20 ft tall and the sail effect.

We heard that if we use a soldering iron it wouldn't fray. I think that's a brilliant idea rather than just cutting holes.

So far we have a 20ft radio tower that is super strong with eight supporting ties made of straps and rachets holding the center pole. There are 12 ropes going out to 12 poles on the perimeter of the parachute that are held down with the ground with straps and rachets attached to triangular metal plates. These metal plates have a hole in each corner with rebar in the holes, each pounded in a different direction for more stability and less rebar bending. There is a ring in the center that is attached to the straps.

Just to because we are paranoid, we also have 12 more poles for more stability, without the ropes from the center.

We are pretty sure that it won't blow away, but we know that we need air to escape since it isn't that tall and we would feel better if the air were able to flow through so that there will be less billowing.

Does anyone have any experience with the size of holes and shape of holes?

phil · Post by **phil** » Tue Jun 06, 2006 5:54 pm

Drop by
http://www.cieux.com/bm/bmtoc.html##abodes
and scroll down to the end of the section on abodes - links to pages by Argyre and Moebius. (Argyre's is two pages; follow the link at the bottom of his page.)

Be sure to read Bob Stahl's page "Desert Structures" (it's more near the beginning of the list of links on Abodes).

From my reading of these articles, you won't need to ventilate the chute. But I could be wrong.

sunnay · Post by **sunnay** » Tue Jun 06, 2006 6:04 pm

Thanks Phil,

I had already found those links and read them, but the difference is the size of shade. We set up ours as a test and found, that even though it wasn't hot out, we found it quite hot underneath. We also had some wind, not as strong as found on the playa and feared the sail effect.

I believe with the area that the chute covers and the lack of height that we have, we will need ventalation holes.

ibdave · Post by **ibdave** » Tue Jun 06, 2006 6:05 pm

Last year the Rino Camp set up a large chute, next to our camp. The center pole was about 30 ft. They had just about as many outside poles and guy wires. They had used this chute 2 years and they had many vents of vary size's in it. Some cut some torn. The biggest issue was the chute tearing while it sat on the center pole. They did a patch job from the 1st year, but it tore early last year but it stay up anyway.. It was a kite at times. It bellowed most of the time in small breeze's. It took a crew of 15 min. to set up. Lot of pre setting also.The chute would hang so low on the outside edge that it was un-useable space for the most part.

Good luck, and welcome home......

blyslv · Post by **blyslv** » Wed Jun 07, 2006 11:23 am

Unless you can find some way to double up the material, it will get very hot underneath. One layer cuts down some visible light, but generally the thicker the better. Camo netting (doubled) works well, but that wasn't really you're question was it.

Start with a few holes, if you need more, bring a flare gun.

Have fun!

Isotopia · Post by **Isotopia** » Wed Jun 07, 2006 5:24 pm

we know that we need air to escape since it isn't that tall and we would feel better if the air were able to flow through so that there will be less billowing.

Does anyone have any experience with the size of holes and shape of holes?

1) hope the chute isn't white. If it is you need to dump it on ebay ASAP.

2) I did a parachute one year and found that small, inverted 2" chevrons work OK. Don't be tempted to just slice a vertical or horizontal cut through your chute in order to get a cross flow of air.

sunnay · Post by **sunnay** » Thu Jun 08, 2006 9:29 am

1) hope the chute isn't white. If it is you need to dump it on ebay ASAP.

I'm curious, why would white be a problem? Ours is a light green.

You can see it here: http://wiki.jonnay.net/many/ourshade

I did a parachute one year and found that small, inverted 2" chevrons work OK.

What is a chevron?

Don't be tempted to just slice a vertical or horizontal cut through your chute in order to get a cross flow of air.

Because holes in general are a bad idea or slices as a shape are a bad idea? I was thinking of a half circle or a triangle might be the strongest and less prone to ripping.

We are pretty apprehensive about putting holes in until we talk to someone who has done this and has some info since we put so much money and time into making this shade structure. I would hate to ruin a very expensive piece of fabric.

Post by **AntiM** » Fri Jun 09, 2006 9:34 am

This is a chevron:

capjbadger · Post by **capjbadger** » Fri Jun 09, 2006 1:27 pm

I think the white is bad since it doesn't block the light or heat worth a damn.

The half circle is a good idea. I'd personally re-enforce the corners of the hole with a patch stitched on since that will be the weak point where it will try to tear. Plus remember, anything that can flap out there can act like a whip. That tip gets going near the speed of sound (thus the popping noise) and that kind of force will shred things.

sunnay · Post by **sunnay** » Mon Jun 12, 2006 11:13 am

What about circles for holes? There wouldn't be any weak points or anything flapping then? I just have no idea what size to make the holes.