Secondary Inlets

[DaveO 0]

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I'll be ordering a 293 Flik in short order

Are you ordering one with or without vents? I'm trying to decide wheather to order a Fox or Flik for my new Vertex. Already have two V-tecs, can't decide if I really need three. Is everybody going to vents on all their canopies now or keeping one non-vented canopy for terminal jumps.
I split this discussion off of the "Blackjack v. Flik" thread, because it looked like it was moving onto the topic of vented v. unvented canopies. ~Tom Aiello

"When it comes to BASE, I'll never give advice, only my opinion"

[hookitt 0]

I'll post my opinion, but given my low jump numbers on single parachute systems, (112 to date) it's a very limited cross section of comparison.

I own a non-vented and a vented canopy. Most of my jumps were on the non-vented. It performed and still does perform extremely well. After only half a dozen jumps on a vented canopy I was sold. It's certainly possible that bottom skin inflation actually occurs quicker on the Nonvented. What was most pronounced, (which is why the vents are there in the first place) was the quicker pressurization. The canopy is flyable noticeably quicker.

I give a big thumbs up for vents.

..Next

My grammar sometimes resembles that of magnetic refrigerator poetry... Ghetto

[TomAiello 25]

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After only half a dozen jumps on a vented canopy I was sold.

How many of those jumps were at terminal? I think Dave was looking for feedback on high speed jumps, since he already has two vented canopies.
If you are making a lot of terminal jumps with good landing areas and low strike potential (wingsuiting big cliffs, or repeated elevator loads, for example), I could see some real value to keeping an unvented canopy.

-- Tom Aiello

[email protected]
SnakeRiverBASE.com

[hookitt 0]

So any way ... I re-read the post. None were at terminal.

I'll go back to work now.

Tom Feel free to remove that all together. Thanks

My grammar sometimes resembles that of magnetic refrigerator poetry... Ghetto

[Dd0g 0]

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If you are making a lot of terminal jumps with good landing areas and low strike potential (wingsuiting big cliffs, or repeated elevator loads, for example), I could see some real value to keeping an unvented canopy.

The risk in this, for scatterbrained old Dogs like me anyway, is that one is always tempted to use the unvented rig when it is "convenient" (i.e. packed, in the trunk, etc.) and a vented-style object is sitting there waiting to be jumped. For me at least, Murphy's Law says that I'll end up with my one unvented rig when standing at exit on a dodgy object that really demands venting.

And, yes, I've finally put my jumping where my mouth is and sold my last unvented rig. Now, I will have ONLY vented canopies in my quiver - even though I do alot of jumping that doesn't need the new technology, I don't EVER want to be caught in a spot where venting would have made the difference, and through the confluence of daily ephemera I'm under my one, old, unvented canopy.

Just a thought.

Peace,

D-d0g
[email protected]
Dog's Den

+~+~+~+~
But this, surely, was the glory that no spirits, canine or human, had ever clearly seen, the light that never was on land or sea, and yet is glimpsed by the quickened mind everywhere.

[bps 0]

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The risk in this, for scatterbrained old Dogs like me anyway, is that one is always tempted to use the unvented rig when it is "convenient" (i.e. packed, in the trunk, etc.) and a vented-style object is sitting there waiting to be jumped. For me at least, Murphy's Law says that I'll end up with my one unvented rig when standing at exit on a dodgy object that really demands venting.

Gosh, isn't this the truth. Just last night, I hopped off an object that demanded the fast opening technology, and after landing, I found myself going to the trunk to grab the packed Mojo. I had my doubts, and these feelings only multiplied on the exit point. I still felt up to the jump, and everything went fine...but my options were much less than what they could have been once I left the launch point!

C-ya,

Bryan

[DaveO 0]

How many of those jumps were at terminal? I think Dave was looking for feedback on high speed jumps, since he already has two vented canopies.

Thanks Tom, Thats exactly what kind of info I'm looking for. What are the benefits of the vents on delays over 7 sec. or are there any. Most of my jumps are between 250ft to 350ft so I don't have much experience with the longer delays. What I do know is that a 7 sec. delay with my Fox 285 V-tec slams me harder than any no slider opening I've ever had. And I used both direct and indirect slider control and rolled the nose. I take it everybody gets slammed with the vented canopies a terminal?

"When it comes to BASE, I'll never give advice, only my opinion"

[TomAiello 25]

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What are the benefits of the vents on delays over 7 sec.

I don't really see a whole lot of benefit to openings. As long as you have adequate separation, and don't have any cigars in the cellar, I wouldn't bother.

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I take it everybody gets slammed with the vented canopies a terminal?

Yep. That's pretty much been my experience.
However,
I think that the bottom skin inlet issue is radically oversimplified in many people's minds. The problem is especially relevant in this case. Here's the key point:
Bottom skin inlets do not have identical effects on all canopies.
The FOX has difficulties in steeply braked approaches, related to it's shallow angle of attack. For this reason, secondary inlets greatly improve the flight performance of the Vtec FOX in deep brakes. The secondary inlets allow air inflow through the bottom skin, maintaining the canopy's internal pressurization even in brakes deep enough to stall a standard FOX.
The Mojo, on the other hand, has a relatively wider performance envelope. In very deep brakes, it tends to maintain pressurization far better than the FOX. I suspect that the effects of secondary inlets on the Mojo's flight profile would be far less pronounced than the effect on the FOX.
The Ace has an an even wider flight envelope--and the effects of the secondary inlets are definitely less than they are on the FOX. In deep brake approaches, it's very difficult to tell the difference between the (unvented) Ace and the (vented) Blackjack.
The Troll also has a very wide flight envelope, so I would suspect that the effect of the MDV's, while probably quite dramatic on opening, are relatively limited (as with the Ace/Blackjack) in flight.
I don't know how this relates to the Flik. I suspect that it's flight profile is very similar to that of the FOX, since the airfoil is identical. However, the trim is different, as is the aspect ratio, so no one really knows for certain. I am uncertain whether BR actually built any non-Vtec Fliks for testing. The Fliks I have seen in the possession of their test jumpers all had secondary inlets, so I rather suspect that the non-Vtec Flik saw minimal (if any) testing.
How does this all relate to your original query? Is it worth spending the money to get secondary inlets on a dedicated terminal canopy?
I think the answer depends on (a) what type of canopy you are using, and (b) what kind of landing area you have.
If you (a) are jumping a FOX (or maybe a Flik), and (b) have to sink in to tight landing areas, then the secondary inlets may be worth the extra money.
But if you don't have to hit small landing areas, then the extra money (and harder openings) are probably not worth it.
My personal preference in a "terminal only" canopy would be an unvented canopy with a wide flight envelope, and a good ability to sink. So, I'd either buy a Troll or an Ace. Since the Troll is cheaper than the Ace (by $100 in your size--and a total of $385 cheaper than that Vtec Flik), I'd probably go with the Troll. Remember, this is all for jumps on which opening characteristics are relatively irrelevant.
Wow, that was a pretty long, rambling post, on a topic that you probably didn't really want that much depth on. Sorry.

-- Tom Aiello

[email protected]
SnakeRiverBASE.com

[DaveO 0]

Wow, that was a pretty long, rambling post, on a topic that you probably didn't really want that much depth on. Sorry.

Great post Tom, and glad you moved it to another thread. With all that said, I really have no reason for another vented canopy around here. The only thing that would make a landing area tight on a terminal jump here is if the damm cows wouldn't move. It's still would be hard to buy a canopy with out all the bells and whistles on it.

Thanks

"When it comes to BASE, I'll never give advice, only my opinion"

[NeilQ 0]

Last year we spoke to Anne about hard V-tec openings on longer/terminal delays. She suggested the use of a fine mesh slider on these jumps. Myself and a jumping buddy bought one. Huge improvement in opening shock. My first jump was a 6 sec which was great, and then a couple of 12/14 sec delays in Italy which was firm but totally doable, as in I could have jumped several times in one day with it. I've taken 4/4.5's off our local 620 footer and have found the openings a bit too comfy, so am thinking of going back to the large mesh for those jumps (I'll be trying it as soon as the weather here improves )

Hope this helps

Neil

[DaveO 0]

She suggested the use of a fine mesh slider on these jumps.

Thanks Neil,
I'm ordering one today!!

"When it comes to BASE, I'll never give advice, only my opinion"