Another Gear Question--This Time Canopies

[imported_Tom Aiello]

Cheerful Greetings:

I have another random gear question, and I'm hoping somebody (Adam F, maybe?) can give me some insight.

I own both a Fox and a Mojo. However, I've also jumped an Australian BASE canopy called the Pooster.

I like the Pooster. Here's why.

When I flare from half brakes under my Fox or Mojo, I still kind of pound in (not a big deal, since I don't do it often, and I can PLF fairly well).

However, when I jumped a Pooster, I noticed that the flare from half breaks was fantastic. The difference was remarkable.

So, I started asking riggers and jumpers why the Pooster had a better flare. It turns out the Pooster has an extra control line (the toggle line cascades to five, rather than four, points on the canopy). Apparently this was largely responsible for the difference. (The Pooster I jumped also apparently had Spectra control lines, which may have also helped--but that's another question.)

So my question is, why don't we put extra control lines on more canopies (I know a rigger who does this mod for Triathlons, to help them land better)?

Is there some danger in having the extra line (maybe increased chance of line over)? Or is there some other reason not to have it?

Anyone know?

Thanks,

--Tom Aiello

[guest]

Hi Tom,
Why you got the type of flare that you did from your pooster and not your other canopies is probably not a function of the steering system. I would tend to believe that it was more circumstance than design. From full-flight the steering system you described does give a more dynamic flare as it would more effectively chamber the airfoil and generate drag. On the other hand from 1/2 brakes, getting a good flare is more about keeping flow attached than it is generating a dynamic motion. In other words the extra trailing edge deflection will not help much when the canopy is already slowed.
Infact we have a Mojo in the field configured as such (4 upper control lines positioned at seams #1,2,5 and 6 - effectively like your pooster) Our initial testing and all reports (100 jumps)don't indicate any better flare pereformance form 1/2 brakes.

One of the reasons that BASE style canopies aren't built using this extra line is that it requires different length uppers to keep the steering geometry the same. This creates a packing scenerio that is not popular. (Remember the Cruiselite). Not to say that it couldn't be done but in our experience the benefits haven't been demonstrated yet. Another consideration is opening performance. It is better to leave a portion of the tail unsupported during deployment. As this unsupported tail deflects, if forms a monorail on which the canopy rides. Very stable. The other extreme would be to support the entire tail. The result would be miserable heading performance. Just how much support is ideal? We haven't pushed those limits yet. The extra line is not a bad idea. I'm just not convinced it was responsible for the flare you got.

Perhaps Aerodyne Research (Bill Hazlet)can give you some feedback on the Trialalon Mod. I know it was not originally done with their consent - maybe that has changed.

Hope that helps.




Adam
Consolidated Rigging, Inc.
[http://www.crmojo.com|CR Home Page]