Katana Question

[skydived19006 4]

I figure that you guys would be the ones to ask. Would a Katana loaded in the 1.4 to 1.5/1 range while in breaks turn and remain in a turn. I'm talking about a turn similar to what you'd see if you were spiraling down to lose altitude. For instance if it were deployed with a half a turn of twists resulting in a spin/turn, but the twists self cleared, and the skydiver was unconscious, would it turn all the way to the ground without other contributing issues?

And yes, this question is tied to an incident.

Experience is what you get when you thought you were going to get something else.

AC DZ

[davelepka 4]

My guess is that most canopies will continue to turn if they are in an asymetrical line twist and no action is taken by the jumper.

If you think about going into or coming out of line twists, the first third of the rotation to a twist generally wants to spin you back out of the twist. The middle third is somewhat neutral, and the last third tends to make you want to rotate into, or lock into, the twist. That's why when you go to kick out, there a great deal of resistance though the first part of the 'untwist', then it gets easier, then to completes the untwist for you. Without jumper input, a canopy is unlikely to put itself through that first, high resistance portion of the untwist.

In reagrds to a canopy turning, it's all about the symetry of the twists and the stability of the canopy. A higher performance canopy which is more sensitive to harness input is going to be less likely to spin up straight and fly that way, especially if the jumper is not participating in the opening.

[boyfalldown 0]

My katana 120 (at a 1.8-2 wing loading depending on my diet) has opened in a pretty vicious diving turn that most certainly continues with no input on multiple occasions (maybe 10 times in the last thousand jumps). The turn feels as aggressive as a stiletto with a toggle buried pretty deep, and requires unstowing of the breaks and an aggressive opposite control to stop it. I don't think I've ever let it go past 3 or so turns, but have no doubt would continue with no further input. While it's a dream to fly and land, the katana is a VERY aggressive canopy that I'd never want to fly or land unconscious, ever.


Jim

[Scrumpot 1]

Quote

...as aggressive as a stiletto with a toggle buried pretty deep, and requires unstowing of the breaks and an aggressive opposite control to stop it.

+1

That is my impression and (limited) experience with a Katana of very similar wingloading actually, Martin - to the incident you are referring, and now asking further about as well. Which is why I posted what I did earlier, directly within the incident thread itself.

The bolded/emphasized part is most critical and possibly pertinent (I think at least possibly) to the incident you refer. If the jumper was either somehow simultaneously incapacitated during his opening, or severely disoriented by/during the event itself enough, or for whatever similar reason regardless - caused his inability/failure to unstow and affirmatively counter his resulting spiral - that spiral very well then could have continued, as it would not otherwise necessarily just "correct itself".

coitus non circum - Moab Stone

[phoenixlpr 0]

This can be one property of an elliptical canopy. If you brakes are set for deployment you canopy in flying with some flare.
If you got some turning momentum it would not stop turning, because you speed vector still point inside the turn.

You can try: leave the brakes set and start a medium turn to one side. After some time you can not stop the turn even with the opposite riser. Solution: release your brakes and stop the turn with toggles.

[RichLees 0]

Loaded at 1.7 and brakes still set, my katana 150 would go into a dive after 120 degrees of harness turn. If I let it build up past 360 degrees, it could dive at 80fps and I'd have to release the brakes as I couldn't counter hard enough with the harness. Add in a twist and a half and it was unstopable as firing the brakes was ineffective due to friction of the HMA lines

[skydived19006 4]

Thanks all, It had this scenario had not occurred to me until Scrumpot brought this possibility up in the incidents forum. I just wanted a few more opinions.

I do know that my Crossfire II at 1.5 will turn until stopped while in breaks, but had not thought to let it go to see what happens if no corrective input is added.

Experience is what you get when you thought you were going to get something else.

AC DZ

[Zlew 0]

If you are worried about the being unconscious part... I think being under an elliptical wing and being out isn't a good place to be. Unless you just happen to be passed out square in the harness, it will tend to turn...and given enough time even a slight harness turn can become fatal.

[LetsGoOutside 0]

I fly my Katana with a wingsuit. I've had multiple twists while uneven in the harness and it does not spin or result in a mal (just a slight turn). The harness definitely plays a role here, though. My older Wings does not respond much to harness input. I also wear my chest strap pretty tight on wingsuit jumps to keep the risers more even after opening (since I can't use my hands).

Same situation with a newer Javelin and looser chest strap and I might expect a spin which would require input to correct or possibly a cutaway. Having the brakes stowed definitely presents drag needed to keep the turn in check for at least a short while.