Crossfire design flaw?

[DBTECH 0]

Crossfire design flaw?
There has been rumor that the Icarus Crossfire has a design flaw in the nose design which can cause it to collapse during very aggressive front riser turns.
The accident/fatality at the Ranch last Sunday seems to confirm this. (almost nil wind/turbulence.
Dave Brownell

[ramon 0]

Rumor has it per Chuck Blue and other eyewitnesses, that there were rotors off the trees, that there are often rotors off the specific trees.
It is very dangerous to hook in turbulence, it will plant you quickly. The poor girl was loaded at 1.4 (per Brummits web page), which is an ok loading for straight flight in turbulence, but in a hook I beleive current thought has it that 1.8 and hihgher is a more stable platform.
Maybe there is somehting wrong with a crossfire trying to be hooked at tha loading, but it is always dangerous if thre is turbulence, and lower wingloadings make it more so.
peace
BSBD
ramon

[cyberskydive 0]

Then why are so many people putting the nose mods on thier cobalts / heatwaves etc essentially making them like a crossfire nose?
C-28534
http://www.sunraydesigns.com

[cobaltdan 0]

the nose on a competition cobalt is completely different from a crossfire.
the crossfire has no continuous spanwise tapes on the nose and both top and bottom skins are brought to meet in the center of the non loaded rib. basically the rectangular shaped inlet on a standard 9 cell with rounded corners. the heart shape you see is because the rounded corners are on the non-loaded ribs and they not being braced float up higher. the mod reduces drag, but is non-structural.
the compt-cobalt has a continuous tape on top and bottom skin with
triangle spanwise cross braces closing the nose to the ribs. it looks sort of like shark teeth. the braces on the loaded ribs are structural spanwise cross braces, the braces on the nonloaded ribs are not structural and only aerodynamic. additionally the a lines are set back and a zig zag bottom skin inlet is formed for opening inflation.
the retrofit that some people are doing aka the 'howard mod'. is a standard cobalt with the structural braces sewn on. this was a mod that howard adams started i believe on alphas years ago. like the comp cobalt it reduces drag and cross braces the nose of the canopy, reducing span wise airfoil distortion and increasing efficiency.
stane and i designed and built several prototypes with noses similar to the crossfire. we had some trouble with stability in these prototypes in certain conditions. the problem was noticable in designs where the bottom skin was brought up into the inlet area. note: the cobalt is a very diferent canopy than the crossfire with different variables, ie airfoil, cg,cl, etc... i am not saying that the crossfire has this or any other problem.
after witnessing the accident and hearing the rumors, i felt better safe than sorry and offered our test data to precision and icarus. i spoke with george galloway last week and offered to send a prototype canopy to him that flew nice with the exception that it could be piloted into a roll under collapse with specific conditions. george was at the ranch last week and is also very upset. even though he stated he is only a 'cut and sew subcontractor, having no design input on these canopies', he is intent on assuring there are no issues, he was appreciative for our test data and everyone will be analyzing the video this weekend. until anything else is discovered, the accident is being accepted as collapse from rotors.
sincerely,
dan
atair

[Gravitymaster 0]

Sounds like you are the one trying to start a rumour. One fatality which was related to rotors coming off the trees and you ASSume their is a design flaw. Real scientific approach you have there.

[skymedic 0]

How is it that Dan is assuming anything?
Maybe I am reading something different from you...
Marc
Because I fly, I envy no man on earth

[DBTECH 0]

Bob said--
Sounds like you are the one trying to start a rumor. One fatality which was related to rotors coming off the trees and you ASSume their is a design flaw. Real scientific approach you have there.
DB> I said "there has been rumor" that there is a design flaw. It is yourself that is ASSuming I came up with the statement "design flaw," which is not the case. Also, what do you know about the source--nothing.
GAL,
Dave Brownell

[SkymonkeyONE 3]

The REAL deal is that there was a significant push coming right over the trees. Some people got caught downwind due to the way we were forced to stack out of the plane and barely had enough altitude to perform their final turn. To make what we would call a "normal" pass at the pond, we would be flying straight crosswind in final. Below the tree level, the winds were not a significant factor, but at the treetop level there were some pretty strong rotors. Most people that chose Lisa's line, or the opposite one (right hand turn over the trees from the opposite end of the lake), made it through with no problem. We were all shocked to see Lisa's parachute go away after so many others had made similar turns over the same trees. Lisa wasn't doing anything wrong; she got a bad gust and lost her life. She was certainly not the only person there jumping a Crossfire, either. Hans Paulson did very well under one. I don't think I would be going on a witch hunt ala the Nova situation a good while ago.

We have a similar set of conditions at Raeford which we refer to as "the Raeford Dragon". Fly near the trees on final when the wind is coming over them and you are just asking for it. It is for that reason that we have our beer line well out from the trees now.
Sincerely,
Chuck Blue
D-12501
Team Atair

[Gravitymaster 0]

We do know from people who were there that her canopy appeared to collapse due to the rotors. We also know from eyewitnesses the wind coming off the trees was causing rotors. So we DO have a source as to that cause, which makes it much more believable than your rumor. Why don't you tell us the source of your rumor?

[DBTECH 0]

This could be a case of "all of the above." When I say all, there are very many factors as we all know, any one of which being slightly different, would have changed the outcome for the better--(or a worse crash.
My sympathy goes out to Lisa's family and friends.
I really wonder if this pond swooping thing is worth the risk?
After all, the main purpose for a ram-air parachute is to deliver one to terra firma in one piece--preferably alive!
Just my .02 worth
Dave Brownell

[Cacophony 0]

Finally we have a good debate going here. I am very sorry to hear about the accident. I know nothing of the incident or of the location or canopy design specifics so I will leave it at that. Take it easy out there people. Take everything into consideration.
Safe landings,
Alex D-23912

[Aviatrr 0]

Quote

There has been rumor that the Icarus Crossfire has a design flaw in the nose design which can cause it to collapse during very aggressive front riser turns.

What is your source for this rumor, Dave? Ever experienced this yourself? Give us some info on where you're coming from..

Quote

The accident/fatality at the Ranch last Sunday seems to confirm this. (almost nil wind/turbulence.

Well, I wasn't there, but I have heard from several that were there that there was a good wind, and some rotors off the trees.. Again, where is your info coming from? You don't seem to have done any research before you commented.. Correct me if I'm wrong, but I don't think I am..
Mike

[weid14 0]

How is this a good debate? Dave has started/spread a rumor with no factual basis. Until the correct people review any evidence, everything is pure speculation and conjecture.
As for the cross fire, I do agressive front riser manuvers (double front, single, one direction then the other - some all at once even) on mine to check it out up high, no problems at all. I do a front riser approach for landing also, have not noticed any problems.

[freeflir29 0]

Well...in my miniscule experience this phenomenon is not really all that isolated. I thought I was watching someone die this weekend when a swooper set up with a 270 approach. As he started his dive the right side of the canopy collapsed. Luckily it reinflated in time for him to save his ass. I have no clue what type of canopy Brian was jumping. I'm just glad I didn't have to see him pile in. We don't need finger pointing. We need cooperative research by manufacturers and maybe even a USPA rep. We need to find a cure for what is killing skydivers. Is it pilot error or can it be fixed with engineering? If it is pilot error let's get people educated as to how to avoid causing this malfunction. I think canopy design often out paces pilot knowledge. Let's get this figured out.
"The cab driver said... he recognized my girly by the back of her head" -Beasty Boys
Clay

[weid14 0]

I don't disagree with safety. I disagree with posting a "rumor" with no basis. I've seen canopies collapse and re-inflate on a straight in approach, too. Stuff happens, was he jumping near buildings? tall trees? remember, objects cause turbulence 8 to 10 times their height downwind (so a 20 foot tall hanger will affect 160-200 feet downwind). It may be bumpy, no big deal, or it may be a significant wind shear that causes more than a little problem --I've seen both.

[Donna 0]

Quote

I really wonder if this pond swooping thing is worth the risk?

And most whuffos don't think skydiving is worth the risk! Sheesh!!
Attention all you pond swoopers! DBTech has decided your sport is not worth the risk so it has been cancelled.
Why don't you let each person decide for themselves, huh?
Skies,
D

[prost 0]

I can tell you that any the crossfire does not have a design flaw that will cause the canopy to colapse in hard front riser turns. I have jumped the cross fire in every standard size from 149 to 109. This at wingloadings of 1.6 to 2.2. I am 239 with camera helmet and all gear on. I have tried almost every type of high speed approach including 360 degree turns where I first went into deep brakes and the unloaded one side of the canopy so I could pull the riser down to my waist. I have combined toggle turns followed by riser turns in the reverse direction.
I HAVE NEVER HAD ANY PROBLEM WITH ANY OF THESE TURNS.
There are a lot of crossfires at our dropzone. We have no problems with them. The most important thing to know when performing high performance landings is knowing when not to perform them. I watched a jumper almost die this weekend when he tried a 180 hook turn in 20 mph winds. He was under a 7 cell canopy and two cells collapsed. Any canopy is capable of collapsing in the right conditions.
As to your comment about pond swooping being worth it or not, have you ever been asked why you would want to jump out of a perfectly good airplane. To the people doing this it is very worth it. We know the risks and respect them just as everyone in skydiving does.

[prost 0]

My thoughts exactly Donna

[Gravitymaster 0]

Hey DbTech
Aren't you that guy who was telling everyone that "hard openings" were caused by slider rebound a while ago. Seems to me you were patenting a solution to slider rebound. Have you gotten your patent approved yet? Maybe you can redesign the Crossfire after you are done with solving the slider rebound problem
Bob

[SkymonkeyONE 3]

Quote

a swooper set up with a 270 approach.....I have no clue what type of canopy Brian was jumping

Brian was jumping his Stiletto 97 and yes, it went away on him for a second then reinflated. He still got a nice swoop out of it, but I am sure it alarmed more people than just you.
Chuck

[DBTECH 0]

The following was posted on rec.skydiving, on the "Crossfire design flaw" thread, and the
"Tube Stows/Line Dump" thread on which Rastro replied with a short thread ending with a personal insult aimed at myself.
Rastro's post--as said-(posted originally on the Tube Stows/Line Dump thread.
>Mr. Brownell,
>You are of course right about the insult. I apologize.
>(never drink and post at the same time)
I have no problem in forgiving, as we are all in fact, only "little-nano-guys" in the total scheme of things.
>I am however, somewhat bothered by some of the statements
>that you occasionally make to the NG regarding equipment from
>various manufacturers. The most recent being: that the Crossfire
>has a design flaw. You offer no proof of your allegations and
>jump to a conclusion that was very obviously
>not supported by the reported facts.
There has been no allegation by myself, as this "rumor" has been around long before the Ranch accident.
>This type of rumor mongering bordering on libel, does nothing
>but attempt to instill panic, fear and distrust. Equipment
>manufacturers unfortunately have to deal with "know it all"
>types like yourself on a regular basis. It takes an extremely
>long time to design, build, test and market parachute equipment
>of this complexity. It takes even longer for it to become popular
>and to make the manufacturer a profit (if ever). It only takes
> a moment and one or two unsupported off the cuff remarks
>to do an immense amount of damage, as most jumpers don't
>take the time to check the facts for themselves. You have
>done this with Flitelines Reflex/grommet issue,
>and now you are doing it with the Icarus Crossfire.
A "rumor" is just that- a rumor--some are based on "alleged" accurate base line sources, and most are based on many other sources.
As far as the Flight-Line grommet issue, I believe I made the correct call, insomuch as all in my circle agreed that Flight Line was dragging it's rear end way beyond the ethical envelope on a critical safety issue they knew was widespread. Maybe two fatalities, close together in time with the same grommet cause would have been a wake up call-but maybe not. I've always believed that over the "long haul" the best policy is at least a "timely" warning that there "may be" a quality control or design issue here that requires immediate attention. In other words-the "timely" grounding of all suspected rigs until inspected/repaired. (not--well it's been five weeks with no reported incidents, but we've been under much increasing pressure, so we mite as well send out a Product Service Bulletin, at least to riggers.
>You seem to have a history of giving your opinions and passing
>them off as fact, without knowing enough about a situation to
>fully disclose the real facts. This is irresponsible and can harm
>the manufacturers you target. You yourself are a small
>manufacturer of after market components.
>Imagine if this sort of thing were directed your way.
>How much would you ( as "the little guy" ) suffer?
As a matter of fact, vicious slamming has been leveled on myself on this NG many times from those that haven't a clue as to what my background is, or where I'm coming from regarding my alleged theories/claims.
No, I'm not a Dr. or even a PHD, even though my father was MIT honor role, but let's face the facts guys, the consciousness of the parachute industry is a far cry from MIT, Cal Tech, or Lockheed Martin. I'm not trying to put down the parachute industry, but considering the above fact, I think it has evolved to the "relatively" high level of performance/reliability due to much hard work, and of course the tried and proven methods of trial and error evolution/fine tuning. (and of course, talent, and "some" edu)
>Think about that the next time you wish to see your name in print.
>It appears you want to play in the same league as the major
>manufacturers by offering opinions on subjects that you seem
>only minimally qualified to comment on. All manufacturers out
>there would urge you to "get out there and do it for yourself"
>to fully understand the ramifications of shooting from the hip.
As far as going out there and doing it for myself, there is test jumping in progress on several canopies with my new design slider, along with other methods in my "physical slider model." I'm receiving good feedback on the openings. (eight new prototype sliders under construction this week-ten more soon)
>I think you owe George Galloway and Icarus, as well as the
>NG an apology for jumping the gun again.
I do offer my apology to George and Icarus regarding the second paragraph in my topic/post; as in retrospect, I was jumping the gun.
As far as the Flight-Line grommet issue is concerned, my earlier statement stands.
As far as any apology to the news group ('s)--what about the apology ('s) it owes myself?
Dave Brownell

[apoil 0]

One forum is enough, Dave.
Actually in this case it was too much.

[freeflir29 0]

Yeah....get the torches and pitchforks. Lets march on the castle!
"Jesus Blessed me with his future...and I protect it with fire!"-R.A.T.M.
Clay