Fair compairson & evaluation of mains & reserves

[Praetorian 1]

Ok after reading tons of manufacture descriptions of products I've noted that every main opens on heading has low riser pressure and impressive turning rates compared to all others on the market.. I know that a lot of this is a matter of opinion so I gotta ask wouldn't it be in our (and the manufacturer's) best interests to have some actual numbers? after reading the Robot parachute post with reference to:

http:www.extremefly.com/aerospace/guidedsystems/ONYX/[url]


why can't a system like this be used to compare mains? so we know just how far a toggle has to be pulled to induce a turn / how hard you have to pull, which equally loaded mains have the highest turn rate etc. the robot makes all inputs 1 the same, repeatable and not subjective 2 measurable in real numbers (total length to pull toggle, total pressure required) the system would need to be modified to be able to do front riser turns .. but that is so do able. Is it cost? I can't be the first to think of this

Good Judgment comes from experience...a lot of experience comes from bad
judgment.

[pilotdave 0]

Quote

Is it cost?

Yep. Who'd be paying for that research?

Dave

[SullyFlyer 0]

Lets convince Consumer Reports to do it. Or better yet, a government grant

~
Fear is the thief of dreams...

[billvon 3,116]

>so we know just how far a toggle has to be pulled to induce a turn /
> how hard you have to pull, which equally loaded mains have the
>highest turn rate etc.

A good idea, but I think that it would be a little tougher than that. Imagine if such criteria were applied to cars. How many inches does the brake pedal have to be pushed to get a .5G stop? How many pounds does the steering wheel take to deflect 45 degrees at 60mph? Such numbers are not that useful when it comes to deciding which car will be more manueverable, which will be more pleasant to drive etc. It takes a human in the loop to figure that out.

Some things that might have relevance (IMO):

recovery arc distance at a specific loading
glide ratio
riser and toggle pressures at trim airspeed

These tests can all be done with a person in the loop.

[cobaltdan 0]

why cant? no reason, in fact the equipment already exist.


So why dont you see logged data in the sport parachutist world. simply because 1: most manufacturers can not justify $30k for the test equipment and 2: most manufacturers would not want to share the recorded data. they find such a trend threatening, and prefer advertising spin to logged data.

sincerely,

daniel preston
atair aerospace

Daniel Preston <><>
atairaerodynamics.com (sport)
atairaerospace.com (military)

[diablopilot 2]

Quote

and prefer advertising spin

You mean like advertising someone intentionally deploying their main canopy while head down?

----------------------------------------------
You're not as good as you think you are. Seriously.

[Praetorian 1]

Ok I'll give you the .5inch break pedal arguement but what about numbers like 0-60 easily measured, the main or reserve equivelant would be something like greatest turn rate in deg/sec or how about Revolutions/altitude loss. I know a human in the loop is gonna change the outcome even if its the same human jumping all the different chutes, and computers/machines can measure riser force in numbers with units attached not just more or less. what good is telling me the riser foce of the X is less then the Y if both are way above my strength? what about if the difference is HUGE? giving numbers lets me comparison shop without having to do the logic problem of Y is less then X and X is less them M so Y is less them M etc. and the equptment exists and could be leased/contracted so 30grand is a little high of an estimate isn't it? (no longer responding directly to Bill) you would think the arguement would be setteled by what a great add campain it would make ours spin faster, has a wider flight range etc .. or ours turn this fast most think its faster then theirs and they wont even do the experiment .. what does that tell you? I don't like negative ads but I like numbers, and I'm not gonna take a company's word on anything when some of their ads have made comments about opening force or stability that most users laugh at.

Good Judgment comes from experience...a lot of experience comes from bad
judgment.