0
riggerrob

Squares for pilot emergency parachutes?

Recommended Posts

Just to stir the pot.
Should we sell square parachutes to aerobatic and glider pilots?
Hint, I am a touch biased on this issue, seeing as how I built freebags when I worked for Butler, helped with the entire P-124A/Aviator drop test program when I worked at Rigging Innovations and convinced Para-Phernalia to "molarize" their freebags when I worked there.
Riggers, do you think we should sell square parachutes for pilot emergency parachutes?
What is the minimum training for pilots?
Let's open this debate with canopies in the 230 - 340 square foot range.

Share this post


Link to post
Share on other sites
After talking to one of the test jumpers on the P124a project, I have to say that as long as the person has half a brain and puts both hands on thier chest straps for landing there should'nt be any issues with it. I've seen video of the test dummies landing very slowly gently and unharmed. Granted the wing loading required ahould be like .6:1 or so but they are perfectly good alternitives to Lo-pos or Phantoms. They can be steered to avoid trees, power lines, etc.
Political Correctness - At least one person at any one time will be offended by something

Share this post


Link to post
Share on other sites
My current pilot's rig is a Butler Bata container, with a 26' conical-Strong LOPO LITE. I consider the Strong LOPO LITE canopy the best round reserve 'canopy' ever built--to bad that the diaper design is the worst design ever! Yes, it can line dump!!--says allot for TSO's! (just my opinion-of course)
As for large ram-air's for none jumping aerobatic pilots, I seem to recall that there is at least one that has no steering lines, and it is trimmed to fly at the same speed as not releasing the brakes.
What about having the non jumping aero pilot do simulated landings with the same 'virtual reality system' that George Bush used? It would be recommenced that he/she stay current every six months?
Dave Brownell

Share this post


Link to post
Share on other sites
The only problem I would see is pack volume. Can you pack a square, that is big enough, into a rig that will be small enough to be useful. Remember...if it isn't comfortable no one is going to want to use it.
"I only have 131 jumps, so I don't know shit..right?"-Clay

Share this post


Link to post
Share on other sites
Quote

Should we sell square parachutes to aerobatic and glider pilots?


I don't think it would really be a good idea, since then there is the possibility of somebody trying to steer it in for landing, realizing their going downwind, and try to get into the wind.......resulting in a low turn.. Pilots that are also skydivers with experience on ram air mains would be ok - but, IMO, not the general population of pilots.. A friend of mine has a couple pilot rigs with, I believe, Raven IV's in 'em..
Mike

Share this post


Link to post
Share on other sites
I really think that an aerobatic pilot could read some simple instructions on square canopy flight and land himself alive and probably unhurt. After all a pilot is not going to leave an aircraft unless it's pretty certain he'll die if he doesn't. It's a free country, if a 70 jump wonder can buy a sub 100 cross braced canopy, why can't a pilot buy a square reserve.
Tad

Share this post


Link to post
Share on other sites
Mike, those would probally be P124's, They are basicly Rave 4's trimed to fly like they are in brakes still, with out steering lines. IMHO they are a sweet setup and a easy system to repack. I've seen lots of pictures of test dummys being deployed at terminal, and landing and the insterments never read a hard opening and the landing was better then most students landings. Granted, they are probally going to be down wind since the canopy will want to turn that way in the moving air flow. But if you are bailing out with it...... its better then crashing the plane and it does offer limited steering (Risers).
Political Correctness - At least one person at any one time will be offended by something

Share this post


Link to post
Share on other sites
Eric said:
Granted, they are probally going to be down wind since the canopy will want to turn that way in the moving air flow.
-------------------------------------------------------------------------------------
Whaaaht!! Looks like someone needs some Newtonian Physics input.
Dave Brownell

Share this post


Link to post
Share on other sites
Well... its kinda hard to explain what i'm thinking. What I wanted to say was the canopy will probally not be pointed in the ideal direction without out some sort of input from the jumper.
I realize that to the canopy the air is still, but to the observer the canopy is moving in a non-linear movement in the fluid mass. The canopy will move at a striaght line unless corrected by the pilot. The straight line will be a vector component of its forward speed and the direction and velocity of the airspeeds that are being applied to it. If the canopy is moving into the wind the forces partially cancel each other out, if the wind is at a 90 degree input then the canopy will travel at a vector off straight ahead to the observer.
Cause I don't wanna come back down from this cloud... ~ Bush

Share this post


Link to post
Share on other sites
"Looks like someone needs some Newtonian Physics input."
I've seen this debate before....This is what I can tell you....If I open my canopy and do nothing but hang in the harness....The canopy will turn down wind and stay down wind until touch down.
"I only have 131 jumps, so I don't know shit..right?"-Clay

Share this post


Link to post
Share on other sites
When I started jumping many years ago I was Angry that they didn't let me transition to a square canopy in say under a hundred jumps. Even though I am pilot They told me I'd kill myself for sure. I almost did kill myself on rounds in which the winds picked up after our little cessna took off. Winds that even a 300 square footer could have easily handled. Fed up I got out of the sport.
Getting back into the sport years later I loved my AFF LVL 1 canopy flight almost as much as my return to freefall. Spirals ,riser turns, stalls all great fun. When I landed at the feet of my jumpmasters ( both pilots) without a peep on the radios they said nice job we can tell you are a pilot. If only my freefall was that good.
YES give them squares. There is nothing any canopy pilot is going to tell a glider pilot about landing out. And if a guy can handle a pitts or an extra300 he can handle a raven. Since these guys are bailing after a structural they most likely
will be lucid enough for a ram air flight. Its the free fall part thats gonna get their attention.

Share this post


Link to post
Share on other sites
Try it on every jump, as the only way this could happen, would be a unique changing wind shear condition from opening altitude to near ground. (and/or a very slow turn in the canopy) Do this also--turn to a down wind heading immediately after opening & see what happens. (same time under canopy not touching toggles)
A static air/fluid mass is the same as a huge fish bowl sitting on a parked railroad flat car, or that flat car/fish tank moving at 1000 MPH across the ground. (very smooth road bed, indeed!)
Dave Brownell

Share this post


Link to post
Share on other sites
Large square reserves have about the same pack volume as the 26' round canopies currently worn by most aerobatic pilots.
Did I mention that I did 15 jumps on the 280 square foot version of the Precision P-124A during the Aviator test drop program. I deliberately landed it downwind a few times with my hands off the toggles. Sliding downwind through Lake Elsinore's sage brush was a lot softer than most of my landings under T-10s.
As for DBTech's criticism of Strong diapers .... please expand.
In my opinion, the latest Preserve diapers (Type 4 with an extra flap are the best), closely followed by most other Type 4 diapers (vertical line stows). Type 2 diapers (only 2 line stows) are a nuisance to pack, but a reasonable alternative, but Type 3 diapers (horizontal line stows, ala. Phantom) are almost as bad as no staging device.

Share this post


Link to post
Share on other sites
With a free packed round parachute, the first element to accelerate away from the container is, of course, the apex of the canopy. If we assume a 26' canopy, that would mean a nominal 12 feet between the apex and the diaper. Doing rough math, the apex would be moving away from the rig at 66 FPS (45 MPH) just before the diaper/area starts to accelerate away from the pack tray. If I use one foot for an acceleration distance for the diaper/area, that would mean that the diaper/area, with it's stowed lines, would experience a change in velocity of 66 FPS in 0.015 seconds.(15 ms) This translates to 137 G's nominal acceleration, for 15ms for the diaper/area and it's stowed lines!!
Comparing this with a 'bagged canopy' with the lines stowed on it--a bagged canopy with it's stowed lines accelerates at about ten G's at lift off from the container. (pilot chute drag over bag weight-minus one)
This translates to ten times more acceleration for the stowed lines on a diapered free packed round parachute, as compared to the stowed lines on a D-bag!!
With a horizontal line stow method, large stow bites can all but eliminate the chance of line dump, because of the large mass of the large stow bite outside of the stow band. The applied acceleration force is, of course, 90° to the line passes.
With a vertical stow diaper, the lines are 'aligned' with the applied acceleration force-most of which is provided by the top stow bands. It can easily been seen that the line mass below the top stow band is pulling directly down on the top stow band during diaper/area acceleration. When you combine this fact with a ten times factor in line acceleration as compared to a D-bag, you can understand my grave concern here.
And then there's the old joke--"You'd be surprised what you can get away with"
(even on a reserve parachute!!)
Dave Brownell
db

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

0