Departing the launch cart - Davis Show
Posted: 2016/02/22 23:48:36 UTC
http://ozreport.com/forum/viewtopic.php?t=9230
Departing the launch cart
- Just hold the fuckin' bar back and wait until your glider's flying.
- When you have an upper attachment on the keel at the trim point the glider comes off when it's supposed to.
- If you move the upper attachment too high/forward/fast you won't be able to push the glider into the air.
- But if you eliminate the upper attachment altogether (eliminate the trim force) you HAVE TO push out to get airborne.
Departing the launch cart
Yeah Davis, awesome write-up of the Big Spring safety issues and the awesome job y'all did building safety into your system. The more of your dedicated sycophants who hear about it the better off they and the sport will be.Davis Straub - 2007/08/23 14:58:11 UTC
http://ozreport.com/11.167
2007 Worlds - nobody diedDavis Straub - 2007/08/23 14:58:11 UTC
The one accident that happened on the line came when a pilot had taken off his wheels (he was the only pilot flying with wheels) and when he came off the cart slow and too early. His English wasn't good so he may not have understood the requests for him to hold on and he was one of the least experienced pilots at the Worlds.
Where was this and who was launching you?Bill Jacques - 2007/08/23 23:11:27 UTC
Boca Raton
I find this interesting because over my last two years of aerotowing (over 100 tows now) I have twice forgotten to grab on to the rope/hose(s) prior to the commencement of towing.
- Don't worry. The weak link will break before you can get into too much trouble.It's one of those "Oh Sh&t!" moments as the cart starts accelerating and you can't reach down and over in front of the basetube and cart to grab onto the rope/hose(s) with any type of safety.
- Just hold the fuckin' bar back and wait until your glider's flying.
Yeah. Whenever you're afraid you may not have enough airspeed push out a little bit to find out for sure.Each time, the glider came off the cart on its own and I pushed forward to make sure it gained a couple feet of altitude relatively quickly (which, thankfully, happened!).
Within a long second, the glider was flying fast enough to be very controllable.
No. They're totally different beasts. You need to fly upper intermediate gliders for years to gain any useable understanding of how toplesses behave.As I am flying a Falcon 3, does this "automatic" liftoff at controllable speed not happen to the higher performance wings?
Because if you can't tell whether or not you have safe flying speed without looking at a cheap wind gauge you shouldn't be flying anyway. But if it really floats your boat stick one on your glider and knock yourself out staring at it.(BTW - This may seem silly, but for safety why not install cheap wind gauges on the front of the cart?
Each pilot who has half a fuckin' clue can do that without a gauge.That way each pilot could determine when he should let go of the tubes based on the airflow over his wings.)
Right.Tommy Thompson, Sr. - 2007/08/23 23:52:38 UTC
Whitewater
When a glider lifts from the dolly is controled by the upper tow point.
- When you have an upper attachment on the keel at the trim point the glider comes off when it's supposed to.
- If you move the upper attachment too high/forward/fast you won't be able to push the glider into the air.
- But if you eliminate the upper attachment altogether (eliminate the trim force) you HAVE TO push out to get airborne.
What? 'Cause you didn't have the upper split of the tow force to trim the glider faster? Do ya think?Gerry Grossnegger - 2007/08/24 00:03:49 UTC
Winnipeg
You sure about the 3rd image? Done that, don't think I had to push out to lift, had to pull in during the tow.
WHAT?As to the 2nd one, gee, imagine the pilot actually having to fly the glider! It should fly him, right, no input required, it knows when it's flying and you have no idea, etc...
But you're totally cool with a pro toad bridle that can and does haul the pilot/glider combo up lethally non-symmetrically. That plus a magic one-size-fits-all fishing line Pilot In Command which very clearly provides protection from excessive angles of attack for that form of towing.George Stebbins - 2007/08/24 01:31:00 UTC
Palmdale
At first glance this seems good, but... Do you really want some stick or other object out there where your tow bridle might catch it and haul the cart up non-symetrically?
But you're also totally cool with towing behind a Dragonfly controlled by some idiot total dickhead like Jim Keen-Intellect Rooney with an ability to fix whatever's going on back there by giving you the rope and is equipped with a tow mast breakaway protector to make goddam sure that you don't ever tow with a functional inappropriate weak link with a finished length of 1.5 inches or less.Even for a second? I think I might refuse to tow on a cart like that.
Get fucked, George.I'd have to see it to decide.
Damn straight. Nothing the least bit wrong with them.George Stebbins - 2007/08/24 01:33:52 UTC
The images are right.
Yeah. Change it to the polar opposite of what he's saying about trimmed two point and "pro-tow".I think the wording just needs work.
The "pilot" is pulled THROUGH.I suspect (but am not sure) that what Tommy means is that with the pro-tow, the pilot is pulled in.
Yeah, right.Then the PILOT must decide to leave the cart by raising the nose. If that's pushing out, ok, but really it is stoping pulling in. Just a wording issue, I think.
Nah, the glider couldn't POSSIBLY make the decision with no upper attachment and the Dragonfly approaching takeoff speed - or later when it climbs out. The glider's gonna stay glued to the cart - and the cart's gonna stay glued to the runway - no matter what.But I've pro-towed enough to know that you do make the decision yourself.
Things couldn't POSSIBLY go wrong - horribly or to any other degree. You've got an appropriate weak link with a finished length of 1.5 inches or less to keep you from getting into too much trouble.The glider doesn't do it for you. Unless things are horribly wrong somehow...
Fuck yeah! He's been at an around all this plenty long enough to understand what's what and who's who. So he should be the one setting us all straight and making all of our pilot and safety decisions for us.And Davis has pro-towed way more than almost all of us, I'd wager...
Better get with the program. You need to pro tow for the extra safety margin you'll need at all the comps Davis runs. Lose the wheels while you're at it - asshole.Bill Jacques - 2007/08/24 02:20:03 UTC
1. Never Pro-Towed...
Bullshit. Start paying attention to the real life issues that kill people in AT.- so I guess you could push out to raise and then stall out before the tug gains enough speed to allow you to control the glider (especially if the oncoming winds die down just as you lift off).
And you'd have been fuckin' DEAD just doing it by feel - INSTANTLY. Too slow and you hit the runway. Too fast and your lungs explode from the pressure drop.2. I suggested the wind gauge because I learned via platform tow, and we never released until we saw the airspeed reached a certain level.
That's not a reasonably good airspeed indicator?Additional stuff on the cart does seem silly, and I always make sure my front wheel lift a little before I let go of the rope/hose...
Right. That's why pro toad bridles are so much safer than three pointers. And lose your reflex bridle and tip struts. You can get down a lot quicker when you really need to.- keep it simple, right?