http://www.hanggliding.org/viewtopic.php?t=32183
Discuss-- aerodynamics of extreme loadings on flex-wings
Steve Seibel - 2014/12/16 17:23:24 UTC
Not to take this discussion in too many directions but--
Lockouts on tow are different-- the line pulls your body to the side but this force goes to the hang point and makes no roll torque. So you only have a few inches left to weight-shift before you are touching the down tube-- and then none at all. You aren't pulling hard with your muscles because you are already full over with no more room to go. Once your body is pressed against the control frame and you haven't stopped the roll, from that point on the tow line might as well be tied to the down tube-- things are going to keep getting more and more exciting till something breaks or releases! After release (or weak link break) the forces are like normal flight-- initially a high G-load because you are flying fast and steeply banked-- in the few lockouts I've developed that progressed to a very steep bank I never had the sense that the glider wasn't responding normally after release-- in cases of bad outcomes I think the ground just gets in the way too soon-- but maybe it's not always that simple?
Lockouts on tow...
I'd make a crack about lockouts OFF tow but...
04-1409
http://farm4.staticflickr.com/3903/14555125331_c930110666_o.png
http://www.kitestrings.org/post6233.html#p6233
...the line pulls your body to the side but this force goes to the hang point and makes no roll torque.
Bullshit. You and your glider feel a sideways vector and trim to the resultant of gravity and the tow tention. The glider rolls in the direction...
10-1900
http://farm8.staticflickr.com/7528/15787746292_f64cccaf31_o.png
...you wish it wouldn't. If it didn't we could all become really excellent tow pilots just by taking our hands off the basetube.
So you only have a few inches left to weight-shift before you are touching the down tube-- and then none at all.
Rubbish. The misaligned towline tension just overwhelms your control authority.
After release...
...if you have something you can actually blow in an emergency situation...
...(or weak link break)...
...if you're using some Industry Standard piece of shit within easy reach...
...the forces are like normal flight--
...assuming you haven't hit the ground yet...
...initially a high G-load because you are flying fast and steeply banked-- in the few lockouts I've developed that progressed to a very steep bank...
Because you're one of those assholes who flies with a brake lever within easy reach on the downtube.
...I never had the sense that the glider wasn't responding normally after release-- in cases of bad outcomes I think the ground just gets in the way too soon-- but maybe it's not always that simple?
No, that part you got right. And if you're LUCKY - like most people - your flying career will end before you get into a lockout situation low enough to matter.
Steve Seibel - 2014/12/17 17:01:38 UTC
Re lockouts on tow: I didn't mean to suggest that the G-load vanishes on line break/release.
"Lines" don't ever break on aerotow.
From wing's viewpoint, G-load/lift is generated by airspeed and angle-of-attack. In free flight, G-load and lift are essentially the same, or at least vary in lockstep. On tow, as the glider is banking away from the towplane, the towline absorbs much of the glider's lift...
The towline is Spectra and isn't absorbing anything. It's transmitting tension to the tug.
...and changes the acceleration resulting from a given lift force. The pilot doesn't feel a G-load corresponding to the full lift force that the wing is generating. The towline breaks, and suddenly you "feel" the full lift force/G-load that the wings were generating. Yowza! Yes indeed the glider can enter a wingover-- the nose will rise rapidly unless the bank angle is very steep, or beyond vertical (worst case!).
So how good an idea is it to push out in a lockout to use your weak link as an instant hands free release?
In fact in my experience I DON'T WANT to roll level too quick or the flight path would curve sharply upward due to all that excess airspeed and lift/G-load. Even with the bar "stuffed". Obviously I'd be thinking differently if I were about to hit the ground.
Bullshit...
http://www.hanggliding.org/viewtopic.php?t=14230
pro tow set-up
Ryan Voight - 2009/11/03 05:24:31 UTC
It works best in a lockout situation... if you're banked away from the tug and have the bar back by your belly button... let it out. Glider will pitch up, break weaklink, and you fly away.
During a "normal" tow you could always turn away from the tug and push out to break the weaklink... but why would you?
Have you never pondered what you would do in a situation where you CAN'T LET GO to release? I'd purposefully break the weaklink, as described above. Instant hands free release
You just fly away. Ryan and...
Jim Rooney - 2009/11/03 06:16:56 UTC
As for being in a situation where you can't or don't want to let go, Ryan's got the right idea. They're called "weak" links for a reason. Overload that puppy and you bet your ass it's going to break.
You can tell me till you're blue in the face about situations where it theoretically won't let go or you can drone on and on about how "weaklinks only protect the glider" (which is BS btw)... and I can tell ya... I could give a crap, cuz just pitch out abruptly and that little piece of string doesn't have a chance in hell. Take your theory and shove it... I'm saving my a$$.
...Jim Keen-Intellect Rooney have both assured us that you just fly away.
So due to concerns about zoom-climbing into a loop, and desire to reduce G-load, and non-proximity of the ground, I'm sure I always stuffed the bar immediately after line break if not before, on the handful of lockouts I've exerienced.
How are you gonna stuff the bar AND blow your instant hands free release? Also...
03-02421
http://farm8.staticflickr.com/7200/14097626583_03972773c6_o.png
What if you're a pro toad and have to keep the bar constantly stuffed just to stay level with the tug?
If this "locked-in" high-G spiral thing is real, a lockout on tow would seem as good a way as any to induce it.
Bullshit. If that were true we'd be seeing a lot of carnage from all these disciples of Ryan and Rooney...
http://ozreport.com/forum/viewtopic.php?t=24846
Is this a joke ?
Jim Rooney - 2011/08/25 04:55:25 UTC
Ditto dude.
It always amazes to hear know it all pilots arguing with the professional pilots.
I mean seriously, this is our job.
We do more tows in a day than they do in a month (year for most).
We *might* have an idea of how this stuff works.
They *might* do well to listen.
Not that they will, mind you... cuz they *know*.
I mean seriously... ridgerodent's going to inform me as to what Kroop has to say on this? Seriously? Steve's a good friend of mine. I've worked at Quest with him. We've had this discussion ... IN PERSON. And many other ones that get misunderstood by the general public. It's laughable.
Don't even get me started on Tad. That obnoxious blow hard has gotten himself banned from every flying site that he used to visit... he doesn't fly anymore... because he has no where to fly. His theories were annoying at best and downright dangerous most of the time. Good riddance.
So, argue all you like.
I don't care.
I've been through all these arguments a million times... this is my job.
I could be more political about it, but screw it... I'm not in the mood to put up with tender sensibilities... Some weekend warrior isn't about to inform me about jack sh*t when it comes to towing. I've got thousands upon thousands of tows under my belt. I don't know everything, but I'll wager the house that I've got it sussed a bit better than an armchair warrior.
...actuating their instant hands free releases in lockout emergencies. And now that so many of us have decided we're happy with 200 pound Greenspot...
Especially if the pilot doesn't pull in. But I don't think the dynamics would kick in until after the line breaks, freeing the flight path to curve as normal in response to the lift from the banked wing. See my earlier post for what I feel is happening before the line breaks.
This thread sure has morphed in many directions!
So how come when you hear all this total crap from all these Jack and Davis Show motherfuckers...
http://www.hanggliding.org/viewtopic.php?t=12682
Landing on your feet (for AEROTOW)- So Dangerous
Jack Axaopoulos - 2009/06/29 14:26:26 UTC
OMG!!! You dont even have wheels!!?!?!?!?
YOURE GONNA DIE FOR SUUUUREE!!!!
I have a brilliant idea. People who cant land for sh*t.... LEARN TO LAND
That way when a weak link breaks on you, ITS A NON-ISSUE. Genius huh???
http://www.hanggliding.org/viewtopic.php?t=22233
Looking for pro-tow release
Zack C - 2011/06/16 03:14:35 UTC
I've never aerotowed pilot-only, but it is my understanding that this configuration pulls the pilot forward significantly, limiting the amount he can pull in further.
Davis Straub - 2011/06/16 05:11:44 UTC
Incorrect understanding.
...you just sit back and don't say anything?