HIGHER EDUCATION
WELCOME TO FIN LAND
by Drs. Lisa Colletti and Tracy Tillman
Fins to the Left, Fins to the Right...Welcome to Fin Land!
(Jimmy Buffett, refs 1,2).
TRACY: It's no secret that we are serious, probably obnoxious, parrot-heads. In fact, you're a famous parrot-head. Your picture made the Tampa Bay Online news when we were there for a concert last year (ref 3).
LISA: Yeah, we really enjoy going to Jimmy Buffett concerts, and we've held way-fun annual "MargariTOWville" fly-ins here at Cloud 9 for years. Jimmy's current concert tour is called "Welcome to Fin Land." We figured that would be a good title for this month's article, since our topic is about the use of fins on hang gliders.
TRACY: "Welcome to Fin Land" is perfect, because our flying site is located in the frozen tundra of the north, and because nearly everyone who aerotows with us here at Cloud 9 flies with a fin on his/her glider.
LISA: That's true. Even though we don't require the use of fins, almost everyone in our club flies with one. It's a main factor contributing to our record and reputation for safety. Last year, our club received the National Aeronautic Association's (NAA) Safety Award for hang gliding. The use of fins on gliders is a huge part of why our club has been able to maintain such an outstanding safety record over the years.
TRACY: It might be good for us to explain why most pilots here at Cloud 9 fly with a fin on their gliders.
LISA: There are several reasons: (#1) it makes towing safer, easier, and more likely to get to release altitude without a problem; (#2) the right-sized fin enhances handling and performance, (#3) our club has a culture of safety; and (#4) our best and most experienced pilots fly with fins, which make them good role models for new pilots.
TRACY: OK, let's look at reason #1. Why does flying with a fin make aerotowing safer, easier, and more likely for the pilot to get to release altitude?
LISA: A fin adds directional stability. Think of what it looks like when someone rides a unicycle compared to a bicycle. Because hang gliders are flying wings, they have a certain lack of directional stability as compared to airplanes or sailplanes, which utilize vertical stabilizers for directional stability. Pilots towing hang gliders without fins don't have much directional stability, so they often have to make relatively severe and quick movements to keep the glider near the center of the cone of safety while on tow. People on a unicycle sort of look like that, too. Pilots in free flight don't need to maintain such a high level of directional control and precision as is required when on tow, so the lack of directional control is not as noticeable in free flight as it is on tow. The pilot can let the glider wander all over the place in free flight, and they won't really notice. But that's not case when towing, especially aerotowing. From the view of the tug pilot, some hang glider pilots towing without a fin often look like a Raggedy-Ann doll on the end of a rubber band, bouncing all over the place while trying to maintain control on tow.
Whereas, when pilots use a fin to enhance the directional stability of their glider, they tend to be much more smooth and rock-solid on the centerline during tow, and they are not moving and bouncing around during tow nearly as much as a pilot who is not using a fin. It puts less stress and wear on the weak link, and it is more likely that the pilot will get a successful tow to release altitude without a weak link break or lockout--which makes it more likely for them to get a great soaring flight. This is a positive reinforcement system, as it contributes to building the confidence of the pilot, making him/her more likely to fly more often--which results in building more skill, more confidence, and more flying. That's what a safe, fun flying experience does. Scary, dangerous flying experiences drive people out of the sport. Pilots who get scared or hurt have a negative experience. They're not having fun, they lose confidence, and they are less likely to continue flying.
TRACY: And worse things can happen. Pilots who lockout near the ground, crash, and die have a more significant negative experience and don't continue flying, either. OK, what about reason #2--why does the right-sized fin enhance handling and performance?
LISA: The key is having the right-sized fin for a particular pilot/glider combination. Single-surface gliders usually have more directional stability and don't need fins. However, some--especially newer--pilots flying a single-surface glider may have trouble with pilot-induced oscillation (PIO) and will benefit from use of a fin. There has been a recent trend for some manufacturers to reduce directional stability in their newer single-surface glider designs, in an effort to enhance light handling for experienced pilots who may prefer to fly a single-surface glider. However, this just makes the glider harder to fly for new pilots, especially by tow. Because of the reduced directional stability in some newer single-surface gliders, it makes sense to put a fin on them for first solo flights.
Then there is the issue of pilots moving up to a more advanced-level glider. There is a tendency for pilots to PIO when moving up to a higher-performance glider, because they have gotten used to the stability, roll/yaw coupling behavior, lighter weight, and quicker response of their lower-performance glider. Higher-performance gliders are heavier and have more aspect ratio, meaning the wings are relatively longer in span and thinner in chord, and thus tend to be stiffer--meaning harder and slower to turn. Designers usually have to make them less roll stable to try to make them easier to turn. The result is that pilots new to a high-performance glider may over-control and oscillate. PIO is even more likely to occur when towing a hang glider as compared to free flight, because of the higher speed of towing and the physics of the pull of the tow line on the glider and pilot. Pilots should use a fin when they are transitioning to a higher-performance glider, especially if they are going to tow it. Using a fin makes the transition safer and builds confidence in the pilot who is new to a glider.
TRACY: First impressions are important. If a pilot gets scared or hurt flying a new glider, he/she may never like it. He may get frustrated, sell her new glider, and perhaps leave the sport. Whereas, if a pilot has had a good experience with a new glider and feels safe in it, he/she is likely to be more confident and fly more often, maintain currency and skill, and stay in the sport. A good experience in a new glider also helps to boost the reputation and sales of that glider design for the manufacturer.
LISA: When an instructor/dealer orders a new double-surface glider for a student or customer, he should ask the manufacturer to prep it for a fin. It would be good for the customer to also order a fin with his/her new glider. But even if he doesn't, the instructor/dealer can mount a rental fin on the glider for the pilot's initial flights in it, since the keel has already been prepped at the factory for mounting a fin. Wills Wing makes fins (ref 4) and can prep the keels on their gliders to accept fins at the factory. This has probably helped to increase sales of Wills Wing gliders, relative to some other glider manufacturers who do not produce fins or prep their gliders for fins. Having a glider prepped to accept a fin at the factory eliminates the need to use an additional keel extension/adapter later on for mounting a fin, and having a glider prepped to accept a fin enhances resale of the glider--both of which are good reasons why it is smart to get the glider prepped for a fin at the factory in the first place. It is important to remind the factory to pin or bolt the stinger to the rest of the keel, so it won't freely rotate when a fin is mounted on it.
If the manufacturer does not offer prepping of their keels for fins, then the instructor or dealer should prep it when the new glider is delivered, or at least have a clamp-on fin available to put on the glider for the customer's initial flights in it.
TRACY: What about the size of the fin?
LISA: Just as gliders come in various sizes, it makes sense for fins to come in various sizes, too. Wills Wing makes just one size fin, a fairly large one. It is an excellent size for adding a significant amount of directional stability, which is good not only for pilots transitioning to a more advanced glider, but also for some pilots all of the time. However, some pilots may not like or need that much directional stability, particularly if their glider is already fairly stable and/or stiff in roll. We have found that a fin that is about 30% smaller is a great size for use on stiffer comp-level gliders and some smaller gliders. It significantly enhances tracking and smoothness while on tow, but does not adversely affect handling or performance off tow.
TRACY: Why does a fin not adversely affect performance in free flight?
LISA: Think about it. The keel of a hang glider is not like an arrow flying straight through the air. The keel is dropping nose-high through the air as the glider flies forward--it drops through the air at some particular glide angle, because the wing's airfoil must have some angle of attack to produce lift. That is why some pilots will try to fly head low--to keep their body as streamlined as possible with the upward relative airflow. Because the keel is dropping through the air--not flying straight through it--the fin that is mounted on top of the keel is flying in the resultant wake above and behind the keel. The fin is not really going to add drag and perhaps may even help to streamline the swirling air above and behind the keel and thus reduce drag. Your university students' fin design is somewhat long and not very tall; it is shaped like a fairing at the base and provides a streamlined shape down a long portion of the top (wake-side) of the keel.
TRACY: In reality, the effect of streamlining the top of the keel probably doesn't reduce drag very much, but it doesn't hurt, either. The bottom line is that a good fin design does not hurt performance.
LISA: Also, some gliders have a tendency to start oscillating on their own at higher speeds, such as on fast glide or while on tow. Flying with a fin can help to reduce or eliminate these problems, both on and off tow. If a glider is not flying smooth and straight on a high speed glide, its glide performance is not going to be optimal. If a pilot has to constantly move his/her body around to try to keep the glider flying straight and smooth on a fast glide, his/her body will produce more drag in the airstream and thus reduce glide performance. In addition, when a pilot is constantly moving his body around, battling his glider for control, he/she will get tired quicker and flying performance, judgment, and ability to land well may become impaired.
TRACY: But what about pilots who claim that a fin makes their glider stiffer and more work to fly?
LISA: First, a lot of pilots who make that claim have probably never actually put a fin on their glider--they don't know what they are talking about, especially in a towing environment. However, if they have tried using a fin on their glider and found it to be stiffer and more work to fly, they simply used a fin that was too big for the glider. Wills Wing makes just one size of fin. It's a big one and can be too big for some gliders. If a right-sized fin is used, it will not make the glider stiffer and harder to turn--rather, it will make the glider easier to tow and fly at high speed, and, thus, less work to fly.
TRACY: Actually, a fin can make a glider easier to thermal and climb faster. You and I and other pilots here at Cloud 9 know and understand that.
LISA: That's right. Most pilots everywhere know that high-performance gliders usually need to be high-sided while holding turns in thermals. Because high-performance gliders have long, thin, heavy, high aspect ratio wings, designers of high-performance gliders must decrease the dihedral or add anhedral to make them less roll stable and easier to turn. Because these gliders tend to have negative roll stability (and thus reduced directional stability), pilots must high-side the glider to maintain a certain bank angle and turn radius while thermaling--otherwise, the glider will continue to roll into its bank more and more, and turn tighter and tighter on its own. Usually, more high-siding is required as more VG is added. This forces many pilots to circle in thermals with less VG, and get lower climb performance--or try to hold themselves farther out on the high-side while trying to fly the glider with more VG to get a more efficient wing and better climb performance. Trying to do that is a lot more work and makes the pilot get tired faster. In many cases, it takes too much work to try to circle in thermals using much if any VG.
Most pilots don't realize that a fin can allow them to circle in thermals with more VG and less high-siding and get better climb performance with less work. It is obvious, both in theory and in practice, that a fin does the same thing as high-siding, as it helps to keep the glider from tightening the turn while circling in a thermal. A right-sized fin will not impair handling--rather, it will help handling in thermals. With a right-sized fin, a pilot can use more VG in thermals, get better climb performance, be more relaxed, and get less tired on longer flights.
TRACY: I'm sure a lot of pilots will not want to believe that a fin can help them fly better in thermals. The key is having the right-sized fin. Based on our early experiments of flying with different-sized fins on various sizes and models of gliders, as well as years of additional experience verifying the results, the advantages of flying with a fin when thermaling are obvious to us. But, the fin must be the right size.
Are there any other flying qualities that are enhanced by use of a fin?
LISA: Yes, it makes the glider behave better when hit by a cross wind on take-off and when landing. If the glider gets hit by a cross wind gust when taking off from a launch cart, the fin will make the glider momentarily yaw and weather-vane a bit to help it more correctly maintain a crab angle into the relative wind behind the tug. A fin helps to yaw the nose of the glider into the wind gust, which makes the upwind wing slow down a little and the downwind wing speed up a little. This helps to keep the upwind wing from lifting and will help to prevent the glider from entering a downwind lockout near the ground. This momentary yaw can help the glider stay on the centerline of tow, or help keep it a bit on the upwind side of the centerline of tow. Staying on centerline is best. But if a glider gets off the centerline of tow when launching, there is more room for error and more time to recover if the glider is on the upwind side of the centerline, rather than the downwind side of the centerline. A lockout can happen very quickly if an upwind wing lifts at take-off and the glider gets on the downwind side of the centerline of tow. In addition to the downwind roll, the crosswind will even more quickly push the glider away from the centerline of tow, toward a lockout. If the glider is on the upwind side of the centerline, the crosswind will push the glider back toward the centerline, away from a lockout.
TRACY: And then there is the additional effect of wind gradient. If the upwind wing gets lifted through the gradient into a higher speed of crosswind, the high wing will be lifted up even more, be harder to keep down, and more likely to progress into a lockout very quickly. Whereas, if the downwind wing lifts through the gradient into the greater crosswind above, it will tend to be pushed back down to level and help to avoid a lockout.
LISA: A fin helps in a similar way if you get hit by a crosswind gust on landing. The fin will help the gliders momentary yaw into the crosswind gust, which will help keep your upwind wing down as you are leveling off in your round-out and it will help point the nose of your glider more directly into the wind so you can land with minimal ground speed and so the wind doesn't get under a wing and lift it when you flare.
TRACY: What about fins on rigid wings?
LISA: Rigid-wing hang gliders have more dihedral than high-performance flex wings, which adds roll stability and aids directional stability. But, in spite of having more dihedral, a rigid-wing hang glider is easy to roll because it has aerodynamic control surfaces. Rigid wings are usually much more stable and controllable on tow than high-performance flex wings and don't need a fin. But, instead of needing a fin to enhance directional stability, many rigid wings need to have a horizontal stabilizer mounted on the keel for pitch stability--which can prevent the mounting of a fin.
TRACY: Are there any high-performance flex wings that don't fly better with a fin?
LISA: Based on our experience, a right-sized fin will enhance the flying qualities of any high-performance flex wing and make them significantly easier to tow.
TRACY: As we've said, most of the pilots who fly in the club here at Cloud 9 have a fin on their glider. It is not so common at other flying sites. Can you explain to our readers why that is?
LISA: First, for many years we have been consistently teaching our students and new club members about the benefits of flying with a fin. Second, it helps when you and I provide a positive example by flying with fins on our own gliders. Third, we are able to provide right-sized fins for the range of gliders our pilots fly. Fourth, you and I have tried to create a culture of safety here (a) by example, (b) by teaching, and (c) by financially rewarding pilots who meet our "Safety Mentor" criteria--part of which includes using a fin if flying a double-surface flex-wing glider. And fifth, it helps when most other pilots who fly here also have fins on their gliders and prove the value of having a fin by towing smoothly, having great flights, and making good landings. Here, it is "cool" if you fly with a fin and "not cool" if you don't.
TRACY: Peer-pressure and leading by example make a big difference. New pilots will emulate experienced pilots and those who get the best flights. It is relatively easy for a club, school, or flying site to create a culture of safety if the best and most experienced pilots demonstrate safe flying practice. We can't eliminate all risk in flying--but with a culture of safety, it is less likely that something bad will happen. If instructors and advanced pilots hot dog and do dumb stuff to show off, and otherwise lead by bad example, it will result in a culture at that flying site of other pilots following that example and doing dumb stuff, too. That kind of culture makes it more likely that something bad will happen there, sooner rather than later.
LISA: As pilots, we accept the baseline risk of flying because flying adds quality to our lives. However, in addition to quality of life, it is good to have quantity. There is no quality of life if you "aren't." There are many risks in flying that can be prevented and/or minimized to reduce our overall risk (ref 5). It takes the right attitude, good training, good equipment, and risk-minimization behavior. Take it to heart. This is not an understatement.
TRACY: No, it's not. We're all heard the phrase that the sea is a cruel and unforgiving mistress" (ref 5). Well, the air can be a lot more fun than the sea, but also less forgiving. If you screw up, the air can be something more like an unforgiving ex-wife than a mistress--something along the lines of "evil, sadistic bitch." That's not an understatement, either.
LISA: Right, you don't want to go there.
TRACY: NOT ME!
Lisa is the Associate Dean and Professor of Surgery at the University of Michigan Medical School, and is past chair of the USHPA Towing committee. Tracy is a retired university professor, current chair of the Towing committee, and regional director for USHPA Regions 7 & 13. He is also a FAAST Team Safety Counselor for the FAA Detroit FSDO area. Lisa and Tracy are both very active multi-engine commercial airplane and glider pilots, tug pilots, and tandem hang gliding instructors for the Dragon Fly Soaring Club at Cloud 9 Field (46MI), Michigan. Please feel free to contact them about towing-related issues at cloud9sa@aol.com.
References
1. http://www.last.fm/music/Jimmy+Buffett/_/Fins
2. http://www.buffettworld.com/tourdates/
3. http://www2.tbo.com/photoalbum/2010/apr/24/jimmy-buffett-2010/19/
4. http://willswing.com/Accessories/stabilizer.asp
5. http://www.planeandpilotmag.com/pilot-talk/grassroots/the-character-of-risk
training wheels
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Tad Eareckson
- Posts: 9149
- Joined: 2010/11/25 03:48:55 UTC
training wheels
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Tad Eareckson
- Posts: 9149
- Joined: 2010/11/25 03:48:55 UTC
Re: training wheels
That's great, Tracy. So what percentages of your gliders fly with:Tracy
"Welcome to Fin Land" is perfect, because our flying site is located in the frozen tundra of the north, and because nearly everyone who aerotows with us here at Cloud 9 flies with a fin on his/her glider.
- load tested 130 pound Greenspot standard aerotow weak links?
- Wallaby and Quest two point releases?
- Lookout old spinnaker shackle and new Matt Mechanism two point releases?
- bent pin secondary / one point releases?
- secondary weak links?
- load tested releases compliant with USHGA/FAA regulations?
- load tested releases which can be blown with both hands on the basetube?
- wheels?
- So what IS your reputation for safety, how did you determine it, what are you using for a baseline, who gets a vote, and who doesn't?Lisa
That's true. Even though we don't require the use of fins, almost everyone in our club flies with one. It's a main factor contributing to our record and reputation for safety.
- Do you count weak link failures, release malfunctions, delayed releases, loss of control upon release in non critical circumstances as kills?
- How do you know use of fins is a main contributing factor to your safety record?
-- Are the pilots using fins crashing at lower rates than the finless pilots?
-- Cite some aerotow launch crashes that would have been prevented or mitigated by fins.
-- Cite some aerotow launch crashes of people who knew how to fly that would have been prevented or mitigated by fins.
- Yeah. *ONE* USHGA member submits a nomination, if the corrupt assholes on the Awards Committee like you they rubber-stamp it and send it on.Last year, our club received the National Aeronautic Association's (NAA) Safety Award for hang gliding.
- Puts you in the company of such tireless and effective campaigners as Mike Meier, Pat Denevan, Malcolm Jones, Peter Birren, Donnell Hewett, Steve Wendt, and Joe "HANG CHECK, HANG CHECK, HANG CHECK!" Gregor.
- And without all those NAA Safety Award winners with which we've been blessed hang glider towing procedures, releases, weak links, landings, and hook-in verification practices would all look pretty much the same as they did about thirty years ago. I shudder at the mere thought.
- And I look with unbridled joy at the coming of The Age of Fins.
Compared to what aerotow operations? All of you use absolute shit for releases and have no strategy for getting off tow other than waiting for the fuckin' 130 pound Greenspot to blow. So how does your crash per launch rate compare to Wallaby, Quest, Florida Ridge, Lookout, Ridgely, Whitewater?The use of fins on gliders is a huge part of why our club has been able to maintain such an outstanding safety record over the years.
What are your recommendations for sanctioning the negligent bastards who aren't pushing fins at their operations and thus needlessly crashing all those gliders on launch?
Because with the shit releases...Tracy
It might be good for us to explain why most pilots here at Cloud 9 fly with a fin on their gliders.
http://www.chgpa.org/forums/viewtopic.php?f=2&t=3107
I have a tandem rating!!!
...and shit weak links...Lauren Tjaden - 2008/03/23 22:20:15 UTC
When Jim got me locked out to the right, I couldn't keep the pitch of the glider with one hand for more than a second (the pressure was a zillion pounds, more or less), but the F'ing release slid around when I tried to hit it. The barrel release wouldn't work because we had too much pressure on it.
Anyhow, the tandem can indeed perform big wingovers, as I demonstrated when I finally got separated from the tug.
http://ozreport.com/forum/viewtopic.php?t=24846
Is this a joke ?
...you assholes are putting everyone up on they're almost all willing to sacrifice some turn responsiveness for the duration of the flight to make them feel better about their prospects of surviving launch and then staying on tow long enough to get to a workable altitude.Davis Straub - 2011/08/26 14:04:52 UTC
We had six weaklink breaks in a row at Zapata this year.
- There are only two problems which prevent people from getting to release altitude:Lisa
There are several reasons: (#1) it makes towing safer, easier, and more likely to get to release altitude without a problem;
- lockouts
- 130 pound Greenspot
So of the finless flights which don't make it to altitude, what percentage are lockouts?
- What percentage of your flights don't make it to altitude?
Bullshit.(#2) the right-sized fin enhances handling...
- Name a club or tow operation that doesn't make that claim....and performance, (#3) our club has a culture of safety;
- Name a club or tow operation that doesn't have a culture of safety and tell me what USHGA is doing to fix it or shut it down.
- You forgot one: (#5) you financially penalize people who DON'T fly with fins....and (#4) our best and most experienced pilots fly with fins, which make them good role models for new pilots.
- What percentage of your best and most experienced pilots fly with:
-- wheels?
-- load tested weak links?
-- weak links in the middle of the safety range?
-- two point connections?
-- releases which comply with USHGA/FAA regulations?
-- releases that can be blown both hands on the basetube?
Yeah. Now that Lisa's made the statement and everybody's accepted it as a fact without asking for anything remotely resembling supporting data, let's look at it.Tracy
OK, let's look at reason #1. Why does flying with a fin make aerotowing safer, easier, and more likely for the pilot to get to release altitude?
Right. If the direction in which you're headed is really:Lisa
A fin adds directional stability.
-a) good it tends to keep you headed in a really good direction
-b) bad it tends to keep you headed in a really bad direction
But - for the purposes of this article, let's just discuss Case "a". Nobody wants to read a lot of downer stuff in this fluffy magazine.
How 'bout we think of what it looks like when someone rides a bicycle compared to a bicycle with training wheels?Think of what it looks like when someone rides a unicycle compared to a bicycle.
They also have ailerons and rudders to use on the odd occasions when they'd rather NOT fly straight ahead. We hafta use muscle - and lots of it. And more of it when we have fins.Because hang gliders are flying wings, they have a certain lack of directional stability as compared to airplanes or sailplanes, which utilize vertical stabilizers for directional stability.
...imaginary...Pilots towing hang gliders without fins don't have much directional stability, so they often have to make relatively severe and quick movements to keep the glider near the center of the...
- Under what circumstances are pilots towing hang gliders not on tow?...cone of safety while on tow.
- Whereas pilots towing hang gliders with fins in thermal conditions rarely have to make relatively severe and quick movements to keep the glider near the center of the cone of safety while on tow.
- Name some light aircraft that can fly through the kind of thermal turbulence we're constantly seeking that DON'T often have to make relatively severe and quick movements to keep their planes right side up.
- People on unicycles can do things that people on bicycles can't even dream of.People on a unicycle sort of look like that, too.
- With respect to skill, the typical person on a unicycle can kick the ass of the typical person on a bicycle.
- You haven't done a whole lot of light air dune flying, have you?Pilots in free flight don't need to maintain such a high level of directional control and precision as is required when on tow, so the lack of directional control is not as noticeable in free flight as it is on tow. The pilot can let the glider wander all over the place in free flight, and they won't really notice.
- Yeah, a "pilot" can let his glider wander all over the place in free flight without really noticing. But the people who don't let their gliders wander all over the place in free flight will be noticing 'cause they're all gonna be looking way down on the top side of his sail.
- I got news for ya Lisa... NOBODY in this sport who's figured out left, right, up, down EVER lets his glider wander all over the place. We're constantly trying to optimize our positions - and sometimes when you dope off for the wrong two seconds you're just guaranteed that you're ass will be on the ground a short time later.
Any idiot flying anything can - barring the fairly rare kick from hell - stay in good position behind a tug without a fin. It's child's play compared to a lot of dune and thermal flying.But that's not case when towing, especially aerotowing.
Have you tried replacing your polypro towlines with Spectra?From the view of the tug pilot, some hang glider pilots towing without a fin often look like a Raggedy-Ann doll on the end of a rubber band...
http://ozreport.com/forum/viewtopic.php?t=1143
Death at Tocumwal
Gregg Ludwig - 2006/01/22 18:15:15 UTC
I just can not understand why operators continue to use poly towlines (for aerotow ops) when spectra towlines are clearly superior. Poly is less expensive... but when considering the cost of a tow plane and HG and the advantages of spectra, a few dollars of savings is foolish.
Just kidding.Gregg Ludwig - 2006/01/23 16:32:52 UTC
Towline elasticity produces a rubber band effect that results in ever changing towline forces that can also produce significant airspeed changes as well. Since Spectra does not offer elasticity (or very little) this effect does not occur and a safer tow results. Trikes normally tow with longer lines of 200-250 feet so the advantages of Spectra are even greater.
Maybe they just need more tandem training....bouncing all over the place while trying to maintain control on tow.
Oh. They TEND to be.Whereas, when pilots use a fin to enhance the directional stability of their glider, they tend to be much more smooth and rock-solid on the centerline during tow....
- A blanket statement that people not using fins move and bounce around a lot more than people with them. BULLSHIT....and they are not moving and bouncing around during tow nearly as much as a pilot who is not using a fin.
- Wanna explain to me how a fin helps keep a towed glider from bouncing?
- Show me some videos or track logs to document that crap.
Especially if you're a fucking Cloud 9 moron flying a fucking loop of 130 pound Greenspot which frequently blows before you've gotten ten feet off the cart.It puts less stress and wear on the weak link...
Gotta protect that weak link. After all...
...it - not the pilot - is the focal point of a safe towing system. If it weren't you assholes wouldn't have filled fourteen pages of the 2012/06 issue of Hang Gliding with the load of crap about it that you did.Towing Aloft - 1998/01
A weak link is the focal point of a safe towing system.
Yeah. The lockout is a really big problem preventing finless gliders......and it is more likely that the pilot will get a successful tow to release altitude without a weak link break or lockout--
http://ozreport.com/13.238
Adam Parer on his tuck and tumble
from getting to altitude in good conditions.Adam Parer - 2009/11/25
Due to the rough conditions weak links were breaking just about every other tow and the two tugs worked hard to eventually get everyone off the ground successfully.
http://ozreport.com/forum/viewtopic.php?t=24846...which makes it more likely for them to get a great soaring flight.
Is this a joke ?
Fuck you guys.Jim Rooney - 2011/08/28 19:39:17 UTC
The frustration of a weaklink break is just that, frustration.
And it can be very frustrating for sure. Especially on a good day, which they tend to be. It seems to be a Murphy favourite. You'll be in a long tug line on a stellar day just itching to fly. The stars are all lining up when *bam*, out of nowhere your trip to happy XC land goes up in a flash. Now you've got to hike it all the way back to the back of the line and wait as the "perfect" window drifts on by.
I get it.
It can be a pisser.
People who get on cart with equipment known to have maimed and killed people - Wallaby, Quest, Lookout, and Bailey releases and standard aerotow weak links with confidence are total fucking morons.This is a positive reinforcement system, as it contributes to building the confidence of the pilot, making him/her more likely to fly more often--which results in building more skill, more confidence, and more flying.
- I'd wager that you assholes have never once had a safe tow at Cloud 9 - just a lot of bullshit you've gotten away with.That's what a safe, fun flying experience does.
- Yeah. We lose so many people out of the sport because of the terror they experience as a result of aerotowing without fins.
No they don't.Scary, dangerous flying experiences drive people out of the sport.
http://www.chgpa.org/forums/viewtopic.php?f=2&t=3107
I have a tandem rating!!!
They're all too fucking stupid to recognize dangerous flying experiences for what they are when they happen up high and extrapolate to what would happen down low. You usually hafta cripple or kill them to start getting the point across.Lauren Tjaden - 2008/03/23 22:20:15 UTC
When Jim got me locked out to the right, I couldn't keep the pitch of the glider with one hand for more than a second (the pressure was a zillion pounds, more or less), but the F'ing release slid around when I tried to hit it. The barrel release wouldn't work because we had too much pressure on it.
Anyhow, the tandem can indeed perform big wingovers, as I demonstrated when I finally got separated from the tug.
- I'm totally convinced. It's the lack of fins that have been putting so many people out of control, getting so many gliders crashed, and keeping this sport in the dark ages all this time. I'm getting a fin tomorrow.Pilots who get scared or hurt have a negative experience. They're not having fun, they lose confidence, and they are less likely to continue flying.
- THIS:
http://www.hanggliding.org/viewtopic.php?t=22176
Paragliding Collapses
is the one that does it. And fins ain't gonna do shit to put a dent in those statistics.Jim Rooney - 2011/06/12 13:57:58 UTC
Most common HG injury... spiral fracture of the humerus.
http://www.hanggliding.org/viewtopic.php?t=26266
Please Take Your Landings Seriously!
The only way to address it is to be vigilante with fiends.NMERider - 2012/06/02 08:17:03 UTC
I've met a few who broke the same arm a year or so later and then they quit. I think more pilots may quit after their friends get hurt. That may be a good reason to be vigilante with fiends.
- Tell me how a fin does anything to mitigate this one:
http://groups.yahoo.com/group/TTTFlymail/message/11545
Cart stuck incidents
Got any ideas on equipment change which would have prevented it? Just kidding.Keith Skiles - 2011/06/02 19:50:13 UTC
I witnessed the one at Lookout. It was pretty ugly. Low angle of attack, too much speed and flew off the cart like a rocket until the weak link broke, she stalled and it turned back towards the ground.
- Holly MIGHT have benefited from a fin - sure wouldn't have made things any worse.Tracy
And worse things can happen. Pilots who lockout near the ground, crash, and die have a more significant negative experience and don't continue flying, either.
- But she didn't half kill herself until she decided to tow her Litesport one point.
- And plenty of people tow Litesports one point minus fins who don't oscillate all over the sky.
- Holly didn't have much in the way of a feel for gliders and was pushing her envelope flying two point but, even so, if she had had something like THIS:
http://www.youtube.com/watch?v=rh3-uZptNw0
...it's a no brainer she'd have come out smelling like a rose.
So watchya think Tracy and Lisa? We're gonna rewind the tape. Do we give her a remote barrel or a fin?
OK, what about reason #2--why does the right-sized fin enhance handling and performance?
Name an HGMA or DHV certified glider that NEEDS a fin.Lisa
The key is having the right-sized fin for a particular pilot/glider combination. Single-surface gliders usually have more directional stability and don't need fins.
And a lot of competent pilots flying double surface gliders have no trouble whatsoever with Pilot Induced Oscillation and won't benefit in any way from using a fin. But they're gonna fly with them anyway because you're gonna financially penalize them if they don't.However, some--especially newer--pilots flying a single-surface glider may have trouble with pilot-induced oscillation (PIO) and will benefit from use of a fin.
Can you think of any circumstances in which reduced directional stability and enhanced light handling might benefit an inexperienced pilot?There has been a recent trend for some manufacturers to reduce directional stability in their newer single-surface glider designs, in an effort to enhance light handling for experienced pilots who may prefer to fly a single-surface glider.
Tuned gliders tend to fly straight for a while just fine without fins as long as the people under them don't make any roll inputs. It's a bit of a stretch to say that enhancing light handling with respect to turns makes a glider harder to fly - for anybody.However, this just makes the glider harder to fly for new pilots, especially by tow.
- Here's what Wills Wing says with respect to their Falcon 3:Because of the reduced directional stability in some newer single-surface gliders, it makes sense to put a fin on them for first solo flights.
without a fin.A minimum USHGA Novice (II) level of pilot proficiency is required to fly the Falcon safely, unless under the direct supervision of a qualified instructor.
Can we trust that or not?
- You wanna tell us who's manufacturing and selling as entry level gliders models that are too dangerous for novice pilots to fly without modification?
Funny, I thought that someone would be MORE likely to oscillate on a quicker responding glider.Then there is the issue of pilots moving up to a more advanced-level glider. There is a tendency for pilots to PIO when moving up to a higher-performance glider, because they have gotten used to the stability, roll/yaw coupling behavior, lighter weight, and quicker response of their lower-performance glider.
Because the manufacturer has designed the higher performance glider to have a turn response approaching that of the lower performance glider. Yeah, that makes perfect sense.Higher-performance gliders are heavier and have more aspect ratio, meaning the wings are relatively longer in span and thinner in chord, and thus tend to be stiffer--meaning harder and slower to turn. Designers usually have to make them less roll stable to try to make them easier to turn. The result is that pilots new to a high-performance glider may over-control and oscillate.
Really makes you wonder how people manage to keep finless gliders under anything resembling control when they're running ridges in 25 mile per hour winds.PIO is even more likely to occur when towing a hang glider as compared to free flight, because of the higher speed of towing...
...and the physics of the pull of the tow line on the glider and pilot.
If you guys are talking about how well respected for his knowledge of towing, bridles, and weak links is Dr. Lionel D. Hewett, professor of physics and developer of the 2-to-1 center-of-mass Skyting bridle for surface towing then you don't understand jack shit about the physics of the pull of the towline on the glider and pilot. So stuff it.Tracy Tillman - 2012/06
Dr. Lionel D. Hewitt, professor of physics and developer of the 2-to-1 center-of-mass Skyting bridle for surface towing, is well respected for his knowledge of towing, bridles, and weak links.
So does towing up in smooth conditions and experimenting with the speed range at altitude.Pilots should use a fin when they are transitioning to a higher-performance glider, especially if they are going to tow it. Using a fin makes the transition safer and builds confidence in the pilot who is new to a glider.
If he gets frustrated enough to sell her new glider and perhaps leave the sport I think the odds are pretty good that he got REALLY scared or hurt.Tracy
First impressions are important. If a pilot gets scared or hurt flying a new glider, he/she may never like it. He may get frustrated, sell her new glider, and perhaps leave the sport.
- Hopefully without any psychological or physical gender identity issues.Whereas, if a pilot has had a good experience with a new glider and feels safe in it, he/she is likely to be more confident and fly more often, maintain currency and skill, and stay in the sport.
- Sounds a lot like Terry Mason. He had GREAT experiences with his new glider and felt safe in it. Too bad feeling and being can be such entirely different states.
- Guess we'll be seeing a dip in Sport 2 135 sales.A good experience in a new glider also helps to boost the reputation and sales of that glider design for the manufacturer.
- Hey Tracy...
Wanna tell me how a fin would have kept miguel in the sport if he didn't live in a state with large bumps all over it?miguel - 2012/05/31 22:57:42 UTC
The glider had a bicycle handle release. When it came time to release, it would not release and in fighting with it, it came loose on the downtube, rotating around it. Fighting with it put the glider in the beginnings of lockout so I flew the glider. I noticed that the truck had stopped but the reel was free wheeling. I had done step towing before so I flew large circles around the towline and landed into the wind. I kissed the ground and swore never to tow a hang glider again.
- Yeah, let's base our decisions to purchase gliders on reports of first flights on them from people who don't know how to fly them.
So while all instructors/dealers are male, customers can be of either gender. And - if they get scared or hurt badly enough - switch. Got it.Lisa
When an instructor/dealer orders a new double-surface glider for a student or customer, he should ask the manufacturer to prep it for a fin. It would be good for the customer to also order a fin with his/her new glider.
Oh. So you sell and rent fins and financially penalize people who don't use them. Good to know there are no conflict of interest issues coloring this article.But even if he doesn't, the instructor/dealer can mount a rental fin on the glider for the pilot's initial flights in it, since the keel has already been prepped at the factory for mounting a fin.
No doubt. And Wills Wing has always done such a stellar job...Wills Wing makes fins and can prep the keels on their gliders to accept fins at the factory. This has probably helped to increase sales of Wills Wing gliders, relative to some other glider manufacturers who do not produce fins or prep their gliders for fins.
http://www.kitestrings.org/post1599.html#p1599
...looking out for its flatland customers. Just read their manuals and advisories and you can't go wrong. When they say to use an appropriate weak link with a finished length of 1.5 inches or less and carry a hook knife then use an appropriate weak link with a finished length of 1.5 inches or less and carry a hook knife.
Maybe if the bastards prepped the glider at the factory for aerotowing that would eliminate the need to use the shitrigged Flight Park Mafia crap you assholes send people up with and enhance the resale value of the glider one helluva lot more - in addition to reducing a hundredfold the likelihood of anyone flying it getting killed.Having a glider prepped to accept a fin at the factory eliminates the need to use an additional keel extension/adapter later on for mounting a fin, and having a glider prepped to accept a fin enhances resale of the glider--both of which are good reasons why it is smart to get the glider prepped for a fin at the factory in the first place.
Yeah. Make sure that fin is properly pinned or bolted to the tubing. You sure wouldn't want it just spinning around.It is important to remind the factory to pin or bolt the stinger to the rest of the keel, so it won't freely rotate when a fin is mounted on it.
http://www.hanggliding.org/viewtopic.php?t=1245
bad tow
http://www.chgpa.org/forums/viewtopic.php?f=2&t=3107T.B. - 2007/01/17 03:08:33 UTC
I reach to hit the release and accidentally push the release on the outside of the downtube...
I have a tandem rating!!!
http://www.chgpa.org/forums/viewtopic.php?f=2&t=3347Lauren Tjaden - 2008/03/23 22:20:15 UTC
When Jim got me locked out to the right, I couldn't keep the pitch of the glider with one hand for more than a second (the pressure was a zillion pounds, more or less), but the F'ing release slid around when I tried to hit it.
Tad's barrel release tested
http://www.hanggliding.org/weblog_entry.php?e=516Janni Papakrivos - 2008/06/30 15:35:44 UTC
With a bunch of tows to boot I can say that it happened once that I tried to release but missed the brake lever, instead I just pushed it around the downtube and had a much harder time reaching and actuating it.
Rick M's blog :: WWDD 09 - Day 6 - Great Day
http://www.kitestrings.org/post2228.html#p2228Rick Maddy - 2009/04/04 20:17:05 UTC
I was overcontrolling like crazy. I actually went for the release just above tree level and missed. I hit the top of the release and knocked it sideways a little.
Weak links
That could be really dangerous.miguel - 2012/05/31 22:57:42 UTC
The glider had a bicycle handle release. When it came time to release, it would not release and in fighting with it, it came loose on the downtube, rotating around it. Fighting with it put the glider in the beginnings of lockout so I flew the glider.
Especially when used in conjunction with velcroed on releases that just spin around when you really need them.If the manufacturer does not offer prepping of their keels for fins, then the instructor or dealer should prep it when the new glider is delivered, or at least have a clamp-on fin available to put on the glider for the customer's initial flights in it.
Tracy
What about the size of the fin?
But of course it makes no sense whatsoever to use various weight weak links for various sized gliders.Lisa
Just as gliders come in various sizes, it makes sense for fins to come in various sizes, too.
Not after several decades of experience and hundreds of thousands of tows conducted by numerous aerotow operators across the county have proven in no uncertain terms that the use of a 260 pound weak link made as a loop of 130 pound Greenspot IGFA Dacron braided fishing line attached to one end of the pilot's V-bridle is the pinnacle of weak link perfection for damn near everyone.Tracy Tillman - 2012/06
Based on several decades of experience and hundreds of thousands of tows conducted by numerous aerotow operators across the county, the de facto standard has become use of a 260 lb. weak link made as a loop of 130 lb. green spot IGFA Dacron braided fishing line attached to one end of the pilot's V-bridle.
http://www.chgpa.org/forums/viewtopic.php?f=2&t=2467
weak links
Whether they like it or not.Jim Rooney - 2007/07/22 22:30:28 UTC
I've heard it a million times before from comp pilots insisting on towing with even doubled up weaklinks (some want no weaklink). I tell them the same thing I'm telling you... suck it up.
Really? I was under the impression that there really wasn't any downside to directional stability. The more the merrier. I'll betchya it's just the same assholes who want doubled up weak links because they're too stupid to appreciate the perfection offered by a single loop of 130 pound Greenspot. Are you sure it's really a good idea to allow these people to tow?Wills Wing makes just one size fin, a fairly large one. It is an excellent size for adding a significant amount of directional stability, which is good not only for pilots transitioning to a more advanced glider, but also for some pilots all of the time. However, some pilots may not like or need that much directional stability, particularly if their glider is already fairly stable and/or stiff in roll.
Any chance we could use thirty percent heavier weak links for thirty percent heavier gliders? Just kidding.We have found that a fin that is about 30% smaller is a great size for use on stiffer comp-level gliders and some smaller gliders.
- Oh really? A little while back the tows just TENDED to be much more smooth and rock-solid on the centerline during tow.It significantly enhances tracking and smoothness while on tow, but does not adversely affect handling or performance off tow.
But now we've removed all doubt.Whereas, when pilots use a fin to enhance the directional stability of their glider, they tend to be much more smooth and rock-solid on the centerline during tow....
- It's a tradeoff. If it significantly enhances tracking and smoothness while on tow it also significantly adversely affects handling off - and on - tow.
Because we tell you it doesn't, right?Tracy
Why does a fin not adversely affect performance in free flight?
- Ya think you could get your university students to design releases that don't suck?Lisa
Think about it. The keel of a hang glider is not like an arrow flying straight through the air. The keel is dropping nose-high through the air as the glider flies forward--it drops through the air at some particular glide angle, because the wing's airfoil must have some angle of attack to produce lift. That is why some pilots will try to fly head low--to keep their body as streamlined as possible with the upward relative airflow. Because the keel is dropping through the air--not flying straight through it--the fin that is mounted on top of the keel is flying in the resultant wake above and behind the keel. The fin is not really going to add drag and perhaps may even help to streamline the swirling air above and behind the keel and thus reduce drag. Your university students' fin design is somewhat long and not very tall; it is shaped like a fairing at the base and provides a streamlined shape down a long portion of the top (wake-side) of the keel.
Or are they all as fuckin' clueless as you morons concerning grade school science?Tracy Tillman - 2012/06
The worst performance comes from a relatively short Spectra or thin pro-tow bridle, especially when the weak link is attached directly onto the thin curved pin of the secondary release...
Yeah, better leave that one alone. They're probably pushing their envelopes with fin design.
- But it's perfectly OK to velcro a lot of Quallaby / Lookout cable crap into the airflow if you're a crappy enough pilot to feel that there may be some slight safety advantage to towing tow point.
It hurts it in turn initiation for the same reason it enhances directional stability.Tracy
In reality, the effect of streamlining the top of the keel probably doesn't reduce drag very much, but it doesn't hurt, either. The bottom line is that a good fin design does not hurt performance.
Yeah? Name a glider which oscillates on its own when an aerobatics pilot dives it for a loop.Lisa
Also, some gliders have a tendency to start oscillating on their own at higher speeds, such as on fast glide or while on tow.
So can knowing how to fly.Flying with a fin can help to reduce or eliminate these problems, both on and off tow.
- Yeah. I see that problem all the time when people are flying without fins.If a glider is not flying smooth and straight on a high speed glide, its glide performance is not going to be optimal. If a pilot has to constantly move his/her body around to try to keep the glider flying straight and smooth on a fast glide, his/her body will produce more drag in the airstream and thus reduce glide performance.
- And, of course, we can ignore the fact that more directional stability demands more misalignment of the pilot's body from the airflow to initiate turns.
- Bullshit. People aren't constantly moving their bodies around, battling their gliders for control to fly in straight lines. People are constantly moving their bodies around, battling their gliders for control to work lift and handle turbulence. This is why...In addition, when a pilot is constantly moving his body around, battling his glider for control, he/she will get tired quicker and flying performance, judgment, and ability to land well may become impaired.
...designers REDUCE directional stability. Adding a fin to increase it is what's gonna cause people to tire more quickly and impair flying performance, judgment, and ability to land well.Higher-performance gliders are heavier and have more aspect ratio, meaning the wings are relatively longer in span and thinner in chord, and thus tend to be stiffer--meaning harder and slower to turn. Designers usually have to make them less roll stable to try to make them easier to turn.
- Ya know what I find tiring, Lisa?
http://ozreport.com/13.238
Adam Parer on his tuck and tumble
http://ozreport.com/forum/viewtopic.php?t=24846Adam Parer - 2009/11/25
Due to the rough conditions weak links were breaking just about every other tow and the two tugs worked hard to eventually get everyone off the ground successfully.
Is this a joke ?
Being suited up in the ground level heat and waiting in line watching the soaring window evaporating while a flock of 130 pound Greenspot douchebags make repeated efforts to get their fucking gliders into the air and are rewarded with cuts back in line in front of me every time they fail.Davis Straub - 2011/08/26 14:04:52 UTC
We had six weaklink breaks in a row at Zapata this year.
What about pilots who claim that...Tracy
But what about pilots who claim that a fin makes their glider stiffer and more work to fly?
...you need two hands to fly a glider through an emergency? Asshole.Doug Hildreth - 1991/06
Good launch, but at about fifty feet the glider nosed up, stalled, and the pilot released by letting go of the basetube with right hand. Glider did a wingover to the left and crashed into a field next to the tow road.
You mean like the kinds of morons who publish fourteen page books on the wonders of the 130 pound Greenspot standard aerotow weak link...Lisa
First, a lot of pilots who make that claim have probably never actually put a fin on their glider--they don't know what they are talking about, especially in a towing environment.
...without ever once having actually tested one to find that it blows at half the load they're assuming it does?Tracy Tillman - 2012/06
We could get into details of lab testing weak links and bridles, but this article is already getting long. That would be a good topic for an article in the future. Besides, with our backgrounds in formal research, you and I both know that lab tests may produce results with good internal validity, but are often weak in regard to external validity--meaning lab conditions cannot completely include all the factors and variability that exists in the big, real world.
It won't make the glider the tiniest bit easier for me to tow and fly at high speed, thank you very much.However, if they have tried using a fin on their glider and found it to be stiffer and more work to fly, they simply used a fin that was too big for the glider. Wills Wing makes just one size of fin. It's a big one and can be too big for some gliders. If a right-sized fin is used, it will not make the glider stiffer and harder to turn--rather, it will make the glider easier to tow and fly at high speed, and, thus, less work to fly.
How many pilots who are topping out in world championship competitions know and understand that?Tracy
Actually, a fin can make a glider easier to thermal and climb faster. You and I and other pilots here at Cloud 9 know and understand that.
You can decrease dihedral - from positive to negative if you want.Lisa
That's right. Most pilots everywhere know that high-performance gliders usually need to be high-sided while holding turns in thermals. Because high-performance gliders have long, thin, heavy, high aspect ratio wings, designers of high-performance gliders must decrease the dihedral or add anhedral to make them less roll stable and easier to turn.
You CAN'T add anhedral. Anhedral means "without face planes". Do the math.
Yeah. If the fin is right-sized there's no tradeoff whatsoever. Only good things will come of it. Just like a right-sized standard aerotow weak link. It increases the safety of the towing operation. PERIOD.Because these gliders tend to have negative roll stability (and thus reduced directional stability), pilots must high-side the glider to maintain a certain bank angle and turn radius while thermaling--otherwise, the glider will continue to roll into its bank more and more, and turn tighter and tighter on its own. Usually, more high-siding is required as more VG is added. This forces many pilots to circle in thermals with less VG, and get lower climb performance--or try to hold themselves farther out on the high-side while trying to fly the glider with more VG to get a more efficient wing and better climb performance. Trying to do that is a lot more work and makes the pilot get tired faster. In many cases, it takes too much work to try to circle in thermals using much if any VG.
Most pilots don't realize that a fin can allow them to circle in thermals with more VG and less high-siding and get better climb performance with less work. It is obvious, both in theory and in practice, that a fin does the same thing as high-siding, as it helps to keep the glider from tightening the turn while circling in a thermal. A right-sized fin will not impair handling--rather, it will help handling in thermals.
Most pilots DO realize that...With a right-sized fin, a pilot can use more VG in thermals, get better climb performance, be more relaxed, and get less tired on longer flights.
- Most thermals are irregular and turbulent and that when they're turning in them they're flying slowly and constantly adjusting their speed and bank angle.
- There are tradeoffs between glide performance and control authority and that glide performance ain't worth shit if you don't have enough control authority and responsiveness to adjust to work the strongest lift or avoid getting kicked out of the thermal altogether.
- When working thermals tight VG and directional stability are about the last things they want most of the time.
- They can get their asses kicked by paragliders in a lot of conditions and can thus extrapolate that the extra glide ratio provided by tight VG usually ain't really worth a rat's ass.
P.S. Maybe I'm just really obtuse but, on the odd occasion in which I found myself in big smooth thermals that didn't require constant adjustment, I never noticed myself needing to high-side the glider or getting worn out doing so. I found myself getting worn out in the regular stuff by constantly adjusting turns to maximize climb.
Well that's just super Tracy and Lisa.Tracy
I'm sure a lot of pilots will not want to believe that a fin can help them fly better in thermals. The key is having the right-sized fin. Based on our early experiments of flying with different-sized fins on various sizes and models of gliders, as well as years of additional experience verifying the results, the advantages of flying with a fin when thermaling are obvious to us. But, the fin must be the right size.
So where's the data from your "experiments" which will make it obvious to US?
This is total bullshit. You haven't verified anything. Running experiments to verify this stuff would be a royal pain in the ass and you motherfuckers are too goddam lazy even to ever load test a loop of 130 pound Greenspot. You've flown a lot and are making a bunch of totally subjective statements and I'm not buying them.
Here's what I WOULD start buying...
- World class XC competition with people flying the state of the art competition bladewings they always do anyway.
- Some use fins, some don't.
- The people using fins top out faster and cross the goal line sooner.
But that's not happening.
Furthermore...
While the comp pilots themselves tend not to have much going for them in the way of gray matter the glider manufacturers tend to operate at a somewhat higher level and they REALLY want their gliders to win so they can advertise and sell them. And if the goddam fins were actually doing anything positive for people who can manage to fly in straight lines without them I think it's a pretty good bet that they'd be stock on all competition bladewings.
Sure. They check traffic and set up your landing approach pattern for you.Are there any other flying qualities that are enhanced by use of a fin?
You mean the way sweep does?Lisa
Yes, it makes the glider behave better when hit by a cross wind on take-off and when landing. If the glider gets hit by a cross wind gust when taking off from a launch cart, the fin will make the glider momentarily yaw and weather-vane a bit to help it more correctly maintain a crab angle into the relative wind behind the tug. A fin helps to yaw the nose of the glider into the wind gust, which makes the upwind wing slow down a little and the downwind wing speed up a little.
WHAT?This helps to keep the upwind wing from lifting and will help to prevent the glider from entering a downwind lockout near the ground.
This momentary yaw can help the glider stay on the centerline of tow, or help keep it a bit on the upwind side of the centerline of tow.
Yeah. John Woiwode can back you up on that one.Staying on centerline is best.
Keep the goddam glider level, allow it to yaw into the relative wind, and don't worry about the fucking centerline.
When the tug gets airborne it will yaw into the relative wind and you'll find yourself on centerline.
This is dangerous lunatic rot. Moving to centerline in a crosswind behind something that's (still) on the ground is analogous to moving off center in a head or no wind. It puts you closer to a lockout. And moving UPWIND of centerline?!But if a glider gets off the centerline of tow when launching, there is more room for error and more time to recover if the glider is on the upwind side of the centerline, rather than the downwind side of the centerline. A lockout can happen very quickly if an upwind wing lifts at take-off and the glider gets on the downwind side of the centerline of tow. In addition to the downwind roll, the crosswind will even more quickly push the glider away from the centerline of tow, toward a lockout. If the glider is on the upwind side of the centerline, the crosswind will push the glider back toward the centerline, away from a lockout.
Ya know what...Tracy
And then there is the additional effect of wind gradient. If the upwind wing gets lifted through the gradient into a higher speed of crosswind, the high wing will be lifted up even more, be harder to keep down, and more likely to progress into a lockout very quickly. Whereas, if the downwind wing lifts through the gradient into the greater crosswind above, it will tend to be pushed back down to level and help to avoid a lockout.
If you let the glider get so rolled so low on takeoff that the wings are feeling different wind effects due to gradient you are fucked - no matter what you're using for a fin, release, or weak link. So how 'bout we gear the conversation a bit more for people capable of executing survivable launches most of the time?
What if you didn't flare? What if you just controlled the glider and eased it down onto the runway like everyone else who flies fixed wing aircraft does?Lisa
A fin helps in a similar way if you get hit by a crosswind gust on landing. The fin will help the gliders momentary yaw into the crosswind gust, which will help keep your upwind wing down as you are leveling off in your round-out and it will help point the nose of your glider more directly into the wind so you can land with minimal ground speed and so the wind doesn't get under a wing and lift it when you flare.
Tracy
What about fins on rigid wings?
Maybe if the designers felt their birds needed fins they'd have built them with fins.Lisa
Rigid-wing hang gliders have more dihedral than high-performance flex wings, which adds roll stability and aids directional stability. But, in spite of having more dihedral, a rigid-wing hang glider is easy to roll because it has aerodynamic control surfaces. Rigid wings are usually much more stable and controllable on tow than high-performance flex wings and don't need a fin. But, instead of needing a fin to enhance directional stability, many rigid wings need to have a horizontal stabilizer mounted on the keel for pitch stability--which can prevent the mounting of a fin.
Now that we've established beyond any shadow of a reasonable doubt that just about all of them DO fly better with a fin.Tracy
Are there any high-performance flex wings that don't fly better with a fin?
Yeah. Based on YOUR EXPERIENCE. The same kind of experience that gave us one G as a good rule of thumb for weak links and the loop of 130 pound Greenspot as the standard aerotow weak link.Lisa
Based on our experience, a right-sized fin will enhance the flying qualities of any high-performance flex wing and make them significantly easier to tow.
Tracy
As we've said, most of the pilots who fly in the club here at Cloud 9 have a fin on their glider. It is not so common at other flying sites. Can you explain to our readers why that is?
Just the students and new club members? 'Cause the people who've been doing just fine for decades without fins are telling you to fuck off?Lisa
First, for many years we have been consistently teaching our students and new club members about the benefits of flying with a fin.
In other words, you fine anyone who flies a non entry level glider who doesn't use a fin. Yep, that WOULD explain some of the popularity of fins at Cloud 9.Second, it helps when you and I provide a positive example by flying with fins on our own gliders. Third, we are able to provide right-sized fins for the range of gliders our pilots fly. Fourth, you and I have tried to create a culture of safety here (a) by example, (b) by teaching, and (c) by financially rewarding pilots who meet our "Safety Mentor" criteria--part of which includes using a fin if flying a double-surface flex-wing glider.
http://ozreport.com/12.081
Weaklinks - the HGFA rules
http://www.chgpa.org/forums/viewtopic.php?f=2&t=3600Davis Straub - 2008/04/22 14:47:00 UTC
Here is the requirement from the 2007 Worlds local rules (which I wrote) for weaklinks:Pilots must use weaklinks provided by the meet organizers and in a manner approved by the meet organizers. All weaklinks will be checked and use of inappropriate weaklinks will require the pilot to go to the end of the launch line to change the weaklink.
Weaklinks will consist of a single loop of Cortland 130 lb Greenspot braided Dacron Tolling line and should be placed at one end of a shoulder bridle.
Weak link question
You've got something similar going on with to explain the universal enthusiasm for 130 pound Greenspot standard aerotow weak links.Jim Rooney - 2008/11/24 05:18:15 UTC
I've personally refused to tow a flight park owner over this very issue. I didn't want to clash, but I wasn't towing him. Yup, he wanted to tow with a doubled up weaklink. He eventually towed (behind me) with a single and sorry to disappoint any drama mongers, we're still friends. And lone gun crazy Rooney? Ten other tow pilots turned him down that day for the same reason.
How cool is it to...And fifth, it helps when most other pilots who fly here also have fins on their gliders and prove the value of having a fin by towing smoothly, having great flights, and making good landings. Here, it is "cool" if you fly with a fin and "not cool" if you don't.
...roll gliders in on the wheels? The landing analogous to the method you use to launch them? Just kidding.Christian Thoreson - 2004/10
Thus wheel landings, the safest and easiest way to consistently land a hang glider...
How many flex wing world record flights have utilized fins?Tracy
Peer-pressure and leading by example make a big difference. New pilots will emulate experienced pilots and those who get the best flights.
So like when Bo Hagewood does aerobatics and blows up a Combat with two millimeter racing wires and throws a chute that isn't connected to his harness new pilots are more likely to do aerobatics and blow up Combats with two millimeter racing wires and throw chutes that aren't connected to their harnesses?It is relatively easy for a club, school, or flying site to create a culture of safety if the best and most experienced pilots demonstrate safe flying practice. We can't eliminate all risk in flying--but with a culture of safety, it is less likely that something bad will happen. If instructors and advanced pilots hot dog and do dumb stuff to show off, and otherwise lead by bad example, it will result in a culture at that flying site of other pilots following that example and doing dumb stuff, too. That kind of culture makes it more likely that something bad will happen there, sooner rather than later.
Bullshit. People aren't crashing and getting hurt 'cause they're following the examples of instructors and advanced pilots hotdogging and doing dumb stuff to show off. They're crashing and getting hurt 'cause they're following the examples of idiot instructors and advanced pilots using Industry Standard releases, one point bridles, and standard aerotow weak links and...
http://www.chgpa.org/forums/viewtopic.php?f=2&t=3695
good day until the wreck
...landing on their feet all the time and at all cost.Lauren Tjaden - 2008/12/31 04:29:12 UTC
came in with no wind after an hour and had right wing drop. instead of wrestling gilder straight i tried to flare while desperately trying to straighten.
- You guys aren't PILOTS, Lisa. You guys are people who fly stuff without understanding what's going on.Lisa
As pilots, we accept the baseline risk of flying because flying adds quality to our lives.
- The baseline risk of flying would be a helluva lot lower for a lot more people if assholes like you would get a freakin' clue before you publish stuff.
And the kind of rot you published in the June issue is guaranteed to contribute to people being "not" down the road. Who knows? It may have even provided a little more inspiration for Terry to slam himself in two and a half weeks ago.However, in addition to quality of life, it is good to have quantity. There is no quality of life if you "aren't."
Yeah. So why don't you figure out what they are and start doing something about the real ones?There are many risks in flying that can be prevented and/or minimized to reduce our overall risk.
Your attitudes, training programs, equipment, and risk-minimization strategies all suck.It takes the right attitude, good training, good equipment, and risk-minimization behavior.
Do your fuckin' homework before before you decide to reinvent aviation and start telling everybody else how they should be doing things.Take it to heart. This is not an understatement.
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Tad Eareckson
- Posts: 9149
- Joined: 2010/11/25 03:48:55 UTC
Re: training wheels
These goddam fins of yours are training wheels for people who haven't yet attained - or are incapable of attaining - proficiency on their gliders, as is obvious from what you're saying in your "Higher Education" article:
So can learning to fly the fucking glider...
- additional time on training gliders
- smooth air tows to altitude
- high speed practice at altitude
The fin will do NOTHING to help a COMPETENT pilot stay in proper position or protect him from a Mother Nature Induced Lockout. It will, in fact, do the PRECISE OPPOSITE.
And WHEN something like that happens to someone down low one of your fucking nominal USHGA recommended 130 pound Greenspot weak links ain't gonna compensate for that shit you throw on gliders and call releases.
Fins are TRAINING WHEELS. You put them on a very stable bike for a wobbly five year old kid to use in the driveway, an empty street on a Sunday morning, or bike trail in the park so he can get a feel for his new toy and - quickly hopefully - dispense with them. You don't send the kid - at ANY age - out into a street with traffic on it where he might be needing a bit of turning response.
You also don't send the kid out into traffic without BRAKES that:
- work
- he can get to before/without slamming into the side of a car
Really enjoyed your dissertations on cones of safety, fins, and weak links. When can we expect a similar quality masterpiece on hook knives?
Any plans for something in the foreseeable future which the word "release" is mentioned more than once or twice?
You always wanna stick with...
Assholes.
However, some--especially newer--pilots flying a single-surface glider may have trouble with pilot-induced oscillation (PIO) and will benefit from use of a fin.
However, this just makes the glider harder to fly for new pilots, especially by tow.
Because of the reduced directional stability in some newer single-surface gliders, it makes sense to put a fin on them for first solo flights.
Then there is the issue of pilots moving up to a more advanced-level glider.
There is a tendency for pilots to PIO when moving up to a higher-performance glider, because they have gotten used to the stability, roll/yaw coupling behavior, lighter weight, and quicker response of their lower-performance glider.
The result is that pilots new to a high-performance glider may over-control and oscillate.
Pilots should use a fin when they are transitioning to a higher-performance glider, especially if they are going to tow it.
Using a fin makes the transition safer and builds confidence in the pilot who is new to a glider.
If a pilot gets scared or hurt flying a new glider, he/she may never like it.
He may get frustrated, sell her new glider, and perhaps leave the sport.
Whereas, if a pilot has had a good experience with a new glider and feels safe in it, he/she is likely to be more confident and fly more often, maintain currency and skill, and stay in the sport.
A good experience in a new glider also helps to boost the reputation and sales of that glider design for the manufacturer.
When an instructor/dealer orders a new double-surface glider for a student or customer, he should ask the manufacturer to prep it for a fin.
It would be good for the customer to also order a fin with his/her new glider.
But even if he doesn't, the instructor/dealer can mount a rental fin on the glider for the pilot's initial flights in it, since the keel has already been prepped at the factory for mounting a fin.
If the manufacturer does not offer prepping of their keels for fins, then the instructor or dealer should prep it when the new glider is delivered, or at least have a clamp-on fin available to put on the glider for the customer's initial flights in it.
...and the statement on the issue from Wills Wing:First, for many years we have been consistently teaching our students and new club members about the benefits of flying with a fin.
At the cost of some measure of turning performance the fin CAN help someone who isn't competent flying his glider on tow - and likely flying his glider period - protect himself from himself. It can reduce Pilot Induced Oscillation, Pilot Induced Oscillation progressing to lockout, and Pilot Induced Lockout.Wills Wing Vertical Stabilizer
Wills Wing has developed a Vertical Stabilizer attachment for the purpose of helping hang glider pilots minimize or eliminate problems with roll / yaw oscillations. The tendency towards oscillations of this type is present to some degree in all high aspect ratio gliders, particularly when flying at faster speeds in turbulence, and when towing (especially aero-towing). Pilots with sufficient skill and experience can usually control or prevent such oscillations. Pilots who are making the transition from entry level gliders to high performance gliders, and pilots learning new skills such as aero-towing, are often unable to adequately prevent or recover from these oscillations. In the case of aero-towing, this can be enough of a problem to be a barrier to learning this new skill. The Stabilizer is a great accessory for the advancing Beginner to Intermediate pilot.
So can learning to fly the fucking glider...
- additional time on training gliders
- smooth air tows to altitude
- high speed practice at altitude
The fin will do NOTHING to help a COMPETENT pilot stay in proper position or protect him from a Mother Nature Induced Lockout. It will, in fact, do the PRECISE OPPOSITE.
A fin helps to yaw the nose of the glider into a gust, the upwind wing slows down a little, the downwind wing speed up a little, and you keep having to turn your head more to the downwind direction to see the tug while your fighting the roll and extra yaw stability to bring it back.A fin helps to yaw the nose of the glider into the wind gust, which makes the upwind wing slow down a little and the downwind wing speed up a little.
And WHEN something like that happens to someone down low one of your fucking nominal USHGA recommended 130 pound Greenspot weak links ain't gonna compensate for that shit you throw on gliders and call releases.
Fins are TRAINING WHEELS. You put them on a very stable bike for a wobbly five year old kid to use in the driveway, an empty street on a Sunday morning, or bike trail in the park so he can get a feel for his new toy and - quickly hopefully - dispense with them. You don't send the kid - at ANY age - out into a street with traffic on it where he might be needing a bit of turning response.
You also don't send the kid out into traffic without BRAKES that:
- work
- he can get to before/without slamming into the side of a car
Really enjoyed your dissertations on cones of safety, fins, and weak links. When can we expect a similar quality masterpiece on hook knives?
Any plans for something in the foreseeable future which the word "release" is mentioned more than once or twice?
Just kidding. In order for anything that doesn't stink on ice to become a de facto standard, that new technology will need to be made available in the marketplace, proven in the real world, and then embraced by our sport. And who knows how many decades that might take?What we have covered in this article is practical information and knowledge gleaned from the real world of aerotowing, developed over decades and hundreds of thousands of tows by experts in the field. This information has practical external validity. Hopefully, someone will develop methods and technology that work better than what we are using as standard practice today. Like the methods and technology used today, it is unlikely that the new technology will be dictated onto us as a de jure standard. Rather, to become a de facto standard, that new technology will need to be made available in the marketplace, proven in the real world, and then embraced by our sport.
It would be totally irresponsible to employ - let alone endorse or even mention - anything that hasn't been used for several decades and hundreds of thousands of tows conducted by numerous aerotow operators across the county.Based on several decades of experience and hundreds of thousands of tows conducted by numerous aerotow operators across the county, the de facto standard has become use of a 260 lb. weak link made as a loop of 130 lb. green spot IGFA [ref 12] Dacron braided fishing line attached to one end of the pilot's V-bridle.
You always wanna stick with...
...the tried and true stuff.The worst performance comes from a relatively short Spectra or thin pro-tow bridle, especially when the weak link is attached directly onto the thin curved pin of the secondary release, which imparts high loads over a very small area of the weak link.
Assholes.