חיקור תאונות ואירועים חריגים
לאור ריבוי התאונות והאירועים החריגים שקרו בתקופה האחרונה, ולאור העובדה שלפני מספר חדשים מינו באגודה אחראית תחקירי אירועים חריגים, מצאתי לנכון לעמוד בפינה זו על מספר דגשים הקשורים בחקירת תאונות אוויריות בכלל בתעופה הכללית, בגופים כגון חילות אוויר וחברות תעופה, ובמיוחד בגופים קטנים כגון אגודות ספורט תעופתי למיניהן.
קרוב לוודאי, הדבר הבולט ביותר באירוע חריג בתחום התעופה היה תמיד העניין הרב שהאירוע משך. למרות העובדה שבדרך כלל, מספר הנפגעים או הנזק הנגרם מתאונה אווירית הוא לאין שיעור קטן מאוד ביחס לתאונות דרכים או תאונות עבודה לדוגמא, למרות זאת, תמיד עורר אירוע חריג בתחום התעופה עניין רב יותר וסקרנות בקרב הקהל הרחב.
מדוע ?!
אין לי תשובה חד משמעית ובדוקה לכך. אני סבור שהעובדה שתאונות אוויריות הן נדירות יותר, בשכיחות נמוכה מאוד, ובנוסף לכך העובדה שלמרבית האוכלוסייה בעולם התחום הזה רחוק מאוד מעיסוק יום יומי, אולי אף מצטייר כחלום או משהו מרוחק ובלתי ניתן להשגה, יתכן ולדברים הללו יש השפעה על הענין הרב שתאונות אוויריות מעוררות בקרב הקהל הרחב.
בעולם, ובגופים תעופתיים גדולים, מייחסים לתחקירי התתאונות חשיבות רבה מאוד, וזאת בעיקר כדי להפיק את הלקחים המשמעותיים ביותר כדי למנוע מקרים דומים בעתיד.
תאונות אוויריות הן מקור מידע וצבירת ניסיון לכל מי שאדרלנין התעופה זורם בדמו. תאונה והגורמים לה הינם מקור ענין ונושא שיחה ומחשבה בלתי פוסקת כאשר מדובר באנשים הנגועים בוירוס הזה.
אצלי למשל, אצורים בזיכרון הפרטי עשרות אם לא מאות מקרים של תאונות ואירועים חריגים בתחום התעופה. כל פיסת מידע, כל אירוע, כל מקרה וכל התרסקות אשר פורסם ונחשפתי אליו מאז שירותי בח”א בשנות השבעים, נחרט עמוק בזיכרוני.
היכולת להפיק את מירב הלקחים מכל מקרה ומקרה הוא ערך אשר בבוא העת עשוי להעניק לך כלים להמנעות ממצב דומה, ואם לא דומה אזי לפחות להעמיק עוד ועוד את המודעות לבטיחות טיסה.
ואולם, תחקיר והפקת לקחים מתאונה או אירוע חריג, הגם שתפקידם העקרי הוא להביא לצמצום האפשרות שמקרה דומה יקרה בעתיד, הרי שהדרך לכך היא חיקור מאוזן, אובייקטיבי, מקצועי ככל שניתן תוך *הפצת* המידע שניצבר בקרב הקהילה הנוגעת בדבר.
אצלנו, בקהילת מצנחי הרחיפה, המקומית והעולמית, עוסקים אמנם בחיקור תאונות והן מרובות לצערנו, אך מסיבה כל שהיא, אנו עדים שוב ושוב לתאונות דומות מאוד, לעתים אף זהות, הקורות השכם והערב והלקחים אינם נלמדים.
הרוב המוחלט של התאונות בתחום שלנו נובע מטעות טייס. עוד לא שמעתי על מקרה בודד אחד בו נגרמה תאונה כתוצאה מכשל מיבני בחופה במיתרים או ברתמה, לדוגמא.
השאלה המתבקשת כאן, היא היכן אנו טועים ?
מדוע אותן תאונות קורות שוב ושוב ואין לימוד והפקת לקחים ?
על מנת לצמצם את אורך ורוחב היריעה הדרושה למענה לשאלה הנ”ל, אביא כדוגמאות את התאונות הקטלניות שקרו אצלנו ב-5 השנים האחרונות ואשתמש בהן להצגת דברי.
התאונה של יוסי קופר ביוני 2001, התאונה של גיל יערי ב-2002, התאונה ביבנאל 2003, והתאונה של שחר דיין 2004.
אם נביט על ארבעת המקרים מהנקודה הבסיסית ביותר המקשרת אותם, נבחין אך במכנה משותף אחד הקושר את ארבעתם: טעות טייס.
אצל יוסי קופר, השיקול המוטעה לטוס נמוך מאחורי מבנה בחוף הרצליה בצד ה- Lee Side.
גיל יערי בחר לטוס על חופה מתקדמת מידי ליכולת האישית שלו, נקלע למצב קריטי ולא ידע לתפעל אותו.
הבחור שנהרג ביבנאל המריא בתנאים גבוליים או אף מעבר למגבלות, היכן שטייסים ותיקים שנכחו בעמדה לא העיזו להמריא, ניקלע למצב קריטי ולא ידע לתפעל אותו.
והתאונה המחרידה של שחר דיין שנגרמה כתוצאה מהמראה ברתמה לא מאובטחת.
מה, אם כן, צריך לעשות כדי להקטין אפשרות של מקרים נוספים של טעות טייס ?
ובכן, לפני הכל בראש ובראשונה… צריך **לדבר** על התאונות !!!
צריך להמשיך ולדסכס על המקרים הקורים לנו וחובה לפתוח דיון פתוח, פורה ומעמיק.
לדבר ! לדבר ! ולדבר ! על כל תאונה על כל מקרה ועל כל אירוע !
אסור להתבייש להעלות את הדיון לבמה פומבית. אסור לשמור את הדיבור על התאונות אך ורק למי שלקח על עצמו לתחקר אותן.
מותר לכולם ! להביע דעה בפומבי.
מותר לכולם לחלוק על דעה זו או אחרת הקשורה באירוע, ובלבד שלא לתקוף את מי שמעז לדבר על התאונות או את המעורב, חלילה, בתאונה או באירוע.
לצערנו, המדיניות שהכרנו עד עכשיו, היתה של *טאבו* !!
אסור לאף אחד לדבר ! הס מלהזכיר ! תאונה או אירוע. התחקיר יבוא בצורה מסודרת, נאמר לנו, ואסור לאף אחד להוציא הגה בעניין.
ובכן, טעות !!!
ככל שנדבר על האירועים בחפשיות מתוך כבוד הדדי, כן ייטב לכולם. לכל אחד יש משהו לתרום, דעה, ידיעה, עדות ראיה ועוד ועוד.
ומה הייה לנו בפועל עד עכשיו ?
אנשים שיש להם מה לאמר, רועדים מפחד ומאימת העעעעעגודה ושומרים את אשר על ליבם לשיחות פרטיות. חבל, חבל מאוד. אפשר לעודד שיח ודיון פורה ומועיל בכל נושא התאונות. כולם יהנו מזה.
בפועל מה קורה ? לאחר אירוע חריג כל שהוא, נכנסת האגודה להליך של “וועדת חקירה”. חודשים עוברים עד אשר מוציאים דו”ח מסודר. וכאשר כבר הדו”ח יוצא סוף סוף, הוא תמיד לא מאוזן, מגמתי, מיושן ולא מעניין. המקרה והעניין שהאירוע עורר, נמוג והתפזר ואת אף אחד זה כבר לא מעניין.
אם יש בדו”ח אשם או אשמים, אזי מנסים לעדן ככל האפשר את מידת האשמה או האחריות שלהם, מתוך סולידריות של *תוך ועד אגודה* והמקורבים למיניהם.
התוצאה, תאונות חוזרות ונשנות ואין לקחים ואין לימוד מניסיון.
אפשר, וגם צריך וכדאי לשנות את האווירה המזיקה הזו. ויפה שעה אחת קודם.
שימי הנגבי
שבט התשס”ה
Comprehensive Business Plan
General Background Paragliding as a sport first emerged in 1988. Since then, the field has evolved to phenomenal dimensions and achievements from several aspects: 1 . The number of paraglider pilots worldwide has reached approximately 5 million in 180 countries. 2 . Paragliding equipment has achieved excellent performance and flight safety levels, with a very high performance-to-safety ratio. 3 . Significant paragliding events are held annually in all countries, including leagues, international competitions, conferences, achievement tables, and major exhibitions organized by global paragliding equipment manufacturers. 4 . The global paragliding equipment market is currently valued at over $100 million USD, solely for equipment manufacturers. There are also additional branches such as paragliding schools and paragliding tourism. To paraglide, one needs to ascend to high places, such as mountains or hills, and from there, take off at a reasonable gliding height, utilizing warm air currents and thermals to gain altitude. The internet and YouTube are replete with vast amounts of information, blogs, videos, instructional sites, articles, achievement tables, and more, offering endless fascinating materials for those engaged in the sport. A key aspect of engaging in the field is the need to reach high places, like mountains, to start gliding. This presents the challenge of dependence on long trips and complex and expensive logistics to go gliding. Additionally, the dependence on weather conditions severely limits the times when activity is possible. In some countries, the terrain is flat without hills or mountains, forcing paraglider pilots to travel to distant countries for paragliding activities. The advantage here is the opportunity to explore breathtakingly beautiful exotic locations that one might not otherwise visit. One alternative method for takeoff is through a towing winch. A cable from the winch attached to the paraglider pulls the parachute at a given speed, allowing the paraglider to gain height until the cable can be detached to meet thermal conditions, at the same height as a mountain or hill takeoff point. There are several towing methods for paragliding using a towing winch: 1. Stationary winch 2. Cable-releasing winch called “pay-out winch” releasing cable from a moving vehicle. These are the most common types, each with its pros and cons. The stationary winch is powered by an electric motor, hydraulic motor, or gasoline engine. The cable-releasing winch consists of a drum containing the towing cable, which is released under constant pressure by the moving vehicle to cause the paraglider to take off in a run. The disadvantage of the cable-releasing winch is its dependence on a moving vehicle that needs a clear travel path, typically at least two kilometers long. The cable-releasing winch is currently the most common and available, marketed in small numbers only due to the lack of a better alternative. However, there is no better alternative to date. At Sitvanit Towing Center, we are in the final stages of test flights for a prototype electric winch with several significant advantages: 1. A powerful 2.5 horsepower electric motor capable of launching a paraglider or hang glider to thermal heights. 2. The lightweight Sitvanit winch can be moved from place to place, eliminating the need for a takeoff path. 3. The prototype development includes at least three unique patents pending registration with the World Patent Office. 4. A simple and easy-to-operate system powered by a standard wide spread 48-volt electric bike battery. 5. The winch operation is remotely controlled. The operator carries a transmitter and remotely controls the winch throughout the flight stages. The global market for electric winches offers very few options. All current market alternatives lack one central feature – there is no mass production or marketing of such a product. This fact can be verified by a simple Google or YouTube search. Several publications contain options for underperforming systems, typically single winches that have not matured to production and marketing stages. Below are several significant advantages that will enable the rapid development of Sitvanit project: 1. The Sitvanit winch is simple to operate, with performance capabilities suitable for paragliding, and easy to maintain. 2. The system is affordable and available to every paraglider at the cost of paragliding equipment. 3. Uses a standard wide spread electric bike battery. 4. A simple remote-control system for all flight stages. 5. Prototype development with a concept for potential mass production. The system is suitable for additional gliding sports: Hang Gliding: Hang gliders share takeoff sites with paragliders. Where paragliders are found, so are hang gliders. The towing conditions required for hang gliders are identical to those of paragliders.Hang Gliders world-wide are as popular and wide spread as paragliders Gliders (sail planes): Gliders need towing to reach heights where thermal conditions can be met. Almost exclusively, gliders worldwide are towed by airplanes. This operation is expensive, cumbersome, and requires logistics, tow pilots, a tow plane, and more.The Sitvanit winch provides an excellent solution to all these problems for gliders as well. Here are several important points in the worldview of the final goal of the Sitvanit factory: – Providing a solution that saves dependence on traveling to mountains and hills for paragliding. This could change the sport of paragliding worldwide. – The possibility of mass production and distribution,
Paragliding Tow Line | Weak Link
WEAK LINKS A weak link is a very simple device—typically a loop of line—that is intended to break in the event towline tensions exceed a safe or desired threshold. Weak links have greatly improved the safety of towing over the years. Unfortunately, there is a significant amount of misunderstanding and inaccurate information about what a weak link can and cannot provide for the pilot’s safety. WEAK LINKS AND LOCKOUTS A common belief is that a weak link will protect a pilot from lockouts, high bank turns high angles of attack and other such perils. This belief is predicated on the notion that these maneuvers cause increases in tow force which breaks the weak link and frees the pilot from the towline. The validity of this argument is entirely dependent upon the kind of towing that is being performed. We can list two general categories of towing: speed-controlled towing and tension-controlled towing. Speed-controlled towing is when the speed of the device doing the towing is maintained at a reasonably constant value. Controls, such as the throttle, are used to keep the speed of the tow vehicle or tow winch operating at a constant speed. Towline tension can vary dramatically in response to thermals, sink, pilot corrections, etc. Aerotowing is clearly in this category as the tug needs to maintain a minimum speed to prevent stalling. Many of the early towing efforts of the ’70s when the vehicle drove at a fixed speed would also fall into this category of towing. Weak links very clearly will provide protection from excessive angles of attack, high bank tums and the like for this form of towing. Tension-controlled towing has become the norm for most forms of surface-based towing. Modern static line systems utilize a tension monitoring device for the tow vehicle and the driver modulates vehicle speed to maintain a constant tension. Payout winches are of this variety of towing with drag systems allowing the drum to spool off line at a controlled line tension. Many stationary winches, especially those using hydraulically driven drums, reel in the line with a controlled tension. Tension-controlled systems keep the line tension reasonably constant and allow vehicle speeds, drum speeds, etc., to vary widely in response to thermals, gusts, pilots, pilot actions, etc. Caution: For tension-controlled towing, a weak link cannot be counted on to break during a lockout, high bank angle, high angle of attack, etc. With a tension-controlled tow, weak links might break but more regularly will not. The reason should be obvious: a good control system will attempt to maintain a constant tension and not allow forces to climb high enough to break the weak link. Reasons for a Weak Link to Break in a Tension-Controlled System It is defective, i.e., it breaks at a tension lower than expected or desired. This can be caused by wear, incorrect assembly, defective string, etc. The tension control system has malfunctioned. It might not be adjusted correctly (operator failure), maybe a bearing seized, the rope jammed on the spool, the driver didn’t slow down (static line) or in some other way the system is failing to control the line tension at the desired level. The pilot, air conditions or some other event has introduced a perturbation in tension, a sudden increase, that occurred faster than the control system could respond and compensate Sometimes a lockout, or high angle of attack or other maneuver may be performed rapidly, producing a tension increase faster than the system can correct. In these situations, the weak link will break if the momentary tension increase exceeds the breaking point on the weak link. However, many, if not most times, these situations are entered gradually and produce no sudden changes in line tension. In these cases, the weak link will not break because the control system will compensate, keeping the tow tension in check. In recent years, two serious lockout accidents occurred with surface-based towing; one resulting in a fatality and the other a very serious injury. In both of these events the line tension was being monitored directly and it never exceeded 120-130 pounds (55-60 kg), well below the breaking point for the weak links! By all means, do not assume you are immune from danger because you are using a weak link. A weak link provides a measure of additional safety in all towing situations. But problems can occur which do not generate high tow forces. The physics of towing do not support the notion you will be immune. Nor does history support this notion. Our best defense against problems also relies upon the use of good equipment, safe policies and sound emergency procedures that must be reviewed and practiced periodically for pilots to remain familiar with them. With these, towing can be Construction of Weak links Like most things in our sports, there are numerous methods of implementation for weak links. These include various loop configurations, knots and various materials for the line. It is tempting to just recommend a particular string, knot, and setup. But experience has taught us that there is extensive variance in line quality between brands, sizes, etc. For example, we have found breaking strength variances exceeded 35%
Lockouts in Towing
The Danger of Towing Lockout Lockouts occur when a glider gets turned away from the towline direction then reaches a point where the pilot cannot recover. How and why, this happens is explained below. First, let us list the most common causes of lockout: l. Turbulence lifting a wing. In this case we will have the situation of position 2 shown in figure 1-6, or position 3 if the glider is also tossed to one side of the tow centerline. 2. Overbanking when performing a correction. If you enter into a roll oscillation, it is possible to veer so far to one side that a lockout begins. 3. Operating in a crosswind, especially when towing from a payout winch. A strong gust from the side can force you off the tow centerline with your heading not lined up with the towline. 4. Not following the tug properly during turns while aerotowing. Allowing your glider to drift to the outside of an aerotow turn is the potential lockout situation of position l. In general, aerotowing is more forgiving of misalignments than surface towing (although four reported tandem aerotow lockouts indicate that tandem is a special case) because the towline angle with respect to the glider is less with aerotowing and the tow forces are lower. In our experience, control problem begins with as little as 15 0 deviation from the centerline with surface towing while a 45 0 deviation (wings level) can be brought back to center on aerotow Now let us look at the forces on tow when the glider gets disturbed from the wings level, centered path. We see a glider yawed to the side of the towline. In this case the wings are level but the glider is being pulled in a slip (partially sideways) by the tow force. This slip may lift the forward wing more than the other, since it sees more direct airflow. As a result it may tend to roll away from the tow direction. The situation is worse if a gust or overcontrol rolls the glider. The resultant (combination of lift and drag) is not aligned with the downward force (gravity and the tow force) so the glider moves to the side. In this case we end up like the third drawing of figure 1-6 where the glider is both rolled and yawed with respect to the horizon and towline. In this latter situation, the pilot will feel an input from the glider resisting his or her attempts to level the glider. If the pilot isn’t successful at leveling the wings, the turn to the side continues until the glider’s bank steepens and it begins diving or slipping (to the opposite side of the original slip) towards the ground. Here we have depicted the interaction of the tow force and gravity with the aerodynamic forces. In the left drawing, the pilot is beginning a lockout situation Because the glider is turning away from the towline, the tow force has increased but is still directed along the towline. The force of gravity always remains the same and is directed straight down. These two forces combine to produce the apparent force (AF) that the glider “feels. ” Note how this force is directed to the side of the plane passing through the glider’s keel and kingpost and is not aligned with the resultant. This misalignment is what causes the glider to continue to move sideways and worsen the lockout. The right drawing shows the more severe situation as the lockout deepens. Here the AF is stronger and even more misaligned with the resultant. When the glider begins a lockout, it is slipping earthward. This action causes it to yaw nose down as shown. In free flight, this yawing is desirable for recovery, but under tow it worsens the lockout condition because the tow force doesn’t allow the glider to follow the necessary curving path. Also, the pilot feels increased force combating his or her roll correction input because the AF is pulling him or her off to the side and the turn is not coordinated. In free flight the pilot centers on the bar with proper pitch control, but in a lockout he or she cannot center the apparent force. The result is a continuously worsening situation. The key to avoiding lockouts on a hang glider is to keep the wings level on tow and follow the towline. If the glider doesn’t respond in a timely fashion to your roll inputs, or if the towline or bridle contact the glider’s front cables, release. Note: The shorter the towline, the faster the above process occurs. The reactions of ultralight sailplanes are similar to that of hang gliders Paraglider lockouts occur in a similar fashion to that described above for hang gliders except the contrary forces are easier to control. Paraglider lockouts occur in a similar fashion to that described above for hang gliders. In this case, the pilot can prevent a yaw very readily, but when yaw does occur, a roll away from the towline also occurs since the pilot’s body is pulled partially sideways to the canopy. If the yaw isn’t controlled for, the roll
Step Towing Paragliders | e-Winch
The Step Tow Method Here is a description of the method: Once the glider has reached the end of the tow, tensions are dropped and the glider turns downwind and pulls the towline behind it. After flying above the original launch point or beyond, the glider turns back into the wind. Tow tensions are reapplied and the glider is pulled again to climb higher. The glider’s altitude ratchets up in sequential steps with each cycle as shown in figure 5-18. Since the climb rate on a winch tow slows down the closer you get to the winch, the second climb should stop short of the winch. Each subsequent climb should stop shorter still, and continue further downwind, even past the limits of the field (if safe clearance is maintained) as the figure shows. This procedure will get you the highest in the shortest length of time. Also, if the winch is equipped with a universal payout head that allows it to tow with the line in any direction, you should fly directly downwind after the first tow so all subsequent reel-ins are headed directly upwind for maximum climb rate. Step towing should not be practiced by inexperienced tow pilots. A very careful turn, from the downwind leg back upwind is required to prevent looping the towline over the wing of the hang glider. If a paraglider pilot turns the wrong way, he or she will become wrapped in the towline. With a tow line 1,500 m long, and take off field 500-700 m, here is the procedure: Step 1. Tow up to 300 m, turn down wind glide to 200m Step 2. Turn up wind, tow up to 400 m, turn down wind glide to 200m. Step 3. Turn up wind, tow up to 600 m, turn down wind glide to 400 m. Step 4. Turn up wind, tow up to cable limit to max 45% slant angle from winch. This procedures can be best achieved by a remote controlled-self towing e-winch. step Towing Equipment Communication and coordination between the winch operator and pilot are extremely critical for the preservation of safety. We believe reliable radios are an absolute requirement for step towing. When the pilot turns back upwind, the glider is generally much too distant for visual inspection of the line by the winch operator. A glider pointed back towards the winch does not indicate a safe condition to resume towing. A radio transmission from the pilot is required to confirm that. The second piece of equipment required for step towing is the correct bridle and release system. Any hang glider bridle connection over the control bar or attached to the keel is unequivocally unacceptable when the glider turns and runs downwind. Such arrangements could cause a hang glider to dive if some tension develops in the line during the downwind leg. The towline must only connect to the pilot below the control bar. The Skyting bridle and V bridle obviously may not be used. A single point connection to the pilot is required. The typical bridle used for platform launch towing may be used. Launches must be from a platform or dolly since these bridle configurations do not readily accommodate foot launching. As an alternative, the two-stage release system which allows release of the top line may be utilized. With such an arrangement the pilot may foot launch and once well into the air, release the first stage and continue being towed by the second line under the control bar. Caution: By the time the glider is ready to turn around for the first time, no part of the bridle should be attached above the base tube (to either pilot or glider) so the control bar is not pulled backwards when the towline is behind the pilot. Paraglider bridles must be attached and releases routed so that wrapping the line half way around the pilot’s body or between the pilot’s legs does not initiate a premature release or entangle them with the harness or ancillary equipment. Furthermore, reliable activation ofthe release must still be possible when in that position. Step Tow Procedures—stationary Winch With the stationary winch, when the pilot has reached the end of the tow, he commands “drop tension” rather than releasing. The winch operator should drop the tension immediately. A few pounds (l or 2 kg) of tension or drag are desirable to prevent freewheeling of the drum and spinning off excess line. It also serves to keep the line off the ground to minimize snagging. Radio back, “drop tension confirmed. ” The pilot now knows he can safely turn 180 degrees and head downwind trailing the line. This phase of the tow is critical. The line must be dispensed smoothly with no jerks or snags. A superior level-wind system is essential for obtaining the tight clean wraps required for this activity. The pilot must not get too low before turning back into the wind nor tow the line over any obstacle that could snag the line. If winds are significant, do not forget to account for drift and begin a turn early. A hang glider pilot must be especially careful when making the winch.
Comprehensive Business Plan
General Background
Paragliding as a sport first emerged in 1988. Since then, the field has evolved to phenomenal dimensions and achievements from several aspects:
1 . The number of paraglider pilots worldwide has reached approximately 5 million in 180 countries.
2 . Paragliding equipment has achieved excellent performance and flight safety levels, with a very high performance-to-safety ratio.
3 . Significant paragliding events are held annually in all countries, including leagues, international competitions, conferences, achievement tables, and major exhibitions organized by global paragliding equipment manufacturers.
4 . The global paragliding equipment market is currently valued at over $100 million USD, solely for equipment manufacturers. There are also additional branches such as paragliding schools and paragliding tourism.
To paraglide, one needs to ascend to high places, such as mountains or hills, and from there, take off at a reasonable gliding height, utilizing warm air currents and thermals to gain altitude.
The internet and YouTube are replete with vast amounts of information, blogs, videos, instructional sites, articles, achievement tables, and more, offering endless fascinating materials for those engaged in the sport.
A key aspect of engaging in the field is the need to reach high places, like mountains, to start gliding. This presents the challenge of dependence on long trips and complex and expensive logistics to go gliding. Additionally, the dependence on weather conditions severely limits the times when activity is possible.
In some countries, the terrain is flat without hills or mountains, forcing paraglider pilots to travel to distant countries for paragliding activities. The advantage here is the opportunity to explore breathtakingly beautiful exotic locations that one might not otherwise visit.
One alternative method for takeoff is through a towing winch.
A cable from the winch attached to the paraglider pulls the parachute at a given speed, allowing the paraglider to gain height until the cable can be detached to meet thermal conditions, at the same height as a mountain or hill takeoff point.
There are several towing methods for paragliding using a towing winch:
1. Stationary winch
2. Cable-releasing winch called “pay-out winch” releasing cable from a moving vehicle.
These are the most common types, each with its pros and cons.
The stationary winch is powered by an electric motor, hydraulic motor, or gasoline engine.
The cable-releasing winch consists of a drum containing the towing cable, which is released under constant pressure by the moving vehicle to cause the paraglider to take off in a run.
The disadvantage of the cable-releasing winch is its dependence on a moving vehicle that needs a clear travel path, typically at least two kilometers long.
The cable-releasing winch is currently the most common and available, marketed in small numbers only due to the lack of a better alternative. However, there is no better alternative to date.
At Sitvanit Towing Center, we are in the final stages of test flights for a prototype electric winch with several significant advantages:
1. A powerful 2.5 horsepower electric motor capable of launching a paraglider or hang glider to thermal heights.
2. The lightweight Sitvanit winch can be moved from place to place, eliminating the need for a takeoff path.
3. The prototype development includes at least three unique patents pending registration with the World Patent Office.
4. A simple and easy-to-operate system powered by a standard wide spread 48-volt electric bike battery.
5. The winch operation is remotely controlled.
The operator carries a transmitter and remotely controls the winch throughout the flight stages.
The global market for electric winches offers very few options. All current market alternatives lack one central feature – there is no mass production or marketing of such a product. This fact can be verified by a simple Google or YouTube search. Several publications contain options for underperforming systems, typically single winches that have not matured to production and marketing stages.
Below are several significant advantages that will enable the rapid development of Sitvanit project:
1. The Sitvanit winch is simple to operate, with performance capabilities suitable for paragliding, and easy to maintain.
2. The system is affordable and available to every paraglider at the cost of paragliding equipment.
3. Uses a standard wide spread electric bike battery.
4. A simple remote-control system for all flight stages.
5. Prototype development with a concept for potential mass production.
The system is suitable for additional gliding sports:
Hang Gliding: Hang gliders share takeoff sites with paragliders. Where paragliders are found, so are hang gliders. The towing conditions required for hang gliders are identical to those of paragliders.Hang Gliders world-wide are as popular and wide spread as paragliders
Gliders (sail planes): Gliders need towing to reach heights where thermal conditions can be met. Almost exclusively, gliders worldwide are towed by airplanes. This operation is expensive, cumbersome, and requires logistics, tow pilots, a tow plane, and more.The Sitvanit winch provides an excellent solution to all these problems for gliders as well.
Here are several important points in the worldview of the final goal of the Sitvanit factory:
– Providing a solution that saves dependence on traveling to mountains and hills for paragliding. This could change the sport of paragliding worldwide.
– The possibility of mass production and distribution, low cost, simplicity, and availability will allow the product to become an essential part of every paraglider’s equipment.
– The ultimate goal is to establish the Sitvanit system as a globally recognized and accepted as a standard, due to its innovations in concept and simplicity.
Executive Summary
Company Name:** Sitvanit Towing Center
Product:** Sitvanit Electric Winch for Paragliding and Related
Sports
Location:** Currently Tel Aviv, Israel
Contact Information:**
Mr. Shimon Hanegbi
Nechama St. 7
P.O.Box 8393
Tel Aviv, 6811533
Israel
E-Mail: sitvanit7@gmail.com
Phone: 972-53-9318295
Skype: sitvanit71
Website: https://www.sitvanit7.com
Purpose:
To secure a business loan for the mass production, marketing, and
distribution of the Sitvanit Electric Winch, a revolutionary product
designed to provide efficient, cost-effective, and accessible takeoff solutions
for paragliders, hang gliders, and gliders.
Business Description
Sitvanit Towing Center specializes in the development and
production of innovative towing solutions for airborne sports. Our flagship
product, the Sitvanit Electric Winch, offers a lightweight, portable, and
powerful solution for paragliding takeoffs, eliminating the dependency on
natural elevations and complex logistics.
Market Analysis
Industry Overview:
– The global paragliding market is valued at $100 million, with
significant growth potential due to increasing participation in airborne
sports.
– Current limitations in the market include the need for specific
geographic conditions and the reliance on traditional towing methods, which are
cumbersome and expensive.
Target Market:
– Paragliders, hang gliders, and glider pilots worldwide, particularly in
regions with flat terrain.
– Paragliding schools, clubs, and tourism operators.
– Adventure sports enthusiasts seeking cost-effective and flexible
solutions.
Competitive Analysis:
– Limited competition in the electric winch market with no mass-produced
or widely marketed products.
– Existing products are underperforming, with single-unit productions and
no scalable options.
Market Opportunity:
– Sitvanit Electric Winch addresses key pain points: dependency on
natural elevations, high costs, and complex logistics.
– Potential to establish a new standard in airborne sports towing
solutions.
Product Description
Sitvanit Electric Winch
Features:
1. Powerful Motor: 2.5 horsepower electric motor capable of launching paragliders
and hang gliders to thermal heights.
2. Portability: Lightweight design, easy to transport, eliminating the
need for a dedicated takeoff sites.
3. Innovative Patents: Includes three unique patents pending registration
with the World Patent Office.
4. Battery Operated: Powered by a standard 48-volt electric bike battery.
5. Remote Control Operation: Controlled remotely, ensuring ease of use
and operational safety.
Marketing Strategy
Product Positioning:
– Positioned as an essential, innovative, and cost-effective solution for
airborne sports enthusiasts.
– Emphasize unique selling points: portability, ease of use,
affordability, and innovative technology.
Promotion Plan:
1. Digital Marketing: Leverage social media, Google Ads, and YouTube for
targeted campaigns.
2. Industry Events: Participate in paragliding events, trade shows, and
conferences to demonstrate the product.
3. Partnerships: Collaborate with paragliding equipment manufacturers,
schools, clubs, and equipment retailers for cross-promotion.
4. Content Marketing: Create engaging content, including tutorials, user
testimonials, and case studies, to build brand awareness.
Sales Strategy:
– Direct sales through our website and e-commerce platforms.
– Distribution through:
* Paragliding equipment retailers,
* Existing worldwide network of equipment dealers,
* Existing worldwide paragliding schools,
* Clubs, and tourism operators.
Operational Plan
Manufacturing:
– Outsource manufacturing to established factories with expertise in electric
motor production and assembly.
– Ensure quality control through regular inspections and adherence to
international standards.
Supply Chain:
– Secure reliable suppliers for components, including electric motors,
batteries, and remote control systems.
– Establish a logistics network for efficient distribution and delivery.
Development Timeline:
1. Phase 1: Finalize prototype testing and patent registrations (6
months).
2. Phase 2: Set up manufacturing and supply chain logistics (12 months).
3. Phase 3: Launch marketing campaign and initiate sales (6 months).
Management Team
Founder and CEO:
Shimon Hanegbi Marciano – Experienced entrepreneur with a background in
engineering and sports equipment manufacturing.
Chief Instructor and founder of Sitvanit Pargliding School and Club with
21 years of experience.
Chief Engineer: [to be recruited] – Lead engineer with expertise in
electric motor design and patent development.
Marketing Director: [to be recruited] – Marketing professional with
extensive experience in digital marketing and brand management.
Operations Manager: [to be recruited] – Expert in supply chain management
and logistics.
Financial Plan
Funding Requirements:
– Total Loan Amount Requested: 5,000,000.- USD (five million USD)
– Purpose of Funds: Manufacturing setup, marketing and promotion, initial
inventory, and operational expenses.
Projected Financials:
Revenue Projections: Based on market research and sales strategy,
expected revenue for the first year is $[250,000.- USD], with a projected
growth rate of 120]% annually.
Cost Structure: Detailed breakdown of manufacturing costs, marketing
expenses, operational costs, and R&D .
Profitability: Projected break-even within 5 Years. with net profit
margins increasing as production scales.
Repayment Plan:
– Structured loan repayment plan based on projected cash flow, with
monthly installments over 10 years. Excluding 24 months grace.
– Contingency plans for financial stability and loan repayment assurance.
Risk Analysis
Market Risks:
– Potential competition from new
entrants.
– Dependence on market adoption and acceptance.
Mitigation Strategies:
– Continuous product innovation and improvement.
– Building strong customer relationships and brand loyalty.
Operational Risks:
– Supply chain disruptions.
– Manufacturing challenges.
Mitigation Strategies:
– Diversifying suppliers and maintaining safety stock.
– Regular quality control and contingency planning.
Conclusion
WE ARE LOOKING FOR INVESTORS/PARTNERS
The Sitvanit Electric Winch represents a groundbreaking innovation
in the airborne sports market, with significant potential for growth and market
penetration.
With the requested funding, Sitvanit Towing Center is poised to
revolutionize the way paragliders, hang gliders, and gliders take off, offering
a cost-effective, portable, and efficient solution that meets the needs of
enthusiasts worldwide.
—
Paragliding Tow Line | Weak Link
WEAK LINKS
A weak link is a very simple device—typically a loop of line—that is intended to break in the event towline tensions exceed a safe or desired threshold. Weak links have greatly improved the safety of towing over the years. Unfortunately, there is a significant amount of misunderstanding and inaccurate information about what a weak link can and cannot provide for the pilot’s safety.
WEAK LINKS AND LOCKOUTS
A common belief is that a weak link will protect a pilot from lockouts, high bank turns high angles of attack and other such perils. This belief is predicated on the notion that these maneuvers cause increases in tow force which breaks the weak link and frees the pilot from the towline.
The validity of this argument is entirely dependent upon the kind of towing that is being performed. We can list two general categories of towing: speed-controlled towing and tension-controlled towing.
Speed-controlled towing is when the speed of the device doing the towing is maintained at a reasonably constant value. Controls, such as the throttle, are used to keep the speed of the tow vehicle or tow winch operating at a constant speed. Towline tension can vary dramatically in response to thermals, sink, pilot corrections, etc. Aerotowing is clearly in this category as the tug needs to maintain a minimum speed to prevent stalling. Many of the early towing efforts of the ’70s when the vehicle drove at a fixed speed would also fall into this category of towing. Weak links very clearly will provide protection from excessive angles of attack, high bank tums and the like for this form of towing.
Tension-controlled towing has become the norm for most forms of surface-based towing. Modern static line systems utilize a tension monitoring device for the tow vehicle and the driver modulates vehicle speed to maintain a constant tension. Payout winches are of this variety of towing with drag systems allowing the drum to spool off line at a controlled line tension. Many stationary winches, especially those using hydraulically driven drums, reel in the line with a controlled tension. Tension-controlled systems keep the line tension reasonably constant and allow vehicle speeds, drum speeds, etc., to vary widely in response to thermals, gusts, pilots, pilot actions, etc.
Caution: For tension-controlled towing, a weak link cannot be counted on to break during a lockout, high bank angle, high angle of attack, etc.
With a tension-controlled tow, weak links might break but more regularly will not. The reason should be obvious: a good control system will attempt to maintain a constant tension and not allow forces to climb high enough to break the weak link.
Reasons for a Weak Link to Break in a Tension-Controlled System
It is defective, i.e., it breaks at a tension lower than expected or desired. This can be caused by wear, incorrect assembly, defective string, etc.
The tension control system has malfunctioned. It might not be adjusted correctly (operator failure), maybe a bearing seized, the rope jammed on the spool, the driver didn’t slow down (static line) or in some other way the system is failing to control the line tension at the desired level.
The pilot, air conditions or some other event has introduced a perturbation in tension, a sudden increase, that occurred faster than the control system could respond and compensate
Sometimes a lockout, or high angle of attack or other maneuver may be performed rapidly, producing a tension increase faster than the system can correct. In these situations, the weak link will break if the momentary tension increase exceeds the breaking point on the weak link. However, many, if not most times, these situations are entered gradually and produce no sudden changes in line tension. In these cases, the weak link will not break because the control system will compensate, keeping the tow tension in check.
In recent years, two serious lockout accidents occurred with surface-based towing; one resulting in a fatality and the other a very serious injury. In both of these events the line tension was being monitored directly and it never exceeded 120-130 pounds (55-60 kg), well below the breaking point for the weak links!
By all means, do not assume you are immune from danger because you are using a weak link. A weak link provides a measure of additional safety in all towing situations. But problems can occur which do not generate high tow forces. The physics of towing do not support the notion you will be immune. Nor does history support this notion.
Our best defense against problems also relies upon the use of good equipment, safe policies and sound emergency procedures that must be reviewed and practiced periodically for pilots to remain familiar with them. With these, towing can be
Construction of Weak links
Like most things in our sports, there are numerous methods of implementation for weak links. These include various loop configurations, knots and various materials for the line. It is tempting to just recommend a particular string, knot, and setup. But experience has taught us that there is extensive variance in line quality between brands, sizes, etc. For example, we have found breaking strength variances exceeded 35% for the supposedly same 205 leech line (sailboat material) procured from different sources.
It is imperative that you make and test your own weak links on a test rig to know at what point they break. You should make and test at least 10 weak links. They will all break at slightly different points, but measure them and find the average. Also, compare several of the highest and several of the lowest breaking values to the average. If they differ by more than 10% you do not have a reliable and predictable weak link system.
The hazard of having a link breaking at a much higher tensions than desired is obvious. However, if weak links are breaking often at lower than desired tensions, then pilots may be tempted to double them over, use much stronger ones, or even remove them. This action negates the point of even having a weak link in the system
Safety Tip: The only way to insure safe, and consistent weak links is to test each batch of new weak link material with the same equipment (release, rings, bridles, etc) for breaking strength.
The easiest way to test weak link strength is to attach a weak link to a solid fixture and place a ring or loop in it of the same size that you will use in actual operation. Now place a stick or dowel through the ring so it can be gripped by a tester. Using someone of the appropriate weight, have the person hold the stick and slowly lift his or her feet. Sudden movements will create more force than the actual weight. If the weak link breaks, it is weaker than the test weight—find a lighter tester. If it doesn’t break, you can add weights to the system or use a heavier tester. You should be able to test within 5 lbs (2.3 kg) with this method.
A number of factors will influence the breaking point of a weak link. If these are not kept exactly the same for every link, the predictability and reliability of the weak link will be compromised.
Written by Dennis Pagen
Lockouts in Towing
The Danger of Towing Lockout
Lockouts occur when a glider gets turned away from the towline direction then reaches a point where the pilot cannot recover. How and why, this happens is explained below.
First, let us list the most common causes of lockout:
l. Turbulence lifting a wing. In this case we will have the situation of position 2 shown in figure 1-6, or position 3 if the glider is also tossed to one side of the tow centerline.
2. Overbanking when performing a correction. If you enter into a roll oscillation, it is possible to veer so far to one side that a lockout begins.
3. Operating in a crosswind, especially when towing from a payout winch. A strong gust from the side can force you off the tow centerline with your heading not lined up with the towline.
4. Not following the tug properly during turns while aerotowing. Allowing your glider to drift to the outside of an aerotow turn is the potential lockout situation of position l.
In general, aerotowing is more forgiving of misalignments than surface towing (although four reported tandem aerotow lockouts indicate that tandem is a special case) because the towline angle with respect to the glider is less with aerotowing and the tow forces are lower. In our experience, control problem begins with as little as 15 0 deviation from the centerline with surface towing while a 45 0 deviation (wings level) can be brought back to center on aerotow
Now let us look at the forces on tow when the glider gets disturbed from the wings level, centered path. We see a glider yawed to the side of the towline. In this case the wings are level but the glider is being pulled in a slip (partially sideways) by the tow force. This slip may lift the forward wing more than the other, since it sees more direct airflow. As a result it may tend to roll away from the tow direction.
The situation is worse if a gust or overcontrol rolls the glider. The resultant (combination of lift and drag) is not aligned with the downward force (gravity and the tow force) so the glider moves to the side. In this case we end up like the third drawing of figure 1-6 where the glider is both rolled and yawed with respect to the horizon and towline. In this latter situation, the pilot will feel an input from the glider resisting his or her attempts to level the glider.
If the pilot isn’t successful at leveling the wings, the turn to the side continues until the glider’s bank steepens and it begins diving or slipping (to the opposite side of the original slip) towards the ground. Here we have depicted the interaction of the tow force and gravity with the aerodynamic forces. In the left drawing, the pilot is beginning a lockout situation
Because the glider is turning away from the towline, the tow force has increased but is still directed along the towline. The force of gravity always remains the same and is directed straight down. These two forces combine to produce the apparent force (AF) that the glider “feels. ” Note how this force is directed to the
side of the plane passing through the glider’s keel and kingpost and is not aligned with the resultant.
This misalignment is what causes the glider to continue to move sideways and worsen the lockout. The right drawing shows the more severe situation as the lockout deepens. Here the AF is stronger and even more misaligned with the resultant.
When the glider begins a lockout, it is slipping earthward. This action causes it to yaw nose down as shown. In free flight, this yawing is desirable for recovery, but under tow it worsens the lockout condition because the tow force doesn’t allow the glider to follow the necessary curving path. Also, the pilot feels increased force combating his or her roll correction input because the AF is pulling him or her off to the side and the turn is not coordinated. In free flight the pilot centers on the bar with proper pitch control, but in a lockout he or she cannot center the apparent force. The result is a continuously worsening situation.
The key to avoiding lockouts on a hang glider is to keep the wings level on tow and follow the towline. If the glider doesn’t respond in a timely fashion to your roll inputs, or if the towline or bridle contact the glider’s front cables, release. Note: The shorter the towline, the faster the above process occurs. The reactions of ultralight sailplanes are similar to that of hang gliders Paraglider lockouts occur in a similar fashion to that described above for hang gliders except the contrary forces are easier to control.
Paraglider lockouts occur in a similar fashion to that described above for hang gliders. In this case, the pilot can prevent a yaw very readily, but when yaw does occur, a roll away from the towline also occurs since the pilot’s body is pulled partially sideways to the canopy. If the yaw isn’t controlled for, the roll worsens as the canopy flies away from the direction of tow. From this point onward, the forces and events follow closely the hang-gliding scenario described above.
Paragliders do not have exceptional yaw stability, so they are susceptible to yawing on tow. To prevent lockouts, monitor the canopy constantly and keep it square to the towline.
This article was written by Dennis Pagen and Bill Bryden
Step Towing Paragliders | e-Winch
The Step Tow Method
Here is a description of the method: Once the glider has reached the end of the tow, tensions are dropped and the glider turns downwind and pulls the towline behind it. After flying above the original launch point or beyond, the glider turns back into the wind. Tow tensions are reapplied and the glider is pulled again to climb higher. The glider’s altitude ratchets up in sequential steps with each cycle as shown in figure 5-18.
Since the climb rate on a winch tow slows down the closer you get to the winch, the second climb should stop short of the winch. Each subsequent climb should stop shorter still, and continue further downwind, even past the limits of the field (if safe clearance is maintained) as the figure shows.
This procedure will get you the highest in the shortest length of time. Also, if the winch is equipped with a universal payout head that allows it to tow with the line in any direction, you should fly directly downwind after the first tow so all subsequent reel-ins are headed directly upwind for maximum climb rate.
Step towing should not be practiced by inexperienced tow pilots. A very careful turn, from the downwind leg back upwind is required to prevent looping the towline over the wing of the hang glider. If a paraglider pilot turns the wrong way, he or she will become wrapped in the towline.
With a tow line 1,500 m long, and take off field 500-700 m, here is the procedure:
Step 1. Tow up to 300 m, turn down wind glide to 200m
Step 2. Turn up wind, tow up to 400 m, turn down wind glide to 200m.
Step 3. Turn up wind, tow up to 600 m, turn down wind glide to 400 m.
Step 4. Turn up wind, tow up to cable limit to max 45% slant angle from winch.
This procedures can be best achieved by a remote controlled-self towing e-winch.
step Towing Equipment
Communication and coordination between the winch operator and pilot are extremely critical for the preservation of safety. We believe reliable radios are an absolute requirement for step towing. When the pilot turns back upwind, the glider is generally much too distant for visual inspection of the line by the winch operator. A glider pointed back towards the winch does not indicate a safe condition to resume towing. A radio transmission from the pilot is required to confirm that.
The second piece of equipment required for step towing is the correct bridle and release system. Any hang glider bridle connection over the control bar or attached to the keel is unequivocally unacceptable when the glider turns and runs downwind. Such arrangements could cause a hang glider to dive if some tension develops in the line during the downwind leg. The towline must only connect to the pilot below the control bar. The Skyting bridle and V bridle obviously may not be used. A single point connection to the pilot is required. The typical bridle used for platform launch towing may be used. Launches must be from a platform or dolly since these bridle configurations do not readily accommodate foot launching. As an alternative, the two-stage release system which allows release of the top line may be utilized. With such an arrangement the pilot may foot launch and once well into the air, release the first stage and continue being towed by the second line under the control bar.
Caution: By the time the glider is ready to turn around for the first time, no part of the bridle should be attached above the base tube (to either pilot or glider) so the control bar is not pulled backwards when the towline is behind the pilot.
Paraglider bridles must be attached and releases routed so that wrapping the line half way around the pilot’s body or between the pilot’s legs does not initiate a premature release or entangle them with the harness or ancillary equipment. Furthermore, reliable activation ofthe release must still be possible when in that position.
Step Tow Procedures—stationary Winch
With the stationary winch, when the pilot has reached the end of the tow, he commands “drop tension” rather than releasing. The winch operator should drop the tension immediately. A few pounds (l or 2 kg) of tension or drag are desirable to prevent freewheeling of the drum and spinning off excess line. It also serves to keep the line off the ground to minimize snagging. Radio back, “drop tension confirmed. ” The pilot now knows he can safely turn 180 degrees and head downwind trailing the line. This phase of the tow is critical. The line must be dispensed smoothly with no jerks or snags. A superior level-wind system is essential for obtaining the tight clean wraps required for this activity.
The pilot must not get too low before turning back into the wind nor tow the line over any obstacle that could snag the line. If winds are significant, do not forget to account for drift and begin a turn early.
A hang glider pilot must be especially careful when making the winch. If the pilot rolls too aggressively while making the turn, the wing will pass below the towline and loop it over the wing (see figure 5-19). This is a very precarious situation which will be dealt with in Emergency Procedures (Line Snags) later in this chapter. Keep the turn very shallow. The towline must be kept in sight during the whole turn. If you lose sight of it, promptly level out and reestablish its position.
The paraglider pilot must make a decision when turning downwind. When the turn away from the winch is made, the line can be routed around his side and back to the winch, or he can lift a leg over the line and pull it back between his legs. The seat of the harness generally prevents any crotch discomfort from the line. When turning back towards the winch to resume the tow, if the line is wrapped by his side, the pilot must turn in the opposite direction of the previous turn. In other words, if he turned right to head downwind, he must turn left to turn back upwind. Otherwise, the line will wrap completely around him. If the line routes between his legs, he must lift his inside leg way up to clear the line. This action can interfere with weight shift control of the paraglider. Because of the risk of not getting a leg up and over the line and compromise to the weight, we suggest pulling the line by your side.
When the glider is oriented back into the wind and aligned with the winch, radio “resume tension”. The winch operator should smoothly reapply tension.
Step Tow procedures—payout winch
The step tow with the payout is similar to the above, except the tow crew has some added tasks. When the pilot commands, “drop tension,” the winch operator should turn the tension’ down to nothing but periodically bump the switch controlling the rewind system to maintain a few pounds of tension and take up any slack. Radio back to the pilot, “drop tension confirmed. ” The driver should perform a U-turn and begin driving in the opposite direction. If winds are light, the vehicle can accelerate out in front of the glider and the tow resume in the opposite direction. However, in very strong it usually is not worth the effort and the vehicle will need to be traveling at 50 to 60 mph (80 to 100 lannl) or more. Rather, follow the vehicle and when you reach the downwind end of the runway, both turn 180 0 for a subsequent tow. the glider has completed his turn and the tow vehicle is in position, the pilot should radio, “resume tension. ” The winch operator should insure the line did not snag or catch on the vehicle during the turn and then smoothly increase the braking force on the drum. The driver should accelerate to the appropriate vehicle speed for the tow.
Some pilots use the terms “all out” or “clear” for the resumption of tension. We are not particularly keen on those signals since occasionally there may be other towing operations in the area. If the tow crew overhears a transmission from another team, it could be particularly hazardous for the pilot.
Comprehensive Business Plan
General Background Paragliding as a sport first emerged in 1988. Since then, the field has evolved to phenomenal dimensions and achievements from several aspects:
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