Frag Out! Magazine
Issue link: https://fragout.uberflip.com/i/1000484
Jumps during the course are performed with Student parachutes; those are large (25-30 m2) canopies that feature low speed of descent, low maneuverability, and it is almost impossible to overdraw them. Theory is one, however, and practice is another thing. That is why it is important to check the behavior of the canopy at a properly high altitude, when we are holding the control cords (drawn downwards) too tightly. The canopy loses its load bearing capabilities, becomes unstable, and the speed of descent increases – it is the so-called overdrawing effect. It is harmless at high altitude, because we have plenty of time to react. It is particularly dangerous while landing. Instructors will not allow a student jumper without the suit, helmet, altimeter, and radio (used for one-side instructor - jumper communication) to get on board. After we jumped from the plane, we keep receiving instructions on our further moves, especially during landing. The radio is usually in the right pocket of the sleeve, at the height of the shoulder (when our hands are up throughout most of the fall, the radio positioned near our ear will ensure good audibility of communications) or hung on the neck, with a headset that is placed in the ear before the helmet is put on. Protective eyewear/ goggles are useful (in case of people who use lenses, they are a must) to provide unrestrained possibility of having your eyes open during the whole fall. I have already mentioned on several occasions the importance of meteorological conditions in case of jumps – I will remind you then once again by referring to places in which I had the opportunity to jump. Theoretically, jumps are permitted up to the wind speed of 6 m/s. Why such a value? Just look at the previous table presenting the basic parameters of training parachutes. If the wind speed changed to 10 m/s and the jumper positioned himself or herself according to the upwind technique, their advance velocity would be almost totally nullified by the speed of wind. Then, the landing of the jumper could last very long or during the fall the jumper would be moved not only away from the designated landing spot but also outside the area of the airport. Wind parameters can change rapidly during one's fall, which must be taken into consideration in case of any doubts. Probably the only worse thing is silence, because there are no conditions at all to decrease the speed of landing (you must then prepare yourself for a harder landing). If the cloud cover is quite low (required minimum is 1300-1500 m), it also can mess with our plans, especially when we are jumping in mountain areas. EXAMPLES OF TECHNICAL AND FALL PARAMETERS OF TRAINING PARACHUTES Mars 330 Mars 291 PD 260 Falcon 300 canopy area 330 feet 2 291 feet 2 260 feet 2 300 feet 2 number of load-bearing cords 20 20 20 20 fall speed 2,5-4 m/s 3-5,5 m/s about 5 m/s about 5 m/s perfection 2,5-3 3-5,5 ok. 4,5 ok. 4,5 max jumper's weight 115 kg 115 kg 117 kg 115 kg advance velocity max 10 m/s max 12 m/s ok 13 m/s max 12 m/s manufacturer Czech Republic Czech Republic USA USA AVIATION