Questionnaire for the theoretical part of education in skydiving. Aerodynamics

Transcription

1 1. The term of is related to air and motion. What happens when you move through the air? a) The friction of air particles along the body cause/ create a drag b) The higher the velocity is while moving through the air, the more drag is created c) The air becomes increasingly resistant and acts with force on the exposed surface 2. Which effect is caused by the airflow around a body with one of the following shapes? a) A drop shaped body has slight air drag b) A concave hemisphere (round reserve) has a big air drag c) A ram-air canopy profile is transforming the airflow into lift. It uses the effects of suction and pressure. 3. The lift which is developing along the profile of a ram-air canopy... a)...is composed of suck and pressure b)...always affects the center of gravity of the canopy c)...is always as big as the flight gravity d)...takes effect at the longitudinal axis of the jumper 4. The drag on the ram-air canopy is created by suction force and pressure force. In which ratio is the force distributed a) ½ suction, ½ pressure b) ⅓ suction, ⅔ pressure c) ⅓ suction, ⅓ pressure, ⅓ lift d) ⅔ suction, ⅓ pressure 5. Which characteristic of the ram-air canopy is specified by the term lift? a) The ascending of the canopy in a thermal b) The loading capacity of the canopy c) The pressure inside the canopy d) The opening tug, which rips the jumper up

2 6. The ram-air parachute gets its flight performance by means of motion in the air. Complete the gap text in the correct order! The descent is caused by... By means of... of the surface, the canopy starts flying forward and down That`s how... is created at the profile, which causes... at the ram-air canopy a) The adjustment - the airflow - the weight - the lift b) The airflow - the weight - the lift - the adjustment c) The weight - the adjustment - the airflow - the lift d) The lift - the weight - the airflow - the adjustment 7. What is the correct label for arrow # 1 in this illustration of a ram-air canopy? a) Drag b) Lift c) Airflow d) Gravity 8. What is the correct label for arrow # 2 in this illustration of a ram-air canopy? a) Drag b) Lift c) Airflow d) Weight

3 9. What is the correct label for arrow # 3 in this illustration of a ram-air canopy? a) Lift b) Airflow c) Drag d) Weight 10. What is the correct label for arrow # 4 in this illustration of a ram-air canopy? a) Airflow b) Ram pressure c) Lift d) Drag 11. What causes the lift on a ram-air canopy? a) A special elliptical profile b) A zero porosity fabric c) A wing profile (Airfoil) d) The stabilizers

4 12. Which are the beneficial characteristics of a ram-air parachute? a) It is steerable and it can be slowed down during landing via flaring b) By the flarability of the canopy, the PLF gets unnecessary c) Malfunctions are eliminated d) The ram-air canopy turns itself upwind automatically during landing 13. Which are the beneficial characteristics of ram-air parachutes? a) The good glide ratio, thats why bigger distances can be covered b) One can fly upwind related to the ground as long as the wind speed is not stronger than the forward speed of the canopy c) One can fly crosswind with a ram-air canopy but will be moved to the side related to the ground (crabbing) 14. What are the stabilizers at the outer ends of the canopy for? a) They are stabilizing the canopy during forward flight, similar to the fin at the hull of a sailing ship b) They are reducing the pressure compensation at the end cells between overflow and underflow and as a consequence they stabilize the canopy aerodynamically c) They maintain the stability of the construction of the canopy at the end cells, because it s the maximum applied load d) They are stabilizing the slider during opening 15. Where does the airflow create the biggest suction at the ram-air canopy? a) At the bottom side at the last ⅓ of the surface b) At the whole upper surface c) On top, right before the tear-off edge d) At the upper side at the first ⅓ of the surface 16. The ratio between span to chord on a ram-air, is called... a) Aspect ratio b) Ram pressure c) Apex ratio d) Glide ratio

5 17. On its flight through the air the ram-air canopy creates not only lift but also resistance forces (drag), which is reducing the total performance of flight. What are those resistance forces? a) Surface and shape resistance of the parachute b) Induced resistance (wake turbulence) and interferential resistance (superposed single resistances) c) Additional resistances (Pilot chute, bag, suspension lines, slider, risers, jumper, jumpers clothing) 18. The flight path forward and down results in an inclination angle compared with the horizon line in a side view. What is the name of the angle between the horizon and the flight path? a) Glide angle b) Angle of setting c) Angle of attack d) Mean Chord Line 19. The ration between descent and path of flight (without any wind influence) results in a value. What is the name of this value? a) Mean Chord Line b) Glide ratio c) Rate of descent d) Angle of setting 20. Due to the characteristic of the air, to naturally look for the lowest resistance or achieve pressure compensation, the highest airflow is at the middle cell and the lowest at the end cells, with a tendency to zero. Which statement is therefor correct? a) The ram pressure is the highest in the middle cell and the lowest in the end cells b) During flaring the lift is lost at the middle cell first c) That`s why the steering lines need to be attached on the total span of the canopy d) That`s why zero porosity (ZP) is better than F-111

6 21. The lift on a ram-air canopy is the best during straight forward flight, because... a)...the total air drag of the canopy and the gravity are exactly countervailing b)...the weight of the jumper is not influenced by an additional force (like gravity) c)...the airflow at the canopy is absolutely laminar 22. In practice, there`s a difference between a slow flight airfoil and a fast flight airfoil. Which are the characteristics of a fast flight airfoil? a) Big airfoil thickness, small aspect ratio, short suspension lines b) Big aspect ratio, small airfoil thickness, steep line trim c) Thin lines, zero porosity fabric, slider with Kill-lines d) Small aspect ratio, small airfoil thickness, micro lines 23. In practice, there`s a difference between a slow flight airfoil and a fast flight airfoil. Which are the characteristics of a fast slow airfoil? a) Big airfoil thickness, small aspect ratio, flat line trim b) Big aspect ratio, small airfoil thickness, steep line trim c) Thin lines, F-111 fabric, slider with Kill-lines d) Small aspect ratio, small airfoil thickness, micro lines 24. What is the difference between a fast flight airfoil and a slow flight airfoil on the ram-air canopy? a) The slim less curved shape with less drag b) Big even shape with the biggest thickness at the first ⅓ of the airfoil c) Stabilizers and less total surface to avoid drag d) Bigger parachute and shorter suspension lines 25. On a ram-air canopy, which of the following characteristics does a thick canopy airfoil have compared to a slim canopy airfoil at the same speed? The Airfoil has... a)...more drag, less lift b)...more drag, bigger lift c)...more drag, the same lift d)...the same drag, more lift

7 26. Where are fast flight airfoils used in practice? a) Reserve parachutes b) Accuracy landing parachutes c) Main parachutes 27. Where are slow flight airfoils usually used? a) Ram-air reserve parachutes b) Accuracy landing parachutes c) Canopy formation parachutes 28. During flaring the ram-air parachute, the angle of attack is getting bigger by changing in the mean chord line, in relationship to the airflow. Which statement is true? a) The canopy is slowed down by parallel pulling of both brake lines. This effect (Flare) can be used during landing b) This brake effect lasts for the time the canopy is still in forward movement with an airflow around its surface. When the forward movement stops it starts to sink rapidly c) Flying in brakes for a long amount of time can cause a stall 29. What`s the difference between the angle of setting and the angle of attack? a) There is no difference b) The jumper can change the angle of attack by using the brake lines. The angle of setting is given by the line trim of the manufacturer but can be changed by using the risers c) During canopy ride, one is referring to angle of attack, during landing to angle of setting d) By decreasing the angle of attack, the angle of setting is increasing 30. The effect of enhancing lift on the slowed down ram-air canopy is based on... a) Enlargement of descent b) Enlargement of the angle of attack c) Reduction of the angle of attack d) Reduction of drag

8 31. What happens during stalling? a) On the top, the airflow stops following the airfoil of the canopy and starts detaching at the trailing edge b) The resistance of wake turbulences is distorting the shape of the canopy c) The profile undercuts the airflow and could start folding under beginning at the leading edge 32. One talks about airflow disruption (stall) on the ram-air canopy, when... a)...the airflow stops following the surface on top of the airfoil b)...the airflow round the canopy is insufficient. The lift is no longer big enough to carry the weight of the jumper c)...the suction force and lift force are balanced d)...the ram pressure point is migrating to the trailing edge 33. How are the changes of aerodynamic proportions on the ram-air canopy during flight near the stall point? a) Even near the critical angle of attack (⅔ suction, ⅓ lift), the relationship between suction and lift remains the same b) The speed of the airflow on top of the airfoil slows down c) The airflow is no longer able to follow the curvature of the profile on top. This causes a detachment of the laminar airflow d) The airflow at the bottom of the profile is breaking off 34. Primarily, the stall point is depending on which parameters? a) The ratio between jumpers weight and canopy size, altitude of flight and velocity b) Weight during flight and glide ratio c) Relation between jumpers weight to canopy size and brake setting d) Glide ratio and brake setting

9 35. Which manner of flight is corresponding to a stall? a) Calm natural glide in full flight b) The part of the opening, when the slider still is at bottom skin of the canopy c) The parachute is collapsing by slowing down to much. It starts to loose its lift capabilities very rapidly d) The sudden pulling down of one brake line from full flight, followed by several line twists caused by the inertia of the jumper with the canopy 36. How do you flare your ram-air canopy during landing? a) By pulling down the brake lines parallel till 100% of the brake setting. If possible upwind and always wing leveled b) The pulling down of the brake lines should begin slowly and pick up speed incrementally (dynamic flare) c) If I feel the ground coming at me quickly, I flare quickly. If I feel the ground coming at me slowly, I flare slowly 37. Is it possible during breaking, that a canopy starts to fly backwards related to the ground? a) No, that`s impossible b) Yes, during flight upwind its possible to be drifted depending on the wind speed c) Yes, this happens always during too much break input d) This only possible in case of flaring with the front risers 38. A turn with the ram-air parachute can be induced by using the break lines or by using the front or rear risers. What happens in the process aerodynamically? a) Nothing. The total mass does not change and all parameters stay the same b) The canopy is rolling in turn. Thats why it depends wether I do the turn upwind or downwind c) By originating gravity, the weight of the jumper seem to increase and the canopy enhances its flight velocity. For this reason the decent increases d) By enhancing the speed of flight during the turn, the canopy creates more lift and starts ascending

10 39. What happens aerodynamically during steep spiral turns? (1) The centrifugal force is pushing the jumpers weight to the outside (Marygo-around-effect) (2) The parachute is pulled in a roll by the suspension lines (3) Due to the increasing descent, it is possible that the canopy starts stalling (4) Because the axis of lift is declined compared to the axis of gravity, the descent of a canopy increases dramatically during turns a) Answers 1 and 2 are correct b) Answers1, 2 and 4 are correct c) All answers are correct d) Answer 3 is correct 40. What happens with the ram-air canopy during aggressive steering movements, simultaneously and reciprocally? a) I am pumping the canopy to increase its performance b) Aerodynamically, the ram-air parachute is an unstable wing. It could build up force in swing leading to total loss of control (line twists) c) The steering lines could be torn off d) The cross ports inside the canopy ensure a good balance of ram pressure. The parachute is manufactured for maneuvers like that 41. Whats happens aerodynamically on the top skin of the ram-air parachute? a) The airflow follows the top skin of the canopy. The velocity of the airflow increases at the curvature of the airfoil and creates a lift. b) The molecules of air which are in direct contact with the surface of the parachute are physically in a state of stasis c) The layer between at top speed traveling airflow and the surface on top of the canopy is called laminar layer. This is the layer which creates the lift. 42. How can you identify if a canopy type and size fits your jumping experience? a) Its not a matter of experience, because all parachutes are the same b) I only need to look on the size of the canopy when it is elliptical c) Considering the wing load I can find the matching canopy type and size compared to my level of experience d) There is no limitation of size on zero porosity canopies caused on their performance

11 43. Which effects do excessive wing loadings have? a) The canopy has higher speeds in gliding and descending. Its much more aggressive and wrong steering inputs are unforgivable b) Its very good for inexperienced jumpers to train their reactions c) Excessing wing loading is used in strong winds. The landing and touch down gets better d) There is no excessing wing loading. The canopy stabilizes itself aerodynamically and causes the same lift and the same speed of flight 44. The most uplift is created on the top skin of the ram-air canopy (⅔ suction). Which statement referring to airflow is correct? a) The airflow on top of the ram-air canopy is exactly the same on all canopies so it is irrelevant b) The impermeability for air on zero porosity material makes this material ineffective for the top skin of parachutes. Thats why hybrid canopies are build with F-111 at the top skin and zero porosity at the bottom skin c) The slick surface of the zero porosity material is worse for the airflow compared too F-111 d) The diffusion of air through the F-111 material at the top skin disturbs the consistent airflow and therefor the creation of lift. Thats why a F-111 canopy has less flight performance than an equal loaded zero porosity one 45. If a canopy is flown in full flight and down wind, it will be taken very far over the ground. Which statement is correct? a) It has a big glide angle b) It has a small glide angle c) It has a big angle of attack d) It has a small glide ratio 46. A skydiver is flying upwind with his canopy. If he does a 180 turn and starts flying down wind... a)...the airspeed increases b)...the airspeed decreases c)...the airspeed does not change d)...he airflow peals off

12 47. How is the point called, when the airflow is pealing off the top skin of the wing? a) Peal off point b) Stall point c) Pressure point d) Flare point 48. Which same sized ram-air canopy is producing more flight performance by creating more lift? (1) Parachutes with a bigger aspect ratio compared to a smaller aspect ratio (2) Elliptical or parachutes chopped at the trailing edge (tapered) compared to rectangular ones (3) Zero porosity canopies compared to F-111 canopies (4) Fast flight airfoils compared to slow flight airfoils a) Only answer 1 is correct b) Only answer 3 is correct c) All answers are correct, besides How do you manage, that your canopy glides further with tailwind? a) Pull the front risers b) Cruising cross wind by using the drift c) Look for thermals and using the upwinds d) Slowing the canopy slightly down by using brakes 50. If the upwind is that strong, that your canopy does not have any forward movement over ground, it is impossible to create more forward speed! Is this statement correct? a) No. Its possible to create small forward movement by pulling down the front risers equally, thus this also creates a faster descent b) Yes, thats correct c) There is the possibility of a 360 turn to create more velocity and speed related to the ground d) This statement is correct only when I am using a slow flight airfoil

13 51. What should a jumper keep in mind when he is flying from a calm advection into a downdraft? a) Improvement of the glide angle b) Increase of forward speed c) Increasing lift d) Increasing descent and turbulences 52. In final approach, shortly before touch down, the wind changes due to additional influences. There are changes happening concerning direction and force of the wind caused by ground friction, turbulences caused by thermal influences and shape of the landscape. The canopy wants to break out of its landing direction when flown upwind. What do you need to keep in mind concerning the final approach? a) Nothing. This only concerns flyers of high performance canopies. b) You need to flare the cells unsymmetrically during landing c) During deployment the body needs to be turned upwind. This prevents a twisted opening compared to landing direction d) The parachute needs to be kept on track during final approach, because it does not stay upwind on its own 53. What happens, if you follow another canopy with low distance on the same track and same altitude? a) Caused by wake turbulences my own aerodynamics could be disturbed and I will get flight stability problems b) The turbulences are pumping more air in my canopy which creates more lift c) I am flying in the lee of another canopy and my forward speed increases d) A small distance makes no odds. It is only a problem if all the canopies have different landing directions and their flight paths cross 54. Complete the sentence: In case of flying upwind with a ram-air canopy, the inclination of the flight path related to the horizon... a)...is flatter than with zero wind b)...is steeper than with zero wind c)...is level d)...is the same like zero wind

14 55. Complete the sentence: In case of flying a ram-air canopy into wind, the inclination of the flight path related to the horizon... a)...is flatter than with zero wind b)...is steeper than with zero wind c)...is level d)...is the same like zero wind 56. Complete the sentence: In case of flying a ram-air canopy cross wind, the inclination of the flight path related to the horizon...! a)...is flatter than with zero wind b)...is steeper than with zero wind c)...is level d)...is the same like zero wind 57. Which flight characteristics can you expect by a fast flying airfoil at a normal landing with 3-5 m/s Wind? a) The canopy keeps its speed and touches down b) The canopy keeps its glide ratio, but slows down in speed because of the flare c) The canopy flattens out in a flat path and glides parallel to the ground d) The canopy glides and touches down after stalling 58. Which flight characteristics can you expect by a slow flying airfoil at a normal landing with 3-5 m/s Wind? a) The canopy keeps its speed and touches down b) The canopy keeps its glide ratio, but slows down in speed because of the flare c) The canopy flattens out in a flat path and glides parallel to the ground d) The canopy swoops and touches down after stalling 59. Why should you never abruptly break a ram-air canopy on landing? a) You will swing far forward if you break abruptly b) Because of the pendulum effect the angle of attack increases additionally to " breaking c) The canopy could stall dynamically, thus its not fully braked

15 60. Which flight characteristics can you expect from a ram-air canopy while stalling! during landing and what else could occur? a) I could pendulum forward and fall backwards seriously injuring my back b) A stall with all its consequences is the aim of every landing c) Stalling on landing isn t possible because of the closeness to the ground and the ground effect. There is no consequence d) Stalling ends in an absolute flare, which ends in a climb of the canopy 61. How do you fly a fast turn with a ram-air canopy? a) Fully pulling down one break line rapidly b) Parallel pulling down both break lines from full flight and quickly releasing the "opposite one c) Pulling down one break line at suitable speed to get a fluid movement of the "canopy. The jumpers weight is suspended ballistically d) The speed of the turn depends on the speed the toggle is pulled, not from the "distance. This is why fast pulling results in fast turning 62. Whats the behavior of ram-air canopies in fast turns? (1) They lose much altitude (2) They are very good to gain speed before landing (3) They are very steep during a turn (4) The canopy dives very steep at the start of the turn a) Answer 1,3 and 4 are correct b) Answer 2 and 3 are correct c) Answer 3 is correct 63. Which of the following canopies will sink at the highest rate during a turn? a) A small elliptical ram-air canopy b) A 240 sqft 7-cell ram-air canopy c) A round reserve canopy d) A relatively big F-111 reserve canopy

16 64. Why are Hook-turns more dangerous than normal landings? a) The dynamic of a hook-turn, close to the ground, needs much experience in order to be controlled b) This extreme maneuver can cause serious landing injuries c) The flying and sinking speed are very high so there is no room for misjudgments 65. What do you need to know about doing hook-turns? a) You need a license to fly a hook-turn b) A hook-turn can only be done with a fast canopy c) Every jumper should be able to do one, so the sport looks spectacular for spectators d) You loose much altitude during a turn leading to misjudgments, which can result in serious injuries and death 66. What means indirect steering at a ram-air canopy? a) Flying a turn by releasing the opposite toggle from half breaks b) If you are told how to steer the canopy over the radio c) If you pursue the flight direction in a way that the natural drift is steering you in the requested direction d) If you do CRW (Canopy Relative Work) and one jumper steers for another 67. What do you understand by flying figure eights and how do you do them? (1) Flying a flight path that looks like an eight over the ground (2) A maneuver always bringing you back to the same point over the ground, used to loose altitude (3) A maneuver you can use when you fly your finals into wind to improve your spot (4) Figure eights should be flown with eyes on the target. Fly them smooth and controlled that there is no danger of colliding with other jumpers a) Answer 1 is correct b) All answers are correct c) Answer 3 and 4 are correct d) Answers 2, 3 and 4 are correct

17 68. When can you use indirect steering on a ram-air canopy? a) Flying your final approach in half breaks to keep the canopy on track b) To turn near to the ground, if losing altitude is acceptable and not dangerous c) To fly figure eights to loose altitude if you set up too high for your final approach 69. How do you fly a slow turn with a ram-air canopy? a) With minimal steering inputs in turning direction b) Always with rear risers c) With front risers and you have to let go of the toggles d) Loosen the opposite leg strap during flight to fly a slow turn by weight shifting 70. How do you fly a flat turn with minimal loss of altitude? a) That is impossible b) You use breaks (50-75%) and lift up the opposite one slowly c) Turns with less altitude loss aren t good because the ram pressure gets to low and the canopy collapses d) You need a slow flight airfoil for turns with less altitude loss 71. Relating to the planned target, from which direction on the wind line is the range of a ram-air parachute over the ground the biggest and for the canopy flight the most flexible? a) The wind line always needs to be in front of me b) The wind line can not be used during canopy ride because it is invisible c) From the direction where it is possible to reach the final approach downwind. That means, one always needs to position oneself in a manner, that it is possible to reach the final upwind approach to the target by a canopy ride down wind or crosswind d) One should always be upwind on the wind line for that the target is in front of the jumper during the whole canopy ride

18 72. What do you have to watch out for if you fly in crosswind a) Crosswind has no influence on the canopy ride b) The drift to the side needs constant correction to stay on track c) One has to counter steer with rear risers d) During stopping the crosswind has no influence 73. What do you have to watch out for, if your flying in strong cross wind to the landing area? a) The crosswind can be so strong that it is impossible to reach my landing area b) Constant correcting needs my full attention c) The unsymmetrical position of the toggles is very unusual 74. You can steer a ram-air canopy with the rear risers if the break lines are broken. What do you need to watch out for? a) During flaring you can stall a canopy very quickly b) The way you need to pull down the rear risers in order to turn or flare isn t big because of the huge change in the airfoil c) The flight behavior is very abruptly; its recommended to do a PLF for landing 75. Which statement about flying turns with risers is correct? a) The fastest turn result from using the front risers b) The tightest turn can be achieved by using the rear risers c) The most extreme turns are carried out using front and rear risers in opposite directions

19 76. What is the effect of steering and breaking with the risers? (1) One is changing the manufactures angle of setting (2) One is changing the trim during steering. It is not guaranteed that every canopy profile stays stable (3) One is risking an overload of single cells during only pulling the loaded ribs" (4) One is putting the canopy profile crosswise and changes the airfoil meant by the manufacturer. This can have very aggressive effects on the flight characteristics a) Answers 1, 2 and 4 are correct b) Answers 1, 2 and 3 are correct c) All answers are correct d) Answers 1, 3 and 4 are correct 77. Which of the following statements about ram-air canopies is correct? a) The driving force of the canopy is the gravity, effecting the mass of the jumper b) Because of the angel of attack the gravity force is transferred onto the wing, whereby the wing is enabled to glide c) By gliding, the the canopy causes an air flow, which creates ram pressure. The ram pressure has to be bigger than the weight pressure of the jumper 78. Which statement about openings of ram-air canopies is correct? a) The opening shock is a bit harder without slider, but therefor faster. This is useful for reserves and the reason they have short opening distances. b) To fill ram-air canopies with enough air a certain amount of time is required and therefor sufficient altitude c) The opening distance of a ram-air canopy is not depending on the packing manner, its always the same d) Minimal deployment altitude is calculated by using the opening distance of the main and the reserve canopy adding up both

20 79. Which statement concerning flying with ram-air canopies is correct? a) I can always learn something about steering a canopy. Flying defensively and planing ahead is the safest way of flying b) In turbulence my wing flies more stable in half breaks c) I have to be awake and concentrate in air traffic to know where I am, where the others are and where I want to go 80. Which statement about landing a canopy is correct? a) Naturally everyone lands in the same direction every time. Therefor it is not dangerous at all to land close together and parallel at the same time for many jumpers b) I should not be distracted by obstacles and dangerous spots and change my "landing direction" c) Many jumpers are landing in the landing area at the same time and very close, thus it is dangerous to not pay attention d) I do not need to pay attention to landing jumpers after I landed because they have "a better over view from the sky anyway 81. Which statement about planning your landing is correct? a) It is better to decide early to land in an alternative free landing area, than to continue with the planned landing pattern and get in trouble (Obstacles, low turns, canopy collisions) b) I continue to correct my flight path in air traffic on the way to my target, because in aviation the person who finishes their plan has the right of way c) I always try to be the lowest of the load under canopy, to have the most airspace for me and therefor no need to arrange in order d) I try everything necessary (Hook-turns, Cutaways, ignoring the wind) to reach the planned target, otherwise I will be criticized and get negative attention

21 82. If an open canopy flies through the air, there is resistance of air particles. Which statement is correct? a) The canopy has to fly normal after opening. I can test this with a steering test and by looking at the canopy b) A ram-air canopy should never change it s shape without the pilots input. If so I have a partial or major opening hazard or even a malfunction c) Imprudent steering can unleash great forces, which can be dangerous to me and others