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                                                                   Javelin Aerodynamics                     .

 

    Angles

 

 

 

 

 

    Angle of Release

Quite straightforward, this is the angle of the javelin though its length and that of the ground at the moment it leaves the hand (as picture below). Different angles of release are needed dependant on the weather conditions and model of Javelin :-

 

 

 

 

 

Angle of Attack
This angle is a bit more complicated and it is the difference between the angle at the time of release (a) and the actual flight angle after release (b).:-
 

                                       

                                        (a)                                                                                        (b)

 

a) Javelin release outside of the arc = Positive                           b) Javelin released inside of the arc = negative

If you imagine that the athlete is approaching the release with the javelin pointing as above (a) and then at release the javelin  is release as at (b) (the athlete pulling down on the grip whilst releasing it) then the difference between these two is the Angle of attack.( A negative angle is preferable with certain models of Javelin ie, OTE / Nemeth). The ideal is to try and get as small an angle as possible, ie. this is then "clean through the point"

 

 

 

 

 

 

Angle of Incidence
This angle is often confused with the above Angle of Attack but is entirely different. This angle is that of the javelin to that of the airflow in front of it.:-

   

 

 

 

The javelins trajectory during its flight will hopefully follow the path of an arc but because the javelin is straight and unbending the javelin will tangent the arc as above and the airflow that meets it will alter during its entire flight. The angle of Incidence is the angle of the javelin to this airflow. This angle determines the "lift" and drag of the javelin and will alter with varying wind conditions hence low release angle into a headwind will give lift.

 

 

 

 

 

 

 

 

 

Other Factors

The "pitching moment" is the term given to describe the actual moment in flight when the javelin starts to tip over for its descent due to the effect of the airflow hitting the shaft of the javelin. This is determined during manufacture by altering the Cg (centre of gravity) and also the diameter of the shaft from the point to the grip and the width of the tail after the grip. The wider the shaft and point before the grip and thinner the tail the longer the distance rating. These javelins will usually land flat and require smaller release angles, ie. OTE Tailwind and Nemeth as mentioned above.

Tighter specifications by the IAAF of the rules for javelin manufacture mean that the "distance ratings" that are applied to javelins in modern times denote the quality of build and not the distance of its flight characteristics

 

Rotation

The rotation of the javelin during flight will increase it stability and lift and that is why more throwers are turning to the 2nd finger and thumb grip which gives the javelin a rifling effect off the second finger (which sits of the shaft itself) as it leaves the hand (also known as Finnish grip). This gives the javelin added stability in flight and for a right-handed thrower the best type of wind is one from the front right hand sector as he throws. The opposite applies to the lefty. This is the best grip technically but it is all down to choice of the athlete as to which grip they feel most comfortable with.