Slide 16 of 158
The hairpin turn was as ideal a set-up for an ambush as any potential assassin could hope for.(4) The Committee was not going to let a chance like this go by. The attack was to be carried out by a team of ten men, including four gunmen, each seconded by an assistant who would be responsible for their protection, evacuation, and radio liaison, and who would retrieve the shells. The ninth man would serve as a central radio operator, and the tenth was to create a last-minute diversion to enable the gunmen to get into position.(5)
The layout of the site (see map) determined an optimum firing zone within which the shots would have to be concentrated, but a target riding in a moving vehicle raised a number of special problems. The first concerned the speed of the vehicle. The Presidential car was watched and timed during Kennedy's trips in September, and its minimum speed was estimated at 10 miles an hour. The sharp turn into Elm Street was expected to slow it down even more, but as Dealey Plaza marked the end of the motorcade and the approach to the freeway, the driver would probably accelerate as he came out of the turn. The estimate was therefore cautiously revised to 15 miles an hour.(6)
Fifteen miles an hour is the equivalent of approximately 22 feet per second. That is extremely slow for a car, but extremely fast for a gunman, particularly if he placed in a perpendicular or even a lateral position. The positions of the gunmen were determined with this in mind. The best possible position for an ambush of this sort (when neither explosives nor bazookas or other powerful weapons are used) is in front of and perpendicular to the car. The layout of Dealey Plaza offered several possibilities. The gunman in position no. 1 would have the car coming straight towards him, on a level with him, as it came out of the turn 400 feet away. This position offered a wide firing angle and the possibility of shooting at the President up to a very close range (approximately 100 feet). It seemed so ideal that it was decided to station another gunman, no. 2, beyond no. 1 and close to the railroad overpass. Both would be firing from approximately the same angle. The other two gunmen, 3 and 4, occupied less favorable positions. They could not fire at the President and hope to hit him until a precise instant determined by a number of different factors.
The first was the obstacle presented by the two Secret Service men who habitually rode on the back bumper of the President's car.(7) The second was the fact that the shots of the four gunmen must be carefully synchronized. After studying these factors and others (distances and angles), the organizers delimited an exact firing zone 60 feet long which took into account the distance of each gunman from his target and the trajectory of his bullet, and which offered the maximum chances for success (see map).
Accuracy was, of course, essential. The gunmen were chosen for their marksmanship, and they were provided with excellent weapons.(8) But they had to aim at the President's head, and they had to be sure to kill him.(9) No plans were made for a second round of fire. It was assumed that the first shots would set off instantaneous reactions. Roy Kellerman, in the front seat of the President's car, would throw himself over Kennedy. The President himself might collapse or drop to the floor of the car. In a fraction of a second the driver could accelerate and the car would roar out of sight.