Cylinders in Kong's hand varied in size from a ¾-in. bore by 2-in. stroke for his fingers, to those with 4-in. bores and 3-ft strokes to flex his 4½-ft diameter, 20-ft-long arms. Remotely controlling these cylinders was to present an equally serious challenge.

Whatever made Glen Robinson, who is chief of special effects in MGM Studios in Culver City, think that he could do what a high-priced mechanical engineering firm had said would take three times as long and much more money to accomplish?

The first thought was to put a special effects man in an ape suit (to be used for some location shots) and outfit him with potentiometers that would be wired to proportional valves controlling the big ape's cylinders. As the actor would move inside the suit, the big Kong would duplicate his movements exactly.

But suppose that while Jessica Lange was in the big hand, the man in the suit sneezed and flung his hand up toward his nose? "We could just imagine the big ape doing the same," said Robinson, "sending the female star flying over his shoulder and into the rafters of the stage!"

They then decided to use manual remote control boxes, one for each cylinder, manned by carefully rehearsed operators. However, there were still problems.

Applying a variable electrical input signal to a proportional control valve controls only cylinder speed, not its final position. In addition, the 30% deadband in the standard proportional control valves they were using caused a delay before the valve spool shifted far enough to actuate the cylinder. This delay meant that the ape would not respond quickly enough when director John Guillermin called for a certain action, and the scene would be ruined.

Master special effects man puts life in King Kong

"After forty or so years of using hydraulics for all kinds of crazy special effects, you can get a pretty good feel for what you can do," Robinson said. "At MGM, we began using hydraulics back in 1934, when we filmed Broadway Melody."
 

Among the jobs he's done hydraulically was that of making it possible for city-bred extras to sweep the backbreaking oars of Roman slave galleon.

"The Roman Empire could have ruled the seas if they'd had what we cooked up in filming Ben Hur - the first slave galleons ever rowed with hydraulic assists on every oar, and hydraulics keeping the oars sweeping in perfect unison!" laughs Robinson.

In the photo, Robinson holds a jointed frame for massive Kong finger, and indicates location of using actuating hydraulic cylinder. Cylinders on the desk show different sizes needed for various parts of Kong's anatomy.

Editor's Note: As this article was being written, we learned that the special effects in King Kong and Logan's Run (which was also shot at MGM) were voted Special Acheivement Awards by the Academy of Motion Picture Arts and Sciences. This makes Robinson eligible for his third Oscar. He previously won for special effects in Hindenburg and Earthquake.