The Alien's Tail

Leading from

Creating the Alien
and
David Watling 

a) An intricate mechanism
The tail built by David Watling, attached separately.  He found it much more difficult than the head, as it was about seven feet long and had to be operated without any external wires. He resolved the problem by examining the way in which a real tail operated and then simplifying that in order to produce the limited number of movements required. They constructed it as a real vertebra replacing the muscles with wires, and there were six hundred separate parts involved. When Ridley witness it, it has been screwed down onto a steel plate because it was very heavy, but when it moved it could be controlled incredibly well, and was a strange site to see. When it was finished it was attached to a molded fiberglass glass plate which was firmly anchored inside the costume.

b) "That will never work"
 Unfortunately the demonstrations in the workshop every week showed Giger that it wasn't working properly and Ivor could see how clear that was as well.  Every week there was a demonstration, every time David Watling used bigger handles and levers and wanted this tail to move, and it went mmmm-puff, and then it collapsed and was torn, and the Watling nearly burst into tears and then he wants to make them wait until further demonstration, and this went on week after week . Gordon Carroll was soon in despair. They thought that if Rambaldi were to do it, it would work. He was there watching and he said "That will never work", his view was that the mechanism in the tail was too heavy and would never work properly and if he had made it himself he would have made it with lightweight elements,

plan for the tail harness (source (source: http://www.proparchives.com/))

The Alien's tail 

1. Cinefex:An articulated tail, built by David Watling, attached separately. "The tail was more difficult than the head," Watling said " as it was about seven feet long and had to operate without any external wires. The problem was resolved by examining the way in which a real tail operates and then simplifying the construction in order to produce the limited number of movements required. Basically, we used a real vertebrate construction replacing the muscles with wires. All together, there were more than six hundred separate parts. When it was finished, it was attached to a molded fiberglass plate which was firmly anchored inside the costume" (Alien The Special Effects, p31, Titan Books,  and Cinefex 1)
2. Giger (30th August 1978, Shepperton Studios): Meanwhile, Shirley, Patty and Butler have got the Alien's two-meter (six foot) tail ready. The engineer is given the job of bringing it to life. There's a demonstration in his workshop every week, which always shows that it isn't working yet. I believe Rambaldi when he says that the mechanism in the tail is too heavy and will never work properly (Giger's Alien, p70)
3. Giger: When the tail didn't work anyway, did it. The tail, it unfortunately wasn't given to Rambaldi to do, but was left over to the other one, and  every time he showed us that he can't do it. Every week there was a demonstration, every time he used bigger handles and levers and wanted this tail to move, and it went mmmm-puff, and then it collapsed and was torn, and the other one nearly burst into tears and then he put us off until further demonstration, and that went on week after week and Gordon Carroll was in despair, and we thought, hey, that would be brilliant if Rambaldi would do that and Rambaldi was there watching too and he said " that will never work" Well it was simply much too heavy, it simply could not work, and Rambaldi said he would have made it with very lightweight elements and that kind of thing, Well , he was really good and he demonstrated it too, he got some Oscars didn't he, well yeah. (report from raw Giger interview for Alien Evolution)
4. Fantastic Films: And the tail
   
   
   Ridley Scott: The same thing on the tail. When it was constructed, we screwed it to a table top for a demonstration. It looked like the tentacle of a massive octopus. It was screwed down onto a steel plate because it was bloody heavy, but when it moved, it could be controlled incredibly well. It was very strange. (Fantastic Film #12, p22)
5. Ivor Powell: l think we had one or two attempts at tails and heads with various people at Shepperton. We had this elaborate mechanical tail that never really quite worked. (The Making of Alien, 1:28:54)