RUNWAY TRIALS AT RAF TAIN [Main Title]
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- Title: RUNWAY TRIALS AT RAF TAIN [Main Title]
- Film Number: AMY 580
- Other titles:
- Summary: A film record of the events staged to incapacitate an airfield runway by bombing, and the effort required to repair the damage. The main purpose of this film is to supplement the records made by the official observers. The ability to run the film in slow motion can also facilitate the interpretation of the explosions.
- Description: A film record of the events staged to incapacitate an airfield runway by bombing, and the effort required to repair the damage. The main purpose of this film is to supplement the records made by the official observers. The ability to run the film in slow motion can also facilitate the interpretation of the explosions. Information was required to determine the depth of most effective detonation which would create the maximum repair problem. In addition, basic information was needed in order to calculate the re-attack cycle, make recommendations for attacking airfield runways to assess the repair problem and determine the engineering effort required to repair the damage. The first part of the film deals with the preliminary work involved and shows the excavation work, the preparation and placement of bombs, the detonation and detailed information thus obtained.” The film cuts to RAF Tain where personnel are marking out the bomb locations at 100 metre intervals along the runway, followed by the drilling of the vertical shafts. With the aid of close up photography, the commentator lists the types of bombs available, choice dependant on the degree of damage required. The bombs are triggered by an electrical detonator placed in the base of the bomb prior to lowering it down the shaft. To contain the blast for maximum damage, the bomb must fit tightly within the shaft, which is back filled and tamped down. During 2nd June 1954, Senior personnel from a wide variety of Trades within the three Armed Forces gathered at RAF Tain to observe a succession of seven explosions. A few days later, the same personnel watched as the damage sustained to the runway was repaired. Film cuts to close up of the blasting box and the ‘Fire’ knob, and then proceeds to record each detonation. During 2nd June 1954, Senior personnel from a wide variety of Trades within the three Armed Forces gathered at RAF Tain to observe a succession of seven explosions. A few days later, the same personnel watched as the damage sustained to the runway was repaired. Film cuts to close up of the blasting box and the ‘Fire’ knob, and then proceeds to record each detonation. First detonation: 500lb at 10 feet depth. Produced the deepest crater. Sappers seen measuring the dimensions of the crater. Camera pans over the area revealing large chunks of concrete and tarmac. Commentator gives further details. Ground water ingress a few hours after detonation. Second detonation: 500lb at 12 feet depth. Different aspect from all the other detonations. Greater proportion of fall- back into the crater. Commentator gives further details. Sappers with tape measures and three theodolites survey the crater. Third detonation: 500lb at 14 feet depth. Camera pans over the area showing cracks in the tarmac surface adjacent to the large crater. Huge piles of debris/soil. Personnel walking in and around the crater. Sappers taking measurements as before. Fourth detonation: 1000lb at 10 feet depth. Clouds of debris fly upwards, large volume of dust seen. Personnel at edge of crater give scale to the film: crater is ‘several personnel’ deep. Debris has fallen few hundred ft. away. A Sapper descends the crater by rope. Fifth detonation: 1000lb at 15 feet depth. Produced the largest crater of all, and the greatest volume of debris outside/around the crater rim. Interest shown by senior officers from the RAF, Navy and Army, seen clambering about. Sappers taking measurements. Impressive amount of damage. Large cracks in tarmac surface seen. Sixth detonation: 1000lb at 20 feet depth. Comparison made with the fifth detonation. Ground water in bottom of the crater. Seventh detonation: 1000lb at 25ft. Some debris ejected but sub-surface heaving is very extensive. Commentator quotes dimensions made by the Sappers. The camera pulls back to give an overall view of the debris surrounding the crater. An aerial view of the whole test site is filmed from a Navy helicopter. Reel two: “Part 2. Engineer exercise on repairs”. The object of the exercise is to determine the most appropriate method for the rapid repair of damaged runways. The task is considered in three main stages. “1 - Filling and compacting the crater. 2 - Reconstructing the pavement. 3 - Clearing the site”. Extensive use is made of a series of animated diagrams that help the viewer to understand the accompanying commentary. Film opens to a sequence of diagrams that illustrate the nature of the problem: a typical crater comprises, from the bottom: water, fall back material, packed soil in the sides, heaved slabs around the rim and debris on the surface both adjacent to the rim and well away from it. The crater is filled with debris from the heaved lips (i.e. of the crater) using heavy and light bulldozers to shift and compact it by running over the shifted debris. Heaved concrete slabs are broken up mechanically or with explosives and removed using a Router. A heavy duty roller compacts the debris further completing the sub-grade repair. The film cuts to the actual process explained in the diagrams underway. A variety of bulldozers, large and small, the Router, heavy rollers, air compressors, vibrators and hand tools are seen in action. The fragmentation of large concrete slabs is a major impediment, and the use of plastic explosive is often necessary when impacts by pneumatic tools or bulldozer blades fail. Smaller items of hard debris are successfully reduced with a bulldozer pulling a medium size router with several large ‘teeth’. After grading and compaction, the subgrade is ready for the laying of the hardcore base. “Reconstructing the pavement”. Another series of animated diagrams help the viewer to understand the accompanying commentary. Film cuts to a series of tipper trucks depositing the 2/3 inch diameter hardcore onto the subgrade surface, and is levelled by hand if a motorised grader is unavailable. A five or ten ton roller compacts the hardcore, followed by the spraying of bitumen at a rate of 11/2 gallons per square yard. This stage is labour intensive job: Film shows the work in progress. Finally, chippings are added as the final surface dressing. “Clearing the site”. Camera shows the repaired runway and the large volume of material remaining to be removed from the site. An overloader is used to drop the material into a series of trucks, and the excess debris driven away. The trials complete, the commentator observes the repair of runways is beyond the skill of unqualified personnel on a station, and requires professional help from trained RAF maintenance units using the appropriate plant. The trials have revealed that for the overall task at Tain, an RAF engineering team of 70 personnel required 14 hours, alternatively an 600 personnel unskilled team, 25 hours to complete the task. Other factors, the local geology is but one, are taken into consideration in the film. The camera shows the variety of equipment required by the different teams, the RAF Engineering team employing a much greater selection of heavy mechanical plant. The film closes as a Meteor takes off from the repaired runway, flies low over the camera and disappears into the distance.
- Alternative Title:
- Colour: B&W
- Digitised:
- Object_Number: AMY 580
- Sound: Sound
- Access Conditions:
- Featured Period:
- Production Date: 1954
- Production Country: GB
- Production Details: ROYAL AIR FORCE (Production sponsor)
- Personalities, Units and Organisations:
- Keywords:
- Physical Characteristics: Colour format: B&W Sound format: Sound
- Technical Details: Format: 16mm Number of items/reels/tapes: 2 Length: 1176ft
- HD Media:
- Link to IWM Collections page:
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