RAF Station Runways
Main Airfield Site consisted of:
- Perimeter Track, with Dispersals
- 3 (Interlocking A Shape) Runways
- Hangars
- Technical / Administrative Site
- Watch Office (Control Tower)
The Specifications set by the British Air Ministry in August 1942 called for 3 Converging Strips, each containing a Concrete Runway optimally placed – if practicable at the Site – at 60°–angles to each other in a Triangular pattern. The Longest Strip was designated the Main Strip and aligned Southwest to Northeast wherever possible, this being chosen to allow Aircraft to Takeoff & Land into the Prevailing Wind. The other 2-Runways were to allow Safe Takeoff & Landing from either end when the Wind was Blowing from other Directions. The Primary consideration was for Operational Safety for any type of Aircraft then in Operation or under Development.
The Runways were connected by Taxiways called a Perimeter Track (Peri-track), of a standard width of 50-ft (15M). However, certain Stations that were designated to be Fighter Bases sometimes had a narrower Perimeter Track, such as RAF Coltishall, whose Peri-Tracks measured 40-ft (12M) across. A 30-ft (9.1M) area was cleared & levelled on either side of the Perimeter Track. Class-A Specifications for Taxiways set a minimum Curve radius of 150-ft (46M) measured from the Centreline for Angles greater than 60° & 200-ft (61M) for Angles less than 60°. Perimeter Track Gradients could not exceed 1 in 40 in any Direction & no Building could be placed closer than 150-ft (46M) from the edge of the Track.
Areas called Hardstands were placed along the Perimeter Track, made of Concrete, with their Centres at least 150-ft (46M) from the edge of the Track & the edges of each Hardstand separated from each other & from the Funnels by a minimum of 150-ft (46M). The purpose of the Hardstands was to allow Aircraft to be Dispersed some distance from each other so that an Air- Attack on the Airfield would be less likely to Destroy all the Aircraft at once. Dispersal also minimised the chance of Collateral Damage to other Aircraft should an Accident occur whilst Bombing-up. Hardstands were either of the Frying-Pan or Spectacle Loop Type, with the Spectacle Type being the easiest in which to Manoeuvre Aircraft.
The Strips were 600-ft (180M) in Width, cleared, graded & surfaced with Turf. A Concrete Runway 150-ft (46M) in Width was Centred on the Strip, with a Length of at least 2,000-yds (1,800M) for the Main Strip & at least 1,400-yds (1,300M) for the Secondary Strips. On each Side of the Strip the Field was cleared of Obstructions & Levelled an additional 300-ft (91M). Gradients for the Strips were a Maximum 1 in 80 Longitudinally & 1 in 60 Transversely. In addition, an area at the End of each Runway was cleared of Obstructions at an angle of 15° Outward from each side on a rising imaginary Plane of 1 in 50 to provide a Flightway called a Funnel.
There are 360° on a Compass Rose. Runway Numbers are determined by rounding the Compass Bearing of 1-Runway end to the nearest 10° & truncating the last Digit, meaning Runways are Numbered ranging from 1-36. The opposite end of the Runway always differs by 180°, so it’s numbered 18 Higher or Lower. For example, Runway 9-27 is Oriented East-West. You might be thinking that the numbers on this Diagram are backwards. On a handheld Compass, South is 180° (so 18 in Runway Terms) & West is 270° (27). But the “W” is numbered 9 because the Runway Number is connected to the Direction the Plane is Travelling. So if you’re on Runway 9, then you’re Heading East (90° on a Compass). Runway 36 means you’re moving North & so on. Most Runways can typically be used in either Direction, depending on prevailing Winds. Furthermore, each Runway End is identified separately. Therefore, an Aircraft taking off Easterly on Runway 9-27 would be considered to be utilising Runway 9 for Departure.
The material needs for Building Runways suitable for Heavy Bombers were approximately 18,000-Tons of Dry Cement & 90,000-Tons of Aggregate. Expected stress factors of 2,000-lbs per sq in led to Runway Thicknesses of 6/9-ins of Concrete Slab Laid on a Hardcore Base, covered with a layer of Asphalt. In areas where there was no natural Rock, such as East Anglia, Stone had to be Imported for the Hardcore. Up to 6-Trains ran Daily from London to East Anglia carrying Rubble from Destroyed Buildings in Luftwaffe Raids. This material was used as Hardcore for the Airfields.
Class-A Airfields were also characterised by Standardised Technical Site Requirements for Repair, Maintenance & Storage of Aircraft. Two T2-Type Metal Hangars (240-ft long by 115-ft wide by 29-ft high) were the Standard for most Airfields, although a few pre-1942 Bases had 3-T2 Hangars & Thurleigh had 4. Three Bases (Chelveston, Molesworth & Polebrook) also had a J-Type Brick-&-Metal Hangar (300-ft x 151-ft) in addition to a Pair of T2’s & Bassingbourn, which had been a pre-war RAF Bomber Station, had 4 C-Type Brick Hangars measuring 300 x 152-ft.
The most successful of the Hangers was the T2. These Metal Hangars became the Standard Temporary Hangar for the RAF during WW2 & over 900 were Built after a Development Period of 2-yrs. Examples survive around Britain, such as at Desborough in Northants. The Airfield Expansion Period, from 1934-39, led to the need for a new Permanent Hangar for RAF Airfields, catering for the need to house Larger Aircraft. This Hangar became known as the Type-C and allowed Aircraft Manufacturers to produce Aircraft with a Wingspan of over 100ft. The Steel Structures initially had Walls Clad with Brick, part of an effort to be in keeping with other Buildings & the surrounding Countryside. This was later changed to Reinforced Concrete for increased protection from Bombing. Type-C Hangars were built at almost every early Expansion Period Airfield with examples surviving at Airfields around Britain, such as at Hemswell in Lincolnshire.
Type-J & Type-K – These Hangars were essentially the same Design, but used for different purposes. Built from 1939, Type-J Hangars were used for Aircraft Maintenance on Operational Airfields while Type-K Designs were used for the Storage of Aircraft on Aircraft Storage Unit (ASU) Airfields. Arched Steel Trusses were supported by Steel Columns, with a Roof of thin Steel Plates. Annexes were Built from Brick or Concrete & used as Offices & Workshops. Examples of both Types survive at a number of Airfields, for example Swinderby in Lincolnshire (Type-J) & Hawarden in Flintshire (Type-K).
Several Airfields had their Runways widened & extended in Length for Emergency Landing of Damaged Bombers after Operations over Germany, these Airfields, RAF Woodbridge, RAF Carnaby, & RAF Manston being Designated as “Emergency Landing Grounds” – ELG’s. These ELG Airfields had some of the 1st Fitments of the Fog-dispersing Installation, FIDO.
Pathfinder Craig 