Introduction
Construction of the RNZAF Base Ohakea began in 1938 with the express purpose of strengthening the newly christened Royal New Zealand Air Force. The timing would prove invaluable when, along with other allies, New Zealand was declared at war with Germany on the 3 September 1939. Hangars No.2 and No.3 were built as part of the overall construction plan that was quickly extended at the outbreak of war.
Early advent of New Zealand’s air defence
New Zealand’s role in World War One was a reflection of its close ties with Great Britain. Over 100,000 New Zealanders were sent overseas, many for the first time, and fulfilled a variety of positions. Included in this were nearly 300 airmen who served with the Royal Flying Corps. They received training at two commercial flying schools, the Canterbury Aviation Company at Sockburn and the New Zealand Flying School in Hobsonville, Auckland. Henry Wigram, the establisher of the Canterbury school and a politically influential figure, insisted that the Government take notice of the importance of air defence. At the end of the war he gifted Sockburn Airfield expressly for the purpose of establishing military aviation.
It was not until 1923 that the Government established the New Zealand Permanent Air Force (renamed the Royal New Zealand Air Force (RNZAF) in 1934), as a division of the army. Initially, attention was given to the establishment of aerodromes, and as early as September 1930 a scheme had been advanced for the establishment of a chain of landing grounds. The Public Works Department (PWD) was to undertake the work, using unemployed labour wherever possible.
In 1935 the Labour Government decided that the air force should become a separate arm, and Tom Wilkes, Director of Air Services, was approached to prepare a scheme. He recommended that an expert from the United Kingdom be asked to draw up a report. Wing Commander the Honourable Ralph Cochrane (1895-1977), AFC, of the Royal Air Force was selected for the task. His report, entitled 'Air aspect of the defence problems of New Zealand' and known as the Cochrane report, took the view that the security of New Zealand, the United Kingdom and their shipping routes required air defence. Cochrane recommended that the air force operate as a separate service controlled by an air board under the Minister of Defence. It would comprise two permanent squadrons of 12 medium bombers capable of locating and attacking enemy raiders before they reached New Zealand; a reserve of personnel to support these squadrons; an army co-operation squadron in time of war; and a territorial air force.
This report was accepted and Cochrane was promoted to the rank of Group Captain and asked to stay on for two years to implement his proposals. The first stage was for the RNZAF to establish two permanent squadrons equipped with medium bombers. This immediately heralded the need for the construction of bomb storage, repair facilities and accommodation for the two squadrons. As the first appointed Chief of Air Staff of the RNZAF, Cochrane selected two aerodrome sites, one at Whenuapai, near Auckland and the other at Ohakea, near Palmerston North. The construction of these bases and the other proposals in his report was begun in earnest on 1 April 1937 under the legislative authority of the Royal New Zealand Air Force Act.
RNZAF Base Ohakea – its beginnings
The escalating tension that was stirring in Europe at this time made it apparent that a second world war was imminent. It was also clear that should war be declared, the aeroplane was going to have a significant role in the defence of the Empire. This gave added impetus to the construction of the RNZAF Base Ohakea, the chosen location of which was considered an ideal site due to its sheltered position and an absence of hills for around 48 kilometres (30 miles).
The properties taken for the Ohakea base were all situated in Block XV Rangitoto Survey District. Previously known as Pukenui, the 700 hectare (1732 acres) tract of land had been sold by James Bull to the Crown in 1899 under the provisions of the Land for Settlements Act. Renamed Ohakea Settlement, it was subdivided into 16 sections and sold for dairy and agricultural farms under the Lease in Perpetuity system.
The previous Maori landowners were Ngati Apa who had been negotiating a number of informal lease arrangements with European settlers from the mid-1840s. These leases and the subsequent Crown purchases became the focus of a recent settlement as part of a claim to the Waitangi Tribunal, which sees Ngati Apa (North Island) as having right of first refusal should the Crown dispose of the land upon which the RNZAF Base Ohakea is located. The RNZAF base at Ohakea is located on the traditional lands of the Kurahaupo people. The area was originally occupied by Rangitane, whose influence in the region had decreased towards the mid 1800’s. Ngati Apa then established themselves in the region, an iwi formed out of circumstances during the early and mid 1800s. Ngati Apa is an old name for these people, signifying that they are the descendants of Apahapaitaketake and Nga Wairiki, the eponymous ancestors of Ngati Apa. Nearby Parewanui is a Ngati Apa centre and is located 8km south-west of Bulls. Two pa sites belonging to Ngati Apa are located almost immediately to the west of Ohakea. One pa (S23/4) is recorded as a gunfighter pa dating to about 1868, the other (S23/75) known only as Mangamahoe Pa.
The area of is also acknowledged to be of significance to Ngati Kauwhata and other iwi including Rangitane o Manawatu. As part of the Deed of Settlement with the Crown, Ngati Apa have agreed to provide Rangitikei-based iwi an opportunity to jointly purchase this property if the right of first refusal is exercised.
Construction of the Ohakea base was also aided by the flat nature of the land and the relatively small amount of earthworks required. Five properties, covering a total area of nearly 200 hectares (491 acres, 3 rods and 33 perches) were taken under Section 254 of the Public Works Act and comprehensive plans were prepared by the design office of the Public Works Department. The base was to include a flying field, 1.6 kilometre (a mile) long runway, two hangars and what would amount to a self-contained township to accommodate the air force personnel. The plans also made allowances for more hangars to be built should they be required. The initial two hangars were to be identical and among the first of the structures to be built. They were designed by Charles William Oakey Turner (1901-1994), Chief Designing Engineer of the PWD.
Turner was born in Cardiff, Wales in 1901 and immigrated to New Zealand in 1925. He had been travelling between the United Kingdom (UK) and New Zealand working as a marine engineer on coal-fired sailing ships when the 1925 British seamens’ strike occurred. He decided not to return to the UK and with his experience and degree in mechanical engineering he was able to secure a job in the PWD design office in Wellington, where he spent the next seven years. During his time at PWD Turner became involved in a number of projects, a significant example of which was the construction of the Mohaka Viaduct (Category I historic place, Reg. No. 4418, built 1930-1937). Following the Hawke’s Bay earthquake in 1931 Turner was seconded to the Hastings, Napier, Wairoa and Gisborne Borough Councils. In this role Turner was responsible for approving construction work and issuing permits. As a result of this work, he made important contributions to the establishment of seismic design principles. These principles were to form the basis of the first earthquake design code for New Zealand.
After winning a Commonwealth scholarship Turner completed his Masters in Engineering, studying at both Stanford University and the University of Illinois. On his return to New Zealand Turner was appointed deputy to William Langston Newnham (1888-1974), PWD’s Chief Designing Engineer (1929-1936), and eventually succeeded Newnham in 1937. During this time Turner played a key role in the design of concrete road and rail bridges. This work included designing arch bridges on the Napier to Gisborne railway line. The construction technique of arch-bridge falsework was to be used again by Turner in the design of the hangars at Ohakea and later Whenuapai.
Monolithic designs
The two hangars that Turner designed were the major buildings to be built on the base. The layout and orientation of the hangars was carefully considered concurrently with the whole aerodrome development, and with close involvement of the Air Department. Each hangar was 67 metres in width and 58 metres in depth, with a door opening 7.6 metres high. The total floor area of each was 3475 square metres. This would allow for ‘a considerable number of modern bombing machines of a wide wing-spread’. The floor area was established by arranging cardboard models of aeroplanes and determining the most economic use of the space. The hangar space was also to be surrounded by annexe accommodation making the total floor space of each building 5333 square metres. The annexe accommodation included space for instrument and repair shops; carpenter’s shop; flight workshop; machine room; fabric and dope room; parachute room; armoury; wireless rooms; navigator room; lecture room; library; and an area for photographic work.
Several options with varying types of construction were put forward by Turner, along with estimates. These options varied in the location of where the arches were to be tied and the position of the openings. There was some debate over whether a rear-ended opening would be more suitable. However, for the Wellington bombers to be housed in the hangars, front openings were adopted. The choice of construction material was debated extensively by the PWD, as the large size of the hangars meant that their weight would not allow normal construction methods of boxing and concreting to be used. Despite the use of structural steel being a cheaper and much preferred option it had to be abandoned as delivery took a minimum of 20 months and such a delay was unacceptably long. So an innovative plan to use reinforced arch construction was devised. The construction process was sped up by the use of readily available reinforcing bars. Turner stated that the choice between ferro-concrete and structural steel was one of ‘economics and expediency’.
Taut string of the bow
The design adopted utilised two-hinged arch ribs. For a structure of this size 10 great arches of reinforced concrete were required, the feet of which would sweep down far outside the outer walls. This ‘shell’ type of structure also allowed for the roof itself to act as part of the stress-carrying structure. The weight of this roof was a major design consideration as it would bring about a large outward thrust from the base of the arches, thus requiring a very strong force to join them together. Instead of the usual method of thrusting up the bases of the arches by heavy concrete foundations, ten rolled steel joists were placed in pairs – end to end – in order to connect the extremities of the arches at ground level. The hangars were believed to have been more resistant ‘… to destruction by bombing than one embodying a structural steel roof.’
However, once in place the joists were found to be out by 2.5 centimetres, so oil burners were then ‘played’ on them until the joists expanded enough to be locked together. Once the joists began to cool, the contractions caused a tension of an estimated 150 tons, which helped to counter the thrust of each arch, ‘providing, in effect, the taut string of the bow’. The buttresses of each arch were poured from the ground up, allowing for the huge steel frames required to support the remainder of the arch to only need to support the clear middle span. This made them mobile and through continuously pouring the concrete arches, three bays at once, the hangars were rapidly erected. Using a system of pulleys and winches each arch was adjusted into position using the back wall as a base. Upon completion of the first hangar, the steel frames could be shifted to the next without being dismantled, despite being constructed of 138 tonnes of steel.
Tenders for the construction of the hangars were advertised for on 11 January 1938, with the successful contractors being McMillan Brothers Limited with a tender of £105,127. Not included in the price was the fabrication of the steelwork by Cable and Co. Wellington, and other structural and reinforcing steel and its transport. The construction phase presented several challenges, as the chosen design was unusual at this time. The standard form adopted in the Royal Air Force stations in Great Britain used heavy structural steel, which as aforementioned was difficult to obtain within the 15-month time frame. However the use of this reinforced concrete ‘shell’ type of construction was gaining favour and there were at the time several examples to study, although these examples were mostly of a smaller size. However, unbeknown to Turner until after his design was completed, this particular method on this scale had previously been used by the French and German Air Forces.
New Zealand at War
New Zealand declared itself at war with Germany on 3 September 1939, and the Ohakea Air Base was officially commissioned on 18 September 1939. No.1 Hangar was completed shortly after the opening, with No.2 Hangar opened later, early in the following year. The hangars, which in the end cost £76,750 each, attracted much attention for their size and for the engineering difficulties that were overcome during construction.
The base’s first role was to train observers and air gunners, and new recruits, the first intake arriving on 20 September 1939. Most were to receive their final training through the Empire Air Training Scheme, based in Canada, before being posted to the Royal Air Force or an RNZAF unit. However, by October 1940 the main role of the base had shifted to pilot training with the establishment of the 3rd Service Flying Training School. In late 1940 the Recruit Training School was closed and relocated to Levin. For a short period in 1940 the Auckland Ground Reconnaissance Squadron, normally based at Whenuapai, was moved to Ohakea for convoy escort duties out of Wellington. By mid-1940, De Havilland Dragon aircraft were operating from Ohakea searching for German commerce raiders off the New Zealand coast.
Japan’s entry into the war in December 1941 initiated further expansion of the base, including the replacement of the hardened earth runways with concrete in 1942. Additional squadrons were created, mostly fighters with a Fighter Training Unit formed at the base in 1942. No.17 (Fighter) Squadron was formed in 1942. In 1943 No.2 (Bomber-Reconnaissance) Squadron was transferred from Nelson to Ohakea, before being deployed to the Solomon Islands.
Post World War Two
After World War Two the RNZAF struggled to find a role. Following demobilisation the Air Force was reshaped into a smaller force designed for peace-time operations whose capability could be increased considerably in times of war. The territorial Air Force was reformed and an Air Force Reserve constituted. The Auckland bases of Hobsonville and Whenuapai (established 1937) became the main bases for RNZAF transport and maritime squadrons, and, from 1949, Woodbourne (established in 1939) became the principal aircraft repair depot and Wigram developed into the main training facility.
Ohakea became the base for the reformed No.’s 14, 42 and 75 Squadrons. Squadron 75 was a Royal Airforce (RAF) squadron initially formed during World War One as 75 Squadron Royal Flying Corps. During World War Two the squadron became part of the New Zealand Squadrons in RAF Bomber Command. In 1946 the RAF presented the squadron title and standard to the RNZAF in recognition of the service of New Zealanders during the war. It is apparently the only time the RAF has ever gifted a squadron title to a Commonwealth Airforce.
The hangars continued to serve the purpose for which they were built. In 1948 the numbering of the hangars was changed with No.1 being changed to No.2 and No.2 Hangar being allocated the number 3.
In the late 1950s the RNZAF underwent a substantial reorganisation. Changes in weapons technology, including the development of nuclear weaponry resulted in a reconsideration of the role of the airforce as a ‘force-in-being’. As a result five territorial squadrons were disbanded. Ohakea became the main base for the RNZAF’s squadrons of strike aircraft – No.14 (Canberra) and later No.75 (Vampire). To accommodate these changes, work was undertaken on the aircrew room, change room, briefing room and ablution area of No.2 Hangar. Changes were also made to No.3 Hangar to accommodate the RNZAF’s communication squadron No.42. Other work undertaken at this time included repairs to the roofing. The waterproof covering of the flat roofs of the annexes was replaced, and in 1959 the decision was made to replace all metal flashings. Another issue remedied at this time was that of the hangar doors. Problems had arisen with the main doors soon after completion. Each door weighed a total of 27 tonnes, being made of 250 millimetre thick reinforced concrete, and were supported on two wheels with guide rollers placed in the upper corners. Their weight made opening difficult. In 1961 they were replaced with lighter corrugated metal doors. 1964 also saw a significant response from the public with large numbers attending an Air Force open day at the RNZAF Ohakea Base, at which visiting aircraft from the Royal Air Force, United States Air Force, Royal Canadian Air Force, Royal Australian Air Force and United States Navy performed flying and static displays, including a supersonic flight by Phantom 4 Bombers.
In the 1970s further problems with the structures arose due to spalling. The concrete that was used in the original construction is believed to have contained beach sand. The consequent spalling from decaying reinforcing necessitated considerable and costly repairs. Since this was identified the buildings have been painted to help reduce water ingress.
In 1970 the RNZAF replaced its ageing Vampire jets with Skyhawks. The Skyhawk fleet was augmented in 1984 with another 10 aircraft acquired from Australia. These aircraft were assigned to a reformed No.2 Squadron, which was also based at Ohakea alongside No.75 Squadron. To accommodate the new squadron No.42 Squadron was relocated to Whenuapai.
During the 1980s the concrete floors of the hangar were relaid and in 1989 the hangars were clad with long-run corrugated iron. Some of the arched buttresses on the sides of the hangars were also enclosed at this time. Both these changes significantly altered the original appearance of the hangars. In 1990 the No.2 and 3 Hangars were recognised by the Institute of Professional Engineers (IPENZ) as part of the ‘Engineering to 1990’ awards.
No.2 Squadron was relocated to Nowra (NSW Australia) in 1991, but remained under the command of Base Commander Ohakea. In 1993 the Pilot Training Squadron and the RNZAF’s Flying Training School returned to Ohakea from Wigram. In 1996 a mezzanine development in No.2 Hangar saw the provision of new bathroom facilities, a lobby, locker room and staircase. The work was carried out by Works Consultancy. In November 2001 following a review of New Zealand’s defence capabilities and funding strategies the Air Combat Force was disbanded. A plaque was placed on the outside of No.3 Hangar in recognition of the contribution of 75 Squadron from 1946 to 2001.
In 2004 one of the hangars was proposed to be demolished to make way for a larger hangar as part of an overall redistribution of RNZAF personnel and craft. However, this did not go ahead. No.3 Squadron, which currently operates the Iroquois and Sioux helicopters, moved to Ohakea in January 2002, and are currently housed in No.3 Hangar. No.2 Hangar currently houses the No.75 Squadron of fixed wing aircraft.
The development of the Base had an economic impact on the adjacent township of Bulls, swelling its population and generating more business from the people connected with the Ohakea air force base. By 1977, there were an estimated 1200 people (including the families of personnel) connected with the air base, with around 400 of these living on the base itself and a large remainder residing in Bulls. During the time of construction many of those working on the base moved their families into the district, swelling the local population significantly. This connection remained strong as was evident by the ‘community criticism’ of the closure in 2007 of the Ohakea Air Force Museum. By 1993, locals had invested more than $500,000 in the museum, which had opened in 1976, and many were therefore dismayed at the loss to the community caused by the closure.
