The work on the wings has continued this week with focus on preparing the ailerons to be fitted and getting ready to fit the replica .50 calibre machine guns to the wings.
The ailerons on the P51 include extra structure to prevent leakage of airflow between the wing top and bottom surface when the ailerons are deflected. This is made up of aluminium sections which go forward of the main aileron and nestle inside the wing. To these are attached stainless steel sections and then a canvas cover which provides the sealing of the front of the aileron.
The replica machine guns have now been assembled and will have the C9 firing solenoids and L4 gun heaters fitted next week. The rear mounts for the guns have now been fitted to the gun bays. The adjustors on the rear mounts were used to harmonise the guns to ensure that the fire from all six converged at a single point ahead of the aircraft.
The wing related systems and components continue to be our main focus. Work continues on the rebuild of the two “clamshell” undercarriage doors and also on the armament and ammunition bay doors. The port wing set was trial fitted this week. The clamshell doors are complex mini projects in themselves with the curve in the new outer skin achieved using an English wheel.
Another significant task underway is preparing the artwork for the multitude of stencils that adorn a Mustang. These are a combination of North American factory stencils, RAAF originated and RNZAF specific stencils. We have completed all required silk-screened markings in the cockpit plus waterslide decals for specific components (custom printed for us by John at Oldmodels Decals in Wellington) so the major effort now will go into the exterior stencils. The artwork is used to create modern computer cut one-time “frisks” whereas in times gone by they would have been applied with a metal cut stencil used over and over again.
One simple example are the five round inspection panels in each gun bay which have the marking “W2” applied on the panel and also on the structure next to them adding up to 20 stencils just for this one area. The Spitfire had a total of 60 stencils for the whole aircraft. The Mustang includes a wide array of servicing and support information in the stencils and decals.
Work also continues on our other aircraft with the Grumman Cheetah having its annual and preparation work underway prior to Harvard 37’s overhauled engine arriving from the US shortly and fitting to the airframe.
I'm really looking forward to seeing the main wheel bays receiving all their plumbing: one of the distinctive features of the Mustang which I hope to one day (partially, I'm guessing) replicate in a 1/32 scale model. On another note, I was surprised to note how heavy some of the material is in the MG covers - some quite thick extrusions used there. Keep up the great work! If only I lived a bit closer!
I'm really looking forward to seeing the main wheel bays receiving all their plumbing: one of the distinctive features of the Mustang which I hope to one day (partially, I'm guessing) replicate in a 1/32 scale model.
I am equal parts excited and terrified of replicating this aircraft with the big Tamiya kit!
Another week rolls by in our journey of restoration for P51D Mustang NZ2423 here at RNZAF Base Ohakea in New Zealand. This week we had a visit to our facility by the Secretary of Defence, Andrew Bridgman who was able to see progress on the Mustang as well as catch the Spitfire flying.
In the workshop we have been trial fitting and fine tuning the large “clamshell” undercarriage doors onto the wing as well as the reworking of the other set of armament bay doors. As well, various hydraulic lines have been completed and fitted to the busy area behind the instrument panel and in the engine bay as well as more electrical wiring in the wings.
Another key task that has started is the assembly of the main undercarriage legs. When the decision was made in 1955 for the main group of RNZAF Mustangs to be flown to RNZAF Woodbourne for long term storage, the focus turned to keeping serviceable the Mustangs used at Ohakea for target towing for the Vampires. The decision was made to rework the undercarriage assemblies on these aircraft with new heavy duty pintles and new bushings in the undercarriage blocks.
NZ2423 was to make relatively little use of the new fittings before it was retired in 1957 and consequently these critical parts of our aircraft show no signs of any wear and have successfully passed all the NDT testing at Fieldair.
Another fascinating timewarp post from Brendon this week (including several shots I'd never seen):
When military aircraft come to the end of their service life, the options are somewhat limited. In the case of fighter aircraft, the options are even more limited. Some will be preserved in Museums, a few make it to a new civilian life but the vast majority are ignominiously scrapped for the metal, disappearing from the face of the earth.
When the RNZAF had finished with its Mustangs, the Government Stores Board put them up for tender in 1958 along with their stock of spare parts and spare Packard Merlin engines. A few went to private owners but the majority went to ANSA orchard supply company in Nelson who were interested in particular in the wheels. ANSA had the task of moving the aircraft over the hill to Nelson and cut the wings off outboard of the undercarriage before moving everything by truck to Moutere near Nelson.
Photographs of the initial aircraft disassembly at RNZAF Woodbourne showed the removal of the wings in one piece but this approach was clearly abandoned early on with probably only two or three sets of wings remaining in one piece. NZ2423 had its wings chopped off outboard of the main undercarriage legs and these outer wings were scrapped. The outer wings from NZ2417 have been incorporated into the rebuild of NZ2423.
Photos: Air Force Museum of New Zealand, Ron Fechney, John Wright, John Saunders
The tail of NZ2422 to the right. This is the aircraft that S/L Allan George flew a radiation sampling flight from Ohakea on 16 October 1953 following the Totem 1 atom bomb test at Emu Field, South Australia on the 14th. The radiation cloud drifted over the country to reach New Zealand and sampling flights were flown to determine its potency on the request of the British government. The previous day George flew NZ2404.
I had the opportunity last week to spend invaluable time with two experienced Mustang maintainers in Australia, visiting David Jones, Maintenance Manager with RAAF 100 Squadron at Point Cook and Robert Eastgate at Essendon airport (Chief Engineer at General Aircraft Maintenance). 100 SQN operates CAC built Mustang A68-170 (built 1949) and the Eastgate family are close to returning A68-104 (built 1947) to the air, carrying on the legacy of the late Bob Eastgate. The level of knowledge of these two gentlemen and their willingness to share valuable knowledge and lessons learned was priceless.
Our work at Ohakea was split between the engine change on Harvard 37 which has been keeping Brian and Joe busy along with Pete continuing work on the Mustang. The engine change on the Harvard is no small task and we are taking the opportunity to refresh hoses and fittings on the firewall.
The Mustang wings continue to have items added with fuel tank vent lines installed and some of the original fibreglass liners and wooden blocks from NZ2423 going back in and into the stress panel doors which close in the fuel tank bays. The ailerons are now top coated and the metal trim tabs being installed. The flaps have also had their top coat and are ready to install on the wings.
A lifting frame has been added to the top of the wing to allow it to be tipped into a horizontal position ready for when it will be mated to the fuselage, a key step in the project getting closer by the week.
Another week of split efforts between Harvard 37 and Mustang 23. We are refurbishing the firewall forward components on the Harvard with a view to having it airborne next month. Efforts on the Mustang include final work on the armament and ammunition bay doors and work around the tank bays. We retained all of the original wooden packers used around the tanks and these have been refitted to the stress panel doors already. Sid and Jim have been continuing their work wiring the aircraft wings.
We have been putting to practice some of the learnings from the Australian Mustang visits. One of the first tasks was to check part numbers, NAA drawings and materials specifications to ensure we have aluminium and not magnesium fittings in key areas like the undercarriage door systems and other key flight control systems – luckily we do, reflecting the late production nature of our aircraft.
Brief update this week as work continues on refitting Harvard 37's engine. More wiring has been completed on the Mustang's wings and we have begun the process of assembling the main undercarriage leg assemblies. We are waiting on some anchor nuts to arrive to allow us to fit the fuel tanks in the wings.
This week the engine change unit for the Harvard has been readied for fitting to the airframe on this coming Monday. It will be great to have it back in one piece for the New Year.
On the Mustang front we have been working on assembling trim tabs to the elevators and ailerons and making a start on the balancing of these control surfaces. During the week I had the opportunity to catch up with Marty Nicoll from JEM Aviation at Omaka and see progress on his work on the fabric covering of our rudder assembly which is nearly complete.
We are held up a little fitting the fuel cells in the wings and the associated stress panels under the wings whilst the overhaul of the Thompson submersible pumps at Fieldair is being completed and the arrival of some small hardware items for this area. Once these tasks are completed, the plan is to move the wings into a horizontal position, ready for the major milestone of mating the fuselage to the wings. Once the main undercarriage units are fitted after that, then the aircraft will be able to stand on its own legs again.