Blind Flying Panels – FB.31 A79-175

In early 2021 I was lucky enough to acquire two original BFPs for my Australian Vampire FB.31s. I deliberated over which panel to allocate to which aircraft, eventually deciding based on the apparent history of each panel. The first panel I started work on I believe came from a spares stock. I believe this because it is of identical configuration and is marked with the same batch numbers as the BFP assembly put together by the Thomas family for A79-14. I think the panels were disposed from de Havilland Aircraft stocks at Bankstown.

The initial production arrangement of the blind flying panels for the RAAF single-seat Vampires were distinctive because they have the hole for the American altimeter (with adjust knob cut-out lower left) and for the AM type (adjust centre bottom). Some later panels, freshly cut, had the American altimeter trim only and the squarish holes for the G3F Compass indicator.

Having worked through the mod status of A79-175 based on what remains in the fuselage, the BFP needs to be assembled to suit. There are three main mods that had been incorporated that determine which gauges were used:

RAAF Mod 62/ DH Aust. Mod. V.175 – G3F Compass – Introduction

RAAF Mod 76/ DH Aust. Mod. V.159 – Sperry Mk 3 Type HL5 Artificial Horizon – Introduction

RAAF Mod 175/ DH Aust. Mod. V.191 – Electrical Turn and Slip Indicator Mk 2 – Introduction

The introduction of a power failure warning light (Mod 143/V.202) in the circuit for the G3F compass and HL5 artificial horizon is also applicable to A79-175 and requires the warning light on the BFP itself. However, I have decided not to fit the light now on the off-chance I come across another panel with the lamp holder hole before I need to install it in the aircraft… which will be in twenty years’ time, perhaps!

There were at least four ASI configurations for the Vampire F.30/FB.31 blind flying panel. The original fit was the American AC-F2 that was used in World War 2 types such as the P-40 Kittyhawk. It was then planned during single-seat Vampire production that this American type would be replaced with a Smith’s ‘safe-hand’ type that also had an inset Mach number in a small arc-window on the face of the gauge. Correspondence in the National Archives indicates there was a supply problem with this gauge, so it is not clear when they began to be fitted. When that ASI was introduced, the Mach meter in the left-hand instrument panel was deleted (but then reintroduced by Mod 74/ V.148 due to dissatisfaction with the inset indicator). Thirdly, RAAF Mod. 153, Inversion of Air Speed Indicator, was introduced. I don’t currently have a copy of the inversion mod, but I’m assuming that it is a simple inversion using the existing holes, as is the case in the unidentified test aircraft shown below. The fourth arrangement has the gauge mounted with holes at about 45 degrees to the usual pattern. It is not known what the mod number is for this version; it may well be an option or revision to either the safe-hand ASI introduction or inversion mods. It is not a commonly seen mod in existing panels, and some indications are that it was not introduced as the final iteration.

There were some mods on the RAAF single-seat Vampires that were not incorporated uniformly across the fleet, but having found that in general the late mods have been incorporated on A79-175, I assume that most if not all applicable mods had been incorporated; any mods where there is no remaining evidence either way, I assume the late mods were actually incorporated. A79-733 on the other hand, has evidence that several of the late mods were not incorporated.

The arrangement for panel then is the inverted ASI and the aircraft arrangement would include the appropriate Mach meter. Ideally at some point I will swap the A/H for an RAAF item and the T&S for an RAAF item without the unified threads – you can call me pedantic! And I need to correct UN screws to slots.

Air Speed Indicator (safe-hand)   G6A/500032, Smiths p/n 156AS

Artificial Horizon Mk.3                   6A/2717

Rate of Climb AC-C2                        p/n 1636-6A-B1

Altimeter C-12                                   CG Conn p/n 80.000

Gyro Compass Indicator G3          G6B/500129, Kelvin & Hughes p/n V951

Turn & Slip, Pullin Mk.2A              6A/3953/1