There is no Mystery of the Missing Generator

About time I put this one to rest. The answer behind this puzzle is that the generator was there. Past tense! I just didn’t know what the guts of one looked like. I didn’t understand that there are the remains in the photo, and I had been put off the scent by the state of the Rotol gearbox fitted to Camden Museum’s A79-14. This gearbox has a blanking plate over the generator position and the Dunlop pressure reducing valve (AHO19682 – for the Canopy Seal line) and its mounting bracket (L002109A) attached on the blanking plate, as if the blanking plate should be there for a serviceable aircraft. (Although I would certainly mount the bracket over the blanking plate if I had just removed the generator – to keep it all together.)

The Generator position on the gearbox of A79-14

Below is the image from AP.1095C Vol.1, Sect. 5, Chap.9, that made me see the light. Notice the long bolts that run much of the length of the generator, holding the casing and mounting together. This is actually for the KX, but is much the same for the KX-B.

A79-536: Now that I know…

Air Diagram AD 4551 and Junction Box 1

In an effort to identify modifications incorporated in to Vampire FB.9 R1382’s Junction Box 1, I went searching for a later revision of Air Diagram AD 4551. We already had issue 3; this came from Gina’s Vampire library. My general Google search came to nothing. Not really surprised!

I found a reference using NAA RecordSearch to ‘Vampire FB Mark 5 Electrical Installation’ by chance while I was having a look for something else on Vampires. The FB.5 and FB.9 are largely the same, the essential difference is that airconditioning (an ACRE 8 cold air unit) is fitted to the FB.9. I imagine that this file is in the Australian archives because the RAAF had a single Vampire FB.5, A78-3 (formerly RAF registration VV465).

So I ordered a digital copy in February; the order cost just under $40 including GST and took 12 days to process. That copy is available at the NAA here:

http://RecordSearch.naa.gov.au/scripts/AutoSearch.asp?Number=3398245&O=I

So it turns out that the file contains AD 4551 Iss. 3. The AD 4551 pages are scanned at a suitably high resolution and overall the result is very clean. I had a look through this just to make sure that Iss. 3 was Iss. 3! Apart from the NAA version not having some small hand mark-ups that our copy had, I didn’t see any edition differences.

When working through the Gun Firing circuit to convert this in to a wiring/routing diagram for Junction Box 1, I had trouble reading some pin IDs on our version. The hardcopy in Gina’s library is a bit tatty (some tears) and grimy; also in the original photographic repro process, the pages weren’t flat so some of the schematic is blurry.

Gun Firing circuit scanned from Gina’s version of AD 4551.

The GF circuit from the National Archives file.

So I took a look at the NAA version to see the pin ID and found a lot more than what I was expecting. There was in fact a significant difference in the actual circuit. The version we already had included Mod 3146. Looking at the circuit diagrams you should be able to see that they are fairly different. There may be other differences too, in other circuits. No idea yet if this was a relevant discovery for R1382, but at least the NAA file is now there for anybody who is interested or may find it useful!

Alternative Fuel Gauge Panel

Five years ago I saw a photo that showed a rather unusual single-seat Vampire fuel gauge panel. The regular panel, when you look at the front face of it is mostly just gauges, placards and the base panel which is made of Tufnol – fibre reinforced phenolic.

This mystery panel had been seriously messed with! The top line of gauges now sat in a folded aluminium part that was attached to the Tufnol. This component in itself didn’t make for a bad looking assembly, but overall it was rather rough looking.

What was this assembly? I thought it was a rough repair, but why so complicated? Why not just replace the panel!

Turns out there were two mods involved. Firstly (RAAF mod 160, DH mod V.204) the Mk.II 8-day clock was replaced by the V.308 stopwatch clock, with the centre fuel tank gauge moving to the old clock position, and the new clock being installed in the centre-top position. The folded aluminium part was required to reinforce the Tufnol that had been dramatically weakened by the much larger hole for the clock, and to provide sufficient space for it.

Somebody didn’t like that idea, so the larger clock was then moved over to the right hand instrument panel, and the centre fuel tank gauge was then moved  back to its original position. (RAAF mod 231, DH mod V224.)

I think that most aircraft bypassed this mess, with the larger clock immediately being installed in the RH panel, as the aircraft came in for servicing and mods.

However, it turns out that A79-14 is a case that was fitted with the mongrel panel (not the panel I originally saw); see the photo below.

Although I still don’t understand why the original panel wasn’t replaced during either mod, given how much work I imagine was involved, I think it is nice that this oddity is preserved. Perhaps for some lessons on how things should have been done properly the first time (new clock in RH panel straight up), or otherwise on the diversity in modifications in our remaining Australian-built single-seat Vampires.

Vampire arrives

On Wednesday 24th May, Vampire R1382 arrived to join Australian-built Vampires A79-175 and A79-733.

IMAG6112 cr br co sml

Thanks to Gina and the guys at Steve Holland Transport and Turner and Central Cranes.

Dispatch

We loaded R1382 on to a semi on Friday morning, 19th May. The truck and load went back to the depot; no travel to NSW this week.

Brian, the aerodrome safety officer, and the almost empty hangar

Brian, the aerodrome safety officer, and the almost empty hangar

IMAG6101 ac sml

Thanks again to Alwin, Catherine, Gina, Rod and the CVT guys, Brian from the Central Goldfields Shire Council, and the guys from Steve Holland Transport.

Disassembly of Vampire R1382 – Day 3

Wednesday: With the headache of trying to get the main gear up and over-centre, I forgot to take any photos! Below is a photo showing that day’s efforts, taken Thurs morning. One of the things that stopped us getting the gear over-centre was the door lock Teleflex, which was seized. Once that was freed, we still couldn’t get her the rest of the way (working on port gear first). Alwin then made an observation about the tyre and suggested we deflate it. That did the trick! The point being that the tyre normally is jammed against a rub strip attached to the cut-away rib that arches over the wheel-well. This is normally done by a ram and with a fair bit of inertia. I was lying on my back pushing the wheel up with my legs – slow and only human! After letting the tyre down, it was 5pm and we had one leg up so that was it for the day.

IMAG6066 wed sml

 

Photogrammetry IV

In February this year I endured the heat in the Camden Museum of Aviation’s Beaufighter 21 to take 400+ photos  of the interior of the aircraft. I was in the fuselage for about an hour from 10am and was drenched with sweat at the end of it. This series of photos focused on the starboard side around the observer’s station. I’m thinking that the 3D result can be useful for several things, such as:

  1. An extended record of the aircraft ‘as is’. This area of the fuselage is basically quite empty. A large number of photos can provide a record on their own, but this always presents the problem of having to layout the photos to identify the relative positioning. VSFM provides the context for all of the images, and the 3D point cloud provides a continuous representation of the aircraft structure.
  2. A means of communicating specifics with others working on Beaufighters. A way of doing this may be to work with a 3D pdf file. This would include any annotations applied to the 3D that identify part-numbers, descriptions, queries or problems to be solved, etc.
  3. When correctly scaled the point cloud can be used as the basis of a Digital Mock-Up (DMU) in a CAD package. Any parts that need to be reverse-engineered can be located correctly and relationships to structure and other components can be assessed in general terms. This would need to be used with caution, but could be used for initial assessments before fabricating new-build parts and could indicate areas that require more detailed study before proceeding.

Context of the photographs that make up the photogrammetry session

Context of the photographs that make up the photogrammetry session

Detail of the starboard side of the Observer's position in Beaufighter A8-186

Detail of the starboard side of the Observer’s position in Beaufighter A8-186