618Sq Mosquito Highball set up

Here’s an assembly of hook anchor points with micarta ‘fish plate’, hook arm with damper attachment, spring damper. All this stuff does not have dH serial numbers, nor is there an Illustrated Parts Manual. Laying upside  down under the Sea Hurricane at Shuttleworth, to disproving frowns, and crawling through the Sea Hornet rear fuselage remains at the always welcoming dH Museum, crawling through shipping containers at always welcoming Avspecs allowed a forensic reconstruction of bits and pieces collected from many locations. The remains of an internal fuselage strake are shown under the fuselage of DZ542 in NZ. The stainless steel hook retention mechanism did have dH serial numbers, which indicates forward planning for the postwar Sea Mosquito design. 

This is the original tail hook from DZ546, very similar to the tailhook fitted to the Sea Hurricane in Shuttleworth. The Highball Mosquitos had an additional bulkhead fitted in the rear at the anchor point of this hook, with additional internal spruce strakes running forward to the rear wing attachment points. The hook anchor points were aluminium castings heavily fixed into large micarta plates fixed to the underside of the fuselage, joining to the internal strakes. Reconstructing this ‘system’ retrofitted to the Highball Bomber fuselages came from piecing together the remains of a number of aircraft scavenged over decades by a number of collectors, then reassembling the pieces like a forensic reconstruction. I don’t ever think that a Highball restoration will ever release a hook onto a carrier deck, but it’s nice to know that it could. 

This photo shows a number of heavy duty ‘mystery clips’ found across numerous known ‘buried Highball Mosquito’ sites in the Narromine area of NSW. I have yet to identify their application, but ‘definitely somewhere on or something to do with a Highball Mosquito’ Beneath them, in ‘Highball Blue’, which the undersides and, I believe interior cradle bomb-bay area, is the lower windscreen framing of the armoured windscreen. These have a standard 5c switch fitted, which I guess had something to do with arming, as it was handy for the Navs left hand to reach while the right hand rested on the sight cradle and fooled with the Barnes Wallis sight. The sight cradle remains of DZ543 confirm that the common image of a ‘boat in sight’ was the aiming method used in 1943-5. Above this is a bank of three lights, that the circuit diagrams suggest was to confirm fusing and release. 

Original Urinary tank and funnel from DZ546

I thought it would be good to update this thread, for the record. In 2020, just before Covid, I was fortunate to get to the RAF Hendon Museum archives, where a helpful staff member and fortuitous flicking through the card catalogue identified original Vickers drawings of the Highball setup, both original 1943 era wind turbine driven version and later hydraulic driven version that were designed for Sea Hornet use. I also visited the superb deHavilland Museum in Herts where the Highball cradle and sighting arm remains from DZ543, ex Yorkshire were displayed, as well as a practice Highball from Loch Striven. These artifacts were matched to drawings and many pictures and vernier measurements taken to allow accurate CAD drawings to be reconstructed. I had previously visited NZ to look at cradle attachment remains held and kindly made accessible by Avspecs, associated with DZ542. In Australia, the remains of DZ546, which had been reduced to pieces, but carefully kept in an old shed by the original farmer owners, were found and catalogued, as well as the remains of other Highball Mosquitos recovered from the Narromine area. All of these artifacts, from the UK, Australia and NZ, as well as the original drawings, constituted jigsaw pieces that could now be fitted into a whole. There are elements of the cradle mechanism still missing, being the guts of the turbine, governor and release arms, so the next focus was digging up the airfield dump, on the theory that the fitters may have disposed off unserviceable components, or, even better, in a rush to go home in 1945, had lazily gas axed a complete cradle in half and just buried it. Covid stopped things for a few years, though. Pictured is the original glazed nose from DZ546. This aircraft was most definitely fitted with half inch thick armour plate across the entire cross section of the front, as this original item remained with DZ546. It was not possible for the Nav to access the front as a usual bomber variant would allow. I wondered ‘why keep the nose glazing then?’. The simple answer is expediency, as the geometry of a glazed nose is different to that of a FB aluminium nose, when you put them side by side. In 1943, there was no time or real need to make a custom nose for an adapted B. I have seen in circuit diagrams and footage how a ‘release flash’ was fitted in the nose, to cue moment of drop in 1943 trials, so the glazing was practically used. Full frontal armour, covering both crew members, including an armoured glass windscreen, was the only thing the conscience of the designers and morale of the crew relied on, when the centrifugal spinning of two Highballs would ‘lock’ the aircraft in a straight line, while looming larger in the sights of anti aircraft gunners. 

I can confirm that armour plate was retro fitted to Highball B omber variants, and that the plate blocked off entire access to the transparent nose cone.
I cannot see British design thought permitting the idea of the navigator to crawl into the plexiglass nose cone to sight a ship throwing 88mm shellfire at an increasingly larger Mosquito in the range finder, held to a straight run by the need to line up Highballs, and even more frighteningly by the centrifugal affect of spinning Highballs preventing short evasive manoevres.

So full armour plate is consistent with the idea that the Navigator was safely protected, but how do you sight through the sloping windshield of a B omber variant, particularly if it was armoured glass? Why keep a transparent nose cone when it was not required?

Now I am thinking there was a periscope arrangement in the sighting. One input end at the optically clear sighting window of the nose cone, perhaps with a fixed torpedo sight, with a periscope shaft running under the armour plate where the ladder would be stowed and up to the Navigator, squinting into it, head safely down, as you would into a cathode ray screen for early radar. That’s what I would want to be doing. The run of cabling under the armour plate is the setup for early radar, so this would be logical for a periscope arrangement.

For 617 Sq Dambusters, what was the sighting arrangement?

Periscope arrangements were well established for drift gauges, so it is not too far a stretch to adapt this for a simple torpedo gauge fixed in the transparent nose cone, running back to the Navigator, chipping in flying adjustments out of the corner of his mouth to the pilot.

Any thoughts? Santa, please find me a Highball AP for Christmas !

Does anybody have any detail for a large scale air raid warning siren, which may have been driven by a turbine similar to that used on the turbine driven Highball? I am thinking that the small number of turbines required for the Highball setup, and the urgency of setting up the cradles would have Vickers casting about for an off shelf unit wind turbine rather than constructing one from scratch. So the theory is they may have adapted the turbine setup from a warning siren. I can’t think of any other applications beyond forced fed ventilation in ships for a turbine like this.

And a lesson to be learned for those who still go wreck hunting often using map references of unknown accuracy or the vague locations on accident record cards eg Thomsons Beck Selby… There have been several occasions where I have dismissed metal and wood objects in the vicinity or even on the walk in as being bits of old tractors, cars . Now I know to be careful, take some pics and leave the parts where they could be found again if indeed they are needed.

Nicko, it would be Christmas to find the AP….

Serendipity ! One of the advantages of not throwing anything out is that one day, you will know what it is…sometimes you collect a lot of mixed gear out of an old shed and there is a strong urge to scrap something that just does not look or fit with anything recognizably Mosquito. So this anonymous rod and bracket, which could have been from an old column shift car, or a PTO lever on a tractor, carelessly mixed with old Mosquito stuff in a farmers shed, ends up being the Navigators torque lever for the air intake of a Single Governed Drive for a 1945 Highball Mosquito ! The diagrams kindly provided via the Barnes Wallis Foundation and a lump of old steel husbanded for a few decades definitely confirm what type of cradle and drive was used in 1945. I can say that on the photographic evidence of post #63 and this bracket, we can call this confirmed.
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This is great Ed.
I have no doubt that there was a manual of some sort. The number of aircraft involved, the potential of the aircraft, and that the aircraft may be (and was) used in a theatre remote from the manufacture and development meant that it had to be supported by adequate tech documentation.
Do we know from the suppliers of this information if this was just a loose bunch of illustrations or was it part of a folio that might indicate its origins?
Does anybody know what level of tech pub support is out there for the Lancasters? What manuals exist for that version? Might give us an indication of what there is to be found for the Mosquito.

My pleasure – pleased that we got there in the end! 🙂

TwinOtter, thank you kindly for your most excellent assistance.
QldSpitty, I anticipate there will be a market for rolling Highballs through the doors of various parliaments, as a method of delivering petitions, so building one might be sensible. As a further dubious thought two rotating Highballs in the fuselage would absolutely ensure no swing on takeoff, so this might have a market. The main thing I am looking forward to is lodging an application with a regulator to drop a half ton, spinning munition at 300 mph during an airshow routine, aiming to punch a giant, inflatable gorilla half a mile away in the guts. What could go wrong?

Someone needs build a replica Mossie belly skin with the highball setup.

Nice to see that your efforts have been quite productive! :eagerness:

The evolution of the wind turbine driven is the use of a hydraulic drive that spins up both Highballs simultaneously. If you have ever seen a shoebox sized hydraulic drive at the heart of a mighty crane you get an idea of how much energy these can harness and direct. The only intimation in the image that it is a hydraulic drive is the reference, half obscured, to Fig 8 for HYD-(RA)ULIC System. On this basis the removal of the air scoop would lessen resistance and perhaps more powerful engines could afford to have their energy tapped into hydraulic pumps. A single hydraulic pump is directed into a gearbox that splits the drive to each Highball, returning to the earliest concept, without the disadvantage of long spin up times. I see this evolution as the Hydraulic Drive, probably for postwar Sea Mosquito, and with a little more refinement something like the cradle shown in post #60, which I interpret as the ultimate evolution designed for the Sea Hornet. There are mighty torsion arms on this cradle that tie both Highballs together, while the earlier cradle structure is largely two independent units. The hydraulic drive is a consequence of more powerful engines allowing an indulgence in high torque energy, for rapid spin up. An Oldham coupling and vee belts allow for slip as the Highballs ‘squeal’ into rapid deployment for some 1953 scenario. I am quite satisfied with the evidence of the air scoop in post #63 and Governed Single Drive that we have found the cradle setup for a 1945 618 Sq Mosquito. The pesky paddle-release remains to perplex and prognasticate over, though I wonder if we have it in post #59….
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The next evolution is what I believe was fitted to 618 Sq Mosquitos, in that the twin duct inlet arrangement concurs with the oblique photograph of the Narromine Mosquito in post #63, where the inlet scoop has been removed, but two ducts are visible. In this design the air is being vented out of the turbine. I interpret this design as a separate, governed turbine for each Highball, or Governed Single Drive. From the cockpit, a control directs the airflow into one turbine or the other, to concentrate the energy of the airflow on a single Highball only. A centrifugal governor uses spring resistance to dampen or hold the drive within a set RPM range, because the energy of the spinning Highball is ‘feeding back’ in the form of a flywheel. Once the RPM generator shows the optimum range the Navigator would switch the duct over to the second Highball. This turbine system does not draw on any of the aircraft’s electrical or hydraulic systems and the mechanical governor and split drive arrangement resolves the disadvantages of the earlier version, but it still takes time to spin up the Highballs, which could be uncomfortable if you are getting shot at.
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Again in gratitude to the Barnes Wallis Foundation, via the RAF Museum, is a sequence of images of the Highball drive mechanism, which I interpret as showing the evolution of the drive mechanism design, all based on the same cradle structure, so I see this as ‘of the WW2 era’. Unfortunately they do not show how the release functioned, so this mystery endures. These images look like they were extracted from an Air Publication. If anybody knows of the existence of this AP or has any further details from it, I would be most grateful to receive these. The first image concurs again with the post #33 image, and I describe this as an Ungoverned Wind Turbine Drive. The drive is located between the two Highballs, and I interpret the louvred section on the right of the air chute as the exhaust end. In this case the inlet to the turbine would be something like the inlet shown on the Speedee arrangement in post #54. The drive shaft of the air turbine feeds a gearbox that splits into two output shafts that spin up both Highballs simultaneously. The disadvantage is the load on the turbine of spinning up two Highballs, requiring a long ‘lead time’, as well as a lack of control over RPM. The designers mind would have turned to cutting down the time it took to get a Highball up to speed.
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I am very grateful to esteemed members of this forum and the Barnes Wallis Foundation for chasing down this image of the Highball cradle from 618 Sq Mosquito DZ543, which crashed in Yorkshire during WW2, originally displayed in Elvington . The DZ54x series of Mosquitos were sent to Australia for the Pacific campaign, so these remains definitively confirm the look of the cradle structure on a Narromine based Mosquito. Unfortunately no remains, or images of the remains of the driving mechanism from DZ543 can be found, but the cradle structure concurs with the image in post #33. I understand these cradle structure remains are now at the Mosquito Museum in Herts, so in their spiritual home.
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