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618Sq Mosquito Highball set up

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  • Nicko
    Rank 5 Registered User
    • Mar 2013
    • 156

    #41
    Here are a couple of photos of the Hornet. The 'general' shot shows the hook. This photo was taken in 2000. Sea Vixen through the window!
    The detail of the back end was taken in 2001.

    David Vincent writes in his book that when the RAF were seeking to offload the two Mosquito PR.XVI aircraft to the RAAF, the RAAF at one point was not interested in them because they wanted the same camera installation as the other PR.XVI aircraft that they already had, and the hook installation would prevent this.

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    Last edited by Nicko; 17th April 2019, 11:18. Reason: Clarification
    Let your soul stand cool and composed before a million universes Walt Whitman
    http://vhjet.com

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    • Nicko
      Rank 5 Registered User
      • Mar 2013
      • 156

      #42
      Geoff Goodall's site notes that DZ542, ex-618 Squadron, went to NZ. So this is the aircraft that is possibly bound for the UK - see elsewhere on this forum.
      An update from Avspecs:
      https://www.facebook.com/Avspecs/pos...9756074724479/
      Perhaps Glyn can advise on what had remained of the highball install?
      Given that the DZ series has no apparent remains of the highball install and considering its secrecy, I expect that it was designed to be largely removable without major work. I mean this in the sense of appearances; the fairings could be removed, and then the standard doors installed to avoid unwanted attention, eg while they were shipped to Australia on the carriers.
      The remains of the hook install can be seen on DZ582 (from Geoff's site - also in David Vincent's book).

      Let your soul stand cool and composed before a million universes Walt Whitman
      http://vhjet.com

      Comment

      • powerandpassion
        Never Be Afraid to Ask
        • Jul 2012
        • 1255

        #43
        Nicko, thanks for the pics and guff. It is highly likely the I would have a beer or three in the pub, and may have seen two inverted Mosquitos in the place of what a more considered observer would detect as one. I have recently devoured Des Curtis Most Secret Squadron memoir of 618 Sq and concur that the Highball equipped aircraft were DZ series. He makes the comment that these were TOP SECRET and never flown out of Narromine. Crews did stage through to PNG for familiarisation with tropic conditions, and may have staged through Kingaroy and other airfields, but never in a DZ. As you surmise, the Highball setup was easily removable from an airframe, and taken to Sydney at wars end to be dumped in the Pacifc Ocean, so no cut up Highball cradles buried at Narromine. A few setups went to Singapore and probably still sit in a non descript hangar in the UK, next to aliens preserved in formalin. What comes out of the book was the fact that Highball and Upkeep were R&D projects until the last minute, and considerable technical issues needed to be worked through. Most likely Highball was good to go in June 1945 and probably the Sea Mosquito and Sea Hornet was designed, in part, to be the vehicle to deliver it. In order to understand Highball, you almost need to re-invent it, posing the questions of physics and operations facing the original designers and using 1945 technology to answer the questions. There is always the possibility that bored 1945 fitters, asked to demolish what they had so scrupulously built, were not as scrupulous in destruction, so that Highball cradle spares or jobs in maintenance May have just been tipped in a hole or ended up with a farmer. In this respect rusty bits of Narromine remains, found in Mosquito material, offer pieces of the jigsaw, while actual Highball dimensions and cradle anchor points embedded in the airframe can allow a forensic reconstruction of the cradle. So herewith we begin an episode of reconstructing Highball, or, as an Ed, Edification.

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        • powerandpassion
          Never Be Afraid to Ask
          • Jul 2012
          • 1255

          #44
          Des writes that HB had green and opposing red flat ends. Red for arming pistol, green for SD pistol. You would want to trigger the right end, on an object without any other visual prompts to the armourer. You would need to positively lock the axle so the HB would drop only on command. You would want positive release, so no hang ups and no delay in the release of one side. I can only think that release must have been electric, using a solenoid, all standard 1945 stuff. But how do you contain the axle and allow it to spin, then release? I can only think of an electro magnetic coupling that spun, then retracted from the poles , withdrawing positive engagement from both sides simultaneously. Basically an electro magnetic clutch, default clamping against the HB, with a few seconds of intense current draw, perhaps with a backup battery. I will later tender Exhibits A and B in support of this hypothesis.

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          • powerandpassion
            Never Be Afraid to Ask
            • Jul 2012
            • 1255

            #45
            Hydraulic driving of kilometre long conveyor belts, using pancake shaped motors, is a solution meeting a need for incredible torque on power up. Getting a HB to spin, from 0 to 900 RPM, would require incredible torque to initiate, with a large electric motor or APU or a half ton of batteries. On the other hand, with no hydraulics to operate on a run in, the aircrafts hydraulic pumps could conceivably be applied to do this. But this would require a bit of hydraulic work, make the cradle more complex and eliminate flap use when perhaps wanting to hop over steep fiord terrain before braking to line up on the Tirpitz. Perhaps even 2000 psi of hydraulics delivered in 1/8 lines could not spin up two HBs smartly. Then Des writes that they reversed the wiring on the cradle to create backspin for U Boat application, instead of the usual forward spin. In other words spinning was by electric motor. But how could a puny electric motor provide the torque in the critical task of initiating spin, like a car starting in first gear up a steep hillside? Suddenly the air turbine makes sense! No way could an air turbine create 900 RPM in a smart and easily controllable manner. But prop driven drouge winches were well established technology generating good torque with no draw on electrical or hydraulic systems. So at a cost of drag, the pilot could pull a cable to engage a free wheeling turbine to a mechanical gearbox initiating spin on the green side of a HB, and an unengaged electric motor on the red side. A tachometer would indicate when to disengage wind power and engage electric, so for the pilot a cable pull then a variac. Ohhh! Someones pounding on the door. Theres a black van pulled out the front and men in sunglasses! I got t

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            • Nicko
              Rank 5 Registered User
              • Mar 2013
              • 156

              #46
              I think that there is probably a lot more technical info out there somewhere and research to find it will yield useful info. My suggestions are that the RAE report(s) on the prototype (DK290/G) be sought. From what I can tell the installation in the DZ series aircraft was called Series II (although this might have been somebody's concoction that persisted), and therefore that the prototype was effectively Series I. I believe that the RAE reports would have to include functional testing of the equipment and therefore if they have issues, the report would recommend improvements. If the UK reports are styled the same as some of the Australian reports then they may include specific technical suggestions for fixing problems. Also, who actually made the installations? Was it DH or the RAE/RAF?
              http://www.plastivitrine.net.br/pap_...oivhb_jfj.html
              This website has what is probably the best photo of the install that I have seen in my general trawl. References worth pursuing. I'm guessing this is the prototype. The fairings if readily removeable would have been hand fitted as the low-rate production run would have had a seal between the fairing and the fuselage to avoid the hand fitting, to ensure aerodynamic sealing and avoid whistling.
              Let your soul stand cool and composed before a million universes Walt Whitman
              http://vhjet.com

              Comment

              • Nicko
                Rank 5 Registered User
                • Mar 2013
                • 156

                #47
                Thanks to Mike Williams, Neil Stirling, and friends, here are notes on an AAEE report and the report itself (plus those relating to a load of other Mosquitos), about the performance of DK290. DK290 in this report just has a mock-up of the installation. The photos referred to in the body of the report aren't included. This seems to often be the case with a lot of (archive?) copies of research establishment reports I have seen.
                http://www.wwiiaircraftperformance.o.../mosquito.html
                http://www.wwiiaircraftperformance.org/mosquito/dk290.pdf
                Let your soul stand cool and composed before a million universes Walt Whitman
                http://vhjet.com

                Comment

                • Nicko
                  Rank 5 Registered User
                  • Mar 2013
                  • 156

                  #48
                  This I like...



                  http://www.royalnavyresearcharchive....R_Gllery_3.htm
                  Let your soul stand cool and composed before a million universes Walt Whitman
                  http://vhjet.com

                  Comment

                  • TEXANTOMCAT
                    Rank 5 Registered User
                    • Mar 2004
                    • 4658

                    #49
                    I'm sure you already have it but I picked this up for 6 at our local discount bookstore the other day https://www.theworks.co.uk/p/militar.../9781906502515
                    Our Beech 18 & T-6@www.beechrestorations.com
                    Visit Sywell Aviation Museum @
                    www.sywellaerodrome.co.uk/museum.php
                    Sywell Airshow 17.8.2014

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                    • powerandpassion
                      Never Be Afraid to Ask
                      • Jul 2012
                      • 1255

                      #50
                      Thanks for the heads up TT, a good book.

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                      • powerandpassion
                        Never Be Afraid to Ask
                        • Jul 2012
                        • 1255

                        #51
                        For the first time since 1946 a 618 Sq landing gear hook assembly is put together ! Thanks to an excellent article by Eric Winkle Brown on Sea Mosquitos the proper alignment can be deduced and parts that have lain anonymously on shelves can be pieced together. Some of these parts were dug up out of the ground 30 years ago, some came from a Museum store and the hook has been borrowed from the Narromine Aviation Museum for patterning. In comparison to modern hooks the tube arrangement is surprisingly delicate. My punt is that the tube is nickel chromium axle tube only part hardened, to give it strength and elasticity. There is a lot of information on the remnants that helps identify the extra bulkhead 5a dimensions and the internal strakes that spread the landing hook arrest forces through the airframe.

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                        • powerandpassion
                          Never Be Afraid to Ask
                          • Jul 2012
                          • 1255

                          #52
                          I am starting to form the impression that there were a number of evolving design solutions to the Highball cradle mechanism, with the ultimate iteration being designed for fit to Sea Hornets. The earliest solutions were very much like the 617 Sq Dambuster Upkeep mechanisms, with the latest versions being far more resolved 'units'. These days an exocet missile will do what a Highball may have done far more crudely, so a lot of photos are emerging of this previously Top Secret technology. In reading through the histories, everything was very last minute in the preparation of Highball for use against the Tirpitz and later in the Pacific. The 'right' mechanism for 1945 will be something between an 'Upkeep' mechanism, most likely the 'Speedee' lent to the US for appraisal and a good half way to what was eventually fitted to the Sea Hornet.

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                          • powerandpassion
                            Never Be Afraid to Ask
                            • Jul 2012
                            • 1255

                            #53
                            Here is the original Barnes Wallis patent for Upkeep - Highball mechanism. I understand that Upkeep originally had the 'gold ball' shaped covering but that during 617 Sq training the covers made of timber kept shattering. Upkeep training them continued with just the internal cylinder housing the charge and no great disadvantage in performance, for this larger munition applied to dam busting, was observed. So Upkeep has embedded itself into the historical record as a cylinder while the smaller Highball continued as a 'golf ball'. In the patent hydraulic cylinders are used to actuate arms that, like aircraft undercarriage legs, fold away from the munition. The disadvantage of hydraulic actuation is different hydraulic pressure arriving at different actuators, like undercarriage wheels that fold up one after the other. The wheel most distant from the hydraulic pump gets more friction in longer hydraulic lines so less pressure, so folds last. With a munition spinning at high RPM, uneven release could have catastrophic results on the airframe. There would either have to be hydraulic valving that provided equal pressure to both release actuators or a single actuator working through mechanical linkages. Even the mechanical linkages could result in uneven release. All in all an awkward system, workable, but could be better.

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                            • powerandpassion
                              Never Be Afraid to Ask
                              • Jul 2012
                              • 1255

                              #54
                              Here are photos of 'Speedee', stolen from the web, codenamed thus by the US Air Force when testing Highball equipment provided by the UK. This had catastrophic results, as the aircraft releasing the Speedee/Highball did so too low, the munition rebounded into the aircraft and it crashed into the water. I do not think the US thought too highly of this "Limey Bomb" after this and I wonder if this additionally influenced the later reluctance of General MacArthur in deploying 618 Sq Highball Mosquitos in the Pacific. The key thing about Speedee is that it looks like a very early version of Highball release gear, hydraulically activated, as per the patent diagram. The wind turbine is clearly shown, so this aspect of initiating spin was a design feature that appears from the outset. My theory is that the wind turbine was mechanically actuated via cable, based on target towing gear used to wind in a drouge. So it resolved the high torque task of initiating spin, otherwise requiring a large number of heavy lead acid batteries powering an electrical motor, or a takeoff from the hydraulic circuit powering a hydraulic motor. It was a simple, elegant solution. Once the Highball was spinning at a reasonable RPM, as indicated by a standard mechanical to electrical engine RPM tachometer, the wind turbine could be disengaged by another pull on the cable, and a light duty, fixed RPM electric motor operating a belt and pulley of fixed ratio could be used to manage exact RPM. My theory is that the UK supplied fairly archaic prototype equipment for Speedee, while 618 Sq Highball release gear was far more resolved.

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                              • powerandpassion
                                Never Be Afraid to Ask
                                • Jul 2012
                                • 1255

                                #55
                                Here is the ubiquitous image of 618 Sq Highball in service, showing a timber or aluminium fairing around the bomb bay with cohones hanging suggestively underneath. This, and the early Upkeep mechanism, are the default plastic model representations of 618 Sq Highball, but I am not so shure that the Upkeep type mechanism was used in 1945 for the Pacific theatre.

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                                • powerandpassion
                                  Never Be Afraid to Ask
                                  • Jul 2012
                                  • 1255

                                  #56
                                  Here is a practice Highball pulled out of the Scottish lake. What it suggests is that there was no mechanical engagement means for driving rotation of the Highball. The firing pistol, on the green side set for depth and on the red side for time delay, would have required a push or pull to be made 'live'. I am thinking in the sense of a conventional dropped bomb, which had a pin connected by cable to the bomb carrier. The act of dropping the bomb removed the pin from the firing mechanism which then made the bomb live. A similar principle would have applied to Highballs. The Highball 'axle' containing the firing mechanism would rotate around the fixed firing mechanism, which would be activated by the withdrawl of the 'holding plates' from the Highball as it was dropped. The 'holding plates' themselves would have to have a rotating part and a fixed part, connected to the aircraft. The Highball with its smooth, round engagement face meeting the 'holding plate' seems to have no keyway or engagement means except friction. Now metal on metal is very slippery. So a guess is that the rotating face of the holding plate was grippy rubber. In the middle of the holding plate was a fixed member with an engagement means, either a cable or small arm, which pulled as the Highball was dropped, activating the firing mechanism. There appears to be a keyway in the firing mechanism housing 'axle', but this is to align the firing engagement means, not to concentrate the forces rotating the Highball.
                                  Last edited by powerandpassion; 23rd May 2019, 07:49.

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                                  • powerandpassion
                                    Never Be Afraid to Ask
                                    • Jul 2012
                                    • 1255

                                    #57
                                    Now here are some images of the development Highball mechanism for use on the Tirpitz in 'Most Secret Squadron' by Des Curtis. This looks nothing like an Upkeep mechanism, being a 'neat faired box' with a smooth, circular 'holding plate' that must move inwards to engage with the Highball as it is offered up. I will now postulate a radical hypothesis : the 'holding plate' was rubber bladder, that filled with air, gripped the Highball. This would be easy to achieve on the ground, with compressed air being readily available. You would offer up the Highball on its lifting trolley, pump up the bladders and remove the trolley. Where would you find such bladders ? Well they were used in Mosquito Dunlop air actuated brake systems, so the concept was under your nose. This would also allow instant, even release, with an electromagnet controlled valve allowing the bladder to rapidly deflate. More importantly, even if there was uneven deflation, the rotating Highball would not be deflected by a saggy bladder, given the simple physics. So what we are looking for is a doughnut rubber bladder, rotating around a fixed shaft, in other words something similar in concept to a car tyre, where the grippy sidewalls are driving the rotation of the Highball. The only difference is that the air is provided through the axle, as is a valve system which allows this doughnut to rapidly deflate.

                                    The elegant turbine fairing in this prototype looks nothing like the cruder duct in the Speedee setup. From the turbine side, peering inside the 'box' the disc shaped 'holding plate' had to somehow advance to grip and then rotate the Highball. Your correspondent believes this was a doughnut bladder, which could apply a great force, many atmospheres strong, under air pressure. The greater the height and thinner the atmosphere, the stronger this grip would be. Again, it looks like nothing other than friction was relied upon to drive rotation between the smooth face of the 'holding plate' and the smooth matching face of the Highball. Only something like rubber, reinforced with fabric, could achieve this. Fabric reinforced rubber bladders were used in Mosquito brakes, so the technology was unremarkable and readily available to adapt. Think of a doughnut shaped airbag in a modern car airbag system, understanding how you can readily control inflation and deflation rate. In the centre is a mechanism that must either advance or retract to operate the firing mechanism, without rotating itself.

                                    Comment

                                    • powerandpassion
                                      Never Be Afraid to Ask
                                      • Jul 2012
                                      • 1255

                                      #58
                                      When you zoom into the chaps fiddling on the outside of the mechanism, you start to see a bit of detail of this 'centre mechanism'. Is this an electro magnet controlled release valve that had a fixed portion, connected to the fixed 'box fairing' and a rotating portion, framing the port of the doughnut bladder? Come on scared looking chap, have a pint and let us know ! What is clear from this outside view is that there are no articulating arms as per the Upkeep mechanism or original patent image. There is gusseting for the faired aluminium box. There seems to be a white electrical supply cable running to the widget and barely discernible above is what looks like a black pneumatic air supply hose, methinks. These supply cables could not rotate, but the centre of the widget had to. Remember this is the prototype being tested for the Tirpitz, not the later and evolved system sent to the Pacific theatre. This image is as good as it gets in the UK in relation to trying to beat fuzzy US photos of aliens being escorted in gasmasks to a vivisection chamber in Roswell, New Mexico. Click image for larger version

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                                      • powerandpassion
                                        Never Be Afraid to Ask
                                        • Jul 2012
                                        • 1255

                                        #59
                                        Any Squadron should have spares on hand, even for top secret Highball equipment. When 618 Sq was demobbed, they were instructed to destroy everything Highball. But they would have felt a little let down about being passed over for the campaign against Japan, after all the effort of getting to the Pacific and keen just to get home. Maybe they did gas axe Highball equipment but maybe some spares were just dumped with less care. Now here is a mystery piece which was dug up out of the ground in Narromine. Does anybody recognise what it is? It looks like a pneumatic housing with electro magnets. Is this the Highball release mechanism? On the driving side there is scope to fix a doughnut bladder to a rotating 'axle', while compressed air can be supplied or ported out through the centre. There are two fixed elbows on the fixed outer circumference which allow air in and air out. On the other side, underneath the bellhousing, is an array of electromagnets, which would pull or push the centre. This would allow a 'spool valve' arrangement to open or close entry and exit ports for air supply or exhaust, as well as actuate a cable or arm that could make a firing mechanism live. These are all guesses. This could be the internal mechanism of something else, but it fits the theory and it came from Narromine. It looks a little more evolved than the prototype images in the previous post. I will keep looking for more evidence.

                                        Attached Files

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                                        • powerandpassion
                                          Never Be Afraid to Ask
                                          • Jul 2012
                                          • 1255

                                          #60
                                          Here's a picture from the Barnes Wallis papers held by the Science Museum. I reckon this is a postwar Highball cradle for Sea Mosquito and Hornet. There seems to be some commonality between the triangular shape on the outside of the drive mechanism between this unit and the prototype photographs shown previously. Close up, it looks like heavy electrical cable is being provided to each 'drive unit', with a ground starter plug supplying power. The cradle itself is a sophisticated bit of tin bashing, quite resolved, which suggests more leisurely peacetime development rather than the hurried Upkeep-Highball Tirpitz days. The most excellent Hornet and Sea Hornet history contributed to by a certain Dave Collins makes brief mention of Highball setup for Hornet, where delays were associated with the development of a new drive mechanism for the Highballs. Is this the new cradle for Hornet under development at Vickers? I figure that 618 Sq Highball cradles were something between this 'Hornet' version and the prototype version shown above. In any case, the cradle was an aluminium box structure with a unique drive mechanism, not an Upkeep -Speedee type framework mechanism so often incorporated into models and representations. Click image for larger version

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