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Thread: Help to Identify aircraft part please

  1. #1
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    Help to Identify aircraft part please

    Hi Guys

    I was at Flying Legends last week helping out on the Typhoon project stall. I was chatting to a chap about RB396 and he showed me a photo of an item he had been given some years ago. He said it had originally come from a crashed aircraft somewhere near RAF Usworth. He asked me if I could identify it - I couldn’t but I thought somebody here might have an idea
    There are various numbers on the aluminium joiner sleeves. - PD62708AR, PD32708AL and another bigger number, PA31079
    It seems to be some kind of differential unit driven by the centre sprocket. The joiner sleeves are about 35 mm diameter and the sprocket about 90 mm across. It has wood pressed in each end of the steel outputs presumably to stiffen them from distorting. Possible traces of dark green paint on one tube.
    Any assistance gratefully received!
    Attached Images Attached Images  
    pb::

  2. #2
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    Possibly Miles-Percival in the aircraft manufacturers parts list PAC and PPA is near to PA/ PD. 17G could be balloon

  3. #3
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    It's a differential gearset of some sort. I'm suspecting controls but can't imagine where it was utilised - unless it's some sort of mixing unit.

    Anon.

  4. #4
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    I thought it might be part of an autopilot, but that is just a wild guess!
    pb::

  5. #5
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    Its a bit like a car differential where the big sprocket would turn both shafts simultaneously in the same rotational direction but the pair of shaft can also be rotated on opposite directions, flaperons perhaps.
    Did any aircraft use rotating drive shafts to function control movement.

    Richard
    "Where are you from?"
    "America" Somebody laughed politely.

  6. #6
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    Taking a clue from what scorpion63 said about this possibly being something from Miles/Percival which obviously links to Hunting as well and going on my previous post on it being part of a differential control system. Could this be something to do with the Hunting H.126 research aircraft, XN714 survives at Cosford and another was part built, never completed, before disposal from Aston Down, has anyone seen pictures of the Cosford one with the panels off, its all a bit unlikely I know.

    https://www.flightglobal.com/pdfarch...0-%200477.html This part might even be visible in the image from Flight 1963.

    Richard

    Richard
    "Where are you from?"
    "America" Somebody laughed politely.

  7. #7
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    Thank-you all for your interesting responses. It's remarkable how often parts are identified on here, but I guess even with a part where there are numbers available and the item has a clear mode of operation that is not always possible

  8. #8
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    Is it not for aileron? I seem to recall something similar possibly off a B17 but that part I am sure is British
    SMOKE SMOKE GO!
    TA out

  9. #9
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    It reminds me of a differential control/flap unit, where the main lever controlled the flaps or ailerons via the main gear to operate them both, but some element of roll control was available via the differential.

    It's obviously old because anything after the 1950's would have had hydraulically operated controls. Seems to me it certainly came from a smaller single or twin-engined aircraft type but big and expensive enough to justify such a piece of good engineering. Most likely military.

    Anon.

  10. #10
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    looks like the inner differential control for a turret of some type, tank or aircraft, i have never seen an aircraft with a differential type flap control but could be wrong.

  11. #11
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    Not necessarily pre 1950's, the flaps and slats in the Panavia Tornado are rotating mechanical control runs with a similar arrangement, hydraulically driven by a central FSDU (flap slat drive unit).

  12. #12
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    Pogno's suggestion of H.126 is worth following up - it did have an unusual control system, including something at the tail which may well have had a differential control linkage.

  13. #13
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    I will see if I can find more information on that particular aircraft, thanks

  14. #14
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    Looking at the pics again, and the part numbers; the sleeves appear to be marked L (left) and R (right) so at least that rules out a vertical installation.

    Hydraulics weren't (or were very rarely) used on small aircraft, cdmurray. My guess is a small twin or small-to-medium single.

    Still very curious as to what it came off.

    Anon.

  15. #15
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    The purpose of a differential is to usually allow two driven shafts from one single input, to turn at different speeds whilst travelling in the same direction of rotation not, in an opposite direction. They will however, rotate in different directions if force is applied to one side only.
    Given that the drive appears to be from the chain sprocket, I would think that the rotational input speed is relatively low, (mechanically speaking) but, as to it’s application, I have no idea!

    GYD

  16. #16
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    It says "Controls" to me.

    Anon.

  17. #17
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    This certainly is a good one to puzzle on. Been looking at pics. for a couple of nights now and cannot think of an Aircraft application, even though it seems to have come from a crashed one. I've been trying to think what sort of loads it worked and if the sprocket was 90mm dia. (I have to convert to imperial, lol ) that means it is 4-1/2" dia. just measuring the sleeves dia. against my computer screen and they came out at 35mm, so great. That worked out then for sprocket to have some 21 teeth of 3/16"width x 1/2" pitch. Looking at the hefty cog drives makes me think this would take same sort of loading that a 500cc British single M/cycle would put on its drive system as a 3/16"x1/2" chain was used on the primary drive in virtually most makes circa 1930--40--50-s. And they would be REYNOLDS (UK Made ) Chains. Brit aircraft used REYNOLDS Chains too. So, definitely this unit carried hefty loads.
    Dunno if I'm mis-looking at pics. but it looks like that steel "Band" on left unit up by bevel gear has been brazed on. If it has, that suggests motor cycle design thinking involved here, because up to 1960 all Brit Bikes frames were brazed up and pinned. These kept the build stresses low as against steel welding. This makes me think this Aircraft part is from 1940-50's. Of course, that "Brazing" might just be corrosion so then back to start again. Anyhow, those are thoughts this unit throws at me. Keep it going guys, we all like a challenge.

    Bill T.

  18. #18
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    I'm glad that I was not the only one to think of the motor cycle application Bill. Although I was thinking more of a tricycle drive or, even 'go-kart'! Could it be possibly manufactured from aircraft parts for such a 'ground' use, given the superior quality of aircraft materials??? It was certainly not uncommon for (private) motorcycle engineers to use aircraft materials during the 50's and 60's. The supercharger my Dad fitted on his single cylinder (Velocette) sprint/drag bike is a cabin blower from a Vampire T11!!!

    However, I can also see why Mike suggests a control use, turning the sprocket left or right would give opposite directional movement of each shaft but, it seems a bit over engineered (and heavy), to replace simple bell cranks to achieve a similar action or movement for an aircraft, just a thought?

    GYD

  19. #19
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    Could it be from a split control surface, so that if one portion jams the other can still move?

    I'd hoped the part numbers might have revealed more than they seem to have!
    pb::

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