Mk XIV bomb sight in the Mosquito

Discussion in 'Aviation' started by wuzak, Aug 19, 2014.

  1. wuzak

    wuzak Well-Known Member

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    The Mk XIV bomb sight was designed to operate below 25,000ft. Since the Mosquito regularly operated and bomb between 25,000ft and 32,000ft trials were needed to see how the sight would perform. The report was issued in March 1945 by the Bombing development unit.

    The first obstacle is that the standard air pumps used with the sight did not provide enough pressure for operation above 25,000ft. A new set of pumps had to be obtained and fitted. Even then the supplied pressure was marginal for the sight's operation. The sight was disassembled and modified such that lower pressure was needed for it to work. This had been devised in 8 Group's PFF.

    The next problem was that the practice bomb was known to be inaccurate when dropped from higher altitudes. But it was also thought that using 250lb GP bombs would take too long, as the Mosquito could only be fitted with 6.

    The method adopted was to perform simulated bomb runs. The pilot would call out "bombs gone" when he felt he had an accurate reading for speed, altitude and course. The bomb aimer would then switch off the sight and take its readings. These would be compared and the error calculated.

    The sight was tested at altitudes between 25,000ft and 32,000ft and
    • level flight
    • losing and gaining height
    • bombing in a turn

    It was calculated that the likely error for the sight in a Mosquito was approximately 350 yards which, it was concluded, would probably be acceptable. The error included a figure of 250 yards for "cross trail", which the Mk XIVA did not compensate for.

    Speeds in the test varied from ~175mph IAS to 235mph IAS (at 24,200ft) and 225mph IAS (at 30,300ft). Angles of the bomb run ranged from 4° climb to a 9° dive.
     
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  2. Juha

    Juha Well-Known Member

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    Thanks wuzak, Intresting info!
    225mph IAS at 30,300ft means appr 370mph TAS.
     
  3. wuzak

    wuzak Well-Known Member

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    Might be difficult for any WW2 bomb sight to be accurate from that height and that altitude!

    I don't recall seeing anything about the bomb bay doors being opened. The speed loss from opening the doors is ~20mph, but there also must be a limit at which they can be opened.
     
  4. Greyman

    Greyman Active Member

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    According to the Pilot's Notes: 350 mph IAS.
     
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