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Thread: Climbs in large aircraft above 10/10 cloud

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    Default Climbs in large aircraft above 10/10 cloud

    A report regarding high altitude trials with Fortress FK192 states: "The flying time time has been restricted partly by unserviceability and partly by the fact that in large aircraft of this kind climbs above 10/10 cloud have not been permitted."

    The latter part seems like a strange limitation for mid-to-late 1943. Can anyone offer an explanation?

    Robert.

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    Hi Robert

    If you go to www.aerosociety.com and check out Journal of Aeronautical History Paper 2012/06 you will find a pretty detailed history of the work from Boscombe and its predecessors.
    Apparently the first airborne flat plate thermometer was flown in a Fortress, followed on 22/12/43 by the Dobson-Brewer frost point Hygrometer. Dr Brewer was in charge of the unit.

    This work was involved in the first measurement of humidity in the stratosphere. There are comments that the early equipment could not be flown in or near cloud due to changes in ambient solar radiation caused by the proximity of cloud. Put simply, if you fly in or near a cloud it cools everything off, messing up the experiment.

    I offer this only as a suggestion, I did do A level Physics but think 5 minutes in a dark room is now called for after reading all that! Very interesting though and worth a look.

    Also metoffice.gov.uk has a large section on all this and the Fortress use.

    They both say the aircraft was stripped very severely in order to reach 37000 feet. Could this have included the de icing boots, possibly for weight and aerodynamics at this extreme height?

    regards Peter

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    Robert,

    I should have picked that up before sending the paper, but Peter's response has made me look at the statement more closely.

    As you suggested it really is most peculiar and quite ambiguous, especially as he doesn't amplify the statement. Without wishing to state the obvious 10/10 cloud can occur at any level between the surface and 30000+ ft, often a layer no more than a couple of thousand feet, or less, thick, and I cannot believe he is seriously stating the B17 was not permitted to fly in such conditions.

    I suspect, no more, that he is referring to occasions of thick cloud (5-10000 ft +) which could deposit large amounts of moisture or ice on the instruments during a climb, making them unusable for trial purposes. Unfortunately that doesn't really fit with his statement - or operational practice elsewhere.

    Peculiar

    Brian

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    Thanks for your thoughts, Peter and Brian.

    I gather I need to be a member to read the journals...?

    Regards:

    Robert

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    Perhaps the explanation lies with the words "aircraft of this type".
    An analysis of Fortress I losses of the RAF reveals that 90 Squadron lost 3 aircraft and 19 crew in cloud:
    AN522 broke up in cumulo-nimbus cloud 22/6/1941
    AN534 broke up in turbulence 28/7/1941
    AN536 broke up in cloud 9/1/1942

    So until it was sure that the Fortress II did not do the same, a restriction was placed?

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    Hi Sean,

    In the bureaucratic mind its possible!

    However the aeroplanes you mention were Mk I or B-17C models.

    FK192 was a B-17E Mk II and this is two years later. FK192 s contemporaries were all over the North Atlantic in the worst of weathers at this time with no restriction, on ASW and Met duties.
    regards Peter

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    Default Halifax March 1945

    I have seen the official ORS (Op Research Section) narrative report copied from a Court of Inquiry Report for the crashes after take-off through cloud of seven Halifaxes on 6th March 1945 and it states that the RAF have conducted an exhaustive Court of Inquiry into the crashes [approximately 15 to 30 minutes after take-off].

    Two Halifaxes collided, but the other five Halifaxes were lost due to icing having ascended through cloud varying between 2,000 and 10,000 feet and 8,000 to 10,000 feet the Court of Inquiry concluded.

    It was suggested that aircraft be moved to other bases to avoid taking off through similar cloud, but the Met had not forecasted the conditions they actually encountered.

    Mark
    Last edited by Mark Hood; 12th June 2013 at 20:11.

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    Mark,

    Were these involved in an operation or training flights? I only ask because the Bomber Command War Diaries only refers to Lancasters and Mosquitoes as being engaged on operations during the 6th and 6/7th.

    There is a reference to nine 6 Group aircraft being lost in icy conditions soon after take-off the previous night - the 5/6th - implying the accidents occurred on the 5th.

    Just curious (after looking at the pressure analysis)

    Brian

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    Default Halifax March 1945

    Hello Brian

    I have rechecked the date in the photographs of the official file and they have put 6th March 1945.

    I have rechecked the Halifax serials due to Icing and they were given as Halifax NA 184; NA 190; NP 793; LW 210 and MZ 454.

    The crash Log for all of them states 5th March 1945.

    The file indicates that:-
    NA184 took off at 1628 hrs from Tholthorpe and crashed 1 mile west of Dishforth aerodrome approx. 1700 hrs.
    NA190 took off at 1629 hrs from Tholthorpe and crashed near Church Fenton aerodrome at 1659 hrs.
    NP793 took off at 1642 hrs from Linton on Ouse and crashed near Kirkby Moorside at 1700 hrs.
    LW210 took off at 1639 hrs from Linton and crashed on Bishops Thorpe Road, York at 1700 hrs.
    MZ545 [MZ454] took off at 1640 hrs from Tholthorpe and crashed near Little Ouseburn at 1715 hrs.

    Very sad occurrences. Some civilians on the ground were killed too according to Nicholas Roberts.

    Mark
    Last edited by Mark Hood; 13th June 2013 at 22:25.

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    Mark, Brian,

    Your replies to this thread rang a bell for me, and I found what I was looking for in Kevin Wilson's excellent "Journey's End" (Book three of his history of Bomber Command operations). There is a chapter (Chapter 14 - 'A Cold and Silent Killer', pg 266 on) devoted to the raid on Chemnitz on 5-6 March and in particular the losses from icing, including witness statements from the aircrew involved, the Courts of Inquiry, and witnesses on the ground. He notes two civilians by name killed on the ground when one of the aircraft hit houses, plus two soldiers and an Italian PoW killed and a number of other personnel wounded when bombs aboard that aircraft later went up during rescue work.

    If you don't have these books already, I thoroughly recommend all three.

    Jeff

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