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Thread: Blenheim IV vs Maryland

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    Default Blenheim IV vs Maryland

    Hi guys

    How did these two aircraft compare? The Maryland was slightly longer with slightly greater wingspan, but had more powerful engines. Therefore it was faster but I understand not a great performer above 10,000 feet.

    I would appreciate comments, please.

    Cheers
    Brian

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    Brian,
    My understanding is that the Maryland (in 1940/41), was greatfully favoured for its speed and range, and was therefore highly sought after as a PR aircraft in the Mediterranean theatre in particular, although I believe the FAA also used it to a certain extent for some PR sorties to Norway early in the war. The greatest disadvantage of the Maryland was its very cramped crew quarters (it seems that the designers probably made this aircraft just a bit too tight a fit for average sized humans), but if they could squeeze into it they had themselves a worthy steed for their hazardous occupation with a fair chance of securing their photographs and getting safely home. By way of comparison, the lower-powered Blenheim had a rather indifferent performance and consequently tended to suffer a rather higher loss rate when used on PR operations (or any other operations for that matter), but as this aircraft was kept in production and the Maryland was not, the limited number of Marylands in RAF service were slowly frittered away on operations. The Maryland was of course replaced in production by the heavier and more powerful Baltimore, but the latter aircraft seems not to have been favoured for PR work, although by then of course superior aircraft for this specialised work were becoming available.
    David D

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    Default Blenheim v Maryland

    Thanks David

    Most interesting.

    Cheers
    Brian

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    Brian,
    Have since had a read of the Profile Publication No. 232, by Christopher F Shores and published in 1971 (which covers the life and times of the Maryland and Baltimore in some 24 pages), and this tends to confirm my first post (which was largely based on memory). However it is obvious that although the Maryland was almost certainly the only aircraft available which could have undertaken the PR mission for the RAF in the Mediterranean theatre in 1940/41, it was getting hard pressed through much of this time by the opposition, although it suffered more badly when used in small formations in daylight raids which tended to result in indiividual aircraft loosing their freedom of action.
    Although the original prototype (XA-22) was powered by P&W Twin Wasp (R-1830s) radials, most of those aircraft supplied to the French as Martin 167Fs were powered by single row 9-cylinder Wright Cyclones (R-1820s) turning Curtis electric propellers. The later aircraft (including most of those supplied to the RAF) tended to have the Twin Wasps with Curtis propellers, and I suspect that the Maryland was probably the first aircraft to serve in the RAF with full feathering propellers, which would have been a great advantage on operations whhen the going got tough.
    I have always thought the Maryland an asthetically pleasing aircraft from most angles although some will be put off by the rather over-prominent "glassed in" nose, which reminds me more of other French, Italian, Polish and Russian bombers of this era.
    David D

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    Brian,
    Something else I forgot to mention (and was previously unaware of until I re-read the Profie publication) was that many of the RAF Marylands were powered by Twin Wasp engines with two-stage superchargers (NOT just two-speed), possibly also a first in the RAF. It is little realized that the P&W Twin Wasp was the first engine in this form to go into prooduction and front-line service, initilaly I believe in the F4F-3 Wildcat naval fighter. Such an engine would have been a great advantage, I would have thought, to an aircraft being used for PR work.
    David D

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    I think that is worth checking, as the US were not noted for two-stage superchargers (the Allison in the P-63 comes to mind) being more interested in pursuing the turbocharger route. I don't recall seeing that noted against the Twin Wasp anywhere else, and the Maryland, like other TW-engined aircraft, appears to lack the additional intercooler that would be required.

    The same comment does appear in Putnam's Aircraft of the Royal Air Force, although not in any reference I can find to the TWs in Hudsons or Wellingtons.

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    Graham,
    I do not think there is any room for doubt that P&W introduced the two-stage supercharger on the R-1830 Twin Wasp, as a check of any reputable reference will confirm. For instance Bill Gunston's World Encyclopaedia of Aero Engines (1986 edition) on page 111 notes that "In 1936 Mead and Hobbs set the company on course again, concentrating on the R-1830 with single-stage and two-stage or turbo-chargers, and embarking on the big R-2800 Double Wasp ...". Also Putnam's United States Navy aircraft since 1911 (Swanborough and Bowers, 1990 edition on page 223 in the F4F Wildcat chapter) notes that "... in October 1938 the Navy contracted for the XF4F-2 prototype to be rebuilt after a crash, powered by a Twin Wasp with a two-stage two-speed supercharger, the XR-1830-76." "The first flight of the XF4F-3 was made on February 12, 1939, and in subsequent Navy trials a speed of 333.5 mph was recorded at 21,300 ft, ample evidence of the improvement bestowed by the two-stage supercharger." This source also notes that initially the new two-stage engine suffered from "major" engine cooling problems in the early stages, and to guard against further major problems in service, the US Navy ordered 95 F4F-3As with R-1830-90 engines with single-stage superchargers. However the vast majority of the F4F-3 and -4 versions were powered by the two-stage engine. Any detailed reference for aero engines such as Janes AWA lists the wartime two-stage P&W Twin Wasps along with the single-stage single and two speed versions (as used in DC-3/C-47/C-53, PBY Catalina, PB2Y Coronado, etc) as well as the turbo supercharged versions as used in B-24s, etc.
    I am unaware of the exact sub-type of Twin Wasp fitted to the Wellingron Mk. IV, but my guess would be that this was a single stage two-speed version.
    David D

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    The designations given to exported engines are not in the -xx number sequence but civil designations such as SC3G (not intended as an actual example, but to demonstrate the format). I don't have any work that would correlate these.

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    According to the P&W engine index Wellington Mk IV was powered by 1830-90B, 1200hp and the table gives two impeller rations, 7.5:1 and 8.47:1. So IMHO 2-speed. It is mentioned that it was sold also commercially.

    Juha
    Last edited by Juha; 15th November 2010 at 17:56.

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    The Wellington was initially re-engined with the SC3-9, but this was cancelled and I cannot find the designation for the engine in the later Mk.IVs, so thank you Juha.

    Turning to Putnam's Grumman history, the R1830-90 was also the engine fitted to the F4F-3A/Martlet Mk.III and is described as a single stage two speed engine. Other F4Fs had the R1830-67 (later -86), which is described as two speed two stage, although I haven't found the performance quoted at two full throttle heights.

    However the G-36B Martlet Mk.II was fitted with the S3C-4G single stage two speed engine. If we turn to Marylands sources agree that the Mk.I has the SC3-G single stage engine, and the S3C-4G (or S3C4-G) engine. This is the engine described as single stage when fitted to the Martlet. The Maryland profile repeats the story that it is a two-stage engine, but the Martin Aircraft History 1909-1960 by Breihan/Piet/Mason only states two speed.

    To me, this says that P&W had 2-stage engines but did not sell them for the Maryland. I remember getting confused between 2-speed and 2-stage engines when I was younger, and feel that this has happened early in telling the Maryland story, and the same error has just been repeated by following historians.

    Perhaps more information can be squeezed from Juha's listing?

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