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Sheepster
Post subject: Re: Handley Page "heavies" family treePosted: September 20th, 2018, 7:31 pm
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ForceA1 wrote: *
Are the dorsal and ventral turrets meant to be the Boulton-Paul Type H and Type O? I'm not aware of any other 20mm cannon armed designs that would be available in 1939.
Yes. The tail turret was also considered to be replaced by the twin gun Type D, but in the event that turret was not available until 1944.


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eswube
Post subject: Re: Handley Page "heavies" family treePosted: September 20th, 2018, 7:32 pm
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Great work! :D


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Hood
Post subject: Re: Handley Page "heavies" family treePosted: September 21st, 2018, 8:32 am
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The thought of the whole Halifax, Halton, Hermes, Hastings lineage in FD is making my mouth water!

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Sheepster
Post subject: Posted: September 22nd, 2018, 6:33 am
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H.P.59 Halifax II

The continuous fine-tuning process to get the relatively poor performing Halifax to fulfil its potential were continued with aerodynamic improvements into the Mk.II series.

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The initial B.II's were actually still identical to late model B.I's. As production developed the Lockheed Hudson-style dorsal turrets were installed and the rear antenna masts removed.
To counter the glowing exhausts which were considered to be too visible for a night bomber asbestos shrouds over the exhausts were trialed.
As the Halifax's role was not just bomber, but also as a transport Halifaxes were used to support SOE and partisan activity in captured territory. Not being bombers these aircraft had reduced defensive armament to allow greater speed and range. The nose turret was removed and replaced with the variously named Tollerton/Tempsford Z-nose, creating the B.II (special).
Experience had shown that defense against frontal fighter attacks was not required for bombers, and some aircraft were initially modified in the field to have the bulkw,drag-inducing nose turrets removed. Although initially labeled B.IIZ, common usage has led to all Z-nose aircraft being referred to as B.II(special).
To increase the defensive armament the four-gun Defiant-style turret was adopted. Initially mounted raised, later aircraft had a more aerodynamic lowered positioning.
Some aircraft were allocated to Coastal Command as GR.II's (General Reconnaissance). Most aircraft were equipped with the naval version of H2S, the ASV Mk.III.
Further streamlining the Halifax nose led to the complete recontouring of the nose, rather than just removing the turret, with a further revised model becoming the B.II series 1A (HP seemed to be rather reticent about changing the model numbers). Additional aerodynamic refinement was devoted to the Halifax's inherent directional stability problem. It was determined that disturbed airflow from the nacelles was to blame, and an extended nacelle was successfully trialed on the series 1A testbed - although this modification was not carried forward into production aircraft.
The revised nose contour was now filled with a glazed nose, mounting a single Vickers K gun. The gun was referred to by crews as a "scare gun" as it was completely underpowered for defense, but with tracer ammunition attacking fighters were unaware of the gun's impotence.
Series 1A aircraft were also allocated to Coastal Command. For better action against U-boats, the scare gun was replaced with a heavier weapon, necessitating additional strengthening on the gun mountings.
An alternative method of correcting the directional stability problem was by reworking the shape of the rudder. The definitive rectangular rudder, once the design was finalised, was used on new build aircraft and retrofitted onto aircraft already in service.
Continuing aerodynamic testing revealed that the root cause of the Halifax's poor performance was interferance drag from the mounting position of the engines. An alternate Lancaster-style low slung mounting was trialed for the B.II series 2 prototype, however official interest in further reworking the Merlin Halifax had waned, and design and production was instead transferred to the radial-engined B.III.
As a final post-script to the B.II several aircraft that had been returned for scrapping with their squadron re-equipping with more modern bombers, were instead not scrapped. They were instead unofficially converted to a freighter configuration for shipping disassembeled Spitfires. The bomb bay was removed and solid metal plates placed on their side, to provide sidewalls for the fighters to be underslung. These aircraft were the last flying B.II's.


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Sheepster
Post subject: Posted: September 22nd, 2018, 7:10 am
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H.P.63 Halifax V

Supply problems with the undercarriages for the Halifax led to a replacement of the gear with an alternate Lancaster-style gear. As the designation B.III had already been allocated to the radial-engined Halifax project, and B.IV to the advanced Merlin project, the B.V was entered into production first. Apart from the gear, the B.V was identical to the equivalent B.II model.

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The new gear castings were quickly determined to be inherently weak, and so the Mk.V was restricted in take-off weight. For this reason the Mk.V's tended to be used in the maritime, transport and glider towing roles.
For paratroop and glider towing duties Mk.V series 1 aircraft were designated A.V series 1 (Airborne Forces), with the H2S access converted into a paradrop position with external baffles.
As the Mk.II and Mk.V were identical airframes, the aerodynamic developments of the B.II were mirrored in the B.V and A.V.
Coastal Command GR.V's were used not only during the day, but also used in the night patrol capacity. These night use aircraft sported the standard bomber command night camouflage, but with grey rather than red identification lettering.
Also the Mk.V's were used for weather reporting, these aircraft being referred to as Met.V's. Many of these aircraft were fitted with the Preston-Green ventral turret, which although trialed on the bombers had not been widely used.


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eswube
Post subject: Re: Handley Page "heavies" family treePosted: September 22nd, 2018, 9:10 am
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Awesome work! :)


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Sheepster
Post subject: Posted: September 22nd, 2018, 1:36 pm
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H.P.60A Halifax IV

The ultimate Merlin Halifax.

[ img ]

The Merlin-engined Halifax finally had its performance problems rectified in the Mk.IV. Higher powered Merlin's in underslung power egg cowlings, fully enclosed main landing gear, reworked retractable tailwheel, extended cowlings and extended wings, added to the extended bomb bay finally allowed the Merlin Halifax to live up to its potential.
However frustration with the Merlin variants had already sealed the fate of the Merlins, and all attention was concentrated on the Hercules radial engined Halifaxes. The prototype B.II series 2 aircraft was prepared for modification, but was never completed.

While rivals Avro seemed to have been at a disadvantage with the Vulture engined Manchester put into production while HP dropped the Vulture and went straight to the Merlin, this was not to be. The Manchester/Vulture combination was an unmitigated failure, but Avro was able to work through the aerodynamic issues so that when the decision was made to go to Merlins the new Lancaster was a world beater from the start. HP went through the fine-tuning of the Halifax at a slower rate and had finally created a world beater with the Halifax Mk.III. However the Lancaster was seen as a fantastic aircraft from the start, and the farce of the Manchester seen as problems from a completely different aircraft. The Halifax though was always haunted by the substandard performance of the Merlin models. Perhaps if HP had renamed the Mk.III as the Hastings Mk.I history would have considered the late model aircraft more favourably.

The difference in performance between the Merlin and Hercules Lancasters, and the Merlin and Hercules Halifaxes shows an interesting feature of aerodynamic interaction between engines, propellers and airframes. Although both engine type were equivalent on paper the Merlin worked well on the Lancaster and poorly on the Halifax, whereas the Hercules performed poorly on the Lancaster and well on the Halifax. The problem was how to mount the engines - wide footprint short radials versus the small footprint long flat engines. The mounting of the Merlin worked better in the Lancaster-style underslung position, as was finally determined for the Halifax B.IV, while the Halifax's original mid-wing mount was ideal for a radial engine. Unfortunately for the Halifax, this knowledge came too late to keep Merlins.


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Rhade
Post subject: Re: Handley Page "heavies" family treePosted: September 22nd, 2018, 3:03 pm
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Excellent job!

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Sheepster
Post subject: Posted: September 22nd, 2018, 11:21 pm
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H.P.60 and H.P.59A "Ideal Bomber"

Why was the Halifax IV given the odd H.P.60A designation?
Because H.P.60 had already been allocated previously, out of sequence.

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In 1939 the "ideal Bomber" specification was issued, which led to the Avro 680 four-engine Manchester design and the Bristol 159 already modelled on SB. HP's design was based on the Halifax, but from this distance in time no diagrams or pictures appear to still exist. Only this one photo of a model included in Buttler's "British Secret Projects" which may not even be the H.P.60.
To confuse foreign espionage the project was given the H.P.60 designation, and the 9/20 scale flying prototype also ordered given the unexpected H.P.59A designation.


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Hood
Post subject: Re: Handley Page "heavies" family treePosted: September 23rd, 2018, 8:49 am
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While I agree attempting to draw the H.P.60 would be difficult without any line drawing to base it on, I noticed that the H.P.60A tail surfaces and boom look quite similar in layout. Perhaps suitably rescaled they could form the basis of something to work from but of course the lack of ventral details would make it highly speculative.

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