Shipbucket

Its really great to see that we convinced you to carry on with your fine work.
These Hampdens and Herefords (I'm sure there are more of these to come) look great. First time I've seen the Swedish Hampden represented too.

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H.P.52 Hereford

A production run of aircraft with the alternate Napier Dagger engine was constructed by Shorts in Belfast, differing from the Hampden solely by engine and the fact that the tailwheels were not retractable.



The Hereford performance was identical to that of the Hampden, but the Dagger engine was very noisy (running at a higher RPM) and unreliable. The Hereford were quickly withdrawn from combat, with some being relegated to training units, but most being re-engine to become Hampdens.

H.P.62 Hampden Mk.II

As an insurance against lack of supply of Pegasus engines for Canadian production of the Hampden, two aircraft were fitted with Wright Cyclone engines to become prototype H.P.62 Hampden Mk.II's.



However there were no engine supply problems, and the two prototypes were converted back to standard Hampden B.I's and placed in squadron service.

Good work. Keep it up!

Unbuilt Hampden projects

Several development projects of the Hampden were worked on, although none progressed even as far as being allocated an HP design number.


https://i.imgur.com/WNNA6Vq.png
While the Hampden was still on the drawing board, HP tendered a design to specification M.15/35 for a land based torpedo bomber. This design used the wing and tail of the Hampden, married to a widened, beefed up fuselage able to mount a dorsal turret and able to carry the largest torpedo internally. The tender was declined in favour of the Bristol type 152 Beaufort.



The above design was published in Flight magazine in May 1936. It appears to show an enlarged, single-tail, semi-swept wing Hampden potentially with Sabre or Vulture engines. This aircraft is described in the magazine as a development as the still-on-the-drawing board H.P.53 Swedish seaplane. This is before the issuing of Specification P.13/36 which eventually led to the Halifax, and I can find no other reference to the existence of this design???

Finally, in November 1938 HP suggested an enlarged Hampden with wider fuselage and either Merlin or Hercules engines. The RAF would have placed this aircraft into service immediately if it was available, but were not willing to wait the 18 months required for development - instead needing HP's resources to be devoted to the Halifax. However the traces of the Hampden design surfaced again in the initial, unbuilt H.P.58 Halifax B.II design.

Unarmed bomber concept

Although not a part of any design tree, and actually a concept design rather than an actual aircraft design, I'm including the alternate proposal for Specification P.13/36 as an indication of the direction HP wanted to take the bomber before WW2.



HP tendered the H.P.56 to bomber specification P.13/36, which eventually led to the Halifax, in parallel with Avro's Manchester. However the team that were working on the project that would eventually fly as the Halifax also looked at producing a superior aircraft to the specification by removing the heavy, draggy defensive turrets. HP's research produced a sleek bomber that would have been virtually invulnerable to fighter interception by being as fast as a Spitfire.
The RAF were interested in the concept - describing it not as an unarmed bomber, but rather a highspeed bomber. But the RAF were not in agreement with HP's optimistic performance figures, and HP continued instead with their work on the design that eventually became the Halifax. The Halifax design saw a gradual adoption of aspects of the highspeed concept, with turrets being continually dropped as the Halifax design developed, a trend that was also followed by Avro on the Lancaster.
The concept was also further investigated by the RAF by Ian Flemming, of later James Bond fame. He agreed entirely, modelling a significant reduction in crew loses with higher speed bombers flying without multiple gunners. The unarmed highspeed bomber concept was eventually passed to De Havilland who produced the Mosquito as the embodiment of HP's original concept.

Impressive!

H.P.75 Manx

With design work starting in 1936, construction starting in 1938, first taxi trials in 1940, first flight in 1943 and allocation of name and HP design number in 1945, the gestation of the single H.P.75 Manx test aircraft was very protracted.



With the completion of the H.P.52 design programme, Lachmann further continued his work on designs eliminating the drag and weight penalties of conventional tail units, which he considered to be a totally parasitic appendage able to be minimised or removed with improved wing design.
Looking to hand build a prototype, the facilities at HP were too committed to building bombers, so the work had to be subcontracted out to a small glider manufacturing company, which eventually had to be bailed out from extreme financial problems. One aspect of the design that never reached flight status was a novel HP improvement to a standard canard forward wing, named a rider-plane. By adding a leading edge slat and trailing edge flaps the rider-plane is able to be 50% smaller than a canard, although with significantly increased complexity. The design of the rider-plane progressed even slower than that of the H.P.75, and was only completed and ready for flight testing by the time that the H.P.75 was already completed its flight programme.
With the start of WW2, Lachmann as still nominally a German citizen was interred and sent to Canada. Under special request from HP Lachmann was eventually transferred to the Isle of Man, but the imprisonment of the chief designer added even further delays to the programme.
The initial design had no fuselage vertical tail, fixed nose wheel but retractable main wheels. Initial taxi trials were started in early 1940 without a canopy as the locking and latching mechanism of the canopy was unworkable.
Before passing on to actual flight trials, an additional tail surface was added to the fuselage. Eventually painted in military colours, the aircraft first flew in 1943, and was revealed to the public in 1945, where it was named Manx and finally allocated an HP model number. The name Manx was doubly apt, both for the tail-less cat breed and for the site of Lachmann's imprisonment.
Modifications during the flight programme included modified air intakes to cure persistent engine overheating problems, a nosewheel fairing in a failed attempt to centre the nosewheel in flight, and the addition of a hand rail across the top of the airframe.
The test flight crew were both killed in the Hermes crash, and again the programme was put on hold, and the aircraft only flew another two times in 1946, before being withdrawn from service and destroyed in 1952.
The Manx's performance was poor, but it proved the soundness of the Lachmann's tailless wing planform design.

Great work!

H.P.75 development

In March 1944 HP proposed a 15 tonne tailless transport design as a scale-up of the H.P.75, while being a practical size for a study on fuselage layout.



The aircraft was proposed to the RAE to compare against an all-wing and an orthodox aircraft design. The Tailless Aircraft Committee instead recommended the development of an all-wing aircraft with a low-drag airfoil section and jet engines which led to the Armstrong Whitworth A.W.52 flying wing, and effectively the rejection of this design and any civil derivatives of HP's canard 70-tonne bombers.