Hampden Bomber an German Design?
 

What part played Gustav Lachmann (former WWI Pilot) with the design of the Handley Page "Hampden"?

Re: Hampden Bomber an German Design?
 

Lachmann was Chief Designer at Handley Page at the time of the Hampden's conception. The specification was issued in 1932: in 1935 Lachmann gave up this job to specialise in aerodynamic research, but there's no doubt about his importance to the design.

However, this does not make it a German aircraft any more than the Ju88 was an American one, despite the participation of Americans in its initial design stages.

Re: Hampden Bomber an German Design?
 

I would be happy to credit the Hampden to Germany, were to not for the fact that by that criteria they could claim the P-51 Mustang as well!

Seriously, it shows that aircraft design in that era was "global" in a way that non-specialists (especially political leaders) were not aware. This applied, for example, when Stalin had Tupolev arrested when he though the only explanation for the Bf 162 "Blitz bomber" resembling the prototype Tu 2 could be treachery.

Handley Page was there to design the Halifax, in part, because Lachmann's leading edge slate designs (which he had originated working for Rumpler in the Great War) were licensed to Messerschmitt (for money).

Re: Hampden Bomber an German Design?
 

I thought the "Stalin" confusion was with Petlyakov over the Bf110 and the Pe2? Tupolev was arrested before he designed the Tu2. The type number has been said to be that of his cell.

However that was, this somewhat simplifies the matter of slats to give all the credit to Lachmann. HP was using the idea before contacting Lachmann. Bringing him into the company managed to avoid expensive patent legislation whilst being a fairly good idea in itself. The HP company did indeed survive, it is said, largely on the income from the patents on the slats, but Messerschmitt was a fairly small contributor to it. At least, prewar.

I think there are two points to be made on the matter of "national" aircraft. One is that even the Chief Designer is only one contributor to the whole. Many other individuals play their part. The second is that all aircraft are designed and made to national criteria. Such things as chosen alloys (or woods), metal thicknesses, screw fittings, aircraft loading limitations, will all differ from nation to nation. As Eric Brown and others have said, German aircraft smelt differently, presumably due to differing oils and greases rather than crew diet!