I've worked up a speculative 2-view drawing of the HCP-25 based on my assumption that the Hindustan aircraft was derived from the Noorduyn Norseman (any critique or suggestions welcome).
There are two obvious detail differences between the 1950s HAL design and the 1030s Norseman -- the HCP-25's curved vertical tail (more Otter-like than Norseman) and the aerofoil undercarriage attachment stubs. The Norseman had anhedral attachment stubs built up from steel tubing (these simplified the seasonal undercarriage changes required for Canadian bush flying but wouldn't be all that useful in India).
The wings and fuselage are very much like the Noorduyn, differing only in small details -- cabin side windows, twin cabin doors, taller and forward-positioned tail wheel, etc. The wings appear all but identical. The HCP-25's bracing struts attach further out (but that could just be a result of the inboard attachment points). Judging by the fairings, it also seems that HAL abandoned the Norseman's drooping ailerons.
Superficial appearances aside, what suggests that the Noorduyn design influenced Hindustan? As mentioned earlier, HAL was exposed to USAAF UC-64As during WWII. At the end of the war, 39 Norseman were sold in India (1 in China, another 8 left India). Some 28 USAAF UC-64s in India were disposed of for salvage, at least 19 were condemned (although some flew again postwar, eg: c/n 191 (ex 43-5200) as VT-AZR with Mistri Airways, Bombay.*
To me, the strongest evidence of a direct connection is ex-USAAF UC-64A Norseman sold as surplus to the Hindustan Aircraft. This Norseman (c/n 736, formerly 44-70471) was registered as VT-CGS in October 1946. Hindustan cancelled the registration for VT-CGS in 1952. Was the HAL Norseman written off or was it taken to pieces as a pattern aircraft (or even to provide components) for the HCP-25?
Can anyone shed light on any of this?
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* See the Noorduyn Norseman website: http://www.noorduynnorseman.com/
