The Buchons were in fact Merlin engined 109 airframes. The obvious differences are from the firewall forward. The DB engine was an inverted vee. The exhaust stacks were lower on the side of the nose and it has no chin scoop. The Buchons have higher exhaust stacks and the scoop. Not to mention an entirely different nose profile to accommodate the different engine.
There are only a handful of 109s left flying with the original DB engines. Makes a sweet sound.
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