I want to convert a PBY-5A into a -6A "super cat", these used (at least from what I understand) the same engines and cowlings as the B-25. Is there an actual conversion to the PBY-6A or an aftermarket set of B-25 engines I might use for this?
I will be using the 1/72 Academy PBY-5A Black Cat. I believe the engines are the only required mod, but if there are others I'd apprecite knowing about them.
The biggest change I'm aware of (and there are probably others, but I don't have any of my references here in front of me right now) are the vertical tail surfraces. The -6A vertical surfaces are much taller and slimmer than the tail surfaces on all the earlier versions. I also believe the horizantal tail surfaces were different. See if you can find a copy of Squadron's PBY in Action. That's about the cheapest reference I know of.
About 30 years ago I built a model of of a -6A by taking a Revell model of a 5A and grafting on the tail off or Revell's model of Jaques Cousteau's -6A which was very easy. Actually, if you could find a kit of Cousteau's model, all you would have to do is add the B-25 engine/nacelles and the doors in the belly to create a "Super CAt". (Well, you'd still have to sand off a lot of rivets)
Going from a -5A to a -6A Super Cat is really two conversions at once. Squadron's "PBY in Action" shows -6As in WWII and later Navy service. These have the new tail surfaces (drawings included), plus an overhead radar pod above the cockpit, but engines in the R-1830 series like earlier models. The Super Cat development apparently was a post-war civilian modification with the larger engines and nacelles. This was also applied to some -5As. PBY in Action shows several variations, including water bomber 54E with drop doors and no wingtip floats. These all also lack the radar pod and nose turret.
AM engines are available (try Roll Models), but most likely you'll have to cannibalize a B-25 for the nacelles.
Here's a conversion kit for a -6A that is specifically designed to be used with your Academy -5A
I've seen RVHP products and they are very nice stuff.