Grumman J2F-3 Duck. Lukgraph's kit converted to "Blue Goose" J2F-3 aircraft. Step 1 : validating the conversion concept.

[HubertB]

The Duck has always been one of my favorites, and, in despair of ever seeing one released in 1/32, I was seriously considering launching myself in the dauntring task of designing and 3d-printing it.

Thank God, the prolific Lukasj of Lukgraph has come to the rescue and released a fully 3D-printed kit of the Duck. You can already see an incredible build log of the kit, by member Boch. I am not sure I will be able to match his skills in painting and weathering the kit, but his build is a great indicator of what can be done with this marveouis kit.

 

There is however a slight twist to my build (as you could expect  ) ...

 

Lukgraph have chosen the J2F-5 version, which was characterised by a long-chord engine cowling, and wore mostly wartime camos.

 

I like my kits not too war-like, and especially not too camoed. So my choice fell upon a J2F-3, BuNO 1539, used as the personal aircraft of Rear Admiral William Brown when he was commanding the US Naval Academy in Annapolis, in 1939. It's a typical "Blue Goose" aircraft, with an Admiral blue fuselage, and silver wings and empennage. However, some pics of the said aircraft lead me to believe the upper wing was chrome-yellow : when applied  the yellow was overlapping a part of the underwing at the leading-edge. And one pic of this specific aircraft, taken from the front, shows a distinct darker area (vs silver) on the leading-edge of the upper wing, which I interpret as chrome-yellow. 

 

The J2F-3 was different from the -5 however.

 

So, before committing to this version, I had to understand the differences. They focus mainly on the cowling, which was short-chord, and the front fuselage fairing, which had a different carburetor airscoop, a fairing for the oil-cooler scoop, and distinct louvres to evacuate the air from the accessories compartment.

BuNo 1539 also sported a bomb-rack under the lower wing, which, unless I have missed it in the kit's extensive parts count, has not been represented by Lukgraph.

 

So, these parts had to be designed and printed in 3D, before converting Lukgraph's kit the -3 version. In the design process, btw, I found out that the front fuselage fairing, above the float, as designed by Lukgraph is too "flat" and not rounded enough. The way the engine bearer is represented is also completely fanciful, and the front fuselage too short, but this is of little consequence for the -5 version with its long-chord cowling, which will hide the issues. 

 

I am happy to report that the design of the conversion parts is finished, barring some (probable) mods when I try to mate them to the kit.

 

The new cowling, in two halves :

 

 

The underwing bomb rack was a rather involved piece of design :

 

 

And, finally, and most importantly, the front fuselage fairing, with the new carburetor scoop, the oil-cooler scoop, the revised profile and the louvres :

 

 

You can see that the engine bearer ring has been designed as an integral part of the new fairing.

 

I have also opened the metalsmith workshop. Lukgrpah's kits tend to be heavy, and the Duck will be no exception. When converting the Potez 25 to the TOE version, the weight of the solid wing was 186 grams, and I went to great lengths to have the landing gear reinforced with metal rods. On the Duck, the representation of the landing gear in printed resin is beautiful, and scale accurate, but I suspect it will not bear the weight of the finished kit. This suspicion is reinforced by a cryptic remark in the instructions (cryptic surely as a consequence of translating from Polish to English) that mentions adding additional supports to avoid the splaying of the landing gear.

 

So I have undertaken to redo the whole landing gear in soldered brass. More on this in a later post.

 

Hubert.

[Fran]

Can`t wait to see more of this build!