Finally, a way to build the Allison V3420-powered XB-39 in 1/72
scale! This conversion includes two
outer nacelles, forward stubs for the inner two cowlings, and four spinners.
For the inner nacelles, assemble the kit’s plastic nacelles,
then cut off most of the forward section, just forward of the wing cutout. Trim the resin cowling to fit and
attach. You will need to then smooth out
the joint with putty. The kit landing
gear wells and doors don’t need to be modified if you can fair in the cowling
ahead of the well.
The inner engine cowlings are both interchangeable. They are not right or left-handed as the
exhausts are all on the port sides of each nacelle.
The outer engine nacelles are also interchangeable – the port
and starboard sides are the same. This
is because they mount perpendicular to the wing and the exhausts are both on the
port sides of the nacelles.
Regarding the orientation of the cowlings about the roll axis
(as seen from the front), the drawing
from “US Bombers” incorrectly shows the intake tops (the flat surface) parallel to the
ground. The one frontal photo that I
could find (“Cleveland Tank Plant” book) shows those intakes parallel to the
wings, in other words, aligned with the wing dihedral. FYI, the B-29 wings had a dihedral of 4.5
deg. The B-29 “Doc” recently made an
appearance in my town and I was able to confirm with certainty that B-29
nacelles are indeed perpendicular to the wings (the Academy model is
wrong). Given that and the photo of the
XB-39, it’s pretty clear that the XB-39 nacelles were aligned to the wings, not
the ground.
You will need to adapt the kit propellers and fabricate exhaust
pipes. Make the intake splitters with
sheet plastic. There are also several
small intakes scattered around the outside of each nacelle that you will need
to fabricate.
Fisher Body was contracted to replace the four Wright Cyclones
on the first YB-29 Superfortress prototype which was named “Spirit of
Lincoln”. Since the V3420 was
essentially two V1710 12-cylinder engines coupled together, this particular
B-29 was basically an eight engine bomber with four propellers!
Unlike those other ill-fated attempts at building coupled V-12
engines (He177, Manchester) the V3420 was actually a reliable engine that could
have seen service. If it hadn’t been for
the excellent 28-cylinder P&W R4360 “corncob” radial engine and the
turboprops then in development the V3420 and B-39 probably would have seen
production. The follow-ons to the B-29,
the XB-44 & B-50, used the P&W R4360.
The only external differences between an early B-29 and the
XB-39 were the four very large nacelles for the water-cooled V3420
engines. Being an early prototype, it
was painted OD and Neutral Grey, so if you (like me) don’t like to deal with
natural metal finishes, here’s an opportunity!
Just the engine nacelles and the wing and tail leading edges are all
bare aluminum. The rudder (which is
fabric covered) appears to be painted with aluminum dope.
The new nacelles have a graceful sloping shape that took me
months to properly grasp based on the few available photographs. They were based on the nacelles that Fisher
Body previously developed for the huge Douglas XB-19. Photos of the modified XB-19 are also helpful
(be aware that those nacelles are not exactly the same as the XB-39). If you want to superdetail the engine
compartment, there are a couple of great XB-19 photos that show the panels
removed.
In the cockpit, the XB-39 pilot and copilot instrument panels
had a longer top extension compared to the B-29s. That is not included in the conversion set.
This is a major conversion and requires some skill. For experienced modelers – requires sourcing
small parts, fitting and aligning, filling dimples, use of CA glue, etc. Wash parts thoroughly and wet sand with 800
grit wet/dry paper to provide a good surface for priming.
Part(s) will be mailed in a padded bag. If ordering multiple items, please place them
in your cart first and shipping will be combined automatically.
From a smoke-free home.
Sold as-is, no warranty or returns.