Monogram 1/48 XP-47H Hemibolt (Conversion)

             The IV-2220 inverted V-16 cylinder engine was produced by Chrysler for the United States Hyper Engine Program. This engine's projected output of 2,500 horsepower and a weight of 2,430 pounds showed much promise.

            Two Republic P-47D airframes were converted to test this new motor. The resulting XP-47H achieved a top speed of 414 mph, well short of the projected 490 mph. Who knows what could have been with further development to the Chrysler Hemi, as it was still not out of its teething stage. Due to Thunderbolts already in production having better performance and the promise of jet technology no further development was done.

            The Koster XP-47/H kit is vacuum formed conversion kit. The ‘vacuform’ parts consist of two fuselage halves and a jig, to help with proper alignment to the spinner. The prop blades, spinner, chin intake, and rear intake scoops are resin. The parts are well molded and have very little flash.  Also provided is a vac canopy.

            Another kit is needed for this project. Koster recommends either the Monogram or Academy P-47D, a bubbletop or razorback kit can be used. I used a Monogram bubbletop kit. The wings, horizontal stabs, cockpit, landing gear and doors will all be needed.

             I started with the vac fuselage halves. First step was to cut them from the sheet. I used a no. 11 exacto knife blade to score around each part at a 45 degree angle. With that done all that is needed to free them is to pull down on the scrap while holding the fuselage.  This will “snap” them out.  I then sanded down the parts to remove any flash by laying a sheet of sand paper flat and running the halves across it while using the canopy, headrest and front radiator as a guide to know how much to sand off. I continued sanding the fuselage halves until the desired fit was achieved.

            Painting and installation of the cockpit is next. There are no mounting posts or alignment points for it. I made my own mounting posts using sprue from the Monogram kit. Gluing in the headrest first helped to center the cockpit. The fuselage halves do not have any alignment tabs either so I crafted my own using cardstock.  The tabs were then trimmed down and the fuselage halves test fit until they lined up. A toothpick was then used to run CA glue in to the center gap of the two halves to join them together.

            From pictures that I have seen of the prototype, it did not carry guns or wing pylons, so off they came. Removal of the pylons will leave a hole in the wing that can be remedied by the use of cardstock. The shell ejector chutes were also filled in at this time.

            Wing, tail fit and alignment were surprisingly good.  Only a small amount of filler is needed at these joints.

            At this time, the intake, rear wheel well and rear side scoop were attached. The fit of these parts were good, only a little sanding and filler was needed.  One of the side scoops had a small sink hole that was filled.  Mistakenly, I opened the tail wheel bay a little too much.  Cardstock was used to fill in this gap.

            After sanding and filling, primer was applied to access minor defects and flaws. Surprisingly enough only minimal sanding would be needed on the fuselage joint. Afterwards, one more coat of primer was applied prior to painting.

            The two prototypes were painted with olive drab upper surfaces and neutral gray undersides. I used Model Master’s olive drab (FS34087) and neutral gray (FS36270).

            After a coat of clear gloss it is time for decals. No decals are provided in the Koster XP-47H kit, all that is needed though is National Insignias and the tail number. I used the insignias from the Monogram kit, although after market ones maybe a better option. The tail numbers will be a little more difficult.  From what I could gather they were painted in yellow.  The Monogram kits tail numbers were close and also in yellow.  I used these even though they are not correct for either prototype.  A coat of flat clear was then applied.

            Now it is time for the last of the Monogram kit parts. The landing gear and doors were painted and then glued on, as well as the radio mast. Koster provides a single vac canopy.  I mangled the canopy beyond all recognition.  Don’t know what happened.  I cut it three times and it was still to short.  So in the trash it went.  I then turned to the Monogram kit canopy.  That did me no good as I used the bubbletop kit.  As luck would have it I had a Monogram razorback kit in the stash to be used with the Koster XP-72 kit.  A quick test fit showed promise. Some trimming of the fuselage had it fitting well enough. After a little touch up painting it was glued into place with Elmer’s white glue.

 Lastly, the prop/spinner was built.  An alignment jig was provided allowing a smooth assembly. All the pictures I have seen are in black and white, but from what you can tell the spinner is a lighter color than the rest of the plane.  Koster instructs painting it white, so that is what I did.

            Being both a Mopar and P-47 fan I just had to have this kit in my collection. This was my first vacuform kit and I found it to be a challenging, yet fun build. The Koster parts fit well not only to each other, but also to the Monogram kit. This is by no means a wonder kit though. Do to the extra work and skill involved with fashioning the vac parts to line up, I would recommend this kit to experienced modelers only.

            The internet

            Squadron Signal P-47 in Action