Tuesday, April 16

Construction Guide Pt.2: Kitty Hawk 1/48th scale Sukhoi Su-34 Fullback

Andy Moore continues with his build of Kittyhawk's 48th scale Su-34 Fullback in this continuing guide. In the 6th part of the story here on TMN, we see him get to work on sealing a lot of the cockpit. IFR and other minor parts of the aircraft together to make a big difference in the final outcome.

Construction Guide Pt.2: Sukhoi Su-34 Fullback
Manufacturer – Kitty Hawk
Kit Number – KH80141Scale - 1/48th
Price -  ¥10,350 • US $99 • £78 • €87 from Hobbylink Japan
In-Boxed: KittyHawk 1/48th scale Sukhoi Su-34 Fullback
Dry Fit Review: KittyHawk's 48th scale Sukhoi Su-34 Fullback
Review: Zactomodels 48th scale Khibiny ECM Pods for Kitty Hawk/ HobbyBoss Su-34
Galaxy Models 48th & 72nd SU-34 / Su-35S / F-35B Paint Masking Sets
Construction Guide Pt.I: Kitty Hawk 1/48th scale Sukhoi Su-34 Fullback

In the previous instalment of the Fullback build, we got the cockpit built up and painted, and added some detailing to the inner side of the canopy, leaving them ready for installation in the main fuselage. Before we can fit them though, there are a few areas on the fuselage that require some attention. 
The most significant of these being the two mould steps either side of the cockpit. These are remnants of the multi-part mould used to form the upper fuselage part and, left unaltered, they would be very noticeable on the finished build. In the photo below, I've added a black wash to highlight the mould step which runs vertically up the fuselage sides then steps across horizontally to the back of the cockpit opening. 
Since the remedial work would involve a fair amount of scraping and sanding, which would inevitably mean losing some surface detail, I first deepened the panel lines and rivets around the mould step. An engraving tool was used to reinforce the panel lines, while the rivets were deepened using a needle held in a pin vice. I kept the work subtle, but continued to use the engraver and needle during the sanding process if it looked like the surface detail was about to disappear.
The raised step was then carefully scraped back with a knife blade until almost level with the rest of the fuselage. The final finishing was done with various sanding sticks, going up through the grades until the surface was smooth. Any remaining work to reinstate the panels and rivets was done, after which a coat of primer was sprayed over the area to check if any remnant of the step was still visible, which fortunately it wasn't. All in all, not a huge amount of work was required to fix the problem, and no filler was needed which made the process quicker and easier, but it's still work I'd rather not have had to do.
Since I was working at the nose end of the aircraft, I decided to deal with the in-flight refuelling probe next. Kitty Hawk supplies a very nice part for the probe, but it's only designed to be installed in the extended position, which seems a slightly strange design choice to me. Luckily, it's not a big job to modify the part so it can be positioned in it's regular retracted position. Of course, if you want to display it extended, then simply fit it as it comes in the kit.
My initial modification was to simply cut off the extended pipe, leaving just a short stub to slot into the mounting hole in the fuselage recess. The hole is shaped to take the original uncut end of the pipe and, as such, will need to be drilled out to accept the stub. That seemed to be that, with just the cover plate to add over the pipe recess.
However, with the pipe removed again, a quick check with the cover plate showed the fit to be poor. The plate isn't designed to be fitted in the closed position, and it was clear it would need to be trimmed and re-shaped to fit cleanly over the fuselage recess. In addition, with the pipe back in place and viewed from the front, it was clearly protruding out too far which would prevent the cover plate from dropping into place.
The cover plate was trimmed down until it would drop into the recess, then cemented in place. The fit still wasn't perfect, and it'll probably require some filler before painting, but it'll do for now. Having the plate fitted before the probe will mean the small stub I'd left on the end of the pipe will need to go, as there isn't enough space for it to slide down behind the plate. The back side of the probe will also need to be sliced away or sanded down to allow it to sit lower in the recess, but this will be done later, as I'll be painting the probe separately and installing it right at the end.
Moving further back along the fuselage, we get to the gun bay. Kitty Hawk has designed this to be displayed open to show the gun breech, although in this case (unlike the refuelling probe) they have also given the modeller the option of closing it up too. The 30mm cannon is nicely moulded, although the bay itself looks rather spartan and could use some additional detailing.
In my case, I chose to have the gun bay closed up, so fitted the cover panel in place. Unlike the refuelling probe panel, the fit here was excellent, although there's not a lot to hold the panel in position – only small lips at the front and back of the fuselage opening. As such, I reinforced the joint around the panel on the underside with some epoxy adhesive. I didn't bother to install the gun bay, or the gun itself, as neither is seen with the cover panel in place. The barrel, which is the only part of the gun that remains visible, was replaced with a short length of aluminium tube glued into the opening in the cover panel.
As we head further back towards the tail end, the next detail to deal with is the drogue parachute housing. Again, Kitty Hawk has designed this to be positioned open. It seems like they wanted to the kit to be posed with absolutely everything open or extended. While that's a nice idea, it would have been better if they'd given the modeller the option of fitting these parts in their regular in-flight or on-ground positions too.
With the parachute housing, changing it to a closed position is essentially a matter of leaving out the small block that props it up the open position. However, mounting it flat in the opening does result in it sitting too low in relation to the surrounding fuselage. Sorting that out was a simple matter of glueing some styrene strips along the lip of the recess to raise the housing up flush with the airframe.
While we're in the vicinity of the chute housing, there are two rather perplexing problems that need to be addressed. The first of these relates to the two small inlet scoops that sit either side of the fuselage, just ahead of the drogue chute. The problem here is with the instructions, rather than the parts themselves, but it's the sort of thing that would really spoil your day if you spotted it too late. The upper fuselage has openings for the scoops, with the scoops themselves provided as separate parts.
If you flip the fuselage over, you'll see a recess around the back of the opening that's clearly intended for the scoop part to drop into. Well, that's all fine so long as you spot this early enough.
If, however, you just follow the instructions, you're told to add the scoop parts (D15 & D16) over the top of the openings on the outside of the fuselage. Not only that, but this stage in the instructions (step 12) comes after the fuselage halves have been joined together, meaning it would now be impossible to attach the scoops in their correct location on the inside of the upper fuselage. I only spotted this myself as I'd seen the holes for the scoops and checked ahead in the instructions to see which parts filled them. How this error made it past the test builds of the kit I don't know, but make sure to add the scoops to the inside before you close up the fuselage.
While the issue with the inlet scoops is simply down to an error in the instructions, the second problem to deal with is more fundamental. On the upper fuselage moulding, there are two holes, one either side, just inboard of the tail fins. If I'm honest, I'm not sure what these represent. They look like fuel filling points, but they could be something else entirely. Either way, Kitty Hawk has moulded them open but, and I'm pretty astounded by this, they haven't supplied any parts to plug the holes. Unless I'm missing something obvious, there are no parts on the sprues that correspond to the holes, and no reference to them in the instructions. It's as if they simply forgot about them.
Dealing with them isn't that much trouble in truth. I blanked off the bottom of the holes with some scrap styrene sheet, then glued two styrene discs into the holes themselves. I can't say for certain how accurate this is (close-ups of this section of the aircraft are hard to come by), but it's certainly better than two open holes through the top of the fuselage. The fact that the fix is easy doesn't hide the fact that this shouldn't have happened in the first place though.
With those niggles out of the way, I turned back to the cockpit. The instructions tell you to add this to the lower fuselage half, but I felt it would be better mounted in the upper half as it's easier to get the correct alignment that way. Before installing it though, I wanted to get the canopy attached, and before doing that, I needed to add the HUD to the coaming. This is a neat little assembly consisting of a photo-etched frame to which the clear screens are added. The frame then sits on top of a box structure, which in turn sits in a recess in the coaming. The instructions for fitting that box though are a little vague, which caused problems later.
I'd test fitted the canopy when I first started the kit, and it seemed to line up very well. However, when I came to fit it now, it wouldn't drop into place, and it didn't take long to see what was causing the problem. The inside of the canopy was hitting the HUD frame and, as you can see from the photo, wasn't even close to sitting correctly. I did at first wonder if the extra over-head controls I'd added to the canopy earlier in the build were contributing to the issue, but they weren't. It was simply down to the HUD sitting too high. Whether this was due to me incorrectly positioning the HUD assembly, or because of an actual error in the kit, I can't say for certain.
Whatever the reason for the HUD sitting too high, it had to be dealt with. To fix the problem I had to remove the screens from the photo etch frame, then bend the upright frame sides, angling them inwards until they left enough clearance for the canopy to drop into place. Once I'd got them in a position that worked, I re-attached the screens, each of which needed to be trimmed to fit the revised angle of the frames.
With that issue dealt with, the canopy could finally be attached, and the fit, thankfully, was perfect. With the cockpit module installed, the upper fuselage was almost ready to be joined to the lower half. One final thing to address was the question on nose weight.
No mention is made in the instructions of adding any weight to the nose but, given the huge amount of airframe behind the main wheels, some degree of ballast seemed essential. The obvious place to add this would be the separate nose cone but, as the attachment area for this is fairly minimal, I didn't want to risk the joint cracking later on. There's ample space ahead of the cockpit in the main fuselage anyway, so adding the weight there isn't a problem. To contain the weight, I added two styrene bulkheads, one blocking off the cockpit footwell, and the other closer to the front of the fuselage. The resulting space was filled with approximately 50 grams of lead shot, then closed off with another piece of styrene, preventing the shot from spilling out.
And that's where we'll wrap up this instalment of the build. Next time we'll be adding the engines, detailing the stinger tail, getting the first paint on the exterior, and closing up the fuselage. 

Stay tuned for that.

Andy Moore

Andy will be giving us more insights into his build int he next few weeks so stay tuned. Thanks to Kittyhawk for sending this kit to him to show you all in this series.