A 1/7 stand off scale model of a WWII-era British Supermarine Spitfire fighter plane assembled from an early 90’s-era Pica balsa wood kit.
History & Kitting Up
When I was a teenager way back in the early ‘90’s, I came to learn how to fly RC airplanes as a hobby. I put a basic “trainer” plane - not much more than a large styrofoam wing attached with rubberbands to a basic fiberglass and aluminum body - through more than one crash landing and rebuild until I was confident enough to fly unassisted and eventually ready to upgrade to a “real” plane. Of the many options to choose from, I’ve always been a fan of the visual aesthetics of Britain’s WWII-era Supermarine Spitfire series of fighter planes. I was able to acquire a kit for such a war bird at my local hobby shop at the time. The kit - from a now-defunct company by the name of Pica - promised the parts to build a complete 1/6 scale Supermarine Spitfire Mk IX. Back in those days, kits tended to be much more involved compared to the wealth of ARF (Almost Ready to Fly) models that are on the market today.
The Pica kit consists largely of a set of scale plans, a collection of printed pages that make up the step by step instructions and a box of balsa wood and other assorted parts needed for the build and assembly. Given that this kit originated sometime in the late 80’s or early 90’s at the latest, the documentation is a bit on the sparse side. The full instructions list somewhere around at least 200 steps printed double sided on a dozen or so pages. However, there is not a single photograph - only small sketches and section cut aways - to guide the lengthy build. The other thing the pages don’t entirely prepare you for - the amount of sanding you will do. “Sand to shape” in so few words packs the hours and hours of sanding raw chunks of rectangular balsa into something eventually resembling a WWII warbird.
It also turns out that this is one of two different Spitfire kits that Pica produced. It sold both this 1/6 scale as well as a larger 1/5 scale. The larger 1/5 scale has a wingspan of a bit over 80". This smaller version is a bit over 60" between wingtips. In fact, even though it is advertised as 1/6 scale, it is closer to 1/7 scale. The plans don’t even designate a specific Mark (Mk), but rather an idealized or representative amalgamation of the Spitfire across its various revisions. Although, the plans do provide some brief customization options for an alternative canopy design as well as clipped wings (which amounts roughly to - just do more sanding).
As far as kits go, this one has a lot against it in terms of build complexity and any sort of historical or scale accuracy. It’s important to keep in mind that this is a “Stand Off” scale model. This means that if you’re “standing off” from the model from 10-15’ away, it resembles a true scale Spitfire. Viewing the plane from a distance closer than that, discrepancies from the real thing may start to become much more apparent. For RC aircraft it’s also a heavy beast being constructed entirely of balsa, basswood, and ply. Many accounts of owners also put it as being excessively tail-heavy and requiring additional forward weight added to get it balanced well for flight.
All of that to say that this is in no way a novice project. Experience is highly recommended if not otherwise simply the patient willingness to figure it out for yourself and stubborness to do it without knowing any better anyway. It is left an exercise of the reader to determine which path I’ve taken. In fact, I’ve taken this path twice. I never managed to finish building the kit I started as a teenager. From time spent doing other teenager activities, moving away to college, and my parents endless moving from house to house every few years, it spent most of its time wrapped up in plastic wrap, safe for transport and without a place for work. Eventually, I lived halfway across the country and it sold off in its partially completed state to someone else interested in the hobby.
Sometime around 2009, I ran across an unbuilt 1/6 scale kit on Ebay and snatched it up. Others occasionally pop up for sale even today, but they are mostly the larger 1/5 scale. This one sat in its box until I finally had time and space to start in on it sometime around July 2023.
Build Gallery
This is a view of the v1 build with the sheeted wings and fuselage. The bank of servos for controlling rudder, elevators, and throttle are installed in the fuselage. The servo control cord for the ailerons is protruding through an access hole in the center section of the wings. The plans are taped to a sheet of drywall to make it easy for push pins to be stuck into it and covered with plastic film to prevent any glue from sticking to them. The table itself is just a cheap repurposed hollow-core door large enough to hold the plans.
Close up shot of the fuselage servo bank. Push rods have been installed for the rudder and elevators, but the throttle push rod has not yet been attached.
Rough mock up of the progress of v1. This is the state of the build just prior to it being sold off. It was still in a pretty rough state at that point. Some initial sanding had been started on the wingtips and cowl, but quite a bit more was left. Some initial spot putty testing can be seen on the wing, but there are a lot of cracks and gaps still visible that would need to be filled in.
Another v1 close up shot of the mock up. The underside section of the fuselage hasn't been shaped yet and the upper cowl only lightly shaped so far. There are a lot of uneven areas still where different pieces come together. There is a seam in one section of the fuselage sheeting where it snapped in half during glue up. The leading edge of the wing also shows some large gaps where the sheeting meets the edge.
Close up shot of how the vacuum formed clear canopy fits over the cockpit area.
The lid of the box all of this balsa came in has seen better days.
In the process of gluing a top wing spar to the center wing section ribs. Tee push pins are a must for holding parts aligned to the plans. There are relatively few places where traditional clamps are useful during most of these glue ups. Machinist's 1-2-3 blocks work great for holding parts down while glue dries.
A very crowded work surface. I'm working in an unfinished basement without much room to work outside of this table. A large complement of balsa parts are sorted and stacked in front of the initial wing glue up. The table itself is a custom built torsion box design made from 1/2" and 3/4" baltic birch plywood to have a high degree of flatness across its surface. The base at this point is just a pair of 2x4's set on top of saw horses. On top of the table is a large EVA foam exercise mat that has been cut to size and to which the plans are taped. Over top of that is a sheet of thin painter's plastic sheeting.
Progress on one outer wing section. One of the leading edge strips is being glued to the front of the ribs here. Another clamping MVP for this project are rubber bands. The leading edge strips were glued in multiple stages, only gluing a few ribs at a time and working outward from the center to the tip. This approach greatly simplified holding the strip in place as it needed to follow the curve of the wing.
Overhead shot of the leaded edge glue up. Something to note is how the outer wing section joins with the center section. The outer ends of the center section are laminated ribs which provide room for the top and bottom spars for the two sections to mate up. These are relatively weak butt joints. There are some additional strips glued in between the spars to provide more strength. However, this is still an area that builders of this kit have reported problems with breakages. Later in the process I add additional supports to further strenthen this weak point.
Roughly organized chaos.
The left wing section has also been glued up now. Several mistakes have been made by this point also. The primary issue is that all of the ribs are upside-down. The actual shape of the ribs are symmetrical, so this is not a problem for the wing profile. However, all of the notches and cutouts are in the wrong locations now. The notches on the outside edges of the center wing section ribs should be on the bottom and not the top. These are meant to fit support blocking to mount the fixed landing gear. I have other plans for the gear, so this won't become a problem for me. Pushrod routing holes are also in the wrong locations. These are easy to drill and make new ones later. There are angled slots that capture a plywood piece in one of the bays toward the outer sections. These are platforms to mount the turnbuckles used for the aileron pushrods. The platforms are angled so that the pushrod will protrude through the bottom of the wing to connect to the aileron. I'd already glued the plywood panels in place before I realized my mistake. This is definitely a problem that will need to be solved. I'll need to remove the plywood and find a way to reglue it at the correct angle.
Out of all of the balsa in this kit, two pieces came up missing from the box. One wing section top spar and the smaller leading edge strip weren't anywhere to be found in the box. I have no idea if this was a packing mistake or just pieces getting lost over the years. My local Joanne's didn't have the right width of strips, but they did have thinner ones that I was able to laminate together and make work.
Initial glued up full wing assembly, ailerons and flap sections. The inner flap sections will be glued in place to the rear of the wings at a later stage. This is another common complaint with this kit - that the flaps are fixed while the original has functional split flaps. It's a common modification to add controllable flaps, but I'll stick with the fixed flaps in this build.
Laminating sections of the fuselage body sides.
Beginning to glue fuselage formers in place on the first side. The secondary feature that makes the 1-2-3 blocks so useful is that they can help keep parts in place perpendicular to the plans.
Skipping ahead, the second side has been glued against the formers and the sides glued together at the tail end. A support rod has been glued along the top centerline of the forward formers. In progress is gluing the piece that makes the top of the aft section. It has a curve, so I work similar to the wing leading edge, only gluing a section or two at a time to help reduce stress (of the wood and myself during the glue up too).
In process of gluing the top strip and things are looking fishy. Somewhere in the process something has gotten misaligned and there is a slight curve to the tail. This top rail will help pull things back straight.
Fuselage rear side view. The top strip is a straight rectangle as glued but eventually need major sanding to match the shape of the formers as they narrow toward the rear.
The tabletop has gotten a little bit cleaner as more parts have been turned into the structure of a plane. The tabletop itself has gotten an upgrade, replacing the sawhorses with pedastal legs on locking casters.
Attaching the sections of sheeting to the fuselage between the cockpit and cowl is quite an ordeal. The balsa sheets have to make pretty significant bends and it is easy to snap a sheet in two while gluing it in place. The instructions suggest to simply wet the sheets with a solution of isopropyl alchohol to aid in their bending.
Quick clamps make a rare appearance alongside rubberbands and scraps of balsa acting as cauls.
Clear view of a snapped in half sheeting section and uneven gaps. I did eventually find that using a steam bending box greatly helped with getting the sheeting shaped to the curve of the formers. Also note another example of things not quite lining up correctly with the addition of some scraps glued to the side of the former to create a ledge for the sheeting to rest against.
Weigh and pray?
Rubberbands truly are the workhorse of this build.
I added a steam generator for steam bending to my toolset during this build. I converted this section of scrap 4" ABS DWV pipe into a steam box. It has an inlet for the steam generator on one end and some small vent holes on the opposite end so it doesn't build up pressure once it is fitted with the endcaps. There is also a line of dowels that form a shelf for holding pieces to be steamed in the middle of the tube.
The fuselage has started to get its first rounds of sanding and filler to begin smoothing it out.
I'm using a Goodfilla wood filler initially to smooth out dents and small gaps and cracks in the surface. It's easy to apply, doesn't have VOC's, dries quickly, and sands easily.
The aileron control servo sits in a bay within the center wing section. Ball linkages with soldered connections to steel pushrods attach to the servo control horns.
A view of a pushrod running through one of the wing sections. The turnbuckle is on the bottom side of the plywood mounting platform, but will be later flipped to the top side. The repair job to fix the angle of the mounting platform is a bit crunchy, but otherwise solid. The screw connections will be secured with loctite before everything gets sheeted in.
