Piaggio-Pegna Pc-7 Schneider cup, AMP from Ukraine 1/72nd kit

 

 (The completed model is here)

https://wingsofintent.blogspot.com/2022/07/piaggio-pegna-pc-7-amp-from-ukraine.html

 

Piaggio-Pegna Pc-7

The hydrofoil approach

Most modelers usually inhabit the known parts of the aviation universe, while some venture into the fringes and beyond. So do designers. Among these -in general- less recognizable designs, a few somehow make into the general modeler population consciousness, and are even kitted. Not without surprise I saw the Piaggio-Pegna Pc-7 released by AMP in Ukraine (as injected plastic) and SBS of Hungary (as a resin/multimedia kit) both in 1/72nd scale. I believe the call to fame of the Pc-7 is twofold: it was designed to participate in the 1928 Schneider seaplane cup (a very popular subject among aviation buffs) -and alternatively to attempt a speed record-, and its undeniable beauty combined with the unorthodox design. AMP also released an 1/48th kit, as expected with more detail that even includes an engine. So did (again in 1/48th) Roadrunner Models/Italian Kits, and Atelier Noix

It never made it to the Schneider, and actually it never even made it to the air, having only managed to raise above the water on its hydrofoils, when the water propeller clutch failed. The idea behind the approach was nonetheless solid: to replace the cumbersome, heavy, drag-inducing floats / hulls normally used in seaplanes and flying boats by hydrofoils, to manage take-off and alighting. To accomplish this, though, the plane must remain afloat relying on water-tight wings and fuselage and have a water propeller as well as an airscrew, and the latter has to clear the water at the end of the take-off run in order to be able to operate. An interest twist, that in turn created a number of other problems that unfortunately were not solved in time for the race...or ever after.

Still, we have this remarkable, unconventional design of refined lines, in Italian racing red!

From Popular Mechanics, Dec 1932:

L'Aeronautique, even later, 1940:
 

From Les Ailes:

Plenty more information can be found on NACA's Technical Memorandum #691 (it can be downloaded here):

https://ntrs.nasa.gov/api/citations/19930094725/downloads/19930094725.pdf

We will start with the AMP from Ukraine kit. 

Contents of the box:

Nice level of surface detail, almost no flash:

Subtle moldings, and with even locating devices:

The wing is rendered in two halves to avoid sink holes. Nonetheless as it is the case with this type of kit, some sanding is in order to get a good seat:

Decals and minute transparency

Instructions. More on this later, but there are some mysteries to be solve there:

Cockpit are detail:

Locating devices for the horizontal tail, well done AMP!

This area will be revisited with comments later on:

Two types of hydrofoil legs are provided...

...although only one is depicted in the instructions (below). This may be because drawings show sometimes the other (unused) shape:

We can see that the instructions depict an additional lever aside the control column. This part is absent from the kit, although there is a rod in the sprues (part 21) that may be used here (too long, though):

The prop depicted in the instructions (and photos of the original plane) is not what is provided, lacking the pointy spinner:

All parts separated from the sprues. The gates are unobtrusive and easy to clean up. Be careful, as there are small and fragile parts, and store them conveniently if you, like me, like to separate all parts before construction:

The water rudder below the actual rudder (seen in photos of the original) is not provided, and will have to be made by the modeler:

An alternate part (28) seen again only in drawings that could replace kit parts 26/27 (not recommended, as photos  do not show that):

Two parts (24/28) seemingly associated with the prop but not present in the instructions. Notice that the prop spinner had to be carved a bit inside to make room for the actual prop, as the mold had some excrescences there):

The solution used by the manufacturer to render adequate detail on the engine cover may need some attention later in the build:

The wing halves are glued together. Some minor sanding is required to get a good fit. The cockpit interior is being assembled. I added the missing levers from styrene. A caveat: both bulkheads need sanding down,  because like mostly any other interior in the modeling universe, they are too big and will impede proper fuselage closing. Remove at least half a millimeter around both:

The missing water rudder is fabricated carving a piece of styrene:

And the water prop spinner is carved from a leftover thin sprue rod, cut off, and cemented to the kit's part:

A few parts are painted with their base colors:

After shaving some material from both bulkheads the interior is glued in place -the seat looks a bit narrow- and then the fuselage halves glued together. No inst.pan. is provided, and actually the cockpit opening is too small to see anything anyway. To achieve a good fit of the wing, the seat of it (the top of the fuselage sides) had to be sanded down, more towards the back than in the front. A bit at a time and dry runs is the way to go here:

It was decided to glue the engine cover parts together, and then to the fuselage. Before gluing, dry runs proved that again some very small amount of material had to be removed at their centerline (before gluing the parts together), more at the back than at the front. What you see below is yet another dry-run, showing that the curved bit at the front of the cover will need some minor sanding too. The model, as you can see, is quite small.

The spinner in the original plane is pointy, but the part as molded is a bit truncated:

The parts is lightly sanded to reflect that:

The prop retainer will be glued (dry-run here) to the fuselage to insert the prop axle:

Although the mechanical loads are not high, the hydrofoil legs are metal-pinned for a better anchoring and peace of mind:

The horizontal tail is glued in place, as well as the rudder. The hydrofoil surfaces are glued to the legs:

The tiny struts that support the aft foil are cemented, and then the foil itself to them, checking alignment. Although -as you saw- some adjustments are necessary, all in all the build progresses at a good pace, as this is a nice little kit:

The model will need a cradle, which is not provided. Fortunately, SBS, who produced the other Pc-7 in the market (in resin), offers a set in laser-cut wood that is affordable and very nice:

To speed up this build, though, I made my own in styrene (but is much easier to order the SBS set if you did not start your model yet):

The home-made water rudder is also metal-pinned:

Its location drilled and then cemented in place:

Hopefully not much longer now. What you see is the product of intermittent work along three days, building in tandem with SBS' Macchi M.39. Not bad for a nice little kit:

The seam present at the center of the engine cover panels needs fixing, as there is no partition in the original cover. Masking tape was applied on both sides, the seam filled with putty, and then the tape lifted and the seam carefully sanded with an ad-hoc tool:

The legs are added. There is no front view provided in the kit, so take a hint of the proper angle from photos or plans (some are above, and the NACA report link there also provides this below, around 105º):

A coat of primer:

The home-made supports are painted:

A gloss white coat is airbrushed as a base for the red:

Red is airbrushed:

I forgot to mask and paint the windshield. Will do it in the next session:

Will let everything dry thoroughly before masking to paint the radiators. 

Masking and painting the brass color. Masking is a bit challenging due to some curves and the interference of the volumes, but with patience is done:

To a promising result:

One could say the worse is now over, and this time I remembered to mask the extremely minute transparency and paint it. I wish the kit would have included these masks, as this would have been of great help!. The windshield is not perfectly accurate as it doesn't depict correctly a minute front panel (The SBS resin kit of this plane got it right and does provide the masks), but a modeler of some experience won't have a problem:

The windshield, home-made headrest, and water prop are in place:

Propeller on and decal application begins. Only three of the decals provided are seen in photos: the tricolore on the rudder, the letters and numbers under the stab, and the fascia. You may apply the other images, but they are not in contemporary photos (at least the ones I have). The decals are very good and behaved well: