Building an Aeromarine
Model 75 in 1/72

By Dave Miller

The Aeromarine Model 75

In the early 1920s Aeromarine Plane and Motor Company acquired several military surplus Felixstowe F5-L flying boats and converted them into “Flying Yachts”. The conversion, thereafter referred to as the Aeromarine Model 75, was an attractive airplane. Powered by two 330 hp Liberty engines, the airplanes hauled eleven passengers and a crew of three. Nearly all of the modifications were made to better accommodate passengers (Koch, 1999). The deck of the hull was raised to create a passenger cabin that was soundproofed and ventilated. Ten, 18-inch, circular celluloid windows gave an excellent view from the cabin. Other accoutrements of the cabin included dome lights and mahogany paneling, wicker passenger seats upholstered in blue-leather, window curtains, and floor carpeting.

A most interesting feature of the Model 75 was the open-air observation compartment in the nose of the plane. The forward gunner’s cockpit in the F5-L was converted into a compartment that could be entered by passengers while the airplane was in flight (Koch, 1999). It must have been a wonderful experience to stand there in the wind, among the clouds, and watch the panorama passing below.

Selecting a Kit for Conversion

Roden has produced four flying boat kits in 1/72: the Curtiss H-16 as well as the early-mid-and late versions of the Felixstowe F.2A flying boats. These aircraft share an interconnected historical development and bear a strong resemblance to one another and to the F5-L. To build an Aeromarine Model 75, I selected the Roden Curtiss H-16 kit primarily because the Curtiss H-16 was powered by Liberty engines, as was the F5-L and the Aeromarine 75. The Liberty engines contained in the Roden H-16 kit are beautifully detailed, with over 30 excellent fitting parts. The Curtiss kit also contains optional ailerons that have the rounded tips like the Model 75.

In order to build an Aeromarine Model 75 several modifications of the Curtiss kit need to be made. Numerous photos and three-view drawings contained in the Koch (1999) and Kusrow (2004) were used as references in this conversion. The most obvious modifications are on the fuselage: the passenger compartment and cockpit need to be built-up and round window openings need to be cut into the fuselage. A new tail fin and rudder need to be fabricated. Upper and lower wings need to be lengthened a scale eight feet (1.33 inches), and the wingtips need to be reshaped. Wider, un-tapered wing struts need to be fabricated. The overall length of the aircraft needs to be increased a scale three feet (1/2 inch). Finally, decals depicting the Aeromarine Airways livery need to be printed.

Fuselage Modifications

Fuselage modifications begin by locating the round window openings. Most Aeromarine Model 75’s were built with ten, 18 in., round windows in the fuselage – five on each side. The forward passenger cabin contained six windows and the rear passenger cabin contained four windows. The forward windows in the passenger cabin were mounted in the sliding doors to this compartment. Archive photos show that these doors were sometimes open during flight! Photos also show other, smaller, round windows in the fuselage that vary in location and number for individual aircraft. At 1/72 scale and 18 inch window is ¼ in. in diameter and I drilled the windows with a new ¼ inch brad point bit. The floor and cabin partitions were added. The interior was painted to simulate mahogany paneling and blue floor carpeting. At this point in the construction, the fuselage halves are held together with tape.

The roof of the forward passenger compartment begins with the addition of eight formers made from 1/16 in aluminum strip. The strips were bent over a small wooden form, primed and painted. The fuselage halves were joined and exterior painting began. Floquil colors “reefer white” and “weathered black” were applied with an airbrush. Before mounting the formers permanently, passenger seats were fabricated and installed. Once properly located, the formers were secured with CA adhesive. The cabin roof was made from 1/32 thick basswood strips, and finished with Elmer’s wood filler.

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The cockpit surround is molded from .02 in. plastic styrene. A wooden plug was carved to the shape of the surround, finished smooth, fastened to a shaft and held in a vise. The styrene was heated and drawn over the plug. The second attempt produced a satisfactorily molded surround. Excess styrene was cut from the surround, the cockpit opening was made, and the surround was installed. The skylight atop the forward fuselage was made from styrene channel and installed. Elmer’s wood filler was used to fare in the forward fuselage, cockpit surround and skylight.

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Fin and Rudder Assembly

The fin and rudder are fabricated from 0.01 inch sheet styrene. A ballpoint pen is used to score the inside of each half of the fin and rudder to simulate the underlying rib structure. For added thickness in the mid-section of the assembly, a spacer is cemented in place. The fin and rudder halves are then cemented together, finished, primed, and painted black.

Painting and the Aeromarine Livery

It may seem unusual to do the final painting and apply decals at this stage of the construction. However, it would be very difficult to do this work after the long, slender, and fragile wings are attached. After careful masking, the top of the fuselage was painted reefer white. The tail assembly was added and struts installed for strength. A coat of Future was applied to the model by airbrush.

The aircraft markings are black, and therefore can be printed directly onto decal paper with an ordinary laser printer. The Aeromarine Airways logo was produced with Photoshop, and the remaining lettering was created with Microsoft Word (Copperplate fount). Once files were created, I used the trial-and-error method to size the graphics until they looked right. Then I printed them onto decal paper and coated them with Badger decal medium. The cheat line is a 36 point line from Microsoft word, and the walkway was made by using the borders and shading function. All of these can be done with other word processing and graphics systems as well.

At this stage the model sat for about a month, away from dust, to allow the Future and paint to cure. The finish held up very well to the handling that was necessary to attach the wings and do the rigging.

Wings

Each wing was lengthened .65 inch and the wingtips were reshaped. Styrene sheet (0.01 thickness) was cut to fit the H-16 wingtip. The styrene was carved to the rough shape of the Aeromarine Model 75 wingtip, Elmer’s wood filler was added, and the finished shape was carved and sanded. All wing joints were reinforced with soft wire. A slight dihedral was set in the top wing and the joint cemented with 6-minute epoxy. Soon after the epoxy set, the joint was wet sanded smooth. Wire control horns were mounted, then the wing was primed and painted with reefer white. The central portion of the wing was masked and painted weathered black.

Before wings were attached to the airplane, rigging for the tail control surfaces was done. The airplane was attached to the rigging jig, and the lower wing attached with 6-minute epoxy. The wing joints were finished and touch-up paint added.

Wing struts on the Aeromarine Model 75 are considerably wider than those of the H-16, and the Aeromarine struts are not tapered at each end. New struts were cut from basswood to replace those in the Roden kit. The new struts shown have not yet been sanded or given an airfoil shape.

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Rigging

The next 30 hours of work on the Aeromarine Model 75 were spent mounting the engines, installing the wings, and doing the rigging. Admittedly, about twenty hours of this time were spent in three attempts to mount the top wing correctly – details mercifully omitted. Once the wings were mounted correctly, the rigging process, though slow, progressed without mishap. The rigging was done without the benefit of a single overall rigging plan of the Aeromarine Model 75. As far as I know, none exist, and each plane was probably rigged in its own unique way. Rigging was done by referring to photos of Model 75s, rigging plans of the F-5 flying boat, and Internet photos of models of the Felixstowe and Curtiss flying boats.

In order to rig a model of this scale and complexity a rigging board is essential. One must be able to approach the model from all directions and angles during the rigging process. While the board holds the model firmly, it also allows the model to be held in advantageous positions while working. I also used tools designed for rigging model ships to rig the Aeromarine. Nylon thread of various colors and diameters was used for rigging. Rigging under the engines is fine wire.

The Aeromarine Model 75 Completed

I definitely had to stretch my modeling skills to build the Aeromarine Model 75. I started with the Roden Curtiss H-16 kit, which is an excellent kit. Then I had help and encouragement from the Wings of Peace modeling group. My sister Laurie Johnson helped produce the graphics. Finally, Daniel Kusrow provided me with much encouragement and additional photos and information regarding the Aeromarine Model 75. I built the Aeromarine Model 75 that was called “Wolverine”. Now I want to build her sister, “Buckeye”. It should be an easier build, now that I know how to mount the top wings!!

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References

Koch, David
1999. Aeromarine Airways Its Aircraft and History. Skyways the Journal of the Airplane 1920-1940. 52:2-12

Daniel Kusrow
2004. http://www.timetableimages.com/ttimages/aeromtts.htm

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