1/48 scale scratch built
1918 Curtiss MF Seagull Flying Boat

by Michael Robinson

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This is my 1/48 scale scratchbuilt model of a 1918 Curtiss MF (Modified “F”) Seagull, as produced right at the end of World War 1. The MF Seagull was a more “upscale” civilian version of the US Navy MF Boat. Differences were a better finish and wooden slat seats instead of solid boards (wow big difference there). Only about 50 were completed and sold, due to the number of surplus MF Boats being sold at the end of the war.

This particular subject is modeled after the MF on display at the Canadian Air Museum in Ottawa Canada. Altogether about 200 hours over 4 months were spent during construction. I’ll give a brief overview of the construction techniques I used, and you’ll see that nothing out of the ordinary was used, just simple, basic scratchbuilding as shown by Harry Woodman in his book Scale Model Aircraft in Plastic Card.

Fuselage/Hull 

The Fuselage master was carved from basswood, then the sponsons were added and carved separately before vacu-forming. I thought it would be easier to add them after, rather than to try to carve them out of a solid block of wood.  The master was cut in half down the centerline, and vacu-formed using .030 plastic. Seats, floor slats, instrument board, and side panels were fashioned from .010 and .20 plastic sheet cut into strips. The control column, steering wheels, rudder bars and supports are from .020 brass wire and bits of left over PE soldered together. Instrument faces are from Reheat decals, with bezels from Foto-Cut and left over bits from Copper State Models gage sets, and all control cables are present for aileron and rudder and elevator controls. The “headache strut” running to the engine pylon contains the Bowden cables and electrical wiring for the engine, and these are represented by fine copper wire and metallic thread. The windscreen is vacu-formed clear thermoform, and was installed at the very end of construction. The walkways on the bow and aft of the engine are heavy duty aluminum foil that was embossed over a fine gage screen. It was then cut into strips and glued in place using Micro-Scale Metal Foil adhesive. The windscreen framing was made in a like manner, but painted green before installing. It was left aluminum on the backside as the inside framing is not painted. A .010 center keel board was glued onto the bottom edge of each half before gluing the halves together, and then sanded to final profile. To square up all the edges, .060 Evergreen Angle was cemented to the tops and along the ends of the hull steps. These were filled with CA and blended in to “sharpen” the soft corners of the vacu-formed hull. Along the top edges of the hull, they were left in raised relief as the real aircraft had aluminum reinforcing edges. The cover over the Fuel tanks under the engine pylon is a section of .010 plastic cut to shape, with .010 x .010 plastic strips for the raised walkways. A brass PE bit represents the fuel cap.

Picture 3 Hull halves before installation of sponson blanks.

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Picture 4 Completed hull master after sponsons were sanded to final shape.

Picture 13. Hull halves after vacu-forming.

Picture 14 Hull structure and interior going in. Slat floors, seats, and instrument board are all from .010 plastic.  Stringers are .005 strip, and bulkheads are .030 plastic. 1/8^th square plastic acts as reinforcements and something to glue bulkheads to. Fuselage is very light but also very strong.

Picture 15 I made a test strip to try different shades of paint to simulate the mahogany. I finally settled on my own mix, with a Tamiya Clear Orange overcoat.

Picture 16 Shot of the interior fittings before being painted. Brass wire, bits of leftover PE and plastic strip make up the controls and seats. The ruler gives an idea of the size of the parts.

Picture 17 Shot of the interior before everything was closed up. Much of it became lost to sight when the hull halves were joined, but I know it’s all in there.

Picture 18 The Engine pylon is being test fitted, and locating holes for struts are  marked out and drilled.

Wings 

Both top and bottom wing began life as Lindberg Jenny wings, and were modified to correct chord and outline, and sanded smooth to remove all rib detail. I then trimmed 1/16^th of an inch from the lead edge so the chord is correct.  It took two kits to get the number of blanks needed. I used two for each upper wing and three for the lower wing and upper wing center section.  Two fillers had to be added to the kits upper wing cutout to make them rectangular in shape. These are illustrated in the picture below. Once the blanks were done, they were re-sheeted with .005 plastic with the ribs embossed from underneath. Once covered and sanded and filled, the ailerons were cut from the upper wings and hinged with brass wire. Strut locating holes and rigging attachment points were plotted out with a square and a rule, and all holes predrilled. A total of 12 wing struts, and 4 engine pylon struts were made from correct width Contrail Strut material, with Part PE turnbuckles cut in half and glued on all ends to represent strut fittings. These were cut to length as the model was fixed to an assembly jig so the lengths would be correct. The aileron control “tripods” are soldered together from .020 copper wire, then painted black before epoxying into place. Lower wing tip floats were carved from solid 1/8 plastic, with planning skids added from .020. The Anti-Skid plates on the upper wing are from .005 plastic, with .020 brass wire for the struts. All struts were drilled on the ends for .020 copper wire to reinforce the attachment.

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Picture 5 This shows the upper wing blanks with the “plug” to fill the notch in the Jenny upper wing.

Picture 6 This illustrates how I emboss the ribs from the backside of the skin. Nothing more than a strait edge, a blunt scriber and pre-measured locating marks.

Picture 7 Here are the finished wings prior to painting. The yellow plastic of the blanks can be seen on the lead edge. The skin is sealed with CA along the edge, then sanded and fared into the plastic blank.

Tail Surfaces 

The tail surfaces are carved from 1/16th basswood to an airfoil shape, then skinned with .005 plastic, same as the wings. The ribs were embossed on the underside of the card before gluing onto the cores. Once covered, the elevators and rudder were cut loose and hinged with brass wire. Control horns were added from .020 copper wire, flattened and filed to correct shape.

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Picture 9 Same technique was used for the Fin and Rudder. Sealing the edges of the basswood with CA “plasticizes” it and  allows it to be sanded and blended into the skin just like plastic.

Engine 

A Curtiss C6 engine was used to power the Seagull, as opposed to the 150 HP Hispano Suiza used by the military MF Boats. No kit engine exists of a suitable Curtiss C6, and there is very little information, save for one fuzzy photograph I had that showed the basic outline. The Curtiss K6 was derived from the C6, so I used it as a guide, making the notable differences of one piece cylinders and block cast as one unit, and both spark plugs being on one side of the cylinder head. Other than that there were few differences externally. The engine is made from blocks of .060 and .080 plastic, sections of 1/8 plastic tube, and various bits of solder and wire. All plumbing, ignition, throttle and fuel lines are present, as well as oil breather at the bottom of the oil pan. The prop is carved from laminated basswood and rosewood, stained and then Bare Metal gold foil added for the brass leading edged. Prop hub bosses are from Foto-cut, with bolts and crank added from fine wire and solder. The pylon is .060 plastic and Contrail Strut, and the radiator is made from 2 .040 sheets glued together with a header tank from a bit of reshaped strut material. The radiator faces are from a section of material cut from an old pair of pantyhose (with wife’s permission of course).

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Picture 10 Basic block before any details were added. only kit part used was the snout from the Jenny OX5.

Picture 11 More goodies added. Magnetos, camdrives, and beginnings of exhaust and intake plumbing.

Picture 12 Completed engine in pylon with ignition wiring, radiator, cooling lines, carb and intake and water pump added.

Assembly and Painting 

The model was painted with Model Master Willow Green for all the trim and hull bottom. The Mahogany shade is my own mix of red and brown, with an overcoat of Tamiya Clear Orange to give it a varnished look.

The struts are painted with a light Tan Acrylic, also with a clear orange overcoat. Wings and tail assembly are painted with Pactra Aerogloss “Silvaire Aluminum” Dope, and the engine is painted with various shades of Model Master Mettalizers.

Everything was overcoated with either clear Future for gloss, or Dull-Coat for the semi-gloss areas.

Picture 19 Hull right after painting - the green isn’t quite so “loud” on the finished model. The camera flash really enhanced it.

Assembly was done the same as a basic kit. The fuselage halves were joined first, then lower wings added. The model was then secured to an assembly jig, top wings rubber banded into place, struts cut to length and then tail assembly installed. All rigging for upper wing was set in place before final wing installation, and then each strut was epoxied in place, one at a time, until wing was secure.  Rigging then commenced form the inside center and worked outward, doing each line one at a time until all was complete. Rigging material is .006 nylon monofilament, set into holes in upper wing and then poked completely through predrilled holes in bottom wing. They were then drawn tight with a pair of tweezers and CA’ed in place. After all were secure, the excess was trimmed off and decal circles were applied over the holes. They represent circular inspection panels at each strut location. There are 208 decals on the model. Each wing and tail rib has a strip applied over it to represent wing tapes and rib tapes. These were all applied one at a time until all were covered, then sealed in Future.

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Picture 20 The model sits in a jig after final painting, ready for final assembly.

Picture 21 Top wing after being jigged in place. The rib tapes really stand out here as the wing hasn’t been overcoated or sealed yet.

Picture 22 Here the struts are being measured to fit, and the engine pylon has been rigged before the top wing was permanently installed.

Picture 23 Here the rigging is preinstalled into the top wing. It is then pulled taught through holes in the lower wing, seized off with CA, and trimmed flush with wing. The holes were then covered with 1/8^th” circles of silver dope painted decal to hide them.

Base 

The base is solid basswood with a mahogany stain, and the model is mounted on a single brass support. This allows the model to be spun on the base for inspection without having to pick up or move the base.

Picture 24 The rigging is finished and base is cut and ready for staining.

Thanks for looking.

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Model, Images and Text Copyright © 2007 by Michael Robinson
Page Created 31 October, 2007
Last Updated 24 December, 2007

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