XF-103 "Thunderwarrior"

by Phil Brandt

Republic XF-103 "Thunderwarrior"

Collect-Aire 1/48 Scale XF-103 "Thunderwarrior" Number 4834

model completed 9 Aug 2002
 

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The Fifties and Sixties were a veritable hotbed of American aviation development, a highwater mark achieved by everyday "outside the box" engineering. The stillborn Republic Aviation XF-103 "Thunderwarrior" exemplifies this developmental frenzy, perhaps matched only by the later, wildly successful design and construction of the A-12/SR-71 Lockheed Blackbirds.

The XF-103 was envisioned as an extremely high performance (Mach 3.7/100,000 feet!) interceptor follow-on to the F-102/F-106. Although the XF-103 was originally in the same 1951 design competition with the proposed F-102, the F-102 won, and a Convair interceptor dynasty of over twenty years was launched. The Air Force, however, directed Republic to push ahead with three experimental prototypes. A full scale mockup was completed, and one airframe was partially completed when the axe fell in August 1957, the AF citing cost as the reason. Not only were the prototypes cancelled, but also the XF-103's innovative Wright turbojet/ramjet engine and Hughes intercept radar.

The Thunderwarrior was loaded with cutting edge features: dual cycle powerplant (license-built Bristol Olympus turbojet in tandem with a Wright Aeronautical XRJ-55-W-1 ramjet) providing an impressive 37,400 pounds of thrust in a 55,000 pound gross weight aircraft; totally enclosed ejection capsule from which the airplane could be flown; periscopic viewer in place of a conventional windshield and canopy; variable incidence wings; an all-flying stabilator, and wing 'tiperons' in lieu of ailerons.

As with many Collect-Aire releases, the joy of obtaining such eclectic subjects in 1/48 can be substantially tempered by quality issues which often require moderate to heavy effort to correct.

Although major XF-103 component shapes are generally correct, delicately engraved and free of warpage, my kit was plagued with literally hundreds of micropits in the otherwise smooth wing and fuselage surfaces. This seems to be a continuing resin production problem that has been solved by other limited production manufacturers.

Capsule and Cockpit

I looked and looked at the ejection capsule configuration and instrument panel, comparing them with the enclosed Republic line drawings included with the Collect-Aire assembly pamphlet. Something seemed amiss, and it wasn't until I obtained pix of the cockpit mockup from Fotios Rouch that I realized that the master modeler had created major inconsistencies with the real thing: firstly, the ejection capsule as modeled is at least 1/8" too wide and had to be 'sectioned' down the center and the halves reattached; same, same for the sliding capsule hatch. This, BTW, made it necessary to also decrease the width of the movable ejection stabilization platform upon which the capsule is mounted...and also the width of the fuselage opening for the capsule. The capsule lowering rails were scratchbuilt.

From the mockup pix, the only instrument panel in the capsule itself is very small (much smaller than the one in the kit), accompanied by a few ejection switches around the coaming, and the F-102-style, twin-handled stick. There should be no consoles in the capsule. The side consoles, the throttles, flap lever and the main instrument panel w/periscopic viewer appear to be outside the capsule, mounted on 'ledges' in the fuselage sides and in front of the capsule. Strangely, the master modeler molded these side ledges, albeit mis-proportioned. I scratchbuilt the capsule and fuselage interiors and periscopic viewer using kitbashed Monogram F-89 consoles and modified front main instrument panel. A thinned, modified True Details Aces II seat replaced the too wide and much too plain kit seat.

Fuselage

An enclosed cutaway drawing in the construction pamphlet shows the intended missiles, so I elected to scratchbuild missile bays and display missiles on their launchers. The Hasegawa weapons kit AIM-54 was modified into its predecessor, the AIM-47 (also intended for the YF-12), by decreasing fin areas, etc. The smaller AIM-4 Falcon (and launchers) were 'cannonballed' from a Monogram F-102. The thick chunks of resin cutout for the missile bays were thinned into the bay doors with a Dremel tool and an inner layer of plastic sheet laminated for strength.

Mating of the fuselage halves required much adjustment and filling, especially in the region of the "sugar scoop" intake and missile bays. I found the fit of the maingear well very poor and had to shim the fuselage sides approximately 1/8." The interior afterburner tube and turbine wheel were replaced by the same components from an OEZ Su-7 kit. This gave more depth and IMO, realism.

The pitot tube was taken from an ESCI Mig-27 parts kit and mounted into concentric brass tubing glued into a hole drilled in the radome.

Flying Surfaces

The wings are smooth and nicely cast with the exceptions of the micropits mentioned above. I elected to cut off the "tiperons" and display them slightly deployed. The very fine toothed Hasegawa saws are perfect for the smooth cuts needed. The relative massiveness of the resin wings and the fact that the incidence was variable caused me to use lengths of concentric brass tubing as a carry through structure and pivot in the fuselage. This guaranteed that the heavy wings would line up and be well supported. Plus, they could be separately finished! I used the same scheme on a smaller scale for the stabilators. The vertical fin was CA-ed to the fuselage with no problems.

No pivot mechanism is shown or included for the large, foldable ventral strake (much like that in the YF-12!) so it was Scratchbuild City again.

Landing Gear

Monogram F-105 main wheels were substituted because of their size--the Collect-Aire wheels seemed too puny for such a long airframe--and molding quality. After all, the wheels are a Republic Aviation design anyhow! Nose wheels came from the F-4 Monogram kit.

Finishing

After coating all components with gray automotive lacquer primer, the aforementioned pitted resin surfaces were filled with repeated iterations of my favorite lacquer putty, 3M Blue Acryl. Although it does shrink if applied too thickly, its quick drying and sandabilty are IMO unmatched. I also used Mr. Surfacer and slow drying CA glue for major discrepancies. Panel lines were rescribed and added as needed.

Since the F-103 was originally slated to replace the F-106 fleet in the Sixties, I elected to use the same ADC gray scheme overall--the Collect-Aire pamphlet mentions that Republic hinted at an eventual pale blue anti-corrosion color scheme--except for the Natural Metal Finish flying surface leading edges and afterburner section all of which would have been very hot, especially during the ramjet, Mach 3.7 operational envelope.

Two very close gray shades of custom-mixed Polly Scale acrylic flats were created by substantially whitening Light Gunship Gray and adding a few drops of Intermediate Blue. Before decalling, I shot two coats of gloss clear acrylic. NMF surfaces were done in various custom shades of Alclad II shot over a base coat of Steel and were masked to protect from the clear gloss.

The Collect-Aire decals were rather thick and somewhat yellowed, plus they were for the XF airframe, so I substituted SuperScale decals from an old F-102 sheet since there's no reason that the follow-on F-103 wouldn't have used flashy tail logos as did the Deuces and Sixes. The checkered tail scheme is from the 16th FIS at Naha in the Fifties. After sealing the decals, I wetsanded with micro sanding cloths of 8000 grit, transitioning to 12,000 to bring up the gloss.

Ol’ Bondo is weak after fourteen days of concentrated building and painting on this hummer. But, I’m still glad esoteric releases such as this are available, so I’ll keep stepping up for my Collect-Aire ‘beatings’!

Additional Images

 

Click the thumbnails below to view larger images:

Model and Article Copyright © 2002 by Phil Brandt
Images Copyright © 2002 by Milton Bell
Page Created 09 April, 2002
Last updated 04 June, 2007

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