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Thursday, May 25, 2017

Northrop Gamma Experimental Overweather Laboratory - Modified WB kit

 (This is the building article, for the completed modcel please go here:

There is no such thing as too many Gammas.
I know, I just finished the Conqueror Gamma that Jackie Cochrane commissioned:
But, since I had another kit...

During the 30s nobody knew with certainty what would happen to passengers, crew and pilots flying for hours around and above the 33,000 feet height mark (that's about 10.000 meters, you normal people).
May be you would be overcome by the irresistible desire of leaving Birmingham, Alabama, to go to Florida, or you could feel compelled to put a beer bar, or suffer the compulsion of buying dinghies, or the overwhelming desire to ride bicycles in the snow in Canada.
The advantages were obvious: to fly above most of the weather and turbulence, at higher speeds (less air density = less drag) with higher fuel economy and less stress on the airframe. Not to mention to be closer to the angels.
Pilot Tommy Tomlinson made a number of flights in a specially modified Northrop Gamma.
You can read a detailed and illustrated article by Edward M. Young in The Aviation Historian (issue 12 2015) that also covers flights in other machines.
This sort of weather plane can be made modifying the venerable (although a bit vetust) 1/72 Northrop Gamma kit from Williams Bros.
The origin of mine is very satisfying: it came as a surprise birthday gift from Andrew Nickeas of Fogland.
It has raised panel lines (I engraved them) but can be built into a very decent replica, especially if you add detail and accomplish a neat painting and decaling job.
With a little bit of ingenuity, research and work, you can squeeze so many different versions with beautiful liveries of this kit that you will be surprised. Some require minor touches and self-made or commissioned decals, some require surgery and scratchbuilding impetus, like the versions with inline engine. You can have the model representing real planes on skis, floats or wheels, even in registrations from another countries. The kit itself provides from the start several versions, but you can add a long (and very appealing) list. I will leave to others to make a detailed list, since I am not so much of the chatty-chatty but more of the buildy-buildy type.

Among the Gammas -all beautiful no doubt- perhaps the most stylized are the 2G and 2D variants. To the latter belongs the "Experimental Overweather Laboratory" flown by TWA to study flight at high altitudes, pioneering and heralding the era of the now customary 33,000+ region for everyday passenger flights. Flying "over the weather" was the goal then. Needless to say, it required superchargers (for the piston engines), pressurization and control of temperature and breathable air mix (due to the low level of oxygen at that height).
Before its high-flying career, the TWA machine NR/NX13758 was doing the mail route and flew regularly with the airline, together with Gammas 13757 and 13759, all D models.
In 1936 modifications were introduced for high ceiling: a turbocharger, a new engine, and a set of instruments for the observer/engineer inside the fuselage ahead of the pilot.
The 2D is a variant that unfortunately can't just be shaken off from the old William Bros mold, and the modification will take some little effort.
As with the Conqueror Gamma I posted before, modifications are surely needed, none of which is really beyond the skills of a modeler that can call her/himself such.
Modifications include:
Wing: engraving of ailerons, modification of three aileron ribs, drilling new landing lights under the wing. Deletion of kit's landing lights and conduit under central panel. Addition of two conduits running parallel in place of former. Panel lines engraving if desired.
Fuselage: re-location of cockpit, blanking of old positions. Re-shaping and re-location of cockpit floor. New turtledeck. New canopy. Loop antenna (only for the later livery, with bands on vertical tail). Hatches and interior if desired. Conduit on the right upper fuselage. Antenna wire under the fuselage.
Fin/rudder: changing of hinge line to balanced variant.
Nose/ Cowl: adaptation/replacement of kit's parts to match photos. As it is in the kit, the cowl is too small for this version. Many variations can be observed in shape, decoration and details related to turbocharger and exhaust.
Decals: William Brothers produces now a decal sheet that includes this variant (and many others), but not for all the decorations of the TWA/Weather Laboratory during its life, so pay attention to your references and over all, trust only photos. The William Bros set has some hiccups, and may be questionable regarding the color choice of some lettering (Experimental Overweather Laboratory is very likely black, not red, as easily deduced comparing it to the adjacent TWA logo on the fuselage). Decals come as NC, but do not have the NR visible on most photos on the real plane with the Experimental Overweather Laboratory lettering; the "R" can not be chopped from another reg. on the sheet, for the wing, since it is outlined in green, and not in black. Neither for the rudder, where you will have to look for another solution. "Air Express" comes in black, when it was actually red. The little TWA round logo is missing, it goes on the cowl on both, left and right side. The are is a small lettering -also missing on the decal sheet- the reads "U.S. Mail AM2".
Nevertheless, it is a good set, and I encourage you to get it, since it is useful for other liveries.
Beware that there were mainly two liveries in which the "laboratory" flew, one has the three words "Experimental Overweather Laboratory" on top of each other, while the other has "Overweather Experimental Laboratory", one word after the other, and as you can see the first two words were transposed. Arctic Decals is producing a complementary/corrective set as I write this.
Propeller: the plane flew with two and three-blade props, the latter, a Curtiss, with and without spinner. Once more, study the photos so you don't end up combining features of the plane at different stages of its life.

At it:
Erase the conduit underneath the central panel, not accurate for this version:
 Engrave panel lines on stab:
 Retrace and engrave panel lines,  making rudder contour including balanced area, wrong in the kit for this version:
 Fill the original remaining line:
 Engrave panel lines on wing. Drill new landing lights locations:
Partially remove aileron ribs:
 Engrave ailerons:
 Cut out flaps (optional):
 Some of the kit parts will be used:
 Depending on the vintage of your kit, you may get plenty of flash. Of the three I used lately, two were neat, but one (this one) was heavy on flash.
That's not a problem, and parts are cleaned up quickly:
 Wing and trousers halves are glued together:
 The cockpit openings on the fuselage are bridged to start the relocation. The fore section has to be filled-in later:
 The cockpit floor is shaved to fit new, aft location:
 The decal sheet sold by Williams Brothers. Nice to have, although not perfect. Get it, it's useful:
 Lights on L.E. are masked and filled:
 A general view so far:
 Landing gear glued in place. On background proto-cowl (the kit's won't do) and possible engine (the kit's, again, won't do):
 Some bits are brought from the spares box, like spinner, loop antenna (only necessary for the later varian with stripes on vertical tail), some sidewall detail. Observer's inst. panel is cut. Looks like the longer nose plug from the kit would be better than the shorter one:
 Potential engines, an Aeroclub item and a Small Stuff resin built-up. The later is exactly the size it should be, but, alas, won't get inside the cowl unless you sand down the cylinder heads :
 Hatches are marked and masked:
 Hatches and side window excised:
 The custom cowl getting a skirt extension:
 Inst. panels in place, observer seat in place on wing. Kit's cowl visible on photo, it can't be used:
Check for fit as you add interior bits:
Interior bits in place, ready to paint:
Starting to sand the slanting backwards angle on the cowl walls:
Shape getting there:

 With the long adapter from the kit:
 The engine back just pops in:
Color is applied to the interior components:
 The new home-made cowl primed:
 Some additional detail painting and a few more parts like seat belts, instrument panel decals and such will be added and then the fuselage halves can be united:
More components are added:

Stabilizers are angled downwards for a bit of realism:
 Fuselage glued, plug to close gap on  front of cockpit prepared. The seams will be next:
Wing and horizontal tail attached. Plug in place:
 Hatches doors and conduit:
 Getting along well:
The two new conduits underneath. Now all the long work on seams and surfaces can begin:
Turtledeck in place:

 Dry-fit of engine+home-made cowl:
 Addition of conduit.
I was missing the right size of MV lenses (great product by the way) for the landing lights, so I made my own:

Primer goes on:

The opening handles for the hatches and radio compartment are mad. These are tiny!:

 Now to add detail to the deployed flaps:

 Dry-fit of an adapted part to simulate the supercharger intake:

Quite ready to start painting:
Photoetched rings are added on the fuel caps' locations:
The black base coat is applied to all components:

Shades of aluminium are airbrushed:

Flaps are glued in place:
Landing lights and antenna are added, wheels are painted:
 Ready for decaling and final assembly:
The canopy parts are masked before painting:
The canopy is on. The radio hatch is made with a decal, and then the handle added. The retractable stirrups are also in place now::
 Cowl and engine in place:
 Front fuselage hatches are given their handles:
 The Venturi probe is added:
Completion feels close now. If only those mechanics will stop attending those Irregulars' meetings in Puget Sound and do some darn work for a change...

The wonderful set of decals from Arctic Decals:
Decaling ensues:
 The Arctic Decals set is super nice, and caters for many variations of the livery. Very small lettering and even the prop logos are included:

To be continued.....


  1. What a great work, as always. I take my attention to the engine cowling and the lenses... they are fantastic. What do you used, crystal epoxy?


    1. Sí, usé una hoja de aluminio muy finita, el sacabocados, la herramienta de repujar y una resina epóxica de dos components transparente.

  2. Interesante, saludos. Armando Gil.