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Wednesday, February 10, 2016

Scratchbuilt 1/72nd Cactus Kitten triplane racer

 (this is the building article. To see the completed model please go here:

Paraphrasing the enigma that the sphinx presented to Oedipus:
What is it that roars, and first flies in one wing, then in two wings and then in three wings?
Can you give an answer before I throw you into the deep chasms of modeling ignorance?
It is the Curtiss Cox / Texas Wildcat / Cactus Kitten racing plane(s).
All planes have a story behind, many times a very interesting one (although perhaps that's valid for any object in the world, even the simplest, or perhaps everything in the universe) and the Cactus Kitten is no exception.
The story begins with the Curtiss Cox racer...*
*If you think you will seat there while I do all the hard work and on top of that write here the story, you are sorely mistaken, go find out, pal:
As you can see, the concept started with a modern design, and after much research and trials, ended up retrograding to a much older one, outmoded and passé.
And they call that "progress". I wonder to which other aspects of life this may apply...
But I digress.
This model had behind it two driving forces: the book of Michael Gough on the Pulitzer races, and a tall giant that winters in the frozen tundra of Chicago (we shall call him Dave). Michael got me interested in the racers, and Dave -who was also reading the book- was pondering about what plane one may chose to model.
You may think "why this guy scratches models that are readily available from kit manufacturers?". Oh, you weren't thinking that. Silly me, that's true, most manufacturers give a rat's ass about nice planes and only release killing machines. Well, whatever fills your pockets and glorifies death, pal. I am happy I can build my own stuff.
The following pictures and notes describe the building process in case you are mad enough to want to build one.
The prop is hand-carved wood, the metal wheels form a dwindling Aeroclub items' stock, the fuselage was vacuum-formed on a hand-carved basswood master, the rest is Good Ole' Styrene. The flying surfaces are "hollowed" and airfoiled (as per my usual "envelope" approach). Brass airfoiled "Strutz" were used throughout. The "bumps" on the engine cowl were made of heated, bent and cut sprue rod. I got a matching pair after 123,785 attempts. Good luck with that. The radiator "books" were fun to engineer and build, and the rumors of me going to rehab are spurious and unfounded.
Since I am portraying the racer as it won second place in the 1921 Pulitzer, before it was ultimately ceded to the Navy, there are no markings to deal with. So there.
 Primal basswood block shape:

 Prop carved, Aeroclub wheels, flying surfaces:
 General aspect:
 Radiator "books" construction begins:

 The fuselage is measured against the Mattel base:
 The holes are plugged:
 The Mattel Psychedelic Machine in action:
 The two halves are carefully adjusted:
 Formers measured and cut:
 Formers glued:
 Strips at the joints help with gluing surface:
 Interior parts:
 More dry-fit and the engine "bumps" that will later on be added:
The spinner is vacuum-formed from a spare part. In the original, the wide prop base was shaped as part of the spinner, but here the effect will be simulated:
The prop is given a metal axle and the spinner is epoxied in place:
 The holes for the struts are drilled on the wings, and the ailerons are engraved:
Some structure strips are added to the radiators as per photos (the radiators were very slightly different once the Navy took possession):

The inst. panel is under way:
Sorry, wrong photo, here it is:

 Most of the cockpit bits ready to be installed:
Ready to join:
 And joined:
The lower wing is given its dihedral, and notches are cut into the leading edge, where the landing gear aft legs will pass (notice the absence of ribs, the whole plane was covered in plywood):
 The area where the exhaust rows will go is cut out:
 The section where the exposed engine oil pan goes is removed:
The horizontal tail is separated in its left and right components:
 The middle wing is also separated in its left and right parts:
 The vertical tail and stab halves are given locating pins, and corresponding holes are drilled in the fuselage. The small elongated part is the intermediary between the lower wing and the fuselage belly, as seen in photos:
The lot minus the struttery:
The tailskid and associated bump are incorporated:
 The engine front bumps are replaced by smaller, more to scale ones, and the prop is dry-fitted:
Dry-fitting the stab halves with their metal spar:
 Dry-fit of the vertical stabilizer:
 Preparing the three different sizes of airfoiled "Strutz":
 Vertical tail and lower wing support glued in place:
 The spars for the middle wing are located:
 Dry-fit of the middle wing halves, they were cut long, so later on the mating angle can be carved away:
The prop and radiators are airbrushed:
 The fuselage is given a coat of primer to reveal blemishes:
I had to develop a technique to paint the very tip of the spinner red:
A length of wide masking tape is placed on a clear acetate piece. A hole of the required diameter is punched:
 The tape is easily lifted and centered on the spinner, covering the blades:
 White primer is airbrushed:
 Red paint is airbrushed:
 Et voilá!:
A windshield is fabricated:
 The cabane "N" struts are made of airfoiled brass "Strutz":
 Struts in place and dry-fit of the upper wing:
 Middle wing spars glued in place:
The middle wings are glued in place. All components are primed and later on a coat of white paint will be airbrushed:
Landing gear parts:
The landing gear sub-assembly is attached to the fuselage:
Dry-fit of the lower wing, which interlocks with the aft L.G. legs (has to be first painted separately to be attached to the red fuselage):

Gloss white is airbrushed. Aluminum will follow, then masking and red to finalize:
 Needless to say this imposes some patience as you have to wait at least one day for the next step:
Aluminum paint is airbrushed:
The model is masked and the red applied:
 Masks off:
Lower wing, stab and windshield in place:
Six inspection panel lids are punched out from red decals. Needless to say, once applied they are not very visible, but they are there in the real plane:
 The engine oil pan is added to the cutout previously practiced in the fuselage shell:
Vertical wing struts are cut:
 Tail struts are added:
 Vertical wing struts in place:
 Dry-fit of upper wing:
 Diagonal wing struts:
 Solder "exhausts" are cut and passed side to side trough the cutouts:
Rigging is added, including cabane rigging, LG rigging, wing to nose wires, X wires (four positions) in wing. Wheels, Pitot probe and propeller in place:


  1. Hello I might have something that will help in making parts that you want many copies off! I tried emailing but it didnt get sent!

  2. Sorry forgot my name! Its John O'Reilly

  3. Hi John
    I just tested the Contact Form and it works perfectly. I suggest you try again. If you are referring to resin casting or 3D printing, not very keen on those, but thanks anyway.

  4. Hello again! I still keep getting message could not be sent! Try again later! But here is my addy