P-39Q Airacobra USAAF 1/72 indoor glider conversion

[ReynoldsSlumber]

This is a downscale of the 1/30 Fiddler's Green plans, using the "Snooks 2nd" paint scheme. The purchase comes with several P-39 as well as Oddball Productions P-63 plans in various markings. This one was the most visually appealing to me. Regarding the particular prototype aircraft, one can find historical information, museum photos, and a historical video.

This was the most fun I've had making a scale card model airplane so far, just a total joy. Though it's a straightforward model, I also appreciate details like the vertical tail leading edge extension and the engine exhausts. I was eager to find out what the distinctive Fiddlers Green shaded graphical style looks like in person, and it didn't disappoint.

I used Domtar Lynx 32 lb bond / 118 gsm paper, which is thicker and therefore stiffer than the same weight of Domtar Cougar paper. That's due to Lynx being a "lower quality" line of papers, as in during manufacture it's not squeezed as hard as Cougar. It's flexible enough to take curvature, and it holds up well to gluing. Given its better whiteness and smoother surface compared to art papers, I think I'll be using Lynx paper on a lot more small- to medium-sized indoor glider builds.

Modifications for aesthetics:

• Vellum canopy: This time I tried using a printed canopy, leaving the blue shading in the window areas intact for the full Fiddlers Green look, and gluing solid printed paper to the outside surface. It worked pretty well for this aesthetic. I think the look of the structure raised above the window may be a little too steampunk in general, so for other models I'll likely revert to gluing the solid paper bits to the inside for the opaque "structure."
  
• Wing/body fairings: I couldn't square how the wing fillet trailing edges were supposed to line up in a way that closed off against features on the underside. So afterward I added pieces to the underside to fill the gaps.
  

Modifications for flight:

• Undercambered airfoil: A fairly easy mod on this model, given the wing's construction with a center section under the fuselage. One disadvantage is that it leaves an inaccurate hollow in the middle underside of the model, something that's noticeable in profile.
• Clear plastic finger grip: Glued to the center section bottom surface. No internal "spine" this time, as the model is light and strong enough that I don't think it'll need the reinforcement.
• Foam nose: This worked out nicely. I happened to have some yellow-orange craft foam around, so I replaced the frontmost spinner cone section with a foam cone that extended back inside the second spinner section, to be backstopped by the bulkhead at the back of the spinner. For the (oversized) gun barrel I used a short piece of wood dowel, glued to the foam.
  
• Nose weight: I picked up a centigram scale, which took the guesswork out of fashioning an optimally-sized brass wire nose weight. With an all-up weight of 3g, the nose weight is 13% of the total.
  

[ReynoldsSlumber]

Isn't it a cute little beastie? It's swoopy and graceful, like a butterfly except heavier-seeming than that of course. Gliding speed is around 18 ft/s, very stable. The last photo is upside down, for better visualization of the plane's underside.


(Gliding speed estimates on models that I've posted about before were too low by about a third. This time I timed it rather than guessing.)

[Don Boose]

Looks terrific. I appreciate the detailed narrative and construction images.

Many thanks for sharing.

Don

[ReynoldsSlumber]

Thanks Don! And nice to know that folks are interested in the build peculiarities. Hopefully it saves others some time and effort if they try something similar.

[Erik Zwaan]

Thanks for sharing, I like the P39 with its non-standard entrance compared to contemporary aircraft, and the fact that you made a glider out of it. Nice work sir!

Erik

[Siwi]

I'm always impressed how you make a nice looking model that also works as a successful flying glider.

[ReynoldsSlumber]

Thanks Erik and Siwi! On this low-wing plane, I was pleasantly surprised that it didn't need any extra dihedral to have sufficient roll stability. (For an outdoor glider, given launch dynamics and wind gusts, it would be a different story.) With the configuration of a real airplane, these models fly better than many traditional folded-from-a-typing-sheet paper airplanes.
The secret that many scale aircraft card models are hiding is that, if one were to pluck off any draggy landing gear, propeller blades, rigging, etc. and add the right amount of nose weight plus a little up elevator, they could fly too. One might even try it with a damaged or extraneous model.