Scale Matters

The electric P-51 prop to be used on the P-3 during static judging at contests. All photos by Orin Humphries

Mock-ups, Basics: Woods and Glues, Stooge, Second Checking

By Orin Humphries
July 2024

This is a teaser about my present project that has been moving right along, my Lockheed P-3 Orion. The electric P-51 prop shown above will be the basis for all four of the Scale props that it will use during Static Judging at contests.

(The P-3 is now paused for a bit so I can make a simpler entry for the 2025 Nats.)

The size of the P-3 project.

Mockups



P-3 mockup parts.

Building my P-3 from true scratch has been an odyssey of some 50 years, having begun it in 1973, but putting it aside for a long time. This is a complicated design, with a bomb bay and nose wheel well forward of the wing. Those cavities present structural weaknesses if the nose wheel encounters a hard landing sometime. That aside, there are LOTS of parts to be fit together, tabs and slots to arrange, and drawing mistakes are a certainty.

I decided to check my drawings by making a mockup of the bomb bay, the wing saddle, and the nose well before touching any balsa stock. My wing must be removable for transport, as it has a 74.5” span, a bit too much for my Mustang to haul around.



Checking fits and line-ups.



The wing saddle, the bomb bay and the nose wheel well.

Sure enough, I found spots in the drawings that needed correction, but the cardboard assemblies gave proof of principle for my approach. Setting the mockup on the already-constructed top half of the forward fuselage led me to build the bomb bay.



To save finishing time and materials later, I lined the bay and doors with thin styrene sheet from the hobby shop.

Next came the nose wheel well and cockpit deck.


There were a number of places where the mockups showed me errors in tabs vs. slots for them. It is too much to keep straight without something to look at.

Box Project