Certainly one of the celebrities this year at AirVenture is the 2/3 scale P-38 built by Jim O’Hara and his wife Mitzy. It’s an apex experimental, one of those over the top builds defying all norms of dedication and craftiness and it’s available for close inspection next to the Brown Arch.
With the pocket-sized TTP-38 featured in EAA’s current Sport Aviation magazine the project’s basics are well known. What’s being emphasized at AirVenture is it took a very smart man—Jim was a professor of aeronautics and worked for NASA—about a quarter of is life to develop his own scale plans with no access to the original plans, run the engineering proofs, fabricate the parts, assemble them, run all the electrical, hydraulic and cooling systems and ultimately fly his creation in 2007.
Jim and Mitzi have since flown west, however, and after some years of hangared inactivity the airplane is now in the hands of Jim’s nephew, William Pressler. Opening the hangar door on the dormant project presented William with quite a few decisions past the usual cleaning and airing up the tires.
For starters, Jim was in the process of swapping the two Continental TSIO-360 engines side to side, along with finalizing the nose gear door. The latter is a fiendishly complex assembly of doors and actuators which Jim was still optimizing when life forced him off the project. Swapping the engines was to change propeller rotation to match the original P-38’s unusual outboard swinging blades. It seems Lockheed was on to something when they too changed from inboard to outboard rotation after the first prototype.
Thankfully Jim had left copious notes and absolutely reams of mathematical computations, the only issue being Jim was a genius and much of those were indecipherable to William. But he had the plane in front of him and looking at it, along with the notes, he simply worked as far as he could before coming to a roadblock. And then he would concentrate on the issue until he figured a solution and continue to the next step. William, who visited Uncle Jim regularly in his youth, says this is exactly how Jim persevered through the planes genesis.
And there is the key story behind Williams time as the TTP-38’s caretaker and further developer. He’s had to study one man’s work and thereby get inside that man’s head. From there he’s needed to carry the design forward. Luckily for William the huge majority of this impossibly large effort was done by Jim.
As a plane we suspect the TTP-38 flies much like a scaled down P-38 because that’s really what it is. The mean aerodynamic chord, weight and balance and other fundamentals are exact to the original Lockheed fighter down to a couple decimal places says William. The one exception is power; the 450 hp on tap from the counterrotating Continentals is far below the original Allison V-1710’s massive thrust and the result is climb and cruise speeds familiar to almost any private pilot, even if the creation of this magnificent interpretation of the P-38 remains incomprehensibly overwhelming.
