I’ve been a fan of Elliot Seguin’s work for several years now. The dude knows his stuff, flies a lot of cool airplanes, and has an excellent YouTube channel which artfully threads the line of being both informative and educational, while also showcasing some extremely interesting aircraft. One of his ongoing series details the various test flights of the Bowerspony, a 70% scale P-51 replica.
Sure looks like the real thing, save that the 1:1 scale pilot looks just a little larger in the cockpit than in a real P-51D. Bowerspony is a Steward S-51, powered by (IIRC) a Chevy-sourced V-8 driving a propeller speed reduction unit (PSRU) which in turn spins the prop. While the kit itself is no longer for sale, the existing airframes and kits are supported by Stewart 51 Partner LLC (http://www.stewart51.info/home.html). According to their website, they hope to eventually produce new kits at some point.
Interestingly enough, several S-51 builders chose to forgo the automotive conversion + PSRU engine combo in favor of a Walter 601D turbine. (Source) More reliability, more speed, less weight, but at the cost of significantly higher fuel burn.
One of the things I really enjoy about Elliot’s videos is how he thoroughly breaks down the planning, preflight, flight test, and postflight phases in a methodical but easy to understand manner. A lot of the test planning aspects are familiar to me from my QA days, but the application is obviously different. There’s a lot to learn though, especially since I’m still hoping to build my own Experimental some day. Probably not an S-51 though. I think I’m going to stick to something a bit less complex for a first build.