Plane & Pilot
Tuesday, July 23, 2013

The Sound Of Thunder


For those seeking a more economical alternative to the max performance of a P-51, the Thunder Mustang should satisfy your inner need for speed


With all that power on tap, aerobatics thrill. Roll rate is about 90 degrees/second, so a full, max stick deflection roll demands only four seconds. Loops and vertical rolls are no problem, but it's important to keep all maneuvers positive, as there's no inverted fuel or oil system. Push the airplane into even a slight negative G, and that big 12-cylinder engine will stagger. With a 10.9 to one compression ratio, the blades will spool down to a complete stop if you hold outside Gs for more than a few seconds. (That's by no means a measure of the airplane's strength, however. Denny designed the Thunder to withstand +7.3/-4.9 Gs at gross. The airplane's structure is carbon fiber with a honeycomb core, probably stronger than an equivalent aluminum structure.)

If your mission is cruise, you'll see 280 knots at 10,500-11,500 feet, burning 22 gph. With 102 gallons aboard, the airplane has 3.5 hours endurance plus reserve for a range of nearly 1000 nm. The pilot needs only to monitor temperatures and adjust coolant, oil doors and fuel trim as necessary to keep the engine happy. With all those cylinders firing in sequence, the Falconer engine is almost as smooth as a turbine (though some owners have actually installed Walther turbine mills).

Wing loading is just under 30 pounds/square foot, and that translates directly to a fairly smooth ride in turbulence. Like the original fighter, it plows through rough air with little trouble.

Descents are as you like them with liquid cooling out front. Shock cooling isn't a concern, so you can descend as fast as your ears will tolerate with that big four-blade MT running interference. Redline is the same as the P-51's top number, 439 knots, so there's no risk of overspeeding the airplane.

At the bottom of the envelope, approaches work well at 100 knots with a wheel landing at 85 knots. Stall speed is below 70 knots, so you're not pushing the envelope at a final approach speed of 90.

Wayne Richards' airplane represents more than simply another immaculately constructed homebuilt work of art. It is, in some respects, an ultimate, the maximum performance you can wring from a normally aspirated, piston engine. WWII fighters needed superchargers to fly high and fast so they could outpace the bad guys. Today, jets have relegated those wonderful piston fighters to museums and occasional air shows, and the limited supply of 65-year-old Mustangs continues to diminish.

If pilots such as Wayne Richards and Dean Holt are successful at keeping the Thunder Mustang alive, however, we may continue to see a version of the airplane maintaining the legacy of the legendary P-51 Mustang forever. And no one will ever forget that sound.



Labels: Piston Singles

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