David Rose wants to make a splash at Reno this year, followed by a bang--or rather, a series of excruciatingly loud bangs. He is racing what he hopes will
become the first propeller-driven aircraft to break the sound barrier in controlled flight--a feat that will make so much noise and produce so little tangible benefit that he doubts anyone will ever attempt it again. "I won't achieve anything," says Rose, a steely-eyed 67-year-old. "It's just one of those things that should have been done many years ago but hasn't."
It hasn't been done for good reason. In the 1950s
the U.S. Air Force flight-tested a jet-engine-powered, propeller-driven fighter called the XF-84H, but the "Thunderscreech" proved so monstrously loud that it
actually made people ill. With less power and a much smaller prop, Rose's plane, Renegade, should be quieter --but not much. With four propeller tips, each going
supersonic simultaneously, and a roaring 1,700-hp
engine, "it's going to be mind-bendingly noisy," aerodynamicist Barnaby Wainfan says.
Taking a propeller-driven plane to Mach 1 also presents other, more critical problems, such as how to
cram a massive engine into a tiny airplane. Rose had
to scrap the original fuselage because the engine's enormous torque twisted it excessively. To stiffen the airframe, Rose designed a new fuselage around a cage of chrome-moly tubing, like that used by drag racers.
"I could comfortably crash this at 300 mph," he says.
Ideally, Rose won't have to, but the challenge of
piloting such a light, powerful prop plane can't be
overlooked. One of the biggest technical issues is managing the torque of the engine with Renegade's tiny wings. When the engine is revving high at low airspeeds--as it would during takeoff--the whole package could prove uncontrollable.
Rose plans to race Renegade at Reno this fall, win the heavyweight Unlimited class, and impress a potential sponsor enough to fund the $150,000 upgrade from
the current 1,200-hp engine to a 1,700-hp replacement.
If all goes according to plan, by next summer he'll be
piloting the push-prop beyond Mach 1.
The Reno Air Race Association (RARA) conveniently changed the rules for entry into the Unlimited Class before the 2005 race season. The new rules required a minimum empty weight of 4500 pounds. Renegade was about a ton shy of that. Or was it really because somebody didn't want the incumbent contenders to get creamed by a margin of over 100 knots by a scratch built aircraft with a modified automotive engine? Wake turbulence was the excuse I heard.
Let's back up and take a broader look. Here's what I see. In 1991, the Pond Racer crashed, killing its pilot, never again to be rebuilt. The Pond Racer would have easily won every race if it had been around long enough to be perfected. It was capable of well over 500 miles per hour. But, it was the odd-ball, challenging the traditional heavy incumbents. The Pond Racer could not have weighed anywhere near 4500 pounds empty, but nobody squawked about it. It wasn't going to win by 100 knots. It wasn't going to break Mach in level flight. But, it was going to win consistently. Unless it crashed. Being unique, there was no replacement for it.
Jump forward to 2005. Renegade. You know my take on that.
Jump forward to 2011. A highly modified P-51, Galloping Ghost, sports a newly perfected boil-off engine cooling system so effective it allows complete removal of the air scoop, drastically reducing drag. This innovative contender challenged every incumbent by showing up with a unique new design that would all but guarantee consistent wins. Tragedy struck. You've heard the news. But, what really caused that trim tab to separate from the aircraft? P-51s have been flying at Reno since day one, and how many trim tabs have come off? I'm guessing it's not common. Again, unique innovation, can't be replaced.
I have my theories. They aren't likely to be popular. Can anyone honestly rule out a conspiracy, here?
Lots of cash, lots of prestige, maybe some big egos, probably a lot of gambling somewhere by some high rollers who don't like to lose, and some new innovations that are sure to make somebody lose. Connect the dots.
Read more about this at earthsink.blogspot.com
I hope somebody does break Mach in a propeller plane with a piston engine at Reno. There's no technological reason it can't be done. But, unfortunately, there are probably a lot of political reasons it won't be done.