November 2014-
Nothing else quite compares to nudging a throttle
that’s connected to a big radial engine.
In reality I had far more flight time in turbine-powered aircraft over the 50-plus years of my flying career than I did with piston powerplants, but it was those days that I fiddled with old-fashioned whirling and chugging bangers that made me feel that I was a real pilot.
The hot stovepipes that eventually took the place of the big piston engines on airliners were better in every way, excepting one: they just weren’t as much fun to learn about or deal with. I had lots of great experiences with the smaller piston engines on the General Aviation fleet that I owned and/or operated, but nothing (from an engine point of view) compared to nudging a throttle that was connected to a big radial engine.
Even some of the General Aviation cadre that I flew came equipped with round engines of small to medium size (such as the Twin Beech and several exotic singles), but none came close to my experiences behind the Pratt & Whitney 18-cylinder, twin-row radial known as the R-2800.
I spent thousands of hours fiddling with and learning how to nurse those 2,400 hp behemoths during my first several years as an airline pilot, and those operating nuances have stayed in my memory.
The Pratt & Whitney R-2800 Double Wasp was arguably the most remarkable piston aircraft engine ever built. It powered a huge number of World War II fighters, bombers and cargo planes, then went on to power a large fleet of 1950s airliners.
Even today, over 80 years since the first R-2800 wheezed, coughed, sputtered and puffed its way to life, rebuilt R-2800s are still in demand. What made the R-2800 remarkable wasn’t any one particular thing, it was a fabulous combination of truly useful and dependable characteristics.
For a big radial powerplant, the R-2800 could be tightly cowled and thus reduce the amount of “frontal area” and the resulting aerodynamic drag. Cooling air was channeled through its thin, precise cylinder fins and the results were more than adequate; the airliners that I had most of my R-2800 experience in—the Convair 240/340/440—didn’t even need cowl flaps. Instead, the engine’s exhaust was piped into horizontal chimney-like ductwork at the rear of each powerplant, and the rush of the hot air through those ducts pulled in cooling air through the forward part of the engine’s nacelle.
Back at the beginning, the U.S. Navy was Pratt & Whitney’s biggest booster since carrier pilots wanted nothing to do with complex and vulnerable liquid-cooled engines. A liquid-cooled engine could be put out of service by a single coolant leak, while the air-cooled R-2800 was legendary for how it could limp home with entire sections of the powerplant damaged or missing.
Like most reciprocating aircraft engines, the R-2800 had two spark plugs per cylinder—but not for redundancy. The two plugs were there in order to properly fire the intake charge completely across the broad combustion chamber inside each of the 18 cylinders. Failure of one of the plugs could quickly result in detonation and possible destruction of that cylinder.
Now for my own R-2800 particulars, dredged up from memory:
We always bet a beer on how many backfires you’d get during engine start. You played the starting sequence like a piano, with three fingers and the thumb of one hand. There was a boost-pump switch, a starter motor switch and primer switch, and your thumb held down the safety switch so the other three switches would work. You needed your second hand for the mixture control on the center pedestal.
You played with the primer switch to get just enough fuel without flooding it. If you got even slightly out of sequence, the engine would go BANG…BANG…BANG!
It didn’t hurt anything (we hoped), but everybody got a big laugh out of your clumsiness. We knew we had flooded the engine when there was a stream of fuel pouring out of the bottom of the airbox and the mechanic would look up and yell, “Boy, ya got ‘er flooded now!”
We always had a big-wheeled fire extinguisher standing by, since it was not unusual to create a ground fire. If you had another backfire after you had put a large puddle of raw gas on the ramp, it would ignite, and… that was always exciting.
We all thought the R-2800 was a great engine, at least comparing it to other recips. Of course, none of those old round engines had the dependability of the turbines, and it wasn’t uncommon to need to shut one of the big recips down and feather it while en route.
Personally, I had 11 failures with a resulting single-engine landing during my first two or so years with the airline—which turned out to be more single-engine operations than I experienced over the next 34 years in a variety of turboprops and turbojets.
On top of the outright failures of the R-2800 were the incidents wherein a powerplant would begin to run rough. We’d throttle it back to idle and it’d keep running. After landing, we’d discover that one or two of the cylinders had completely blown off, or there was a giant hole here or there from a thrown rod or something.
My own most challenging R-2800 failure had nothing to do with the engines, per se. We had a double engine runaway while climbing out of Ogdensburg, N.Y. one early morning when I was a copilot.
That particular Convair 240 had Curtiss electric propellers, and they were nightmares. The master motor that controlled both props somehow shorted out internally, and it took both props right through the redline—the two engines were howling like turbines and bouncing in their cowls.
The captain, my very good friend and mentor Ed Johnson, was hand-flying the lightly loaded airliner around the traffic pattern, trying to get us back to the runway. “Kid, do something!” Johnson yelled while he continued to wrestle with the ailing Convair.
I did everything I could think of, which eventually got one engine feathered and the other engine calmed down. It was a double-engine, double-prop replacement after we taxied back in.
So, you might ask, thinking back to the beginning of the article, where was the “fun” in that?
There was a whole lot to engine management back then, and you literally learned it on the job from the masters. Those old captains understood how to keep the big recips running, how to get them started, how to get them properly shut down.
There were some written notes here and there about operating technique or reducing fuel flow, but most of this stuff you learned by watching someone else do it. Then you passed your knowledge on to the next guy.
Flying itself was more of an art back then, and recip engine management was an art. A lot of that art was taken away when we went from the R-2800s to the turbines. There was no question that the turbines were more reliable—which made a pilot’s job easier, but not as much fun.
We all felt that the R-2800s were good engines. It was true that they required a lot of technique from the pilots, but it was technique that made you feel you were actually contributing something rather than being just a name and a number on a trip bid. Back then, you had to really know what you were doing or in short order, bad things began happening.
The R-2800 was not an engine that you could hurt, nor could you make it fall apart. It fell apart on its own; it didn’t need any help from you. It would just fall apart when it was time to fall apart. As often as not, the engine would somehow keep going.
I miss the puddles of oil, the billowy smoke, the coughs and bangs, the lopping up to idle power that those 18 cylinders gave back to you when you managed to get it all correct with your sequence of fingertip commands against the switches on the overhead instrument panel. Those are sensations worth remembering… and that’s why it was fun.
Editor-at-large Thomas Block has flown nearly 30,000 hours since his first hour of dual in 1959. In addition to his 36-year career as a U.S. Airways pilot, he has been an aviation magazine writer since 1969, and a best-selling novelist. Over the past 30 years he has owned more than a dozen personal airplanes of varying types. Send questions or comments to editor@www.piperflyer.com.
