This interesting story was published in the September 2009 issue of Business & Commercial Aviation, and is reprinted here with permission of parent magazine, Aviation Week & Space Technology. Mr. Prinz is a world-famous aviator, engineer and aviation lecturer.
It was a relaxing afternoon in late June until the phone rang. "Get over to the airport now. Mr. Hughes wants to see you. There's a problem." I jumped into my 20-year-old DeSoto sedan and headed for the Culver City strip. By then I'd been there many times, a fact that still came as a surprise.
When I graduated from the University of Wisconsin in 1942, I simultaneously received my ROTC commission as a second lieutenant in the U.S. Army. My orders were to report to Fort Belvoir, and who knew after that. There was a war on.
But before departing Madison, I was approached by several company recruiters to come to work for them. I had graduated near the top of my mechanical engineering class and good engineers were in short supply then. So when the man from Hamilton Standard offered me a job, I took it. And the company got my orders cancelled. Amazing times.
Soon I got sent to California to work on propeller applications for experimental aircraft. It's now hard to appreciate the engine advances in World War II, but they were astounding. Pratt & Whitney, another United Aircraft company, had developed the R-4360-31 Wasp Major, certainly one of the most complex air-cooled piston-powered engines ever conceived. I had 28 cylinders -- that's 56 sparkplugs -- divided into four rows, plus turbochargers and supercharger. It was a marvel, but to absorb the thing's 3,000-hp output would normally require excessively long propellers. Rather, the designers chose to fit each engine with counter-rotating props turning two sets of four "Super Hydromatic" broad blades, about which I was made expert.
Two of the earliest Super Hydromatic applications were both experimental machines being developed by Hughes Aircraft. One was the H-1, later known as the Spruce Goose, which used no less than eight of the systems. We loved it. The other was the XF-11, a twin-engine, high-altitude, high-speed reconnaissance aircraft whose design was reminiscent of Lockheed's P-38. It was this latter aircraft about which I'd been hastily summoned.
As was his habit, Hughes was readying the prototype for its eventual first flight. When I arrived at the company field, I saw him standing by the aircraft, and he waved me over. Soft-spoken and direct, he said the props were not delivering full power, and he wanted to know why. Since I had neither evidence nor an explanation, he told me to get into the airplane while he conducted another pre-takeoff run.
That directive from one of my childhood heroes was unorthodox since the XF-11 was a single seat aircraft. But I somehow squeezed my nimble 155-pound frame into the tiny area behind the pilot seat, which hughes occupied moments later. He proceeded to crank both Pratts closed the canopy and taxied to the end of the 2,000-foot long strip. At that point, he advanced the throttles and we began to roll. As we gained momentum, both he and I fixed our eyes on the manifold pressure gauge and RPMs.
I quickly realized that Hughes was correct -- the needles indicated less than maximum output, and I began to troubleshoot in my mind (it turned out that the blade angle at the lower end was not set correctly). But then something above the panel caught my eye. I looked up and was shocked to realize we were rapidly approaching the end of the runway and at this speed would collide with several tall and thick eucalyptus trees just beyond, if we didn't stop immediately. I shouted, but Hughes was already on the brakes so hard that one of the tires actually burst. Still, we continued headlong towards the trees.
Heroes notwithstanding, I almost jumped over Hughes' left shoulder, reached out and lifted thye red safety covers on the two prop reversing switching, and flipped them alive. The results were almost instantaneous, as those 16 blades roared into halting action. The airplane slowed, as if pulled by some tether. The trees came closer and closer and my eyes widened further, but at a less alarming pace. Until we simply stopped. With 50 feet remaining. I could hardly breathe.
We waited there, a few moments, in silence. Hughes turned and looked at me momentarily, saying nothing, and then advanced the throttles again and we thu-thumped back. Once at the hangar, Hughes climbed down the ladder, crossed over to his car, and departed, having said nothing, even though I am quite certain I had just saved both our lives. I never saw or heard from him again.
Less than a month later, , on July 7, 1946, I was at home awaiting a call regarding preparations for the XF-11's imminent first flight, when the radio news announced that Howard Hughes had just crashedm an experimental airplane into some houses in Beverly Hills. I rushed to the scene. Hughes, near death, had already been rushed to a hospital, but I took photos of the engines, prop and wrecked cockpit.
He later complained that the props had somehow reversed in flight, and brought him down. The truth was, the temporary seal between the reversing props leaked oil so that operations were limited to to ne hour or less -- a fact well known to all in the program. But Hughes had spent so much time taxiing before flight and, rumor had it, buzzing a girlfriend's house, that he exhausted one prop's oil supply and the prop went into flat pitch. Had he been at the correct test flight altitude, he could have easily made an airport without incident.
But then, he was Howard Hughes, an aviation legend, and survivor.
Thanks to me.