"I put the blood of my life into this thing. I have my reputation rolled up in it, and I have stated that if it was a failure I probably will leave this country and never come back, and I mean it."
- Howard Hughes during the October 30, 1947 U.S. Senate hearing.
Perfect is the Enemy of Good
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| The elephant in the room. |
In 1942, England found itself cut off from the rest of the world. Supply ships bound for the island nation from the United States were routinely intercepted and sunk by German U-boats prowling the Atlantic. That year alone, a combined total of 1,332 merchant and cargo ships were destroyed by German submarines. Needed troops, supplies, and war materiel failed to reach beleaguered England.
A simple question spawned an ambitious project. What if the ships had wings and avoided Nazi torpedoes by flying over them? This question led to a partnership between Henry Kaiser, a builder of those frequently-sunk Liberty ships, and fastidiously eccentric aviator Howard Hughes. Dubbed the HK-1 (for Hughes-Kaiser), a design was proposed for a monstrous high wing seaplane capable of hauling 150,000 pounds of cargo, 750 fully equipped troops, or two 30-ton M4 Sherman tanks.
However, Hughes' obsessive perfectionism caused delays and cost overruns. Frustrated, Kaiser pulled out of the partnership and the project was renamed the H-4 Hercules. The monster created by Hughes Aircraft designers was powered by eight Pratt & Whitney R-4360 Wasp Major 28-cylinder engines producing a combined total of 24,000 horsepower. With a wingspan of 320 feet, the Hercules had the longest wingspan -- greater than the length of a football field -- of any airplane built until Scaled Composites' Stratolaunch Roc first flew in 2019. It stood 79.1 feet tall -- roughly eight stories -- from keel to the top of the vertical stabilizer. Spanning 113.5 feet, the horizontal stabilizer alone exceeded the 103.75 foot wingspan of the Boeing B-17 Flying Fortress. It remains the largest seaplane ever built.
It is also the largest wooden aircraft ever built due to constraints from the United States government. Because aluminum was a strategic material needed for the war effort, Hughes could not source it to build his Hercules prototype. Thus limited, he chose a high-tech birch plywood laminate produced through the Duramold process. Detractors christened the wooden airplane Spruce Goose, a name that Hughes absolutely loathed. Moreover, it was inaccurate, but Birch Bitch was insufficiently media-friendly for the 1940s.
As the project dragged on while Hughes prioritized perfection over expediency, World War II ended and the need for the Hercules evaporated. Plagued by cost and timeline overruns, Hughes poured his own money into the H-4 only to find himself called to Washington DC and accused of war profiteering and wasting taxpayer funds on a flightless boondoggle.
Thus beset, Hughes found himself at the controls of the H-4 Hercules on November 2, 1947 during a break in the Senate War Investigating Committee hearings. He announced that he only intended some high speed taxi tests. After completing two perfunctory runs, Hughes called for flaps and pushed the throttles farther forward for the third run. Surprising all onlookers, the airplane reached 90 mph and Hughes coaxed it from the ocean's grasp to fly roughly one mile at an altitude of 25 to 70 feet averaging 135 mph. It was the first and last flight of the one-of-a-kind flying boat.
For Hughes, it was vindication.
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| Photo of the H-4 Hercules in flight. |
The Path to Evergreen
After its only flight in 1947, Hughes maintained the Hercules in a state of flight readiness within a climate-controlled hangar. Initially, the airplane was under the care of a 300 person staff, but the company reduced that headcount to 50 in 1962. After Hughes' death in 1976, the company that bore Hughes' name sought to divest itself of the wooden albatross altogether and, at one point, considered parting it out to various museums. In 1980, the Aero Club of Southern California put the intact Hercules on display under a geodesic dome in Long Beach, CA. That facility was purchased by Disney in 1988 and, in 1991, the company announced that it no longer wished to display the Hercules. Michael King Smith of the Evergreen Aviation Museum submitted the winning proposal to build an entire museum around the Hercules, which is why the world's largest seaplane came to McMinnville, OR. It arrived in 1993 and, nine years later, the doors of the new Evergreen Aviation & Space Museum (EASM) opened to reveal the birch monstrosity wrought by Howard Hughes.
Silhouette
Arrivals at EASM are routed directly toward the glass wall of the West Pavilion through which the hulking silhouette of the Hercules glowers.
Once inside, the immensity of the Hercules has to be seen to be believed.
Conventional aircraft displayed nearby appear as toys by comparison.
Eight Pratt & Whitney R-4360 Wasp Major 28-cylinder radial engines dot the leading edges of the wings. They appear tiny relative to the bulk of the airplane, but the R-4360 itself is enormous. It is the largest displacement piston engine mass produced in the United States and the largest -- and final -- radial engine design from Pratt & Whitney. Just imagine the Hercules running up at full power, 224 pistons violently cycling in 224 cylinders fired by 448 spark plugs (2 per cylinder) to drive eight 17 foot diameter Hamilton Standard propellers with the 24,000 horsepower needed to drag Hughes' leviathan into the air. Don't even bother with noise abatement rules.
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| Supercharged variant of a Pratt & Whitney R-4360 on display at the Air Zoo. (Photographed 2013.) |
By way of example, the above photograph shows the four banks of seven cylinders on a P&W R-4360 Wasp Major. A supercharged model is pictured, upgraded from the Wasp Majors sported by the Hercules. Thus, the compressor assembly aft and below the "corncob" of cylinders is absent from the Hughes Flying Boat engines. To my mind, the mechanical complexity of radial engines is already astonishing, but when those engines consist of four rows of cylinders, they transcend exquisite engineering into something approaching art.
A recurring design element throughout the Hercules is fear of fire. That fear is reflected by the lengthy pylons thrusting (pun intended) the engines far away from the leading edges of the wooden wings.
The horizontal tailfeathers posses a wider span than the wings of a B-17 Flying Fortress, an impossible seeming statistic.
I have seen a lot of aircraft emblazed with the word "experimental" over the years, but none of them were anything like the H-4 Hercules.
I pointed at a crank lying atop this equipment compartment. "That looks like the hand crank for a starter on a Stearman," I noted.
Embarkation
Museum visitors are prevented from exploring deeply into the Hercules by a glass enclosure in the cargo hold. They do get an exquisite view of the structure of the aircraft looking toward the tail. I paid the extra fee to receive a personalized tour of the flight deck and it was absolutely worth it.
Red cylinders of carbon dioxide gas are connected to an elaborately plumbed fire suppression system. Beachballs are an inexpensive means to add buoyancy to unoccupied compartments and the outboard floats near the wingtips.
Original blueprints called for a clamshell opening at the bow of the Hercules, but concern about keeping the cargo area watertight led Hughes to eliminate that from the prototype.
A narrow spiral staircase leads from the cargo hold to the flight deck.
From the Flight Deck
These windows along the port side of the flight deck were not original to the aircraft. They were added when the airplane was on display in Long Beach so tourists could peer into the Hercules. From inside, they provide an excellent vantage point to sight along the line of R-4360 Wasp Major engines. My ears hurt just imagining the sound that must have reverberated through the skin of the Hercules for anyone sitting in-line with those massive spinning propellers.
Hughes was hounded by skeptics over whether the wooden construction of the Hercules could withstand the strains of flight. The prototype was equipped with a significant amount of diagnostic equipment and stress/strain gauges to monitor for issues.
Still affixed with a Hughes Aircraft Co asset tag, a literal black box is present as a flight recorder.
In the aft portion of the cavernous flight deck, hatches provide access to the wing interiors. At eleven feet "tall" at the thickest point, a grown adult can walk upright into the wings, even during flight. (In principle, considering that no one ever has.)
Those big radial engines mean an oil capacity measured in the tens of gallons. The large green tank just inside the wing root is an oil tank.
1940s electronics occupy the aft bulkhead of the flight deck.
A massive 139 gallon oil tank hangs in the aft port corner of the flight deck. I could not help but wonder about who dented that tank and how long ago it happened. A "whoopsie" for the ages.
A ladder extends through the ceiling of the flight deck for an observer to aid in maneuvering the flying boat in close confines.
I pointed at a crank lying atop this equipment compartment. "That looks like the hand crank for a starter on a Stearman," I noted.
"Close," responded the docent. This cabinet contained the Hercules' two auxiliary power units (APU), four cylinder horizontally opposed Franklin aircraft engines that assisted in starting the eight Pratt & Whitney R-4360s and powered generators that supplied electricity to run the ship's systems. The hand crank was used to start the Franklin APUs.
"Really?" I asked. "Just ordinary Franklin aircraft engines?"
We moved around to the side of the compartment where I could see for myself. The racket produced by the APUs running on the flight deck must have been a nuisance, but I suspect it would have been overwhelmed by the Pratt & Whitneys outside. On an aircraft as large as the Hercules, I probably should not have been surprised that an entire airplane engine would be used as a glorified starter motor.
The Front Office
Moving toward the bow, we passed additional testing equipment. The framed document is an FAA bill of sale showing transfer of the Hercules, tail number NX37602, to the museum.
Another quirk highlighted by the docent was the open pipe just aft of the pilot's seat in the upper right corner of frame. The Hercules has an extensive ventilation system intended to circulate air throughout the wooden structure. As a germaphobe, Hughes required that a portion of the freshest air, that taken directly from the outside, is passed to the pilot position first before anyone else can breathe it.
The radio operator's station came complete with an integrated morse code key. A hat reminiscent of Hughes' trademark fedora sits on the table (only partially in frame) as though Hughes himself had just set it down and walked away. I asked if it was actually one of his hats.
"No. We used to have one, but someone walked off with it."
Immediately forward of the radio operator's station is the cockpit itself on a raised platform. From outside, the breadth of the flying boat makes these windows seem tiny. But from within, the view is panoramic.
Because of the size of the massive control surfaces, they are actuated by hydraulic systems specifically invented for the Hercules. The joystick on the left was used to adjust trim. Eight numbered power levers stand proudly at the pilot's right hand, though without prop and mixture controls as part of the quadrant, they appear unusually streamlined.
"Where are the mixture and prop levers?" I asked the docent.
"I don't know. No one has ever asked me that before," he answered. I had stumped him with what seemed to me an obvious question. Perhaps those controls are at the engineer's station.
As I peered at the flight instruments, my hand clutching the left seatback for support, I realized that I was grasping the very seat from which Howard Hughes piloted the Hercules on its only flight. With that realization came a sense of awe and historical perspective. It also occurred to me that Hughes would have hated that my grubby hands were touching his seatback.
Controls for flaps and the hydraulic system are available to the pilot on the console next to the left seat.
Controls available to the right seat pilot are considerably more limited.
An overhead panel has toggles for exterior lights and a number of fire warning annunciators for individual engines, fuel tanks, and other high risk locations within the Hercules. Curiously, one switch is marked "flare release". I cannot fathom what purpose the Hercules would have to launch flares unless they were part of a distress signal. Even so, one would hope that any flares launched would fly well away from the wooden airframe before igniting.
Aft of the right seat stands the impressive engineer's station.
This massive vertical console displays all available engine data in columns, one for each of the eight Pratt & Whitneys.
Though the airplane is a prototype, a coffee station was evidently considered to be critical equipment.
I first learned that the Hercules was on display at the Evergreen Aviation & Space Museum in the early 2000s as a student pilot raptly devouring AOPA magazines. I waited over two decades to finally see the Hughes Flying Boat in the cellulosic flesh. Standing on the flight deck was a literal dream come true for me.
In summary, a visit to EASM was a minor detour on the four hour trek back to Portland, but very worthwhile. EASM is an incredible museum housed in one of the most beautiful facilities for the display of aircraft that I have ever visited. That the museum was a labor of love for prime mover Michael King Smith is undeniable, it shows in every aspect of the facility. But what most differentiates this place is the hulking presence of the Hercules, truly an engineering wonder of the aeronautical world.
Hercules in Miniature
My first significant exposure to Howard Hughes and the H-4 Hercules came from the excellent 2004 Scorsese film, The Aviator. EASM displays a miniature set used in the movie that depicted the Hercules under construction. In rewatching the film, it was evident where this miniature was used, presented with actors in the foreground and dimly lit with sparks flashing vaguely in the background. A true cinematic treasure captured alongside the genuine article.
Wrap Up
August 5 was our last full day in Oregon. From ESAM, we drove the remaining hour back to Portland and departed early the next morning on eastbound flights. When people ask where we went on vacation, a common response to my answer of "Oregon" is "why?" Our wonderful trip featured the stunning Crater Lake National Park, exploration of volcanic landscapes east of the Cascades including lava fields and cinder cones, mountains, waterfalls, raptors of the high desert, observation of the heavens and beyond (surely, seeing another galaxy counts as beyond!), and an aviator's bucket list item of exploring the infamous Spruce Goose flight deck. Need I say more?
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