Aviation History

Here’s why Howard Hughes’ Spruce Goose couldn’t be an effective troop transport

Empty the Spruce Goose weighed almost twice what a fully loaded B-29 weighed at takeoff when at combat overload weight. They were just insane numbers for the era.

The largest wooden airplane ever constructed, and flown only one time, the Spruce Goose represents one of humanity’s greatest attempts to conquer the skies. It was born out of a need to move troops and material across the Atlantic Ocean, where in 1942, German submarines were sinking hundreds of Allied ships. Henry Kaiser, steel magnate and shipbuilder, conceived the idea of a massive flying transport and turned to Howard Hughes to design and build it. Hughes took on the task, made even more challenging by the government’s restrictions on materials critical to the war effort, such as steel and aluminum. Six times larger than any aircraft of its time, the Spruce Goose, also known as the Hughes Flying Boat, is made entirely of wood.

Originally designated HK-1 for the first aircraft built by Hughes-Kaiser, the giant was re-designated H-4 Hercules when Henry Kaiser withdrew from the project in 1944.

But would the Spruce Goose have been a viable troop transport with more testing and development?

‘While staying at the floating museum and passenger ship turned hotel, the RMS Queen Mary on a business trip I was able to tour the Spruce Goose (of which 90% was constructed out of Birch, not Spruce. But the media thought “spruce goose” had the right ring to hook readers and listeners),’ says Gregg Gray, former Senior Noncommissioned Officer (SNCO) in the US Air Force, on Quora. ‘As it was very close by where the Queen Mary is moored (when the aircraft was still in Long Beach, California) we felt compelled to go, she has a large drawing effect, its size is overwhelming (and I was then routinely flying on the huge Air Force jet cargo aircraft, the C-141B stateside and often the C-5B overseas, as well as the occasional Boeing 747 and the rare Lockheed L-1011 widebody; and I was staying on a huge ocean going, luxury passenger ship). My military co-workers and I were just gob smacked at the size of the aircraft.

This diagram shows a top and side schematic size and shape comparison of the Hughes H-4 Hercules, Boeing 747-400, Airbus A380, and Antonov An-225.

‘The story we got from the tour guide was that at that time Hughes and his engineers were simply planning the days testing to collect data at faster surface speeds on the water, but it accidentally reach take off speed and flew very briefly, and very low (but somehow managed to get its picture taken for the newspaper).

‘I speculate, as others do, that Howard Hughes, who was at the controls that day, did it on purpose just to see if it would actually fly. I think at that point he was already aware that the project was doomed to end and never going into production. It probably would not have seen service even if the war had continued on. It appeared to be very problematic, as very large, complex, and complicated things tend to be, as well as a gas hog.’

Gray continues:

‘It was 3,700 miles from Norfolk Naval Yard to Southampton and 3,800 miles to La Rochelle, France. Amsterdam is 3,900 miles from Norfolk and Naples, Italy is a staggering 4,650. (All of these are straight line distances, as the crow [or seagull] flies, if I may improvise slightly]. The design flight range was 3,000 miles at 250 mph. So it was going to have to find a refueling ship in the open ocean or an intermediate island like the Azores at 2,751 miles, and then another 1,500 miles to Southampton (Way back in the day I flew on a piston engine, propeller driven passenger aircraft from Scotland to the Azores, and on to New York, [then on to our car in Bayonne, NJ, followed by a drive to Tennessee to get back home to our family in Tennessee] we were very tired.). But just the flying portion by itself sucked, it wasn’t any fun at all, in fact it was miserable and very cramped. The top speed hoped for out of the Spruce Goose was 250 mph, and realistically 200 mph was probably going to be achieved when fully loaded with combat troops in “Full Battle Rattle.” The proposed purpose was to avoid German U-boats sinking troop ships. This aircraft was still going to have to land in the water off the coast of the Azores, or on the high seas for a refueling ship. Now the miserable cramped, tired, and intolerate troops were one thing to deal with, after all it was four days or more minimum on the cramped troop surface ships, so they would have to tolerate that. What they couldn’t tolerate was getting troops killed by U-boats lying in-wait for the aircraft, and no matter where you landed that was an issue. Water landings by aircraft in a sea full of U-boats gives the U-boat skippers an easy sitting duck (or goose in this case) for a target.

‘Flying for between 15 and 20 hours with just a short refueling break would have been exhausting. I have done it more than once, the Pentagon planned our flights to land just after daybreak so we could get in a full days work at our destination. What starts out as huge gets smaller as you go.

‘Now, not only is the aircraft huge now, but it was absolutely ginormous in the mid 1940s, she is almost 2.5 times as long, and has three times the wingspan, and empty weighs more than triple what was then our huge Boeing B-29 United States Air Force Bomber, the Superfortress (of Hiroshima and Nagasaki atom bomb fame). The B-29 had four engines producing 8,800 horsepower together, the Spruce Goose achieved 24,000 total horsepower from “8 × Pratt & Whitney R-4360 Wasp Major 28-cylinder air-cooled radial piston engines, 3,000 hp (2,200 kW) each.” It required three times as much horsepower because it was well over three times heavier at 250,000 pounds versus the Superfortess at 74,500 pounds. In fact, empty the Spruce Goose weighed almost twice what a fully loaded B-29 weighed at takeoff when at combat overload weight. They were just insane numbers for the era. It was another 20+ years before the big C-5A Galaxies and 747s came along which are in the same size range as the enormous H-4 Hercules (Spruce Goose). ‘

Gray concludes;

‘As neat as all the specifications are, she still comes up short. I don’t think it would have worked as a troop transport. Now days we just charter civilian passenger jets for routing troops deployments. The military cargo birds are busy moving heavy equipment and helicopters. Military cargo birds are usually used for pax when the troops have to deploy in full battle rattle and prepared for almost instant action.’

The Spruce Goose is now housed at the Evergreen Aviation & Space Museum near McMinnville, Oregon.

The following interesting video features the first and last flight of the Spruce Goose.

Photo credit: Federal Aviation Administration

Dario Leone

Dario Leone is an aviation, defense and military writer. He is the Founder and Editor of “The Aviation Geek Club” one of the world’s most read military aviation blogs. His writing has appeared in The National Interest and other news media. He has reported from Europe and flown Super Puma and Cougar helicopters with the Swiss Air Force.

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