雷克斯講航空歷史 一戰英國海軍轟炸機 Blackburn G.P發展簡史（原視頻無字幕）

The Blackburn GP, or General Purpose Seaplane, was an attempt by the company to remedy the embarrassing failure of the twin-fuselage Blackburn TB and restore confidence within the Admiralty. Built as a private venture, it was designed by Bob Copley, who had worked on the ill-fated TB, and was proposed to the Admiralty as a three-seat long-range anti-submarine patrol bomber. Though it inherited several design features of the twin Blackburn, the GP had a far more conventional layout, and most importantly, it didn't try to set itself on fire every time the engine was started. It featured a single, long, slim fuselage that would accommodate a pilot and two gunners, one of the latter also serving the role of bomb or torpedo aimer. The wings were almost a direct carryover from the old TB, with the upper being braced by king posts and having a significantly greater span. Both wings were of parallel cord and without stagger, both had a significant amount of dihedral, and they were designed to be folded back for ease of storage. The first GP that was built was powered by a pair of Sunbeam Nubian engines, each producing 150 horsepower. They drove wooden four-bladed propellers, and were cooled by a pair of radiators mounted vertically to the wing struts. The structures that supported the engine also formed part of that which supported the two main floats. These were bungee sprung to help absorb impact on the water, and they were built up of 12 individual watertight compartments that were housed in a treated plywood covering. The first aircraft was completed in the summer of 1916, and with the serial number of 1415, it flew for the first time at RNAS Isle of Grain in July. In its complete form, the GP represented a potent aircraft, at least for one flying in 1916. The gunners each had a .303 calibre Vickers machine gun mounted on a flexible scarf ring, providing the aircraft with two independent arcs of defensive fire. When they were more inclined towards offensive fire, the forward gunner could operate a bombsight that was mounted externally on the starboard side of their cockpit. Though the details of the bombsight appear to be unknown, the aircraft's payload was known to be either four 230-pound bombs slung on underwing racks, or a single torpedo that was carried beneath the fuselage. Though there is no evidence to show that the GP was ever flown with said torpedo during tests, it was among the first twin-engine aircraft capable of doing so. That being said, the single-engine Short 184 had already been successfully using torpedoes since the summer of 1915, and the Blackburn had to rely on other merits if it was to be more attractive to the Admiralty. The greatest of these was hoped to be its range and endurance. It had enough fuel to fly for up to eight hours when carrying bombs or torpedoes, which was significantly greater than the two-and-three-quarter hour endurance of the Short 184. The evaluation of the Blackburn's endurance was taken to the extreme in August 1916, when it was taken out and moored in rough seas to see how long it would last. It endured the aquatic beatdown for several days until finally giving out, and it's believed the data from this experiment was used to make changes to the second Blackburn GP, whose construction began shortly afterwards. This aircraft was built with a considerably reinforced structure. Heavier gauge fittings were used throughout the airframe, and some changes were made to the construction of the wing struts. Details on these latter changes are scarce, but their thickness appears to have increased by about 10-20%. These changes were made due to an Admiralty requirement, which called for strength factors of five and four on the front and rear struts respectively, to make the wings more durable when the aircraft was operating in rough seas. Along with the reinforcements, the second GP also had a few modifications that set it apart from its predecessor. Instead of two, it had four ailerons, two of increased length on the upper wing, and a pair of shorter ailerons on the lower wing. Power now came from a pair of 190-horsepower Rolls-Royce Falcons, though they had not yet received that name, which, like the Sunbeams, drove a pair of four-blade propellers. But unlike the Sunbeams, the Rolls-Royces had exhaust manifolds on the outside walls of the cylinder blocks, which meant the exhaust pipes could be run along the side of the engine nacelles, rather than sticking out from over the top. One other change that set the second GP apart, though it is difficult to see in most of the photos, was the unfortunate decision to use a wire trailing edge on the wings. This resulted in the familiar scalloped pattern that could be seen on many aircraft of this time, but it was poorly suited to seaplanes. Wire and salt water did not go well together, and after no great time had elapsed, the corrosion of said wire would lead to damage of the wing fabric and require a trip back to the hangar for replacement or repairs. Corroding wings aside, the Blackburn GP was an improvement over its predecessor, but it never went into production. Existing aircraft, particularly the short 184, performed the roles of anti-shipping and anti-submarine duties perfectly well, and it was felt that the Blackburn was too big and too expensive for the rough, unforgiving environment of naval use. Indeed, said rough, unforgiving environment was nearly the end for some of the people testing the second prototype. Its manufacturer trials were conducted on the Humber Estuary during the winter of 1916-1917. Launching the aircraft was simple enough, but bringing it back in required a team to wade into the icy waters. The tide was particularly strong that day, and cold, and in fact it even brought in sea ice from the North Sea. By the time the crew had gotten the aircraft onto dry land, they were in a seriously bad way. All of them looked blue, some were incapable of speaking, and none of them could walk. They were carried into the hangar on makeshift stretchers, their clothes literally frozen onto their skin, and a series of small fires were made where they were gradually thawed out. After this frosty experience, the aircraft was sent to Great Yarmouth Air Station for service trials, where, as mentioned before, it was not considered suitable enough for a production contract. However, it was recognised that the aircraft, on the whole, was still a promising machine, and it was suggested that a land plane version of the GP could be of great use, as it wouldn't have to worry about the challenges of water handling. This led to the development of the Blackburn Kangaroo. But that's a story for another day. As always, thank you all so much for watching, and a big thank you, of course, to the patrons. Now, I'm probably going to do more of these shorter videos on interwar aircraft over the next few months, as my list of aircraft to cover has now exceeded 500 items. However, longer videos will still be getting made on the more popular machines, of course. A big thank you, of course, to our Wing Commander-tier patron supporters, our highest-tier members, and a warm welcome to Stephen Eldred, who is the newest member of this special group. Hopefully, this video actually gets to Patreon on time for once. There have been a lot of issues with Patreon video recently, and hopefully I won't have to re-upload it three times like the Curtiss video. We'll see. Anyway, thank you all for your continued support, and I'll catch you all next time. Goodbye.