{"id":201,"date":"2016-07-07T19:27:00","date_gmt":"2016-07-07T23:27:00","guid":{"rendered":"http:\/\/zrsthemovie.com\/?page_id=201"},"modified":"2020-06-27T17:08:39","modified_gmt":"2020-06-27T21:08:39","slug":"zrs-4-evolves","status":"publish","type":"page","link":"http:\/\/zrsthemovie.com\/?page_id=201","title":{"rendered":"ZRS-4 Evolves"},"content":{"rendered":"

\"ZR-1&4The British, in the mid-1920s undertaking\u00a0two 5\u00a0Mil cu ft rigids, had shown how 9\u00a0M cu ft capacity would be need for similar performance with helium. With ZR-1 replacements Congress-funded\u00a0in a\u00a01926 act,\u00a0 but limited by Lakehurst’s 804′ X 172′ hangar, the\u00a0new design was increased only to 6\u00a0Mil cu ft. in hopes of avoiding comparative performance embarrassment. Earliest concepts included lessons learned from the ZR-1 breakup: internal engine rooms, and integrated control car.\u00a0Also not<\/span> planned was any way to recover tonnage lost to fuel consumption. As Garlon Fulton later detailed, the ZRS water recovery equipment itself weighed 16,000 pounds. Typical New Jersey weather required an additional 12,000 pounds of anti-freeze. (At 2300 pounds each, that added up to a dozen<\/em> Waco UBF two-seat hook-on airplanes.) Forgetting its dead weight, on a 6-day mission, the water recovery’s additional drag would increase fuel consumption by 9,000 lbs. It was out of the question.\"Dreadnaught\"<\/p>\n

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This early concept Goodyear-Zeppelin released to\u00a0conceptualize the BuAer Design #60 \u00a0 proposal\u00a0bristles with big guns,\u00a0with\u00a0little use for puny auxiliary aeroplanes – nor had funding been provided for them.\u00a0\u00a0At some time, possibly in\u00a0early 1927, a seaplane-carrying truss was added uniquely inside<\/em><\/strong>, with\u00a0details\u00a0not\u00a0yet\u00a0defined.\u00a0 It was about this time that concepts sprouted water-recovery condensers, the necessary evil of their weight and drag making helium operations at least possible if not cost-effective.<\/p>\n

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\"ring-manThe final 3-keel G-Z design that won the 1928 Zeppelin Rigid Scout competition\u00a0had been\u00a0further increased, to 6.5 M cu ft, and featured built-up main rings offering previously\u00a0unobtainable\u00a0interior access (left). Amid the other innovative design features learned from non-Zeppelin designs were drivetrains allowing the reversible, inboard German-made engines to drive the propellers through a 90 degree arc, offering thrust in any direction. Chief designer Karl Arnstien also accepted a subordinate’s idea to\u00a0align all engine rooms\u00a0along the two side keels to simplify access. G\/Y’s huge “Airdock” assembly hangar was more than 50% complete as ZRS-4 assembly began; her “Golden Rivet” was squeezed by RADM Moffett himself during a 7 NOV 29 ceremony.<\/p>\n

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\"Graf-tailMeanwhile, during the Graf Zeppelin\u2019s<\/i> 1929 routine replenishment in Los Angeles, his\u00a0fuel and provison’s weight was balanced with\u00a0corresponding hydrogen lift\u00a0piped aboard.\u00a0Topped off\u00a0too early,\u00a0the\u00a0day’s California sun expanded the hydrogen in the cells, which then vented gas normally through safety valves. That afternoon, the ship could not lift off the mast and no more hydrogen was readily available on site. After sending\u00a0some crew on ahead by train, and then attempting a heavy, dynamic takeoff on the Graf\u2019s<\/i> landing bumpers, the\u00a0lower fin and rudder dug in as the elevator man skillfully\u00a0wheeled the nose, then the tail, over the Mines Field power lines to safety. (Here, Graf’s<\/em> rudder under repair after reaching Lakehurst.)<\/p>\n

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It is rumored that at the time a comment by Hugo Eckener led on-board observer (future ZRS-4 skipper) C. E. Rosendahl\u00a0to believe it was necessary to be able to see the lower vertical fin from the control car.\u00a0True story or not,\u00a0Navy officers pushed for Design change #2 of 1930.\u00a0 To comply,\u00a0since hull construction\u00a0was long since well underway,\u00a0Arnstien\u2019s design team moved the control car aft, and dramatically altered the fin shape. Author Jeffery Cook’s study on the ZRS fin design<\/a><\/span> discounts the popular story that denying the fin root the strength of main ring 35 was the fatal flaw.<\/p>\n

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\"CURTISS-XF9C-1<\/p>\n

Elsewhere, with no funding to develop a suitable hook-on seaplane, officers accepted they’d have to take\u00a0an existing plane that would fit through the ZRS-4’s projected door width: 25 feet. No seaplane was right; under consideration were three landplanes, including the\u00a0Curtiss XF9C-1 (left), a previous competitor for the small-flattop fighter, rejected as too hot to handle. Curtiss corrected many of\u00a0the problems\u00a0using its own money, building an\u00a0improved XF9C-2. Equipped with a sky-hook and successfully tested on ZR-3’s trapeze, an order was placed for six production units. One advantage was noted over the USS Langley<\/em> then testing landplanes in its added flat-top deck: the airplanes could launch and recover without the parent vessel having to turn into and hold a steady course to keep the prevailing winds straight down its deck. Few appreciated at the time what would later be demonstrated in ZRS ops: airplanes could hook on or drop off with their dirigible on any heading, with any relative wind. (In fact as told by pilot “Min” Miller<\/a>, pilots adapted to the airship’s actually changing course while they were in approach for hooking on.)<\/p>\n

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\"BayVisitors to the Airdock viewing ZRS-4 construction were treated to explanatory signs labeling some components in\u00a0Bay VII, location of the airplane stowage truss structure. The airplane trapeze was not part of the contract; neither it, nor the default airplanes,\u00a0could be pre-tested before\u00a0rollout.<\/p>\n

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\"engine\"First-ever inline engines, numbered per the diagram at left, had to turn in opposite directions for best prop efficiency.\u00a0 Various pitches – even steel props\u00a0in ZRS-4’s\u00a0later days – were tried. Accepting the peacetime helium edict, each engine was plumbed with complex\u00a0exhaust-cooling condensers\u00a0with associated piping and\u00a0baggage to recover water tonnage created in the combustion process.\u00a0 The arduous task of cleaning the sooty plumbing would be come to be handed out as punishment to enlisted crewmen for violating minor rules.<\/p>\n

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\"4<\/p>\n

This NAS Lakehurst Engineering handling drawing (right) shows the ZRS-4 &5\u2019s main frame and bay\/cell Roman Numeral designations;\u00a0our\u00a0inset\u00a0contrasts the original fin plan. With a final length of 785 feet and maximum diameter of 132.9 feet. the overall ZRS 4&5 hull air enclosure was 7,401,260 cu ft allowing 12 gas cells a maximum displacement of 6,850,000 cu ft.\u00a0 126,000 lbs. of gasoline weight contained in 110 keel tanks, and the additional weights of oil tanks, water tanks, and ballast bags were spread along the twin outboard keels, which also served as main ship\u2019s passageways from frame 35 aft to frame 170 forward.<\/p>\n

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\"Plankowners\"Here, the “plankowners” pose in the Airdock with their ship on 30 JUL 31, about six weeks before rollout.\u00a0 \u00a0It would be up to these men and their future shipmates to learn the art of operating the first rigid designed to accommodate the limitations of helium. With these and so many other major design\u00a0innovations in the ZRS-4 evolution, there was a great deal for them to learn before airplanes could be incorporated into operations.<\/p>\n

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\"\"<\/a>In a ceremony attended by thousands, ZRS-4 was christened by Mrs. Herbert Hoover, sent by her husband the President in a show of support. She pulled a rope signaling the forward yaw line hatches to pop open, releasing 48 doves “of peace” that had been staged inside. The lines were let out so the 200-ton airship could float up several feet, while the crowd cheered.<\/p>\n

Columbia Pictures had jumped on the chance to release its new film “Dirigible”<\/a> starring Jack Holt, Ralph Graves and Fay Wray, playing in local theaters that week.<\/p>\n

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Click\u00a0 >\u00a0 for\u00a0a clip from\u00a0our DVD, “The Flying Carriers” ( sound on)<\/p>\n