Browse Topic: Flooring
Harold F. Pitcairn, American aviation and Autogiro pioneer, died from a single gunshot wound to the head in the late evening hours of April 23, 1960 at the age of 62 after a gala evening at which he presided over a celebration attended by more than 450 guests for his brother's Raymond's 75th birthday. Initially labelled a suicide by the press, Pitcairn's widow Clara declared that "she never wanted to hear another word about the tragedy", while friends and friendly local authorities made the argument, duly reported by Frank Kingston Smith in Legacy of Wings, his devotional Pitcairn biography (subsidized by the Pitcairn family), that the death was accidental because "there was no note, no indication of depression or unhappiness" and "the police investigation disclosed that two shots had been fired; one had penetrated the ceiling directly over the desk in the first floor study, another had struck Pitcairn in the eye" and that "the next morning it was discovered the semi-automatic pistol was defective: when cocked, it had a supersensitive "hair trigger," and it had a faulty disconnector so that it would fire more than one shot at a time, a condition known as "doubling."" The Pitcairn families, prominent and powerful, prevailed upon the local authorities to declare the death accidental and Kingston Smith's 1981account became the de facto authoritative story of the death of Harold F. Pitcairn. With the perspective, however, of six decades, it appears far more likely that Pitcairn's death was a suicide for reasons that were not readily evident, minimized, unappreciated or deliberately ignored at the time to craft a result that met the needs of Clara Pitcairn and her surviving family. These included the fact that while the claim was made that Pitcairn was making his nightly rounds to check on the estate’s ground-level windows (and had been doing so since the Lindbergh kidnapping in 1932), he actually died at his desk; that those in the house only reported a single shot; the 1907 Savage pistol had no reputation for a hair-trigger, and had not evidenced such a flaw in almost three decades of Pitcairn's nightly ritual; that even though Pitcairn had been assured that his almost-decade-long lawsuit against the United States government for Patent infringement of his Autogiro patents was going well, he was concerned about the impact this lawsuit was having on his aged associates who had been called to give depositions and he had voiced the sentiment that "if he had known that he would have to sue the government, he would not have gone into the Autogiro business"; that the lawsuit, itself intended as a vindication of Pitcairn's contribution to aviation was dragging on and would reach its first legal conclusion in 1967, and not finally conclude upon appeal until 1977; and most importantly, those who deny suicide and point to Pitcairn’s state-of-mind, have failed to take into account when the death occurred or ready evidence of his 'state of mind' To fail to see the tragic end of Harold F. Pitcairn is to forget that 29 years and one day earlier, he had been recognized for "the greatest achievement in aeronautics or astronautics in America, with respect to improving the performance, efficiency, and safety of air or space vehicles, the value of which has been thoroughly demonstrated by actual use during the preceding year." The memory of that day on the White House back lawn with the President was the high point of his life even as Pitcairn prepared to celebrate his older brother's achievements. The evidence, when marshalled and documented, conclusively points to suicide - a death of an American aviation pioneer before his contributions were vindicated in the largest patent infringement judgement against the United States in history. To fail to see the tragic end of Harold F. Pitcairn is to forget that 29 years earlier, he had been recognized for "the greatest achievement in aeronautics or astronautics in America".
ABSTRACT This paper examines the performance of passive structural vibration attenuating devices in rotary wing applications and introduces a new attenuating device to rotary wing applications, the NASA-developed Disruptive Tuned Mass (DTM) device. The testbed uses an OH-58D tailboom rigidly mounted to the floor as a cantilever beam with a first lateral mode resonant frequency of approximately 6.25 Hz as a representative rotary wing structure. The study characterizes the modal response of the tailboom without an attenuating device installed, with additional mass installed, a mass-spring attenuating device, a fixed orifice Tuned Mass Damper (TMD), and a device based on NASA DTM technology. TMD and DTM devices were tested with 6 lbs (2.72 kg) and 19 lbs (8.61 kg) mitigation masses. The DTM devices achieved greater modal attenuation than the TMD devices, 88% and 96% respectively, for devices with 6 lbs (2.72 kg) and 19 lbs (8.61 kg) active masses.
ABSTRACT The ability to construct a composite, semimonocoque, damage-resistant, cargo floor for a rotary wing application using an IM7 graphite/polyetheretherketone (PEEK) composite with in-situ tape-placement fabrication technology has been demonstrated. Through an evolutionary process, a damage-tolerant thermoplastic composite cargo floor was designed according to realistic requirements, and subelement representative structures were developed to verify the design viability and approach. The fabricated and tested structural composite floor subelements demonstrated the feasibility of the technology, illustrated the ability to customize the design to meet unique cargo floor properties (e.g., cargo-loading features), and validated the maturity of the approach and fabrication technology for rotary-wing applications.
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