Browse Topic: Flotation
This SAE Aerospace Recommended Practice (ARP) specifies criteria for the design, development, standardization, and comprehension testing of placards containing pictures, drawings, symbols, and/or written instructions for locating and operating aircraft emergency equipment. This ARP also provides guidance in the selection and implementation of warning placards intended to instruct occupants inside, and rescue personnel outside, the aircraft.
For rotorcraft emergency water landings, Title 14 of the Code of Federal Regulations (CFR) paragraph 29.801 specifies ditching certification requirements to minimize the probability of immediate injury to or escape provisions for the occupants. Currently, rotorcraft flotation behavior is determined for symmetrical regular waves and at specified sea states by scalemodel tests. The cost and development time associated with scale-model testing is relatively expensive and encumbered with scaling error. This paper presents the state-of-the-art tiltrotor aircraft flotation stability simulation methodology developed at Bell Helicopter based on the multi-material Arbitrary Lagrangian-Eulerian (ALE) technique in LS-Dyna®. The methodology is validated by correlating with the existing BA609 tiltrotor scale-model test data. It is demonstrated that the developed analytical tool is capable of simulating (or "virtual-testing") the tiltrotor flotation (i.e., buoyancy and stability) phenomena correctly subjected to a Sea State 4 hydrodynamics wave condition.
The main aim of this paper is to optimize pneumatic tyre parameters related that improve tyre flotation and performance on sandy soils. Tyre flotation pressure is the pressure of inflation that makes tyre flotation maximum such that it deforms more than it sinks in the soil. A second aim is to predict the tyre flotation pressure on dry sandy soil by using Artificial Neural Networks (ANNs) Technique. A third aim is to predict a new tyre size that improves flotation on dry sand by using Artificial Neural Networks (ANNs) Technique. Experimental investigation has been carried out on three tubeless tyre of sizes (225/75R15, 235/70R15 and 255/60R15) inflated each with four inflation pressures (50, 100, 150 and 200 kPa) on three dry sand with three densities (Loose, Medium, and High). The investigation aimed at determines the tyre deflection-load, sinkage-load relationships were measured and the tyre flotation pressure. The artificial neural network (in MATLAB program) simulating the tyre deflection and sinkage on dry sand was used for all tyre and soil parameters. The artificial neural network demonstrated good generalization of the tyre deflection and sinkage when presented with data not used in network training. It also successfully proved to be a tool for finding out hypothetical tyre sizes that are suitable for locomotion on specific soils.
The SH-2G Super Seasprite tailcone contributes to an abundant, albeit intangible number of benefits for operators of the SH-2G and its variants. Amongst its many benefits, the tailcone affords a significant capacity for accommodating a host of avionics equipment that include navigation, communication, sensors, and mission data processors. In addition to the wide array of avionics equipment able to be fitted in the tailcone’s electronics racks, the tailcone provides adequate space for installation and operation of a dipping sonar reeling machine, as in the case of the Egyptian SH-2G(E), and an environmental control unit, as in the Australian SH-2G(A). The tailcone provides enough volumetric space so that the aircraft’s cabin can remain purposely suited for troop transport of six troops, along with a 7.62 mm MAG 58 general service machine gun (GSMG), and a 7-man life raft. The tailcone provides sufficient surface area for the installation of a host of antennae for communication, navigation and counter-measures, with unimpeded and interference-free operation amongst the various systems. Another significant benefit of the Super Seasprite tailcone is its usage for emergency flotation. The tailcone of the Australian SH-2G(A) and the New Zealand SH-2G(NZ) aircraft provides a significant volume that displaces over 110 percent of the aircraft’s MAUW for passive buoyancy. Coupled with this unsurpassed benefit as far as reserve buoyancy margin is concerned, the Super Seasprite flotation system, with its two forward-mounted deployable flotation bags, provides upright stability up to the top of sea state 5 conditions. The design challenges for sealing the tailcone for utilization as a large flotation chamber, while yielding a serviceable compartment, along with providing adequate cooling to the host of avionics LRU’s were carefully considered and effectively met. Efficient utilization of space has forced the placement of avionics equipment to include innovative consideration for component cooling and service requirements in regards to weight impact and center of gravity envelope, in addition to the treatment for operating in a challenging electromagnetic environment. Additional benefits are derived from its shape and size to provide a vertical fin for forward flight and tail rotor unloading, and stiffness to yield low vibration levels on its tail rotor driveline components. This paper discusses the totality of the SH-2G(A) tailcone design in incorporating and managing the many systems that are housed within it and mounted on it.
This report details the work completed on the Titan Aerial Vehicle (TAV), an autonomous vertical lift aerial vehicle designed to operate on Saturn’s largest moon, Titan. The TAV was designed as the California State University, Los Angeles entry to the 2002 Vertical Lift Aerial Vehicle Student Design Competition sponsored by NASA’s Minority University Research and Education Program. Key requirements for the design included: vertical takeoff from a lander, flight to 2 km cruise altitude in 100 km/h headwinds, mid-mission hover out-of-ground-effect for 1 minute, followed by a vertical landing at a remote site for sample pickup. Moreover, the vehicle’s minimum range was to be at least 300 km while carrying a 10% payload fraction. The TAV is required to conduct multiple flights and missions with a takeoff gross mass not exceeding 100 kg. It was to land on a variety of surfaces while assuming the presence of surface debris up to 0.03 m3 in volume. The final design incorporates a unique ring wing, central fuselage and canards weighing 80 kg gross including 13.8 kg of payload. The ring wing provides lift during horizontal flight, and doubles as a floatation device on methane lakes for refueling. It is powered by a novel methane & oxygen burning piston engine that turns a propeller. All internal components such as avionics, fuel tanks and science instruments are packaged within the carbon fiber/epoxy fuselage.
Figure 1 shows a prototype of a large pressure vessel under development for eventual use as a habitable module for long spaceflight (e.g., for transporting humans to Mars). The vessel is a hybrid that comprises an inflatable shell attached to a rigid central structural core. The inflatable shell is, itself, a hybrid that comprises (1) a pressure bladder restrained against expansion by (2) a web of straps made from high-strength polymeric fabrics. On Earth, pressure vessels like this could be used, for example, as portable habitats that could be set up quickly in remote locations, portable hyperbaric chambers for treatment of decompression sickness, or flotation devices for offshore platforms. In addition, some aspects of the design of the fabric straps could be adapted to such other items as lifting straps, parachute straps, and automotive safety belts.
A real-time machine vision system is presented which enables an autonomous position measurement. This is done by combining a state estimation (4D-approach) with procedures enabling the detection and tracking of a priori unknown features. Thus, the system does not require additional knowledge about the appearance of the scenery seen by the camera. Besides the methods involved, this paper presents the hardware of the machine vision system as well as test results. The method can be used for applications requiring a relative position measurement like a helicopter hovering above a life boat, but the methodology is independent from the flight vehicle being used.
The Emergency Flotation System used in the Super Seasprite utilizes a combination of inflatable elements and a large sealed portion of the aft fuselage in a unique three-float configuration. This design approach has made possible a low gross weight fraction for the system, yet it still achieves an exceptional sea keeping stability at the top of sea state 5. In water tank model testing the SH-2G flotation system exhibited a capability to perform a self-induced migration away from broaching during successive wave crest traverses. This characteristic and the very large reserve buoyancy provided by the aft fuselage flotation chamber played significant roles in the sea keeping capability predicted for the system. Fundamental differences in the behavior of three float and conventional systems during the critical wave crest-traversing event have been identified, and are described. Development history and the preliminary design performance prediction methodology used to develop the system are presented. Water tank model testing results are provided, and the service experience with the three-float concept on early versions of the H-2 series helicopters is briefly summarized.
This Aerospace Recommended Practice (ARP) establishes criteria for the design and performance of aircraft life raft devices to ensure their rapid and effective use as a flotation device in a water landing. This document is not intended to specify particular design methods, mechanisms, or equipment to be used to accomplish the objectives established herein.
This recommended practice sets forth general specifications for the location, accessibility and restraint for those items of survival, emergency, and miscellaneous equipment which are intended to be used by the operating flight crew, and which are stowed on or near the flight deck.
This Aerospace Recommended Practice (ARP) sets forth general specifications for the location, accessibility and restraint for those items of survival, emergency, and miscellaneous equipment which are intended to be used by the operating flight crew, and which are stowed on or near the flight deck.
These recommendations are to aid the air transport industry in providing standard passenger safety information cards for use on commercial passenger carrying aircraft.
This SAE Standard provides general guidelines for the proper selection and application of off-road tires and rims; as defined in SAE J751 APR86; and applied to earthmoving machines described in SAE J1116 JUN86 and J1057 JUN81.
This ARP covers stowage of all portable cabin emergency equipment, such as oxygen bottles/masks, fire extinguishers, first aid kits, megaphones, flashlights, axes, life rafts, survival kits, life preservers, etc. The following criteria are recommended as general provisions in conjunction with the current applicable Federal Aviation Administration requirements.
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