Gross Weight Research Articles

Research on the method of negative acceleration flight test based on simulation

Negative acceleration flight test is an important part of civil airplane to obtain airworthiness certification. According to civil aviation regulations, engine, APU, fuel, power supply and other systems need to be verified by flight test. In this paper, the factors affecting negative acceleration flight are evaluated by simulation method, such as gross weight (GW), center of gravity (CG), pitch attitude, calibrated airspeed, and stick travel. Relationship between flight path angle (FPA) rate and the calibrated airspeed is formed by approximate calculation. The duration of each negative acceleration flight is suggested to be a minimum of 7 seconds. In order to maximize the time to maintain the negative overload state, a more effective flight test method is proposed.

Modified C-17 taxi procedures: a fuel cost savings exploration

Purpose This study aims to explore the viability of using C-17 reduced-engine taxi procedures from a cost savings and capability perspective. Design/methodology/approach This study model expected engine fuel flow based on the number of operational engines, aircraft gross weight (GW) and average aircraft groundspeed. Using this model, the research executes a cost savings simulation estimating the expected annual savings produced by the proposed taxi methodology. Operational and safety risks are also considered. Findings The results indicate that significant fuel and costs savings are available via the employment of reduced-engine taxi procedures. On an annual basis, the mobility air force has the capacity to save approximately 1.18 million gallons of jet fuel per year ($2.66m in annual fuel costs at current rates) without significant risk to operations. The two-engine taxi methodology has the ability to generate capable taxi thrust for a maximum GW C-17 with nearly zero risks. Research limitations/implications This research was limited to C-17 procedures and efficiency improvements specifically, although it suggests that other military aircraft could benefit from these findings as is evident in the commercial airline industry. Practical implications This research recommends coordination with the original equipment manufacturer to rework checklists and flight manuals, development of a fleet-wide training program and evaluation of future aircraft recapitalization requirements intended to exploit and maximize aircraft surface operation savings. Originality/value If implemented, the proposed changes would benefit the society as government resources could be spent elsewhere and the impact on the environment would be reduced. This research conducted a rigorous analysis of the suitability of implementing a civilian airline’s best practice into US Air Force operations.

Descrição alimentar e estágio de maturação de Crassostrea brasiliana comercializadas no mercado municipal de Paranaguá, Paraná, Brasil

Crasssotrea brasiliana (Lamark, 1819) is an epibiont filter feeder bivalve of fast growth and fast gonadal restructuring that feeds by filtration of microalgae, these characteristics are mainly related to the amount and quality of the phytoplankton filtered by the animal. In Paraná coast several sites of cultivation of the species can be found in Paranaguá Estuarine Complex (PEC) and Guaratuba Bay. Therefore, this work had as objectives to evaluate the size and the phytoplankton species ingested by adults of the oyster C. brasiliana and to describe its reproductive characteristics (index of meat revenue and stages of gonadal maturation). Oysters were acquired monthly in the Municipal Market of Paranaguá from cultivation in the PEC. The oysters were measured and length values (L), height (H) and gross weight (GW) obtained. Gonadal maturation stages were evaluated through the macroscopic examination of the gonads and revenue (R) through the wet weight of meat. The digestive gland was removed for the microscopic analysis of the stomach content (identification and measurement of the phytoplankton). The highest value of the R average (12,79%) was in July 2007, when a great portion of the population presented full gonads, however the predominance of individuals with full gonads (partially full and full) occurred in periods of warmer waters. The main microalgae genera found were: Diatoms - Gyrosigma Hassall, 1845; Cyclotella (Kützing) Brébisson, 1838; Coscinodiscus Ratray, 1890 and Pleurosigma W. Smith, 1852; Dinoflagellates - Noctiluca Suriray, 1836 and Ceratium Schrank, 1793 with size of phytoplankton ingested varying from 5 to 260 µm.

Rotorcraft Gross Weight and Center of Gravity Prediction Using Regime Recognition

Several U.S. Navy rotorcraft models are equipped with Health and Usage Monitoring Systems. On-board or on-ground Regime Recognition (RR) programs are used to develop individual rotorcraft usage spectrums to compute component and airframe fatigue life expended (FLE). FLE is a function of rotorcraft gross weight (GW) and center of gravity (CG), but neither are monitored by sensors. Thus GW and CG computation algorithms based on measured engine torque curves and trim equations during hover are developed and incorporated into RR. The algorithms are validated using numerous fleet flights with known GWs and CG positions. Excellent correlation between predicted and actual values is observed with low standard error of estimate. The in-flight variation of GW and CG is determined with the help of recorded fuel weight. RR is used to analyze 32,000 h of data from 111 rotorcraft to develop GW and CG utilization distributions. Furthermore, GW variation is modeled with a beta probability distribution and the joint probability distribution of GW and CG utilization is determined to assess airframe and dynamic component fatigue lives.

Construction of microsatellite‐based linkage maps and identification of size‐related quantitative trait loci for Zhikong scallop (Chlamys farreri)

We constructed the microsatellite-based linkage maps using 318 markers typed in two F(1) outbred families of Zhikong scallop (Chlamys farreri). The results showed an extremely high proportion (56.2%) of non-amplifying null alleles and a high ratio (30%) of segregation distortion. By aligning different individual-based linkage maps, 19 linkage groups were identified, which are consistent with the haploid chromosome number of Zhikong scallop. The integrated linkage map contains 154 markers covering 1561.8 cM with an average intermarker spacing of 12.3 cM and 77.0% of genome coverage. We found that the heterogeneity in recombination rate was not determined by sexes but by different individuals on 18 linkage regions. The phenotypic marker of general shell colour was placed on LG4, which was flanked by microsatellite markers CFLD064 and CFBD055. Four size-related traits including shell length (SL), shell width (SW), shell height (SH) and gross weight (GW) were analysed to identify the putative quantitative trait loci (QTL). Under the half-sib model, using dam as common parent, three, two, two and one QTL affecting SL, SW, SH and GW exceeded the genome-wide thresholds respectively. While using sir as common parent, a larger number of QTL were detected for these four traits: four, five, three and two for SL, SW, SH and GW respectively. The single QTL explained 3.7-19.2% of the phenotypic variation. The linkage map and the QTL associated with economic traits will provide useful information for marker-assisted selection of Zhikong scallop.

Morphometric analysis of indigenous, exotic and crossbred chickens (<i>gallus domesticus</i> L.) In Rajshahi, Bangladesh

Context: The quantification of morphometric variations has been regarded as peripheral to the mechanistic study of development of a species. This is now changing because the rapidly advancing knowledge of development in post-genomic biology is creating a need for more refined measurements of the morphometric changes produced by genetic perturbations or treatments. Objective: To estimate the age at marketable size and body morphometric parameters of indigenous, exotic and crossbred chicken to use such parameters as discriminate variables and to investigate the relationships among the variables of the chicken breeds under study. Materials and Methods: Six chicken breeds namely an indigenous (non descriptive, Deshi), four exotics as Broiler, Cockerel, Fayoumi and RIR, and a crossbred called Sonali (RIR?× Fayoumi?), were used for the study. Results: Age and nine morphometric parameters viz., gross weight (GW), blood weight (BW), feather weight (FW), skin weight (SW), body weight after skinning (BWS), visceral weight (VW), offal weight (OW), net edible weight (NEW) and edible ratio (ER), were determined from a total of 30 adult chickens (6 breeds _ 5 replicates each). All the parameters except FW showed significant differences among the breeds (P<0.01). RIR showed the highest values for all parameters except ER, which was the highest in Cockerel (1.77±0.23) and the lowest in RIR (1.47±0.01). Association between GW and NEW was statistically significant in Indigenous (P<0.001), Sonali (P<0.01) and all exotics except Broiler (P<0.001). Conclusion: Present results indicate that Cockerel, Fayoumi, Indigenous and Sonali chickens are advantageous genotypes as they had higher ER values compared to Broiler and RIR breeds. Keywords: Gallus domesticus; body morphometric traits; net edible weight; edible ratio DOI: http://dx.doi.org/10.3329/jbs.v18i0.8782 JBS 2010; 18(0): 94-98

A new STOL flying boat design.

A four engined turboprop flying boat, the PX-S, gross weight (G.W.) 87,000 Ib, with high open ocean capability has been designed and is under construction. The deflected slip stream and boundary-layer control (BLC) are adopted as high lift devices. Automatic stabilization equipment is included in the fully powered flight control system. A newly developed spray suppressor is applied on the hull forebody. A dynamically similar flying model, the UF-XS, 75% in linear dimension, was constructed and flight tested. The results show the following: the CL measured at takeoff, 40 knots, is 6.9; a takeoff run with 18 knots of wind is about 400 ft in 10 sec; the low landing speed, 45 knots, together with an air cushion effect of the BLC near the surface makes the landing shock very small; the flying quality at low speeds, with automatic stabilization equipment on, is satisfactory except for a large side slip during approach caused by asymmetric force on the nacelles by the like-rotation propellers (this problem was almost solved in the SS-2 design, which is one of the model numbers, by lowering the nacelle position relative to the wing); the hull has a wide stable trim range and the spray characteristics are satisfactory. The estimated utilization of the SS-2 through the year in the North Pacific Ocean is 86%.