Refine Your Search




Search Results

Technical Paper

“RoHS” Compliant Chrome - Free Conversion Coating for Aerospace Manufacturing

This paper presents, chemistry, test data and processing procedures on a non toxic and environmentally friendly chrome-free conversion coating alternative with the same level of adhesion and secondary corrosion resistance as that found in chrome containing conversion coating systems. Test data from military and independent sources will be presented on secondary coating adhesion, electrical conductivity, filiform and neutral salt-spray corrosion resistance as compared to chromate based systems .on magnesium, aluminum and zinc and their respective alloys. The European “RoSH” initiative will not allow for the presence of any hexavalent chromium on imported electrical components as of July first of 2006. Trivalent chromium based systems generate hexavalent chromium due to the oxidation of the trivalent chromium and as such will not be allowed.
Technical Paper

Worst Case Solar Energetic Particle Events for Deep Space Missions

Over the past two decades, various models of “worst case” solar energetic particle event (SPE) spectra have been proposed in order to place an upper bound on the likely doses to critical body organs of astronauts on missions outside Earth’s geomagnetic field. In this work, direct comparisons of organ dose estimates for various models of “worst case” SPE spectra are made by using the same transport code (BRYNTRN) and the same human geometry model (Computerized Anatomical Man). The calculations are made assuming nominal thicknesses of spacecraft aluminum shielding. Discussions of possible acute exposure responses from these exposures are presented.


This SAE Aerospace Recommended Practice defines a method for determining the weldability of weld filler metal in continuous coil or cut length form. It is applicable to all solid (non flux-containing) wires. It is intended as a referee method for testing weld filler metals in case of dispute between purchaser and vendor.


The purpose of this document is to define: - compensation washer application requirements - recommended materials - washer thickness determination - dimensioning
Technical Paper

Variations in Organ Doses Resulting from Solar Energetic Particle Event Spectrum Uncertainties

The effects of uncertainties in published proton fluence spectra for large solar particle events (SPE) on organ dose estimates are largely unknown since uncertainties in the measured spectra are unknown. In this work, input spectra for several large SPEs are adjusted by as much as 50% to account for the spectrum uncertainties. The BRYNTRN space radiation transport code and CAM human geometry model are used to perform the calculations. The calculations are made assuming three organ doses and four nominal thicknesses of spacecraft aluminum shielding. Discussions of dose variations for several events based on different spectrum uncertainty values are presented.
Technical Paper

Variations in Organ Doses Resulting from Different Solar Energetic Particle Event Spectrum Parameterizations

Calculations of solar energetic particle event (SPE) doses typically utilize SPE proton spectra parameterized with either an exponential in rigidity (momentum per unit charge) or a Weibull form in energy. In this work we report organ doses calculated using these two different parameterizations of proton spectra of four large solar energetic particle events. They are the SPEs of August 4, 1972, August 12, 1989, September 29, 1989 and October 19, 1989. The variations in predicted doses to critical organs introduced by the use of these two parameterizations for these large events could be a factor in evaluating the effectiveness of spacecraft shielding. Events similar to the largest SPEs observed during the space age could deliver large organ doses and the potential for an acute radiation syndrome response in interplanetary crews.
Technical Paper

Vaporization of JP-8 Jet Fuel in a Simulated Aircraft Fuel Tank Under Varying Ambient Conditions

This study has been performed to aid in the effort to minimize the possibility of a fuel tank explosion in a commercial aircraft. An understanding of the mechanisms behind fuel vaporization processes in an aircraft fuel tank is essential to developing accident prevention techniques. An experiment was designed to measure the conditions existing within a heated aluminum fuel tank, partially filled with JP-8 jet fuel, under varying ambient conditions similar to those encountered by an in-flight aircraft. Comprehensive fuel tank data, including all temperatures, pressure, and ullage hydrocarbon concentration, was obtained during testing, and is available for use to validate heat and mass transfer calculations.
Technical Paper

Use of Starch Based Blast Media for Dry Paint Stripping

In the 1980's, several processes emerged as possible replacements for chemical strippers containing methylene chloride. A viable process appears to be dry mechanical stripping using wheat starch. It is seen as promising because of its gentle treatment of aluminum alloys and composites. The process itself is reported to be operator friendly, with no fiber or primer damage even with multiple blast cycles. The media has been tested by Boeing Commercial Airplane Co. and is in production use at Beech Aircraft Corp. and Hunting Aircraft. Boeing reports that microscopic examination has shown wheat starch blasting to be smoother and less damaging to fibers compared to hand sanding. Starch blasting leaves a smooth finish on aluminum, bare or clad, and can strip aluminum skins as thin as 0.016 in. without deformation. The media is soft and forgiving and does not cause crack closure or smearing on aluminum alloys.
Technical Paper

Use of Advanced Technology Structures on Boeing 757/767

The usage of advanced technology structures has been a significant part of the success of the Boeing 757/767 mid range airplanes. Extensive use of kevlar, graphite/epoxy, high purity aluminum, powder metallurgy, titanium and metal bonding has reduced the weight of some structural components as much as 28%. New technology in materials and structures have been combined with new aerodynamics, propulsions and systems which resulted in a reduction in fuel burn that is as much as 40% below many of the aircraft in commercial fleets today.
Technical Paper

Understanding Exit Burr in the Drilling Process

One of the chief difficulties in producing close tolerance holes in aircraft aluminum alloys is the problem of exit burrs. This synopsis provides an explanation of the reasons for this phenomenon, as it is observed. This writing is not the result of an empirical study. Instead, it is based upon close observation and experience. Additionally, there is no attempt to explain the complexities of metallurgy and its effects on the drilling process. The assumption is that aircraft aluminum has a malleable quality that is necessary in terms of its function. However, this same property leads to challenges under certain circumstances during drilling.