323. Analysis of RP-1 Fuel Density for Operational Atlas Missiles

Paper

Abstract

This paper was presented at the Twenty-first Annual National Conference of the Society of Aeronautical Weight Engineers at Seattle, Washington, May 14-17, 1962. One of the factors which must be known for accurate prediction of performance of ballast missiles like the Atlas, Titan, and Thor is the weight of tanked propellants. This is especially important when there is no propellant utilization system and the residuals at the end of the flight, and therefore the maximum range, will be a function of how well the propellant weights were predicted. Perhaps the most important factor which enters into this weight predication is the fuel density. This paper analyzes the effect of temperature and manufacturing processes on fuel density.
Density information was obtained from shipment records of the major oil companies who supply RP-1 to the Air Force. Although the nominal indicated that the means, standard deviations, and distribution functions differed significantly from what would be expected using the specifications alone. Since the engine manufacturer may be supplied by one company, the test site by a different company, and the operational sites by still a third company, the analyses of test data must take the fuel density variations into account.
Another factor which affects fuel density is the temperature at which the fuel is stored. Since there are a number of different Atlas site configurations involving above-ground storage, buried tanks, and air-conditioned silos, the temperature effects must be calculated on a site-by-site basis. Tables are presented which combine these effects with manufacturers’ data to yield mean fuel density and standard deviations as functions of site location. They should prove useful for targeting, propulsion analysis, and other areas where accurate simulation of propellant characteristics is required.