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Aviation History
1965
1965 - 0025.PDF
•LIGHT International, 7 January 1965 The Black Brant family of research rockets, and vehicles of comparable performance 15 C b NIKE- CAJUN NIKE- APACHE BLACK BRANT III AEROBEE ISOA AEROBEE 300 A BLACK BRANT V-A JAVELIN from the needs of potential users and the environment to which the research instruments would be subjected. The scientists wanted a minimum-cost, highly reliable rocket able to carry payloads of 10-3001b to heights of 80-1,000 miles, with little dispersion in per- formance. The environmental conditions limited the acceleration load on the instruments to 40g and the temperature to 125°F (with a higher permitted temperature for skin sensors). Compromises were obviously necessary. At the beginning of the design the maximum desired altitude was reduced from 1,000 miles to 600 miles, and it was decided to use as a basis the Black Brant I motor and propsllant. In the development of the three-rocket family, overall design requirements were estab- lished for a lightweight structure with high strength and stiffness, insulating materials to withstand the erosive and heating effects of high-speed flight at low altitudes, a low-drag profile (which in general meant slender bodies with low stiffness characteristics) and acceptable dynamic characteristics with a demand for variable roll rates. The effect of these requirements was to introduce steels with ultimate tensile strengths of 250,OO01b/sq in; ablative coatings of glass-fibre and Avcoat; magnesium, titanium, and composite aluminium-honeycomb structures, which have provided the maxi- mum rigidity-to-weight ratio. Black Brant III is an unguided, single-stage sounding rocket using a 9KS11000 solid-propellant motor, lOin in diameter and approximately 18ft 8in long. The nose fairing encloses a payload volume of 1.4 cu ft and is made of light-gauge stainless steel with either an external glass-fibre ablative coating or an internal insula- tion blanket. The motor casing is of 0.057in AMS6435 high-tensile steel into which is cast the CARDE-developed ammonium perchlo- rate-polyurethane propellant grain, with a central longitudinal star-shaped cavity. The ceramic-coated steel nozzle attached to the rear end of the motor casing has a carbon throat; outside the nozzle the motor casing carries a magnesium aft-body with three Avcoat-covered, solid-aluminium fins bolted to it. Design objective was a vehicle capable of carrying a 401b payload to a height of 110 miles, based on a structure weight of 1641b with a motor delivering a total impulse of 101,0001b-sec. Performance achieved to date represents 51.51b carried to 93 miles, with a structure weight of 1611b and total impulse of 99,0001b-sec. It would be possible to reduce the structure weight further and increase the motor performance to achieve the higher altitude. This performance is the outcome of 53 static firings of the full- scale engine, 20 static tests (both structural and aerodynamic) and nine dynamic nights (table, p. 17). Of the nine flight vehicles, four were of the final configuration: all reached the projected altitude and their impact-points fell within a circle of seven miles radius from the calculated point (compared with a theoretical radius of 30 miles). Telemetry was good. This vehicle is now in production and is being supplied to customers. With the development of Black Brant III complete, the next logical step was to make it a two-stage vehicle, using the proven and reliable Black Brant I engine as booster. This engine has a near-perfect record in some 40 flight tests. Alternative boosters such as the US Nike and Terrier were investigated as possible first stages, but the predicted performance of these combinations, al- though attractive in many respects, was only half as good as that of the Black Brant I/Black Brant III vehicle. A particular application of this vehicle, which is designated Black Brant IVA, is to study the Van Allen layer of radiation, which descends to a relatively low level over northern Manitoba. The Black Brant IVA vehicle comprises the lOin diameter Black Brant III, fitted with a conical stabilizer in place of fins and boosted by the 17in diameter 15KS25000 motor. The conical stabilizer is made of titanium, protected from aerodynamic heating by an ablative coating. The second stage is supported by an alumin- ium spigot structure on the booster through contact at the nozzle throat and at the bottom of the stabilizer. Construction of the first-stage motor is generally similar to that of the Black Brant III and the same propsllant is used. The two- stage vehicle is stabilized by three fins fabricated from a composite aluminium sandwich structure. The complete vehicle weighs about 3,1001b and is 36ft 2in long. In the first two development flights of Black Brant IVA, made from the Churchill range in Manitoba in June and July last year, premature separation of the two stages occurred. The flight records were analysed and modifications have been designed to be incor- porated in the next two launchings, scheduled for early this year. The performance of the combination vehicle appeared satisfactory, and there was a radar indication that the dynamic behaviour of the second stage was reasonably good. The defect appeared to be in the detail design of the stage attachment and separation components. To cover the intermediate height-band between the low-altitude Black Brant III and the high-altitude Black Brant IV, a third vehicle has been designed to reach altitudes of 200 miles or more. This will be accomplished by the Black Brant VB rocket, using an improved version of the 17in diameter 15KS25OOO engine. The improvements consist of the use of AMS6435 high-tensile steel for the motor case, and a high-energy propellant of Aerojet-General composition. The existing 15K.S25OOO engine, as used previously to power the Black Brant I and IIA vehicles, will be utilized in an
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