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Stephan Shurn 16 January 2008 Propulsion Rail Guns and Conventional Guns. Rail Guns. Low cost per launch High G’s at small scale ~10,200 g’s at 180m Slightly lower g’s at large scale ~928 g’s at 2 km 2 nd Stage needed High energy input ~1.5-20 GJ High heat loading on nose and body ~3000K
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Stephan Shurn16 January 2008PropulsionRail Guns and Conventional Guns AAE 450 Spring 2008
Rail Guns • Low cost per launch • High G’s at small scale ~10,200 g’s at 180m • Slightly lower g’s at large scale ~928 g’s at 2 km • 2nd Stage needed • High energy input ~1.5-20 GJ • High heat loading on nose and body ~3000K • Technology Development AAE 450 Spring 2008 Propulsion
Conventional Guns • HARP – 1960’s • Low Cost • High G-loading (~20,000 g’s) • 2nd or 3rd stages Future Work • Rail gun feasibility study AAE 450 Spring 2008 Propulsion
Backup AAE 450 Spring 2008 Propulsion
Electricity Cost Calculation -Power =~ $75.00/ MWhr, 1 KWhr = 3.6MJ • For a 3 GJ Railgun 3000MJ*(1KWhr/3.6MJ) *(1MWhr/1000KWhr) = 0.833 MWhr 0.833 MWhr * $75.00/MWhr = $62.50 in power AAE 450 Spring 2008 Propulsion
Railgun Scaling • Ve ~ 6000 m/s L = 180 m t = 0.06s • Acceleration = (6,000m/s)/(0.06s) = 100,000 m/s2 • (100,000m/s2)/(9.81m/s2) = 10,204 g’s • If L = 2000m, Ve = 6000 m/s, using same model: • t = (2000m)/(6000m/s – 0m/s) = 0.66 s • Acceleration = (6000m/s)/(0.66s) = 9,090.9 m/s2 • (9,090.9m/s2)/(9.81m/s2) = 926 g’s AAE 450 Spring 2008 Propulsion
Sources • “Electromagnetic Railgun Technology for the Development of Small Sub-/Orbital Payloads,” Executive Summary, CCN No. 01 to ESA Contract No. 13420, Sep. 2003. • McNab, Ian R., “Launch to Space With an Electromagnetic Railgun,“ IEEE Transactions on Magnetics, Vol. 39, No. 1, January 2003, pp. 295-304. • McNab, Ian R., Candler, G.V., and Barbee, C.S., “Projectile Nosetip Thermal Management for Railgun Launch to Space,“ IEEE Transactions on Magnetics, Vol. 43, No. 1, January 2007, pp. 491-495. • Wade, Mark, “Martlet 4,” [http://www.astronautix.com/lvs/martlet4.htm. Accessed 1/12/08.] AAE 450 Spring 2008 Propulsion