High Velocity Aircraft Rocket The High Velocity Aircraft Rocket , or HVAR , also known by the nickname Holy Moses , was an American unguided rocket developed during World War II to attack targets on the ground from aircraft . It saw extensive use during both World War II and the Korean War . Design and development . The HVAR was designed by engineers at Caltech during World War II as an improvement on the 5 - Inch Forward Firing Aircraft Rocket ( FFAR ) , which had a 5 inch diameter warhead but an underpowered 3 . 25 inch diameter rocket motor . The desire for improved accuracy from the flatter trajectory of a faster rocket spurred the rapid development . HVAR had a constant 5 ” diameter for both warhead " and rocket motor " , increasing propellant from 8 . 5 lb to 23 . 9 lb of Ballistite . U . S . Ballistite propellant had a sea level specific impulse of over 200 seconds , compared with about 180 seconds for the British Cordite , German WASAG and Soviet PTP propellants . Hercules Powder Company was the principal U . S . supplier of high performance extruded Ballistite propellants : 51 . 5 % nitrocellulose , 43 % nitroglycerine , 3 . 25 % diethylphthalate , 1 . 25 % potassium sulphate , 1 % ethyl centralite , and 0 . 2 % carbon black . The propellant in U . S . 3 . 25 ” and 5 ” rocket motors consisted of a single large X shaped “ cruciform ” Ballistite grain . This went against the common practice of filling rocket motors with different numbers of smaller same - sized tubular charges , the number depending on motor diameter . The central hole in a tubular charge makes it more difficult to extrude , requiring a softer propellant blend that also yields somewhat lower performance . Rocket ∆V increased from 710 ft / sec for the 5 ” AR to 1375 ft / sec for HVAR , giving the coveted flat trajectory . Operational service . Two different versions of the HVAR were built during World War II . The warheads were either 1 ) Mk 4 general purpose warheads with 7 . 5 lb of TNT and both nose and base fuses or 2 ) Mk 25 shaped - charge semi - armor - piercing warheads ( having an internal copper cone ) with 7 . 5 lb of Composition B and a base fuse only . HVAR testing was complete by D - Day , 6 June 1944 , and air - lifted Navy HVAR rockets were soon being loaded on Ninth Air Force P - 47D s to support the break - out at Normandy . Other single - engine delivery aircraft included the F4U Corsair , F6F Hellcat , TBF / TBM Avenger , and SB2C Helldiver . Twin - engine aircraft sometimes armed with HVARs included the P - 38 Lightning , PBJ Mitchell bomber and the PV - 2 Harpoon bomber . HVAR could penetrate 4 ft of reinforced concrete and was used to sink transports , knock out pillboxes and AA gun emplacements , blow up ammo and oil - storage dumps , and destroy tanks , locomotives , and bunkers . Navy F4U Corsairs and TBF / TBM Avengers made the most extensive use of the rockets in the Pacific theater after the victory in Europe . Over a million HVARs were made during World War II , and production continued until 1955 . HVARs remained in the Navy ' s inventory until the mid - 1960s . After World War II , newer versions included a new general purpose type with a proximity fuse , and a new shaped - charge warhead for use against tanks . HVAR was an effective weapon in the hands of skilled , experienced pilots . It was less effective in the hands of average or inexperienced pilots who were accustomed to taking less careful aim and then “ walking in ” their gunfire to finally engage a target . HVARs could be fired in pairs or a single rapid - fire salvo but required accurate initial alignment and careful attention to range , or at least a good instinctive sense for the range to the target . HVARs were widely used in the Korean War . AD - 1 Skyraider s often carried a dozen HVARs , and sometimes an additional pair of much larger but less accurate Tiny Tim 11 . 75 " rockets . Targets included ships , bunkers , pillboxes , coastal defense guns , ammunition dumps , and occasionally even destroyers and major bridges . Numerous F - 51D Mustang “ Six - Shooters ” ( six 50 cal machine guns plus six HVARs ) and carrier - based F9F Panther jets flew close air support in Korea . Panthers carried 6 HVARs and four 20 mm cannons , while both planes could carry an additional pair of 500 lb bombs , napalm , or fuel tanks . Neil Armstrong and John Glenn were among the Panther pilots . It was in Korea that HVARs and Tiny Tims bridged the gap between prop planes and jets : F - 80C , F - 84E , F9F Panther , and F - 86 Sabre . Jets gave the fighter pilots improved forward visibility . F - 84E Thunderjets proved to be the most capable load - lifting fighter / bombers in Korea , demonstrating an ability to loft up to 24 HVARs and 2 Tiny Tims with a combined rocket weight of 5800 pounds .