Davidka The Davidka ( , " " Little David " " ) was a homemade Israeli mortar used in Safed and Jerusalem during the early stages of the 1948 Israeli War of Independence . Its bombs were reported to be extremely loud , but very inaccurate and otherwise of little value beyond terrifying opponents ; they proved particularly useful in scaring away both Arab soldiers and civilians . It is nominally classified as a 3 inch ( 76 . 2 mm ) mortar , although the bomb was considerably larger . Etymology . The Davidka ( " Little David " ) was named for its inventor , David Leibowitch , although the name also metaphorically evoked the biblical battle of King David and Goliath ( I Samuel chap . 17 ) : In 1948 , the state of Israel defended itself against the " giant " British - trained and British - led professional Arab Legion . History . The mortar was designed at the Mikveh Israel agricultural school in Holon in the winter of 1947 – 1948 . It was first used in combat on March 13 , 1948 , in the attack on the Abu Kabir neighborhood of Jaffa . The greatest victory attributed to the Davidka was the liberation of the Citadel , a strongpoint in the center of Safed , on the night of May 9 – 10 , 1948 . Six Davidkas were manufactured in all , and two were given to each of the Palmach ' s three brigade s ( " Harel " , " Yiftach " , and " HaNegev " ) . One was used by the " Yiftach " Brigade in the battle for Safed , and now stands in a square in Safed . Another stands in Jerusalem ' s Davidka Square , memorializing the " Harel " Brigade ' s participation in the battle for Jerusalem . The Hebrew inscription on the monument ( " וגנותי על - העיר הזאת , להושיעה " ) is from 2 Kings 29 : 34 , meaning " For I will defend this city , to save it . " Characteristics . The secret of the Davidka was its 40 kg ( 88 lb ) bomb , which was much larger than the mortar from which it was fired . In conventional mortars , the bomb is inserted into the tube and the entire projectile travels through the tube to gain initial guidance at launch time . The Davidka ' s tail tube is the only part of the shell which fit inside the launch tube . This contributed to the weapon ' s notorious inaccuracy , as the shell lacked adequate guidance during the launch phase to acquire aerodynamic stability in the intended direction . It is not a spigot mortar , either ; in a spigot mortar the " barrel " is a guiding rod inserted inside the shell ' s propellant chamber . The Davidka ' s propellant chamber fires inside the mortar tube ( barrel ) as does a conventional mortar , but the 3 inch ( 76 . 2 mm ) caliber of the barrel is much smaller than the caliber of the warhead of the bomb . It is therefore an oversized conventional mortar , where most of the bomb , and especially its center of gravity , remain outside the barrel — an aerodynamically unstable design , which only worked at all because the center of pressure was still within the barrel . The head of the bomb was essentially a large can filled with nails , rocks , or any other material which could be used for shrapnel . This meant that the blast effects of the weapon were completely random and of dubious efficacy as an anti - personnel weapon . It was of no practical value for siege combat or other light artillery purposes , but it made a loud bang . Small pieces of metal and tubes were welded onto the outside of the casing , reducing the weapon ' s accuracy even further than its already non - aerodynamic design , but contributing greatly to the whistles and shrieks which it made when in flight . The noise was its most important effect , so that anyone attacked by a Davidka mortar would hear the shell seeming to fall very near to them before bursting very loudly , increasing the fear factor . It is said that the Arabs , having been told that many of the designers of America ' s atomic bomb were Jewish ( e . g . , Einstein and Oppenheimer ) , thought that they were being attacked with atomic weapons . The Davidka was used in the battles for Haifa , Ein Zeitun , Safed and Biddu . According to Palestinian historian Walid Khalidi , the Davidka carried a bomb that weighed 60 lb . and caused fear and panic when used in built - up areas . Syrian rebels ' copy . In a May 2013 AlJazeera video , the first still photo on the title page shows a concept copy of the DAVIDKA made by the Syrian rebels , but with larger wings and an LP tank added to enhance the effect of the high explosive payload .