Indirect fire
A projectile arcs through the sky without the gunner seeing its destination. This is indirect fire, a method where line of sight between weapon and target becomes unnecessary. The trajectory follows a parabolic path determined by calculation rather than visual alignment. Gunners predict azimuth and inclination to hit unseen objectives. Atmospheric conditions like crosswinds or drag alter the flight path significantly. These factors make accuracy harder to achieve compared to direct fire weapons. The result is often a scattered grouping of shots over a wide area. Modern field artillery relies on this curved path for long-range support missions.
Ancient armies used archers to shoot arrows in high arcs during sieges. Governor Chen Gui described using traction trebuchets inside city walls from 1127 to 1130. He instructed crews to monitor impact points from the wall while remaining concealed below. Adjustments involved moving the aimer's stand or changing the number of pullers on the rack. By the 16th century Niccolò Tartaglia invented the gunner's quadrant to measure elevation angles. Burgundian forces reportedly employed similar techniques during that era. Russian troops at Paltzig in 1759 fired over trees as standard practice. The first documented use of Guk's methods occurred on the 26th of October 1899 during the Second Boer War. British gunners applied these principles without lining-plane sights initially.
Lt Col K. G. Guk published Field Artillery Fire from Covered Positions in 1882. His work introduced geometry-based aiming relative to any target direction. German engineers solved the missing azimuth instrument problem by inventing the lining-plane around 1890. This rotatable open sight measured large angles directly from the bore alignment. Open sights eventually gave way to telescopes and the term goniometer replaced lining-plane in English. Early devices required layers to move around for viewing which proved unsatisfactory. The Goertz 1906 design featured a periscopic panoramic sight with an eyepiece at the rear. Both Britain and Russia adopted this configuration before World War I began. Robust gyroscopes later enabled pointing guns in any required azimuth or elevation without external references.
Artillery units require organized structures to coordinate dispersed firing positions effectively. Ground observers report where shots land so aim can be corrected immediately. Aircraft served as vital artillery spotting platforms during the First World War. Naval ships often used different colored dyes to distinguish their shell impacts on water. A director or aiming circle became the primary method of orienting guns in most armies. These instruments allowed batteries to record angles to one or more fixed points. By the late 1950s most nations adopted grid bearing methods over zero settings. The United States remained a notable exception until much later periods. Electrical communication systems simplified reporting between widely separated fire teams.
Observers provide feedback about actual impact points to adjust subsequent firing angles. Predicted fire calculations include corrections for prevailing weather conditions and target movement. Map shooting was introduced during World War I to calculate data precisely. Geospatial relationships between gun and target must be known accurately beforehand. Moving targets require continuous observation to maintain effective engagement ranges. Adjusted fire may use predicted data while predicted fire sometimes needs manual correction. The trajectory cannot change once fired unless smart munitions are employed. Maximum range for common guns reached approximately 24 to 30 km by the end of the 20th century.
Longer flight times expose projectiles to deflectional factors like crosswinds significantly. Curved trajectories create unpredictable external ballistics leading to scattered shot groupings. Explosive ordnance blast distances increase risks of unintended destruction dramatically. Shrapnel from these weapons creates higher danger zones around impact areas. Friendly fire incidents become more likely when firing near allied positions. Danger-close situations pose particular threats to personnel operating nearby. The inherent inaccuracy of indirect methods translates directly into increased collateral damage potential compared to direct line-of-sight engagements.
Continue Browsing
Common questions
What is indirect fire and how does it work?
Indirect fire is a method where line of sight between weapon and target becomes unnecessary. The trajectory follows a parabolic path determined by calculation rather than visual alignment.
When did Governor Chen Gui use traction trebuchets during sieges?
Governor Chen Gui described using traction trebuchets inside city walls from 1127 to 1130. He instructed crews to monitor impact points from the wall while remaining concealed below.
Who invented the gunner's quadrant in the 16th century?
Niccolò Tartaglia invented the gunner's quadrant to measure elevation angles by the 16th century. Burgundian forces reportedly employed similar techniques during that era.
Where was the first documented use of Guk's methods applied?
The first documented use of Guk's methods occurred on the 26th of October 1899 during the Second Boer War. British gunners applied these principles without lining-plane sights initially.
How do artillery units coordinate dispersed firing positions effectively?
Artillery units require organized structures to coordinate dispersed firing positions effectively. Ground observers report where shots land so aim can be corrected immediately.