Fighting began in 1928, when Bolivia tried to establish an outlet to the sea via the Paraguay River. Paraguayan troops wiped out a newly established Bolivian border fort. An exchange of sporadic raids and skirmishes commenced. But formal warfare did not start for four more years. The League of Nations carried on a series of desultory negotiations and arranged a truce.
When full-scale hostilities commenced in June 1932, both countries immediately faced daunting logistical difficulties. The swamps and forests, together with the lack of roads, the harsh climate, and the vast distances involved, made assembling and moving troops extremely difficult. Soldiers and animal transport were ravaged by disease, ill-fed, and chronically short of materiel. Yet the belligerents were determined to fight a proper, modern war, in so far as their means would allow.
At first, Bolivia had the advantage militarily, particularly in the air. In the course of the conflict, the Cuerpo de Aviacion had about sixty combat aircraft available, including various fighters, Curtiss bomber-reconaissance biplanes, and Junkers W.34 bomber-transports. In 1930, it used the proceeds of its mines and a line of credit from Standard Oil of Bolivia to conclude a major arms deal with Vickers.
Fighters, Cuerpo de Aviacion Boliviano, 1930-35: Curtiss Hawk II (top); Vickers Type 143 Bolivian Scout (bottom)
Bolivia acquired a number of Vickers 6-tonne tanks and Carden-Lloyd Mk. VI tankettes (machinegun carriers), 55-mm mountain artillery, Vickers machineguns, and six Vickers Type 143 Bolivian Scouts, an export fighter for which Bolivia proved the only customer—surely one of the shortest total production runs on record. The Scout's supercharged, 500-hp Bristol Jupiter VIA radial engine and generous wing area gave the Scout a good high-altitude performance for its day, an important consideration in Bolivia. It spanned 33 ft 6 in, was 26 ft 3 in long, and weighed 2246 lbs maximum at takeoff. Service ceiling was 20,000 ft and maximum speed was 150 mph. Like all the fighters in the conflict, it was armed with a pair of rifle caliber machineguns, .303 Vickers in this case.
Four Curtiss P-1 Hawks were acquired in 1927 and nine Hawk IIs in 1932-33. The Hawk II was the principle Bolivian fighter. It was essentially a land-based version of the US Navy’s BFC Goshawk. A 600-hp Wright R-1820 gave the Hawk II a 202-mph top speed and a 25,000-ft service ceiling. Nine Curtiss Falcon two-seat reconaissance bombers—radial-engined variants of the US Army O-1/A-3—were added at the same time. The ground troops were meanwhile provided with organic air defense in the form of excellent SEMAG-Becker 20-mm AA guns, two of which were supplied to a division (Bolivian divisions were actually of regiment or batalion size).
Bomber-Reconaissance, Cuerpo de Aviación Boliviano, Villa Montes, 1935: Curtiss Falcon
While Bolivia began the war with new, Vickers- and Curtiss-built equipment, impoverished Paraguay’s armed forces were caught between procurement cycles and desperately short of cash. From 1927-1929, the country had re-equipped its air force with a number of French-made Potez 25A.2 reconaissance bombers and seven Wibault 73C.1 fighter monoplanes (numbered 1-7). The Potez 25 was a widely exported two-seat biplane developed primarily as what would later be called a COIN airplane. It was designed for use against the fractious, independence-minded natives of France’s colonies. It looked very much like a WW1 type. While excellent for its intended purpose, it was at a definite disadvantage when facing aerial opposition. It spanned 46 ft 4.75 in, was 29 ft 10.25 in long, and weighed 4317 lbs (t/o). It could reach 137 mph and 23,600 ft. Range was 410 miles and bombload was 440 lbs. The Wibault was a rarity for its time, an all-metal parasol monoplane covered with Wibault’s own system of corrugated metal skinning. It was about 25 ft long, spanned 35 ft 11 in, and weighed 3351 lbs. Performance closely approximated that of the Potez.
Combat aircraft, Paraguayan Air Force: (top) Wibault 73C.1 fighter, Primera Escuadrilla de Caza, 2nd Lt. Juan Gonzales Doldan, Campo Grande, 1932; Potez 25A.2 reconaissance-bomber, 1932-35
Unfortunately, the aircraft were already obsolescent in 1932. Worse still, Paraguay had tried to economize by standardizing on one engine for both fighters and bombers. Unfortunately, the engine Paraguay chose was the 450-hp Lorraine-Dietrich 12Eb. This was a water-cooled, W-12 with three banks of four cylinders each. It was heavy and old fashioned, and its cooling system had been marginal even in northern Europe. In the sweltering Gran Chaco, it was a disaster. So much had been spent for the airplanes, however, that nothing could be spared for replacements. What little finance was available had to be spent on other, more urgently needed armaments. Shortly after the start of operations, Paraguayan mechanics found themselves frantically cannibalizing aircraft to keep a minimum number of flying. Many were lost to forced landings and in-flight fires. Soon, serviceability was so bad that the Wibaults had to be grounded so that the remaining engines could be reserved for the more urgently required Potez.
The army was in somewhat better shape. During the final months prior to the outbreak of war, Paraguayan diplomats secured a secret loan from Argentina. Unlike Bolivia, Paraguay had almost no standing army and no peace-time budget for mobilization stockpiles. While their troops fought the first skirmishes of the war armed with machetes and one castoff Argentine Mauser rifle for every 3-7 men, a civilian purchasing commission frantically shopped the arms bazaars of Europe for bargain equipment. Ironically, the inexperience of the men selected for the task and the crippling, national lack of funds now proved fortuitous. While Bolivia's professionals spent lavishly on "serious" weapons, like heavy Schneider howitzers, water-cooled heavy machineguns,tanks, and the all but useless little Vickers mountain guns, the Paraguayan amateurs bought poor man's artillery—light, cheap, Stokes-Brandt mortars, three of which could be had for the price of one field gun—and Madsen light machineguns (right). Cartridges and artillery shells could be had clandestinely, free of charge, from the Argentine army, and grenades were in production in Paraguay itself. In the heat, dense brush, and mud of the Chaco, lightness, mobility, and a high trajectory were the dominant requirements. Mortars, grenades, and light automatic weapons so dominated the battlefields that Bolivia was forced to return to Vickers for large quantities of both. Later in the war, when Paraguay's funds were exhausted, she relied almost entirely on capturing this fresh Bolivian materiel for her own needs.
