Heavenly Pursuits 1965
In this month's supplement we continue our history of the rocket by looking back at the progress made at the Argentine Maquichao Research Station during, and after, the South American War in the mid 1930s.
Aircraft Propellant Rocket Programme
The RFNA (red fuming nitric acid) solution used was a mix of 96% nitric acid with 4% ferric chloride. This corrosive substance required the use of stainless steels and other precautions. While it was storable chemists were working on more storable solutions of nitric acid which by the mid 1940s had met with success. The concentrated red fuming nitric acid and kerosene programme had minor success with the FMA/ RRF RL-FNO-101 which produced 250lbs of thrust during mid 1935 and performed well in both static trials and installed in the rear of a Vanquish bomber for brief flight trials. Some minor improvements during late 1935 led to testing of the improved FMA/ RRF RL-FNO-102 producing 350lbs of thrust during May-August 1936. Four rockets were used in static trials and the Vanquish flying test bed was refitted but lost when the rocket exploded on the third flight. A replacement aircraft burnt out during ground power trials and a third bomber made just four flights during December.
The effort to produce a worthwhile rocket resulted in the FMA/ RRF RL-FNO-103 which produced 950lbs of thrust and was packaged as a single unit with one kerosene tank, two smaller pressurised concentrated red fuming nitric acid tanks and a more advanced combustion chamber and improved nozzle. Early trials in 1937 were limited and only two of the six static test engines proved satisfactory but the Vanquish was re-equipped during August 1937 and used for a series of eleven flight tests (a twelfth was scuppered when the plane was written off in a landing accident on a transfer flight).
By 1936 other nations had taken note of Argentina’s lead in this field of development and the Italian air force asked FMA to produce a rocket capable of take-off assistance for future heavy bombers. To this end the ‘unit’ principle of the FNO102 was refined with extra safety systems, rapid dump valves; fire-proof shielding and stainless steel casings surrounded the complete rocket and tank system as the FMA/ RRF RL-FNO-105. It weighed 68kg (150lbs) and produced 1,000lbs of thrust.
Atlantis-Argentine Rocket Programme
Work moved on from the AAM-1 rocket (‘Triumph’) during 1936 and Mr Minia’s Atlantean team at the Maquichao Research Station. The AAM-2 was designed in early 1935 and six were tested during late 1936 and early 1937. The rocket was codenamed ‘Silver’. It was 1.6m long, had a take-off weight of 107kg and was powered by a modified ‘Bold’ alcohol/ liquid oxygen rocket engine known as ‘Harmony’ (FMA/ RRF RL-AO-102) again producing 3 kilonewtons of thrust (FMA/ RRF RL-AO-102). The main difference between the AAM-1 and 2 is the use of Gyroscopes in the centre of the rocket between the alcohol and oxygen tanks for stabilisation, which makes the AAM-2 more stable.
While ‘Bold’ seemed to work well, three of the six early production ‘Harmony’ engines were destroyed in static tests. One blew up on Test Stand No.3 causing a large explosion after 2 seconds of full firing and putting the stand out of commission for three months. The third engine blew up on ignition due to a faulty combustion chamber and the third failure was the fourth engine when the pump failed causing a LOX leak which exploded killing two engineers. The other surviving engines were tested to destruction and achieved 2.5kN of thrust and met the specified burn times. Another two test ‘Harmony’ engines performed well during July 1936 and so the next six engines were built as full production ready engines for mating with the ‘Silver’ rocket.
The gyroscope guidance system was built in Atlantis and shipped to Maquichao in July 1936 for initial tests. The gyroscope equipment was tested in the centrifuges at the smaller test site and stood up well to high G levels up to 18G and in the freezing temperatures of the climatic test chambers. In October the first system was mated to the nearly complete Silver 1 rocket. This was destroyed 5 seconds after ignition due to a rocket malfunction on November 27. Silver 2 was tested on December 15 and reached 130 feet before it tumbled out of its trajectory and exploded within the safety range. Silver 3 was tested February 7 but the engine did not produce enough thrust and after lift-off the rocket dropped back down and tumbled off Test Stand No.1 exploding in the water trough area which limited the damage. Silver 4 was used for static full power trials and the engine was removed and the rocket stored for mating with another engine. Silver 5 made a fully successful flight on March 20, the gyroscope system working perfectly. Silver 6 on April 25 made a successful take-off but soon after take-off went out of control and broke up in flight. Silver 4 was re-engined with an improved ‘Aqua’ engine, on tests the two prototype engines had much improved reliability with a new pumps and a basic automatic cut-off system. Silver 4 as Silver 8 thus on August16 1937 made the final, and most successful, flight of the Silver series.
By early 1937 attention had switched to a scaled-up AAM-2, the AAM-3.
The AAM-3 differed in appearance having tail fins and an aerodynamic pointed nose. It was 5.82m high; 0.78m in diameter and a fin span of 0.93m. The gross weight was 900kg. The successful ‘Aqua’ engine and a series of basic chamber test beds fired in vertical and horizontal test stands led to the development of the FMA/ RRF RL-AO-200 producing 14.7kN (3,305lbs) of thrust. The main aim was to get to 12km (36,000ft) altitude and supersonic performance from the rocket.
Design work took most of Mr Minia’s time and much of the work was done in Atlantis, they developed the rocket aerodynamics and guidance system while the Argentine engineers developed the engine. Vanquish bombers dropped no less than 25 scale models to study the aerodynamics.
In order to iron out the faults of the ‘Harmony’ engines no less than ten FMA/ RRF RL-AO-200 prototypes were used in static tests from partial short tests, safety checks and eventually full power trials for long periods. Atlantis provided some of the more exotic alloys needed and the use of active cooling by using a walled chamber through which the alcohol was pre-heated and also cooled the chamber saved weight and solved some of the problems. Eventually six of these engines performed as expected and by September 1937 production began on the eight series engines for the AAM-3 programme.
Army Ballistics Programme
The Argentine Army drafted the requirement for an artillery rocket for development work in 1933. Observers had witnessed foreign trials during the early 1930s and when work began on the Powered Ranken Dart (see below) the design teams were merged and transferred to Maquichao. The first crude diglycol 50mm diameter rockets entered the test phase in 1935 and around 60 were expended in trials until mid 1937. These rockets were spin stabilised but very inaccurate with a range of around 4500 metres.
Powered Dart Programme
The Atlantean Air Ministry in 1934 laid down a requirement for a “powered Ranken Dart” able to destroy the newest airships now under development across the world. Some of the ground firing trials were conducted at Maquichao during 1935.
Basically based on the Army's rocket shell the rocket is crude diglycol powered missile. About 50mm diameter it had a warhead of around 5lb. It consisted of a steel piercing cap and behind this the warhead which was inside a shrapnel casing. If the rocket missed its target then a time detonator exploded the warhead after 750 metres flight time. It was tube fired. The Vanquish II was chosen as a flying testbed, the bomb bay was stripped and ten tubes fitted inside, these were inclined around 10-15 degrees. The bomb bay doors and dorsal doors were fitted to cut drag in cruising flight. The tubes could be fired upwards or downwards and the tubes tilted either for or aft (not changeable in flight). The gunner in the dorsal turret was the rocket gunner with electrically operated firing switches, he could choose between salvoes of two, four or ten rockets. This RI-21R first flew in July 1935 and undertook ten hours of aerodynamic trials before the tubes were installed. Three trials with single rocket launches were made and the rockets worked perfectly. In December 1935 the aircraft was destroyed in a RSAF bombing raid on the FMA facility in Cordoba and aerial trials thus ceased and the Atlantean Air Force thereafter undertook all further development and the FAA declared no further interest in the Ranken Dart as a weapon.
WesWorld »
The SIM »
News and Stories »
Quoted
Originally posted by Hrolf Hakonson
Monday, September 30th 2024, 5:10pm
Go to the top of the page
