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History of Raketgruppen IRA




1965 The club was founded in september-october 1965. I.R.A. stands for International Rocket Association. Founder was Claes Frostell and David Gordon.  Small zinc-sulphur rockets was launched to 200 meters altitude. Much ideas and inspiration from the book: "Rocket Manuals for Amateurs" by R. Brindley in US.  
1966 A small workshop was set up. The first primitive testbench was designed and built INSIDE a little wooden house. This house is still 'alive' today but outside the club's reach, situated 10 km north of Stockholm. A small military field F2 Hägernäs was used for many years for launching. This field is only 15 km outside of Stockholm.  
1967 A test-bunker was built 25 km outside of Stockholm (in Åkersberga). In this bunker many rockets was tested for the following years. The first 'big' rocket was successfully launched to an altitude of 700 meters. 1.5 kg of zinc-sulphur was used.
Launching at F2-Hägernäs north of Stockholm 1967
1968 The second little and primitive workshop was setup in the cellar of a school. Only a short time later the club got bigger room in an old building, very suitable for designing rockets. Plenty of rooms for the club.
Launching at F2-Hägernäs north of Stockholm 1968
1969 A very big launching-campaign was organized in the south part of Stockholm archipelago, on an island named UTÖ during 3-8 of august. Totally 8 rockets was launched. The first ejected parachute (1400 meter) and altitude‑record of 2000 meter was obtained among many other more or less successful experiments.  

Two launching-campaigns was organized: In middle of july in the military-field: Veckholmen, 60 km from Stockholm. Three small zinc-sulphur rockets was launched to 600-850 meters altitude.

 The second launching took place on the military‑field Villingsberg (a very big field 260 km West of Stockholm) 11-14 october. 5 rockets was launched:

 - An 65 kg heavy 2-stagerocket (ZN+S) launched, second stage did not ignite.

 - One 50 kg heavy 1-stagerocket (ZN+S), explosion.

 - One 3-stage-rocket (ZN+S), 3:rd stage did not ignite.

 - One 1-stagerocket with  parachutesystem and transmitter worked properly.

 - One 1-stagerocket with no parachute and no transmitter worked properly. 

Experiments started with more powerful propellants, such as Potassium perchlorate+asphalt, and similar. No success, many exploded rockets and destroyed five (!) testbenches completely. Calculations on liquid propellant rockets was made, but no rocket was built.
1971 Ammoniumperchlorate and PVC was tested with a little motor containing only 1.1 kg of propellant with success. A little primitive heatingoven was built, for curing the PVC.  

Launching of the first successful PVC + Ammoniumperclorate rocket. It was a heavy loaded testmotor, reaching 400 meter altitude, 1.3 kg propellant. 

Problems with the quality of the Ammoniumperclorate, containing 'anti‑plumbing‑agent' which gives the propellant unwanted behaving. Different quality each delivery.

A bigger heatingoven was built, for curing the PVC-propellant at 150-155 degree Celsius. 

Again the club had to move to another buildning. Now the club moved for the last time, so far. Area of 100 sq.m. A very well equipped workshop could now be setup.
villingsberg_1972.jpg (280497 bytes)
First successful launching of a PVC-composite propellant motor.

First contact with Youth and Space. Participating in the 2:nd European conference in Belgrade, Yugoslavia. One of the IRA member (Ulf Torberger) participated in the swedish science fair for 'young scientists', and with a Zinc-sulphur-aluminum project. He recovered 1:st price, which was a 2-week trip to USA and partition in the american science-fair for 'young scientists'. The trip also included a visit to Cape Kennedy and the launching of SKYLAB in May 1973. Two 2-stage Zn+S rockets was launched to 3 km altitude.


Contact with the Italian club CRS from UDINE about a very simple and reliable parachute-system. This system was tested several times with success.

Again participating in the science fair (Christian Nissen), recovered 2:nd price, which gave him a 6-week stay in the 'Weizman institute' in Israel July 1974.

Design and construction of a strand-burner, also called Crafoord-bomb. This consist of a nitrogen pressurized chamber. Thin strands of propellant was tested. The aim was to measure the burningrate under different pressure


Scoutstuga_verkstaden_maj-1978.jpg (845411 bytes)
The workshop 1974--1999


1975 200 kg Ammoniumperclorate was bough from Japan (The Japan Carlit Co) for a very good price, and with a very high and pure quality.  
1976 Developing of a new ignitionsystem. Cooperation-project with the Dutch rocketclub NERO started. Static testing of many PVC-ammoniumperclorate motors with success, much thanks to the new delivery of ammoniumperclorate and new ignitionsystem. The new developed rocket ODEN is launched to 4.2 km altitude, containing 27 MHz transmitter measuring altitude, flyingtime and burningtime of the motor.
Launching to 4.2 km altitude. 3kg propellant.

4 static test in the NERO testbench in Netherlands, all with success. Annual report 1977 (verksamhetsberättelse) Swedish only, pdf-format.

Participating in the big execution 'SPACE-WEEK' in Stockholm, which over 100,000 people visited in 7 days. A new launchingtower was designed and built.

Two PVC-propellant rockets was launched to 4.2 km altitude.
holland_Pierre-Lingheim_1977.jpg (406725 bytes)
Final assembly of the motor in the NERO testbench in Holland.

 holland_197x.jpg (412695 bytes)
Static test in Holland was a total success. Measured specific impulse=185 sec. 3 kg propellant.

Final test in the NERO testbench, also as demonstration during the Youth and Space congress in EINDHOVEN arranged by NERO.

Two ODEN-rockets launched to 4.2 - 4.5km similar to the ODEN launched in 1976.

Presenting the IRA-NERO report from the cooperationproject, also wellknown as the 'yellow report'.
Acceleration 20 "g".
Altitude 4.5 km. 3 kg propellant.
Acceleration 50 "g". Photo approx. 0.5 second after start when speed is 900 km/h. Altitude 4.5 km
Max speed is 1900 km/h
Herkules-test_maj-1978_JN.jpg (1398305 bytes)
Static test "Herkules". Burningtime 5 sec. 8 kg propellant.

 PVC-test_maj-1978_Hires.jpg (1605120 bytes)
Static test. Burning-time=0.54 sec and then explosion destroying the motor and the testbench.Thrust 1 ton. Measured specific impulse=215 kps/kg

1979 Unsuccessful launching of the biggest PVC-motor ever. 8.5 kg of propellant. Bad casebounding to the outer wall resulted in a explosion in the tower, which was partially destroyed.

 Static test
with enhanced propellants (PVC+AP)
 in december 1979. Enlarged photo to the right.


Startrampen-01.jpg (1108197 bytes)
Final assembly of Herkules in the launchingtower. Herkules is propelled by 8 kg PVC+AP.

Antenna for the transmitter vired around the nosecone.

1980 A big and stable static testbench was built for test of motors. Electronic evaluation of chambrepressure and thrust was possible.  
1981 Launching of a PVC-rocket. Hangfire and no success. Problems with the home-made chemicals for the ignitionpowder. Also a static test of a 2 kg PVC-rocket with 75% oxidizer with success. This mixture however gave a very high burningrate.  
1982 Developing of methods for curing propellant in small tablets. This was a result of the unsuccessful launching 1978. This method was however never used in real motor production. Many propellantcastings were made with success.
Filling the mold with propellant by pressurized nitrogen, direct from the vacuummixer.
1985 Start developing of the HERCULES 2-stage project.

Starshaped coremandrel made in steel and Teflon-coated.

For the first time this starshaped propellant grain was used with success.
1986 Start the High-Altitude project. Developing the most sophisticated altitude computer calculation program, available to amateurs. This program was used for the final calculation of the 2-stage HERCULES launched at Skillingaryd (Sweden) in July 1986. The software was also verified agaist professional calculations, with success. Skillingaryd-2-stegare-montering.jpg (942203 bytes)
Assembly of the 2-stagerocket. Total
weight=16 kg.

Instrument included a 450 Mhz transmitter and a computer onboard.

1987 Planning the 2:nd stage motor development of the 'High Altitude project'. Start developing of the motor which will be built in carbonfibre reinforced epoxy. For this purpose a computerized machine was designed for the manufacture of the motortube.  
1988 Theoretical analysis of motor-construction, propellant, electronics etc. First manufacture of motor-tube in carbon-fiber reinforced epoxy. 90-95% of theoretical strength was obtained during a test. A completely new system for fastening nozzle and top plug of the motor was also developed, and static tested with success.
Carbonfibre-reinforced epoxi  motorcasing.
1989 The first prototype of the core mandrel internal burning star was manufactured in aluminum. This is to be used in the second stage.  
1999 Workshop was closed down and club is in heaven. The End !

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Last updated: november 09, 2005.


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