the GRETSS* history : 1977 - 1983

Logo du GRETSS **

The GRETSS* pioneers

1977 - 1983

 ©1996-1997 Papy Jason (updated dimanche 05 mars 2000)

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[Hilare] [Pléonasme2] [Jtenpoz] [Faontasme] [Gretss connection] [L'aplubel] [Léviathan]


HILARE (1977 - )

This was the first project of GRETSS*.

In the absence of detailed documentation or the clubs founders, I am unable to describe this rocket in detail.

The rocket was to be powered by a chamois & measured 1.50m long with a diameter of 90mm.

It had two moustache like antennas for its telemetry system, which still exist covered in dust in the stores of the club.

It was never launched, which is a complete mystery to me. Nevertheless, we will pass quickly onto the second project of the club which is much more interesting.


PLEONASME2 (1978 - 1979)

Again a chamois was chosen for propulsion of the clubs second project.

With a length of 1.75m & a diameter of 90mm (the same as the motor) it carried two telemetry channels using an IRIG standard method of coding ( Frequency modulation with an excursion of 7.5% by channel).

The recovery system separated the rocket in twice and was blocked with two pins..

The launched on the 25th August 1979 at la Courtine was considered a partial success (we have to remain optimistic!) :

  • The telemetry ceased after 6 seconds of flight due to an undetermined cause.
  • The parachute opened normally. However, the rocket was lost in the depths of the wood at the military camp.

This loss influenced considerably the direction of future club projects. The majority of subsequent rockets carried systems to aid location. This is true to this day, despite the fact non of the current team participate in the development of PLEONASME 2.
 Note: The antenna clamp (on top of the nose) is not representative of the actual arrangement on this diagram.


 JTENPOZ (1979 with the MAC and the CAC)


With the aim of being fully involved in the organisation of launch campaigns, GRETSS* helped MAC (from Marseille) & CAC (Club Aérospatial de la Celle Saint Cloud) to build a rocket powered by a bambi motor in less than 24 hours during the August 1979 campaign.

The aim of this project was to qualify all the teams involved in the launch of a rocket (PC, weather constraints, tracking stations, telemetry etc). In general this is the first launch of the campaign.

Rather than launch an empty tube, the three clubs collaborated to build a real "experimental rocket" which was launched on the 25th August 1979.


 FAONTASME (1979 - 1980)

It was with this project that things seriously started & GRETSS* gained a reputation for "know how" in experimental rockets.

The slogan of Bruno-B at this time was "small is beautiful". So the team decided to use a faon motor with a 63mm diameter & believe me it wasn't obvious how to do anything in such a small diameter.

The electronics was comprised of the following :

  • Acceleration measurement by a professional resistance sensor (made by Grasseby).
  • Static pressure measurement by a sensor built by the club. This used a gauge bridge to detect deformation of a metallic membrane.
  • Flight phase signalling (launch, end of propulsive phase, parachute opening). The telemetry channels were encoded in IRIG format.
  • A radiobeacon at 27 Mhz built in house which was activated 25 minutes after launch to assist in recovery (the loss of PLEONASME 2 had left a mark).
  • A telemetry transmitter operating at 144 Mhz, also developed by the club (the majority of other clubs participating in the campaign used an IBIS transmitter provide by ANSTJ).

Mechanical construction:

  • Electronics boards fully removable & packed into a very small payload compartment
  • Static pressure sensor
  • A system to close the payload compartment without screws, using a screw in nose cone
  • Construction entirely in aluminium.
  • un sytème de goupilles sortantes à axe décalé pour éviter le phénomène de banane

We had wanted to build a light rocket, matched to the faon motor, but in the end it became a flying brick with a weight of 3.7kg. Anyhow, it was a nice piece of work for a small (63mm) diameter & 1.36m length without aerials

A peak altitude of 2250m after 23 seconds of was predicted for this rocket.

 Toute l'équipe du GRETSS* autour de Faontasme

From left to rigth around Faontasme: Jean-Louis Lilienfhein, Etienne Sigel (squat), Tu flippes, Bruno Hébert, ???, L'asocial (squat), Jean-Louis Galani, ???, Bertrand Eiselé (squat),???, Claude ???, ???

Le tir de Faontasme

A launch was attempted on the 31st August 1980 at the military camp at Ruchard. However, due to several problems, above all with the telemetry transmitter, the launch was not made. After a month of analysis & repairs a second attempt was made to launch FAONTASME. on the 19th October, near to Auxerre. Finally, after a number of last minute "glitches" we launched. In an instant the little metal arrow left the launch tower & thundered skywards to be lost from view. A moment of anxiety & then someone caught sight of her near maximum altitude. The parachute opened & she descended slowly to earth in full view of everyone. The telemetry had worked perfectly & two members of the club already had graphs in front of them. After 15 minutes the rocket was recovered. After a short explanation to the public we cracked open the champagne & celebrated a successful conclusion to a years work.



A years work, & camaraderie, an essential combination.



writing in progress

Like FAONTASME, GRETSS CONNECTION used a faon motor, but smaller & more compact.


 L'APLUBEL (1980 - 1981)
writing in progress

An all aluminium rocket carrying 5 IRIG telemetry channels propelled by a Chamois motor

It was launched in August 1981 at the Ruchard military camp (37).

The telemtry worked fine, but the parachute didn't open.

Around l'Aplubel (from left to right), Bruno, ?, ? and SAM


LEVIATHAN (1980 - 1983)

Propelled by a bambi motor this rocket measured airspeed using a small propeller mounted on the top of the nose. An opto-electronic sensor measured the propeller rotation rate & transmitted this to the ground using an IRIG telemetry system.

The rocket was also know as the "Spanish Kit". This is because the rocket was finished during holidays in Spain (Imagine the conceptor with all the necessary tool, at 1000 Km home on a beach in Spain with its rocket!).

[Hilare] [Pléonasme2] [Jtenpoz] [Faontasme] [Gretss connection] [L'aplubel] [Léviathan]

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