21 Years of Thrusters
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21 Years of Thrusters |
| Thruster Operator Support Group | |
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The Thruster Operator Support Group is celebrating 21 years of Thruster history and the contribution of this remarkable ultralight series as the workhorse of Australian ultralight aviation over so many years.
Tony Hayes is the author and Roy Gilby is responsible for the desktop publishing and layout of the original print publication. The Web document is contained in three html pages:
1. A brief history of the marque's evolution and chronology from 1982 — 1990
2. Thruster chronology — 1991 onwards
3. The Thruster main models [with photographs]
This is surprisingly difficult to write clearly for it is not a straight line story. Several things happened in parallel with each other. Describing one part, and its outcomes, tends to leave behind other aspects starting at the same time – when they were in fact running concurrently. I will be as clear as I can but we are covering ground from the earliest days of ultralighting to the present T600s and Vision 600s.
The Thruster really comes down to one guy, Steve Cohen, who designed the first aircraft named Thruster. Steve came from a background of Hang Gliding and evolved into the very beginnings of ‘minimum aircraft’ that was to become the Australian Ultralight Federation in this country.
Steve presumably got tired of walking up hills to jump off, or walking back up them after flight to get back to the car! So he started experimenting with fitting lightweight engines to hang gliders. These rapidly evolved into what we see as the origins of minimum aircraft which moved from primarily needing gliding ability to a regular concept of ‘go when you want’ form of aviation.
The Thruster has three direct ancestors – the Condor, Avenger and Stolero – each becoming slightly stronger, faster, and more refined. Despite efforts TOSG has been unable to trace a single remaining example of any of them!
But from them came another type which was named by Steve as the Thruster. This made its first flight from the sands of Kurween in the early days of November 1982. It had no pod and resembled more the Stolero it had directly come from. This machine went from concept to flying in just six weeks!
In a short pace of time the wings had been tidied up and a pod had been fitted (copied from what is believed to have been an Avenger pod). The aircraft was a roaring success and, having flown it, I class it as the nicest handling Thruster of the many I have flown.
The first of the Thrusters as she is today, fully restored and regularly flying from her home at Watts Bridge, S.E.Queensland. This aircraft was the turning point between the very 'minimum' open aircraft into what we now enjoy. Compare this photo of the T1 with the photo of her being readied for her first flight in the type sequence photo record.
Within just a couple of months a production factory had been brought together and so also came together a number of people who were luminaries in those early ultralighting days. From the viewpoint of the Thruster Operator Support Group [TOSG] there were two particular guys who between them gave me so much help in again piecing together the history of the Thruster, and the many models, which were already fast becoming forgotten.
Those guys were Brian Fimmel and Kevin Mitchell. Like Steve they both had hang gliding and recreational aircraft production backgrounds. Brian went on to having a major hand in building every main model of Thruster ever created and Kevin likewise created skins for all of them, later inventing the stitching that allowed progression into the Ultralam skins as an alternative to the previous Dacron covers.
The Thruster enterprise did its share for Australia as a country. Initially Thrusters were exported. Very soon an Australian owned subsidiary factory was established in UK. Kevin Mitchell made all the skins for the UK Thrusters and exported them. The Aussie Aerofibre ‘Brolga’ propellers was specified as standard and rapidly the UK Thrusters were certified for the Aussie Jabiru 4 stroke 2200 engine – which the vast majority are now fitted with.
The Thruster story is far from over! In UK development of the type continues from a successful and enthusiastic factory. The Aussie Thruster factory is now quiet and producing little but the UK T600 is manufactured in Australia by Vision Aircraft at Orange (although at the time of writing they are still sorting out paperwork with CASA!). TOSG meantime is steadily working towards the Thruster ‘Swift’ that will be re-manufactured two seaters with all the retrofit options the marque has developed over the years.
Note: TOSG type designators are used here which were not necessarily used by the factory. Arbitary designators were given to cover ‘lost’ types that may be found and the designator used which they fitted into. For example stating a T84A and a T84G does not indicate that there were B, C, D, E, & F models. What follows now represents what is considered to be a final list of the Thruster models. The only area presently missing from the record is data on the single seater float versions which were made and flown by private owners.
1982
In the first week of November the first Thruster flew after just six weeks of development. Over the coming few weeks the geometry of the aircraft was adjusted and a pod fitted. Plans for its production successor commenced.
1983
The first Thruster factory formed with the T83 single seater (as an enlarged version of the prototype) going into series production. 49 were built that year.
The new endeavour was in two parts. Ultralight Aviation, under Steve Cohen who looked after research and development. The aircraft came out with Ultralight Aviation decals on them. The other parts was Thruster Aircraft under David Belton, which looked after manufacture and marketing.
1984
This was a very big and eventful year for the Thruster with a lot happening. Under the presumed stimulus for a more ‘sporty’ aircraft the T84A was built and reverted back to the wing span of the Prototype. This rapidly became the T84G (only 5 or six T84’s were built) and then equally as rapidly became the T85SG. Later in the year the T85B was produced with wing span going back to 29’6”.
Concurrently with all of this a two seater was developed. This was intended in two forms - the Thruster ’84 TPT (Two Place Trainer) and the Thruster ’84 Utility. Nine examples are known to have been built and they are generally recognised by the name ‘Glasshouse’ by virtue of their large, slab sided, glazed noses.
Glasshouse Prototype today at Watt's Bridge. Now in single seat configuration
The now almost forgotten Glasshouse was massively important for Australian Ultralight Aviation. Not only was it our first home designed and manufactured two seater, it also represented the main structure that would lead directly to our first certified two seat trainer that flying schools could use.
Sadly in this year Steve Cohen and Ultralight Aviation went their own way leaving Thruster Aircraft as the sole controller of the factory.
1985
By this time the single seaters were doomed. ANO 95.25 could now be seen, if not yet present, and the market was going to be for the pent-up flying training demand. Therefore the main effort went into developing a two seater that would be 95.25 compliant. There was no money for a 95.25 single seater!
The single seaters did continue that year but it was mainly 1984 T84s and T85SGs coming back for up-grading into T85Bs and the T85C (with span extended to 31’6”).
The only missing part of the single seat record is any photos of data on the several single seaters that were put on floats. This definitely happened and two sets of photos were promised – but never turned up.
In the two seater area the Glasshouse was taken as the basic design and strengthened. From factory photos of the structural testing it is obviously a Glasshouse main structure that is being used. But by this time it was en route to becoming the Gemini X complete with a pod and windscreen. So was born what most people now think of as the ‘Thruster’ for although they have changed a great deal, their general appearance has not.
Serial number 8501 was the first of them and became the development test bed. Maybe about 20 Gemini X’s were built that year, most being exported.
One Gemini X was displayed at the Paris Air Show that year and received favourable reviews and comment.
1986
8501 finished its development (to that stage) and became 085-001 and was registered with the AUF as 25-0001. Australia had its first ANO 95.25 aircraft and Ultralight Aviation had its first legal two place trainer – a Thruster!
The Geminis were put into quantity production to meet demand and schools were hastily set up to build a core of instructors and CFIs to get the training part of the movement going.
Some experimentation with Geminis happened with the fitting of flapperons to at least one. This was discontinued as the Gemini was anyway slow and the huge ailerons on it were something of an over-kill when in flap mode.
In addition a crop spraying/property version – the Gemini Utility – was proposed as a single seat two seater. The chemical tank (or space for other equipment took the place of the second seat and used the two seater weight lifting capability. This tends to be a part of history several people would like to forget, but there is no reason to. The project was sound and probably still is – for people with large properties who could be self sufficient and drastically cut costs. However some of the few aircraft produced were found to stray ‘over the fence’ to the neighbours with money being involved so that was commercial Air Work and the authorities put their foot down. The project was therefore shelved.
The earliest Geminis began showing wear on the all aluminium airframes in school use and so the Gemini B came out about mid year with several strengthening features and narrower chord ailerons to improve handling.
The factory put out an offer for any of the now clearly illegal Glasshouses and Gemini Xs to be returned to the factory for up-grading to 95.25 standard. Two Glasshouses were returned – one of which was destroyed by the factory and the other was put through to Gemini B standard and is still flying in very good condition. Another Glasshouse was rebuilt privately to T500 look-alike standard somewhat later.
A subsidiary factory was established in UK which initially assembled and sold Aussie built Geminis but then went on to begin building them locally. The name Gemini was already in use so in UK the aircraft became known as the Thruster TST (Two Seat Trainer).
1987
Further airframe strengthening by the inclusion of more chromoly structures while retaining the wing of the Gemini B, saw the emergence of the TST as a model in its own right in both Australia and UK (although this was probably more confusing for the Poms than it was for us – but our turn was to come the following year!).
1988
This was another major year for the Thruster factory with again a lot happening. About March the TST had a substantial upgrade and came out in two models – the (confusing) TST (designated by TOSG as the TST L) and the TST E with a more enclosed cockpit and fully enclosed rear fuselage. More chromoly went into the airframe but the main feature was an overhaul of the wing to make it more efficient by the inclusion of 30 more wing battens and new wing tips.
By around November the two new types had been designated as the T300 and T500 (with no structural change). What became of significant problem to TOSG before this was unravelled and pinned down by description and serial numbers, was that the literature given with (particularly) the TST L simply gave them as TSTs. This creates problems for parts sourcing on what are four quite different aircraft types although still looking very similar.
In UK the T300 went into production but the T500 was too heavy to meet UK requirements and therefore never appeared there although some TST Es were exported to other contries (eg Austria) and one was demonstrated at Oshkosh.
The factory again turned its attention to single seaters and produced a large single seater, on traditional Thruster lines, with a much larger single seat pod.
The machine was intended to be built as an ANO 95.25 type and so could be sold ready to fly. One complete example was built and parts of a second. The intention was for a dual market with crop spraying again being contemplated as well as a dual role as a recreational aircraft. This was named the Sprint.
The Air Work gate however remained firmly closed and apparently a decision was taken that the remaining recreational market was not large enough to support the 95.25 development costs, so another project was shelved.
The Thruster factory however were nothing if not ambitious and Project T88 was launched. The concept was using the basic Thruster design, cleaning it up, strengthening it and offering it primarily as a valid GA training and recreational aircraft. This anticipated by several years what happened with the Skyfox, Gazelle and Jabiru.
Once again it would appear that development costs beat the project which went no further than a handful of parts being made, a model, some plans and some promotional material – none of which TOSG has been able to get its hands on.
The other main event in 1988 was the availability of the Rotax 532 and Rotax 582 engines. These gave sufficient power to make the heavier T300 and T500 types far more valid, particularly for flying school use.
1989
Nothing much new happened this year other than building a devil of a lot of T300 and T500s.
The 'Rainbow Warrior' crash in Kakadu. The only known Glasshouse not to have survived in one form or another. Easily repairable, it was destroyed by the Factory. Not the fault of the N.T. but ironically the only surviving Glasshouse not 'in care' is also in Darwin.
1990
This was probably the landmark year in the Thruster history. Something very significant nearly happened but something that was to change the future of Thrusters most certainly did happen.
The demand for school and recreational two seaters had stabilised, presumably at a production level below what the factory needed. The T100 was therefore proposed and a single example of it was built.
The concept was simple – a single seat T300 using mainly stock parts and jigs, but stripped down (eg TST style wing) and available as a fly-away complete aircraft for under $10,000 in 1990 prices. The aircraft however had weight and balance problems and despite increasing the tailplane area it was only tamed by replacing the 532 motor with a 503. The completed machine was demonstrated at Holbrook NatFly in this configuration.
The T100 was a brilliant prospect (as the Sprint before it could have been) for it anticipated the market shift to increasing numbers of members who do not want to build and fly them but want a ready made new single seat aircraft. The only two types that made it into 95.25 were the Sapphire and Vampire – both of which were sophisticated, expensive and were leaving traditional ultralighting behind them.
Within a couple of months the factory was in the hands of the receivers and it all stopped. Well, not quite!
What was left of Thruster Aircraft was sold by the receivers to the family that still presently own it – the Robinsons. The UK factory and its manufacturing rights were sold to a UK buyer and the factories became independent of each other.
It would also appear that all the records of the aircraft prior to 95.25 arrival were either lost or destroyed. This was certainly something that gave TOSG a headache – even a serial number list would (and still would) have helped greatly. Even when writing this 8402 came up for air and while most certainly should have been a T84 was in fact a T85SG built very late in the year with a beginning of the year serial number. The puzzles still continue!
This is where the story becomes more convoluted because a number of things began happening in parallel.
[Next page: Thruster chronology — 1991 onwards]
Tony Hayes
thayes@bordernet.com.au.
Copyright © 2003 Tony Hayes