The auto-tow launch mode can help Antares 18T and Antares 23T gain a whole new level of independence. Now there were the first extensive tests for the approval of the launch type.

With Antares 18T and Antares 23T, self-launches are almost possible. There is no approval for safety reasons. Without risk, on the other hand, these turbos, using their powerful engine, can be brought into the air with very little effort in an almost forgotten type of takeoff: car towing. They thus reach heights from which they can fly on independently.

At our home airfield in Zweibrücken, the Antares 18T has already taken off several times for testing purposes in self-launch. The good performance of the engine, the possibility of power control and not least the starter, with which the engine can be started already on the ground, have made this possible. On the 2675 m long Zweibrück runway, on which a landing is possible again at any time, this was also no problem. At the end of the runway, a safe height of 200 m was reached. On short runways and with water ballast, however, self-launching is not an option – not to mention the fact that there is no certification for it. The Solo also lacks an important safety aspect: dual ignition. But what to do if no tow plane is available or the tow pilot is missing – not to mention a winch operation? Autostart requires just one helper to get behind the wheel. In Germany, the current SBO still requires an observer in the vehicle. This makes this launch mode highly interesting for the Antares with turbo.

To perform an auto-launch safely, the engine is already extended and started on the ground. After disengaging at 220 m, you can then continue to climb with the motor.

If the engine fails during the towing operation, a release altitude of 200 m is still achieved. In this case, a shortened aerodrome circuit can then be flown safely with the engine extended.

For the approval of this type of launch, we have now completed extensive car towing tests in Reinsdorf near Berlin. On the three-kilometer grass runway, all eventualities of this type of takeoff were played out and recorded on video for the approval process. In addition to ‘normal takeoffs’ takeoffs with the engine extended and idling were tested with partial load, with simulated engine failure (ignition off) and also rope breaks at various altitudes. The most important finding of these tests is that the pilot does not behave any differently than during winch launching, and the requirements placed on the driver are the same as for a winch driver. Nothing special, then. The engine must be operated at idle speed during the towing process, which quickly turned out to be another important finding. Then the Antares 18T can climb at its optimum speed of 120 to 130 km/h. If the engine is operated at partial load during the starting process, there is a risk that the rope parachute will open during the first gearshift of the car. This situation is clearly visible in the picture.

After takeoff, an engine tends to overspeed at part load. Somewhat unusually for the drivers of the four-wheel drive BMW 530 used, they had to accelerate very quickly right at the start of the launch and only reduce to the correct towing speed after the acceleration phase. It is also advisable to deactivate some of the driver assistance systems by selecting the Sport driving mode. Without switching off the many electronic helpers, short delays occurred during gearshifts despite the dual-clutch transmission, which in turn could cause the rope parachute to open. And that had to be prevented at all costs.

For the approval of car towing, it is now necessary to evaluate the extensive data material. An assignment in the scope and requirement of a student research project. Rope parachute and coupling can be optimized. The Tost coupling, which can be fitted to trailer couplings without any effort, was used for the tests. It would also be useful to have a retrieval winch directly on the car towing device on the vehicle so that the rope does not have to be collected by hand after launch. In addition to the approval of Antares 18T and Antares 23T, the airfields must of course also include the takeoff mode autotow in their approval. The national regulations apply to the inclusion of the launch type autotowing in the license.