|SinusLeistungsSteller - Solarboot "Brummer" 10.07.2008|
Torsten Wernecke´s Solarboat "Brummer"
With his 6m long several 100kg heavy solarboat named "Brummer" Torsten Wernecke participates for years in the german solar boat racing championchip. In 2008 his boats were placed again high in the winners list! Congrats!
Of course this boat has batteries on board, besides the discipline "Marschfahrt" (driving a maximum distance during a specified amount of time) there is also driving a slalom course against the clock. Not only raw power, but a very good efficiency and good maneuverability of the motor are important. So far, brush motors were almost invariably used. Slowly but surely the call for brushless motors and fitting controllers is getting louder. Highly efficient ring motors are available from the company Bieschewski ; for the controllers, we are responsible with the SLS ;-) ... a combination, that should turn out ideal ...
We were able to perform the first test drive with the "Brummer" on 02.07.2008 during our visit to Bieschewski company - Many thanks to Rudi and his wife for the hospitality and the free and undisturbed access to the lake! With the existing propeller of the E-Jet-Motors (Type 2-170/48V) the motor did not allow more than 6KW at 200Aac (the current limit of the SLS-60-200). The pitch of the propeller simply was too high for this configuration, but did not have an negative effect on the driving fun.
Only one week later (10.07.) Torsten Wernecke visited us together with his family in Kist, to perform another test. The motor now was equipped with a new E-Jet-propeller with lower pitch and only 3 blades ... and of course "Brummer", which was transported on a trailer.
On the boat slip of the Segelkameradschaft Maintal Würzburg in Margetshöchheim "Brummer" was also fast and safe in the water.
Many thanks to SKMW for assisting!
With noticeably more thrust but without any noise from the motor, the boat drove along the Main soon afterwards. On the steering wheel: Torsten Wernecke - I was in the "engine room" desperately trying to recongnize something on the notebooks screen shaded by a lifejacket. Simultaneously I tried to protect the (not potted!) SLS from splashing water. First I controlled the thrust via the notebook to make the final tuning during the first rides. Everything worked fine. And Torsten finally was able to drive a round with his family - but now with fully autonomously throttle-control, realized with our Servotester (ST).
Conclusion of this day: the new propeller works better than the replaced one - but still not perfect! We were able to get 8KW (2KW more than the last time), but we achieved only 160Aac in the motor, because the motor reached his RPM limit. So the propeller needs a bit more pitch to get the 200Aac. The motor already showed in this first tests (with the old propeller), that 200Aac are absolutely no problem. With a optimal propeller more than 10KW should be possible - we will see ...