On Thursday, December 8, 2016 at 10:30:26 AM UTC+3, Per Carlin wrote:
On Thursday, December 8, 2016 at 7:26:05 AM UTC+1, Bruce Hoult wrote:
On Thursday, December 8, 2016 at 2:21:34 AM UTC+3, Casey wrote:
I've noticed that 13.5m FES are advertised as Front Engine Self Launchers and 15m are advertised as Front Engine Sustainers. I did here of a LAK 17b FES launch off asphalt. I wonder if the batteries heat up more from a 15m launching than a 13.5m? Or if the batteries heat up during prolong usage with either the 13.5m or 15m?

Any glider with a sustainer can self-launch from a sufficiently long hard surface, with plenty of pressure in the tyre and a push start. Or, better, a tow to 100-120 km/h with a car.

To be certified as SLG according to JAR 22 do you need to meet specific performance in roll-out distans and climb. The 13,5m FES is only SLG in dry condition, if you load it with water is it only SSG. I guess that the LAK17 is to heavy to meet the performance requirements to be a SLG.

Yes I know. I wasn't talking about certification :-)

Of course there are lots of places that you'd be foolish to try it, but given an airfield large enough that you can circle within the boundary with less than 30 degrees of bank, the difference between a car tow with an aerotow rope and an aerotow to a release on downwind at 500 ft (which lots of people do) is probably ... about 300 ft by the time the motor starts.