On Sunday, May 17, 2015 at 2:43:09 PM UTC+1, Craig Funston wrote:
Slow tow with full water?

I don't know anything about the circumstances but there has been an advisory email to all owners to emphasise the need to make sure that tug pilots are briefed that the minimum aerotow speed for a fully ballasted JS1C/21m is 70 knots (130 km/h) in turbulent conditions. The minimum in calm conditions is 65 knots.

The wingloading of a 21m JS1 at the MAUW of 720Kg is 58.7kg/m2 which is higher than any other glider that is likely to be regularly aerotowed in any numbers. The only other production gliders with similar max wing loadings are the Quintus and the EB29 with its shortest 25.3 tips (which are all self launchers) and the Antares 23T of which there are not likely to be many. It is this unusually high wingloading that needs to be fully appreciated at both ends of the tow rope IMHO.

John Galloway