Towing performance SF25C Rotax Falke 912S?

I am looking for some reliable data on the Rotax Falkes towing performance,
but I have until now not found any consistent values.



I would therefore very much appreciate if you would send me some
information, if you have any experience in this area.





To put it simple, I would like to know how many minutes it takes for a Rotax
Falke with the 912S engine, to tow an ASK-21 (fully loaded, or close to) to
4.000 ft./1.200 meters, in calm air?





My question arises because I have heard one club say 12 minutes, and others
say 25 minutes.



Maybe both answers are true, and the difference is due to different power
settings, towing speed and propeller. In a manual (from 1999), I have read
that the 912S engine may run with a maximum of 5.800 rpm for 5 minutes, and
4.800 rpm for continues flight. I would therefore also like to know the
power setting during tow, for which you have provided the time:





First part of the tow: XXX rpm for YYY minutes

Remaining part of the tow: ZZZ rpm for NNN minutes

Propeller (fixed or variable):

Landing gear:



Please do not hesitate to answer the first question, even if you don't know
the answers for the last 4 questions.



Thank you in advance!



Steen