If you're comfortable with spreadsheets, make your own or borrow an
existing one and modify it for your glider. My LAK-17a came with a
spreadsheet which I've modified to include installation of a flight
computer in the panel and replacing the tail battery with a heavier lead
weight. It also has cells for wing and tail ballast (water) and is
duplicated for 15- and 18-meter spans and baggage compartment load. I
don't know whether it came from the factory or the previous owner, but
it's pretty simple to make. I did one for the company King Air years back.

On 10/24/2015 11:49 AM, Burt Compton - Marfa Gliders, west Texas wrote:
Essential: Obtain the Schleicher ASK-21 Flight Manual in english.
It will be specific to your serial number.
Note the manual revisions listed at the Schleicher website.
If you attach the spin weights, consult the recent manual revisions.

Optional: A calculator but only for a specific ASK-21 in Nevada: http://soaringnv.com/WeightBalance.php

Best to develop your own. Consult your A&P / IA.


--
Dan, 5J