For a time flaps were allowed in the standard class as long as they were not interconnected with the ailerons. Non-flapped gliders of 15 meters maximum were still eligible for the standard class during that period. The change to the rules made on behalf of the Standard Cirrus (and the other German gliders of the period) was the removal of the requirement for terminal velocity limiting dive brakes in the standard class when it was discovered none of them met that requirement. It rather annoyed the Schweizers who had spent considerable time and money engineering and testing terminal velocity limiting brakes on the 1-23H15 and 1-34 in good faith. They (as well as Laister and Schreder) were then even more ticked off when after designing ships with flaps to meet the definition of the then current standard class rules saw the rules changed again to disallow flaps. Eventually we got the 15 meter class and the standard class rules we have now out of the whole mess.

Two European gliders built to the flapped standard class rule were the original Pik20 and the single LS-2