A VNE table against altitude does not exist for the Standard Cirrus. Being an early glass type the Std Cirrus has big margins and very strong stiff wings. As long as the tailplane bushes are not worn and the free play of all the controls, especially the tailplane, is well within manufacturers limits the Std Cirrus is one of the few gliders that has a healthy safety margin on VNE.

I believe that the method of calculating these figures is to find out the altitude that the manufacturer did the test flying, calculate true VNE at that altitude and then not exceed that true speed. The altitude will be between 2000 and 3000 meters. Assume 2000 to be on the safe side. Then reduce VNE in proportion to the square root of the density reduction as the altitude is increased.

I will get the subject discussed at the BGA Technical Committee meeting onSaturday.

The BGA Technical Committee agreed with me that there is no need to impose a formal reduced VNE on the Cirrus as in UK conditions the danger of high altitude flutter is negligible if a little common sense is used. However, if you wish to, you may placard your Cirrus as per the attached calculations. Afandi Darlington who used to design Airbuses and now designs the Farnborough F1 confirmed that this is how the glider VNEs are reduced with altitude (JAR 22) and that this gives pessimistic figures.