Hello, I have made program for simulating aircraft motion. I am able to obtain natural modes of motion like phugoid, short phugoid, etc. but to check whether it is simulating correctly, I need to validate it with some existing data, so i tried to compare the time period of phugoid of Boeing 747-200 with some data but it seems nowhere on the internet I am able to obtain the time periods of phugoid motion of different aircrafts like boeing 747, cessna 182, beechcraft 99, etc. Can somebody suggest a good source where this data will available ? or atleast tell the reason why such time period data is hard to obtain ? Even approximate time periods will be helpful. Thanks.