Thats why I made my comment - the first 5 1-11s Dan had were a hodge podge TL/TJ were 300s ex Eagle - CK/CP were 400(ish) ex American and we wont talk about ZED it was a total hybrid that came out of rebuilding an ex Phoenix aircraft at Lasham - ALL five aircraft had clackers not bells - my comment was simply that this may have been done because the overspeed warning on MF resembles the fire bells on the Dan Air aircraft- and that it was an attempt to differentiate between warning sounds. (By the way another Ex Braniff 1-11 I rode on had the same overspeed clacker - so maybe DMs comment that it was American mod would ring true except that the 2 ex Eagle Aircraft had the same sound. Seems silly to be discussing this as it doesnt make much difference to the "realism" of the model I didnt really expect the Spanish Inquistion
Leif