So while some members were Swan-ing (gedit!) around in a very sunny Sisteron this morning…..

..…it was Coronation Day, and whilst many in the nation were tuned to their TV sets, a few club members ventured out on to the airfield at Shawbury in an attempt to defy gravity. Unfortunately, their best of intentions were thwarted by the weather, a combination of low cloud and rain grounding those who had ventured out to the launch point. En-route to the launch point a Juno looked very lonely having been left out of the Coronation Fly-past because the driver probs didn’t turn up.

Meanwhile Sophie, having taken orders in the hangar, had popped off to get the bacon butties and just got back in time ……

…..to listen to Nigel R’s stories, amongst them the fantastically unknown fact that a coffin can’t be draped in the RAF Ensign. We also learnt that the Union Flag is called the Union Jack when it’s at sea and other gripping stuff.

Nigel was about to launch into his favourite topic, the Palmgren-Miner linear damage rule (P-M Rule), when, by sheer luck for the rest of us, the beep of a horn announced the arrival of a man with a rather large tractor. As Nigel went out to engage the driver in friendly banter, the rest recalled how went the last interaction between Mike O and the runway sweeper driver, a discussion that went so well that the runway didn’t get swept!

Anyway, we digress from what is, on a rainy day at the launch point, a riveting subject. The P-M Rule rule predicts fatigue failure of the component when the summation of the cycles of reversed stress amplitude, N'i, to the cycles of stress causing failure at each stress amplitude, Ni, equals unity, i.e., ΣiN'i/Ni=1. It is shown that the failure strength curve for a rolling element bearing represents an “energy of failure.” As such it is possible to sum the total “energy of failure” for a variable loading duty cycle and derive the P-M Rule. It is shown that the Rule assumes the rated fatigue life curve exponent incorrectly, but that it is possible to revise the Rule to take into account the correct rated life exponent. The revised P-M Rule predicts a somewhat longer fatigue life under varying loading conditions than the standard Rule. The method of derivation of the revised P-M Rule allows one to fit experimental data. There is a test on Monday!

With no flying, we put the aircraft to bed and turned to admin duties amongst which two old lads changed the wheel on a trailer and then engaged in putting up some Christmas lights inside another.