There is a definite link between climate and problems with the MW44s flaming out on acceleration. This is due to surge which is made worse by high ambient temperatures. Mike Murphy says that the remedy is to increase the acceleration delay to slow the rate of acceleration slightly. Without having a climatic test cell (and only Rolls Royce have one of those!) we can't anticipate what settings are going to be needed. We have had engines tested in warmer climates and David Gladwin has had no problems in Australia at 40 degrees C, but all engines are different and the smaller ones are more sensitive, so some will be affected more than others. All engines are tested thoroughly before they leave here and only the ones which perform well are sold, but we cannot tell how an individual engine will react to high ambient temperatures.

We have recently discovered that another cause of flameouts can be the position of the tailpipe. Two years ago we recommended 10mm from the end of the exhaust, but have discovered that with the higher-power 44s a larger gap of 25-30mm is needed.

Sara Parish
Wren Turbines