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Old 18th Jan 2019, 18:51
  #19 (permalink)  
Ascend Charlie
Join Date: Sep 2002
Location: Great South East, tired and retired
Posts: 2,478
This is completely incorrect. It stalls because of a lack of pressure, not because of too much pressure. Turning on anti ice is to remove any ice that may be blocking the inlet causing low air flow and low pressure.
Geez, Bront, why then is a bleed valve or a bleed band fitted to turbine engines? To remove the excess air that can build pressure at the back of the compressor, and cause the flow to break down and stall the compressor blades.

A C20 on start-up has the bleed valve open to allow acceleration of the compressor without getting too much air into the combustor. It stays open, closing gradually, until around 92% N1 when the engine can take all the air OK. It opens again on sudden accelerations. To let out the back pressure and allow the wheels to spin up faster.

Try leaving the wedge in the bleed valve when you go to start next time, hear the stalls start very early on. Too much back pressure.

Anti-ice is still turned on in hot countries too! Because it removes some of the excess air and pressure, not because there is ice in the intakes.
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