PPRuNe Forums - View Single Post - Best Range Speed - AEO vs OEI
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Old 17th October 2008 | 23:32
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HeliComparator
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Joined: Aug 2004
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From: Aberdeen
Generally agree with Dark and the sheep

Turbine engines are most efficient (in terms of power to fuel burn ratio) at high power. Therefore its likely that close to OEI max continuous power speed gives the best range. Being AEO at the same speed would mean engines running really slow, poor efficiency - more economical (in terms of power to fuel burn) at higher power settings/speed. Go to higher altitude and its even better.

In the case of the EC225, best range speed AEO is Vh minus about 5 kts - ie around 145kts - but this is because the bleed valve starts to open only a bit below max continuous cruise power esp at low level. Bleed valve partially open = big loss of efficiency.

HC
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