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Old 29th Jun 2011, 06:41
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TJQ
 
Join Date: Jun 2011
Location: Dubai
Age: 47
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Unhappy Max Endurance Speed / Min Fuel Flow

Hi Guys

Why is the speed for Minimum Fuel Flow (i.e. Holding Speed or Max Endurance Speed) BEHIND the drag curve...?

You would expect minimum fuel flow to occur with minimum drag but this is in fact NOT the case! The speed for minimum thrust/fuel flow occurs at a slower speed where there is greater drag - which strikes me as unusual.

I've been doing a lot of research on the web and in these forums and although I can find the confirmation that it is indeed true, I can not find a reason explaining why.

Obviously there must be more factors involved than just "thrust required to overcome drag"...

I've had a read of Boeing's "Jet Performance Test Methods" manual (1989 edition) and they don't really give a comprehensive reason in layman's terms as to why you burn less fuel with more drag.

Anyone want to give it a go and make my day...?

Many thanks if you can help...!


TJQ
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