Thread: Worse mileage with gryphon on interstate
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Old Mon, December 14th, 2009, 11:43 AM
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Jackpine Jackpine is offline
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Quote:
Originally Posted by soutthpaw View Post
As Jack said, the Wind resistance makes such a huge difference... that's the one big reason I am not a fan of 5th wheel Trailers... they give you this huge air brake the whole time you are towing.
Also its really not possible for the rpm to be different at the same speed if the TCC is locked up... what differs is the amount of fuel needed to maintain that RPM at any given point
Nicely stated, soutthpaw!

I can also see I wasn't particularly clear with my explanation about "drag". I'm going to say it differently, and I think it will make much more sense.

If you are seeing a 10 mph headwind at 70 mph, you are moving approximately 14% faster through the air. But, the wind resistance has increased by a whopping 30.6%! A 20 mph headwind (28.6% higher airspeed) causes a 65% increase in wind drag. And, a 30 mph headwind more than doubles the wind drag.

Bottom line, even a small change in wind is going to have a large effect on fuel economy.

- Jack