When my mother moved to her new home in South Regina, she no longer needed her kitchen table set. and thus gave it to me. I managed to stuff the 4 chairs and table in the rear hatch, but not without keeping the hatchback wide open.
Because it was late at night, I managed to be able to cruise at a speed of about 35 miles per hour on the Trans Canada Highway with my precious cargo, all the way home. What amazed me was how much of a blow to my gas mileage occurred, even at that snail-like speed. Because the Kitchen set was maybe only a 100 pounds, the culprit was simple gesture of opening up the hatch that robbed my fuel economy.
Here is a video of just how massive this loss can be when hauling something that requires a hatchback to be open:
Feel free to discuss.