Quote:
Originally Posted by mort
Almost the opposite. "Coupling" is misdirection. Rockets make vertical climbs totally decoupled from ground friction. If the propeller makes more thrust than than needed to climb the hill then you go up.
Air shows often have hopped up crop-duster biplanes that can make vertical climbs. The Piper Cub can make a 45 degree climb, and no road is that steep.
-mort
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It's all power to weight ratio, if the thrust exceeds the vehicle weight, then it can climb vertically (but not with a car whose wheels would be spinning long before it reached the vertical portion of the road).
Even though the Cub's nose is pointed up at 45 degrees, the wing's 10 to 20 degree angle of attack means the aircraft's flightpath isn't anywhere near a 45 degree angle.
But propulsion via ground friction allows you to use a "granny gear" to climb up a steep road on very low horsepower. According to my owner's manual, 1st gear allows the 54hp engine in a 67 VW Beetle to propel the 1900 lbs car up a 45% incline (VW beetles are known for their extremely high 1st gears that redline at about 12mph). Show me a 54hp, 1900lbs airplane that can climb out with a flightpath anywhere near that angle.