What is the forward velocity of a laden swallow and how does this compare to the unladen swallow of Monty Python fame?

Answer 1

An unladen swallow may fly at around 11meters per second, but common sense suggests that if the swallow is carrying extra mass (i.e. is laden, and not too heavily) it will have to work harder just to stay in the air, and will have less capacity to make forward progress through the air.

Christoph Schiller, author of the Motion Mountain free physics text book, reproduces a graph (on page 41 in the 21st version) by Henk Tennekes (probably from his book The Simple Science of Flight: From Insects to Jumbo Jets) that appears to show that there is a direct relationship between wing loading and cruising speed for both birds and aircraft, such that higher wing loadings are directly related to higher cruising speed. I queried Schiller on this point and was brushed off.

It seems to me that, in the case of any particular model of fixed-wing aircraft, a heavier load (giving a higher wing loading) increases the craft's weight and the wings would have to operate at a higher angle of attack in order to generate more lift for the same airspeed. The higher angle of attack would give rise to more drag which would tend to slow the craft down, assuming that the thrust remained the same.

So there you have it. Christoph Schiller (a physicist) seems to quote Henk Tennekes (supposedly an expert in aerodynamics, and part-time climate-change skeptic) as claiming the velocity would be higher in the laden case, whereas common sense and my high-school physics suggests that a heavily laden flyer will make slower forward progress.

12.2 feet per second :) depending on whether it's African or European.