Since the good Lord gave me the chance to fly two of the finest airplanes in the sky in the same time period, I thought I'd like to share some of the differences with fellow aviators.

The two airplanes are at the opposite ends of everything airworthy, it makes quite a contrast. By now you're probably wondering just which two airplanes I could be talking about. They are the venerable Cessna 172 Skyhawk and the big old 747-400.

The 747-400 weighs in at a gross weight of 875,000 pounds which equals to 365 C-172's. The max fuel load of the 747-400 is 385,000 pounds or as much as 160 C-172's. At 385,000lbs. fuel, that equals 58,333 gallons. This would be enough to fill up 1,215 C-172's.

If we take this fuel load and put to (notice I said to, not on) that would be enough to fly around the world 33 times or to the Moon and back and then around the world again.

The C-172 I flew had an engine rated at 150hp, while the 747-400 had 4 engines rated at 58,000lbs of thrust. That equals to 232,000lbs of thrust, and since thrust to horsepower conversion is 1:1 at 330 kts, about cruise speed, we now have enough horsepower for 1,547 C-172's.

An interesting point, usually brought up is that, the big jets don't have the horsepower to weight ratio of smaller planes, that myth explodes in the face of reality when it can be seen that if the C-172 had the same power as the 747-400, it's engine would be a whopping 636 hp.

Next on the list is the sheer size of the 747-400 and how the C-172 would "stack up". The distance between the main mounts (airline-talk for tires on the landing gear) at 36 feet is enough to have the C-172 to taxi between them (very carefully !).

The wingspan is large enough to set 3 C-172's on each wing without ever touching, How big is big? Well you could set a 737 on each wing , they would not touch and the wing could easily support the weight.

While on the subject of the 747-400 wings, and the reason I made the distinction, this is the 747 with the wingless on each wing tip. They are 6 feet in height, about the size of the C-172 vertical stabilizer and rudder.

The seating capacity as we all know of a C-172 is 3 passengers and a crew of 1. The 747-400 has a seating capacity of 450 plus a crew of 21. At this rate the miles per gallon per passenger is 55 miles per gallon fully loaded, and amazing enough the "Big Hog" 747-400 has an astonishing 93 miles per gallon per passenger fully loaded.

If these figures don't impress you, think of this one... if you took all the wires in a 747-400 and laid them end to end.....none of the radios would work !!!

J.J. Quinn Captain 747-400 UAL, Retired