The Power of 25
Think of it as a crash course in aeronautical trivia.
- By The Editors
- Air & Space magazine, May 2011
(Page 4 of 4)
21. Flirt with towering cumulonimbi.
Crashed: Beech 35-B33, Nov. 30, 2008, Homosassa Springs, Florida
22. Take off with frost on the wings.
Crashed: Cessna TU206, May 6, 2009, Bethel, Alaska
23. Inadequately secure a single-engine aircraft before hand-starting it via the propeller.
Ran into airport fence: Piper PA-15, Nov. 30, 2008, Pleasanton, Texas
24. Have a few beers before flying.
Emergency landing: Boeing 717-200, May 12, 2005, Union Star, Missouri
25. Begin any maneuver with the words, “Hey, watch this!”
Way Faster Than a Speeding Bullet
Mach is a relative measure (affected by air density and temperature); in the upper reaches of the atmosphere, Mach 25 is about 17,500 to 19,000 mph. According to a landmark study by DARPA (Defense Advanced Research Projects Agency), the theoretical upper limit of a scramjet is Mach 25. At that speed, a scramjet could take off, reach an altitude of 47 miles, and have enough momentum to glide into orbit around Earth. The space shuttle and most man-made satellites orbit Earth about every 90 minutes, which translates to an orbital velocity of Mach 25.
The 25-and-Under Club
Some airplanes were so special, expensive, or complex that their production runs fell short of 25 airplanes. Some examples: The 1950 Northrop YC-125 Raider utility transport (23 built); the 1970s-era Aérospatiale-British Aircraft Corporation Mach 2 Concorde airliner (20, with 14 entering service) and its Russian counterpart the Tupolev Tu-144 (16); the 1931 Northrop Alpha (17); the 1929 Lockheed Model 8 Sirius (15); the 1960s-era Lockheed A-12 (16); the 1955 Martin P6M SeaMaster (12), and the 1938 Boeing 307 Stratoliner (10).
Twinkle, Twinkle Little Satellite
The 25th satellite to reach Earth orbit, Echo 1, was launched on August 12, 1960. The enormous metallic balloon (also called a “satelloon”) was an experimental NASA communications satellite that functioned as a passive reflector of microwaves, redirecting telephone, radio, and TV signals. It was the first to successfully demonstrate the potential of communication satellites. Because we are sticking to official satellite launch records, we must reluctantly ignore 1957’s Project Thunderwell, in which, several months before Sputnik’s launch, an explosion inadvertently sent a four-inch-thick steel plate (part of an underground nuclear test in Nevada) into orbit.
Is Everybody In?
The first craft to get 25 people into the air at once was Henri Giffard’s huge tethered balloon, which in 1878 lifted 52 giddy Frenchmen and -women at the World’s Fair in Paris. For powered airships, it was the Zeppelin LZ11 Viktoria Luise, which first flew in February 1912, and could carry 25 passengers and a crew of eight. And for powered airplanes, Germany’s Claudius Dornier created the 12-engine, 157-foot-wingspan Do X flying boat, which broke through the 25 mark with 66 passengers. Its first test flight was in July 1929. In October of that year, it hoisted 169 people off of Lake Constance on the border of Austria, Germany, and Switzerland. The current record for most aboard was set during Israel’s evacuation of Ethiopian Jews from Africa in May 1991 in a cargo version of a Boeing 747: 1,122 people—including two babies born on the flight.