Tuesday, July 29, 2014
20 Things You Never Knew About Your Airplane (Or Someone Else’s)
A few little known thoughts. Ever heard of the Cessna 620? Why T-tails? A Seneca Tri-Motor?
1 Beech Barons have always been among the best-handling twins in the sky, but they did have a curious anomaly.
The throttles were mounted in the middle between the props and the mixtures. This could've resulted in pilots trained in conventional twins accidentally feathering both props on short final. Many pilots never understood why Beech opted for this seemingly nonstandard placement, but the answer was actually fairly simple. It was a carryover from the Beech 18 of the '40s and '50s. Those airplanes were often flown with a copilot in the right seat. Beech positioned the throttles in the middle so either pilot could reach them with equal facility. Barons didn't share the commercial application, but Beech continued the throttle placement in the middle on the models 55 and 58 anyway. (The company eventually made the argument that it was the rest of the world that was out of step and moved the throttles to the far left on the 58 Baron.)
2 The reality is that Skyhawks are forever, unchanging, gentle to a fault, capable, everyone's friend.
The myth is that there were only two or three versions of the Skyhawk built. Depending upon how you count them, there were actually seven variations on the 172 theme. The first 145 hp Continental-powered Skyhawks were introduced in 1958 (1) along with the Cessna 175s, a 175 hp, geared version of the same airframe and wing (2). In 1968, Cessna switched to a cambered wing on the 172M (3). The Hawk XP was introduced in 1977 with an injected 195 hp Continental and a constant speed prop (4). Cessna's Cutlass RG debuted in 1980 with retractable gear and a 180 hp Lycoming IO-360 engine (5). A fixed-gear version of the airplane was introduced in 1983, and that model (6), along with the standard 160 hp version, continued in production until three years ago, when all Skyhawks were standardized as the 172SP (7) with the 180 hp injected Lycoming. In other words, there have been seven variations of the Skyhawk in the last 56 years, and a diesel-powered model may still be in the offing.
3 I first flew a SIAI-Marchetti SF.260 20 years ago in conjunction with a pilot report for this magazine.
The airplane was an absolute delight in almost every respect. During that flight and subsequent hops (including a delivery of a pristine example from California to Coventry, England), I learned quite a bit about the airplane and its quirks. Everyone agreed the Marchetti was a remarkable flying airplane, but for reasons only the Italians understood, most SF.260s were fitted with carbureted engines. This meant the airplane had little tolerance for negative Gs or even low positive Gs. Pull a hammerhead stall too steep, and the engine would quit. Similarly, because this was primarily a military trainer, the pilot flew from the right side, and all instruments and radios were biased to that seat. Also, the wing was notoriously intolerant of any contamination—read "icing." On my Atlantic deliver, I was advised by several very experienced Marchetti pilots to avoid icing at all costs. It seems the airfoil that was so perfectly suited for aerobatics and formation work wasn't happy in icing. My ferry flight was in late fall, not the best season to avoid icing, but I managed to steer clear of most frozen sky, ironically picking up a small amount during the final leg into Coventry.
4 When Piper introduced the Arrow in 1967, the airplane's automatic gear extension system helped it knock Mooney off the pedestal as best-selling retractable.
The Arrow featured a simple airspeed switch that automatically lowered the wheels if the airplane subceeded about 80 knots with the gear in the up position. The system was so reliable that it was copied by both Bellanca and Beech. As so often happens with good ideas, the auto-extend system proved to be too good. A pilot ran out of fuel in an early Arrow during a cross-country flight, was gliding toward an airport within easy reach and got a little slow. The gear dropped down obediently, now with no way to get it back up. This compromised the Arrow's glide and caused the airplane to land short. The owner survived and, of course, sued Piper. Piper lost, and that was the end of the auto-extend feature.
5 Depending upon whom you ask, the unusual Cessna Skymaster is either the safest twin above the planet or just another idea that didn't make it.
Accident statistics suggest the latter, indicating the same safety record as for many asymmetric-thrust twins. The Cessna 337 was a push-pull multi intended to eliminate asymmetric thrust following an engine failure. The 337 did have a few quirks, however. Incomprehensible as it may sound, a few pilots allowed the rear engine to idle out and initiated takeoff with only the front engine running. Most of these takeoffs didn't work out too well. Another lesser-known glitch had to do with retracting the gear during an engine failure. Counterintuitively, Cessna recommended the gear be left down until the aircraft ascended to a safe altitude. With the well doors open to accept the gear, the resulting belly cavity serves as an air dam that subtracts 240 fpm from climb. True, the gear cycle is probably only 15 seconds or less, and that's fine if you have that much to spare. If you don't …
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