In 1977 the Cessna Aircraft Corporation of Wichita, Kansas manufactured an airplane that it accounted for with the Serial Number 18265554. As the first three digits of the serial number indicate, the aircraft is a Model 182. It is further defined as a sub-type "182Q". This particular aircraft, after its first flight on 18 March 1977, was assigned the U.S. Civil Aircraft Identifier N631S. Of course, to Cessna's marketing department, the airplane was a Skylane and so to this day, it is known on the ATC frequency as Skylane Six Three One Sierra.
N631S is a single-engined four-place all-metal monoplane configured with a strut-braced high wing and fixed tricycle landing gear. It is powered by a six cylinder piston engine of horizontally-opposed geometry, designated as an O-470U by its manufacturer, Teledyne Continental Motors. The engine is carburated and normally aspirated and has a displacement of 471 cubic inches. At sea level on a standard day, it produces 230 horsepower at 2,400 revolutions per minute.
N631S has a Maximum Gross Takeoff Weight of 2,950 pounds. Empty, it weighs 1,888 pounds and therefore has a Useful Load of 1,062 pounds. However, with full fuel tanks holding 75 gallons of aviation gasoline weighing 450 pounds, and 117 pounds of normally stowed equipment, its normal Ramp Weight is 2,455 pounds and its normal Payload is 495 pounds. The payload can be increased by reducing the amount of fuel carried. For example, if departure fuel is reduced to 50 gallons, Payload is correspondingly increased to 645 pounds (while endurance is still in excess of four hours).
In normal cruise flight, N631S will achieve a True Airspeed (TAS) of 137 knots at altitudes of 6,000 to 8,000 feet above Mean Sea Level, while consuming about 11.7 gallons of aviation gasoline per hour. Over time, with normal headwinds taken into consideration, the machine will provide an average ground speed of about 120 knots (or about 138 statute MPH) for about 5 and 1/2 hours (with prudent IFR reserves). This offers a practical range of 660 nautical miles (or about 760 statute miles) except in unusual weather conditions.
Like all Skylanes, N631S is comfortable, stable, quiet, efficient and
well-behaved. It is a most excellent airplane.
The 182Q airframe is a lineal descendant of the tailwheel-equipped Cessna 140 designed near the end of World War II by Dwayne Wallace and his colleagues in Wichita. The 140 led to the four place 170 and the larger 180, then to the tricycle-geared 182 that debuted in 1956. By 1977 when the "Q" model of the 182 was introduced, the airframe was highly refined.
The major changes within the "Q" series are: 1977 (N631S's year) - Introduced with the O-470U engine; 1978 - adoption of 28v electrical system; 1979 - adoption of "wet wing" integral fuel tanks of 92 gallon capacity. So, N631S is a C-182Q that has the "U" engine, a 14v electrical system, and bladder fuel tanks.
There is little more to be said about N631S's basic structure. The only significant airframe modification accomplished to date has been the addition of flap-gap seals.
The airplane spent the first 27 and 1/2 years of its life in the Great
American Midwest -- in Illinois and Iowa. As a result, it is an essentially
corrosion-free airframe. In 2004, before it moved to the maritime environment of
Connecticut, it was treated with CorrosionX to arrest any incipient corrosion
and to prevent deleterious effects due to the proximity of salt water. The
CorrosionX treatment was repeated in the fall of 2006 and will continue to be
repeated at biennial intervals.
The powerplant installed on N631S is the original Continental O-470 engine driving the original McCauley C2A34C204/90DCB-8 constant speed propellor. Both engine and propellor have undergone two overhauls.
The salient distinction between the "Q" series of Cessna 182's and the preceding "P" models is the adoption of the "U" version of the O-470 engine. The "U" engine has a higher compression ratio than earlier versions and as a result it produces its rated 230 sea level horsepower at 2,400 rpm rather than 2,600 rpm. This results in a 7.7% decrease in maximum propellor tip speed and a significant reduction in radiated noise.
The "downside" of the adoption of the higher compression "U" engine is that there is no approved option for the use of automotive gasoline in lieu of 100LL AvGas. However, with the ubiquitous addition of ethanol to auto gasoline, this is rapidly becoming a moot point, as widely available forms of "mogas" are incompatible with engine materials
The O-470 series of six-cylinder horizontally-opposed piston engines dates from 1947. The pistons are 5 inches in diameter and have a 4 inch stroke, giving an aggregate swept displacement for all six cylinders of 471 cubic inches. As originally installed, the "U" engine (like its predecessors) had a recommended time between overhauls (TBO) of 1,500 hours. Subsequently, Continental (TCM) specified modifications which, if accomplished at overhaul, would increase the TBO to 2,000 hours. The engine in N631S is so modified.
The engine drives N631S's constant speed hydraulically-actuated two-bladed McCauley propellor. The prop has a nominal diameter of 82 inches, a maximum pitch of 29.4 degrees and a minimum pitch of 15 degrees.
By the winter of 2005-6, N631S was nearly 29 years old and its interior was tired, to say the least. And so, late in January of 2006 the aircraft was entrusted to Air-Mod, Inc. of Batavia, OH for a complete restoration of the interior.
The interior restoration process at Air-Mod encompassed three segments: Rehabilitation, Reupholstery and Enhancement.
The Rehabilitation segment involved removal of the existing interior, removal of existing insulation and damping materials, remediation of all incipient corrosion, chromate priming of all interior surfaces, renewal of any deteriorated original parts and installation of new multi-density acoustic insulation.
The Reupholstery segment encompassed the cutting and fitting of new carpet, the complete teardown and refurbishment of all seating and the renewal of all side-panels and the headliner, as well as painting of all plastic interior parts.
The Enhancement segment of the job included installation of a new Dennis Ashby glareshield, installation of new glareshield "eyebrow" switchable red/white lighting, a new Osram gooseneck rheostat-controlled map/reading light at the pilot's position, replacement of the co-pilot seat with a six-way articulated seat similar to the pilot's seat, installation of BAS inertia-reel shoulder harnesses, rewebbing of the existing harnesses and their relocation to the rear seats, new armrests, new Wemac "eyeball" vents for the rear seating area, and installation of the Selkirk STC'ed extended baggage area.
It is most convenient to discuss Instrumentation and Avionics in three segments: Flight Control Instrumentation; Powerplant Instrumentation; and Avionics.
Flight Control instrumentation begins with the most excellent SIRS Navigator silicone-filled wet compass. The panel offers a conventional array of primary flight instruments: airspeed indicator, attitude indicator, altimeter, turn coordinator and vertical speed indicator. The heading instrument is an EDO NSD-360 unslaved horizontal situation indicator (HSI). There is also an Astrotech chronometer and a Davtron 655 instrument that provides outside air temperature (OAT), avionics bus voltage, pressure altitude and density altitude. Finally, control of flight is normally managed through an S-TEC System 50 autopilot with altitude hold and electric trim. The autopilot receives yaw command guidance from the turn coordinator and pitch command guidance from its own pressure sensor. As a result, the autopilot function is independent of the vacuum-powered gyroscopic instruments and is immune to the effects of a vacuum pump failure.
Powerplant Instrumentation includes the original Manifold Pressure Gage and Tachometer. The "Cessna Six-Pack" (left and right fuel levels, ammeter, oil pressure and temperature and cylinder head temperature) continues to function well. In addition, a JP Instruments EDM-700 graphical engine monitor provides analog and digital indication of exhaust gas temperature and cylinder head temperature for each cylinder. Finally, a Shadin MiniFlo-L fuel totalizer provides fuel flow rate and quantity used/remaining.
The avionics suite begins with a PS Engineering PMA-8000B audio switching panel (which includes a 4 place intercom). The primary nav/com is a Garmin GNS-530W approach-certified navigator with WAAS capability and moving map. It drives the CDI functions (localizer and glideslope) of the NSD-360 HSI and also provides roll steering commands via an S-TEC GPSS module to the autopilot. The second nav/com unit is a Bendix-King KX-155 with glide slope reception capability. It drives a KI-209 indicator that gives full backup ILS capability.
The panel also includes a King KN-64 DME receiver, a Garmin GTX-330 Mode "S" transponder with TIS capability (that displays traffic on the GNS-530 in approach radar airspace), and a Cessna ARC 300 series ADF receiver with indicator.
A Garmin GPS-396 portable is semi-permanently mounted in a RAM mount on the console between the seats. It provides backup navigation capability and, most importantly, in-cockpit weather obtained from XM Weather.
Three "out-of-sight" items complete the avionics outfit: a King KA-33 avionics cooling fan, a Caltron Altitude Encoder that provides pressure altitude data to the transponder and the GNS-530, and a 121.5 MHz emergency location transmitter.
Here follows a list of the things yet to be accomplished on N631S as it comes ever closer to being the "perfect" airplane:
To be continued...
This page last edited: 4/14/08
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