AOPA Pilot Magazine - February 2011 - 55

This is the most significant difference between the Bell 47 and more modern machines. In newer helicopters, particularly turbine machines, power is increased automatically with an increase in collective, and vice-versa. This greatly simplifies flying the modern helicopter. The difference between the new and the old is loosely analogous to the difference between driving an automobile with an automatic transmission and one with a stick shift. Irrespective of what a Bell 47 pilot does with the collective control, it is imperative that he match changes in blade pitch with appropriate changes in power to maintain rotor speed above 322 rpm (minimum allowable) and below 370. As the Bell became “light on the skids,” I began to pressure the left pedal to prevent the torque of the main rotor from causing a right yaw. This is opposite to the habit developed by those who fly only single-engine airplanes. Instead of pressuring the left rudder pedal, fixed-wing pilots are accustomed to applying right rudder to compensate for an airplane’s left-turning tendency in a full-power climb. A little more power and the spritely 47 came off the ground, which is when I began to feel as though I were trying to stand and balance myself atop a greased beach ball. After a while, though, some of my ancient helicopter skills began to return, and I could hover over a spot (a very large spot!) without an imminent sense of crashing, but it was not pretty. I then pulled up on the collective a

bit more (while concurrently adding throttle), pushed forward slightly on the stick, and accelerated to a climb speed of about 50 mph. At altitude, Obi had me do some maneuvering and then asked me to hover at altitude. This takes a lot more power than it does when hovering in ground effect. He then asked me to settle with power. This means allowing the helicopter to descend at zero airspeed into its own rotor wash at a sink rate of at least 300 fpm. The beleaguered 47 began to shake and buffet almost the way an airplane does when held in a stall. Recovery is similar, too—just lower the nose and pick up forward speed to escape the downwash.

SPECSHEET
Base price when new: $46,950 Price as tested: $200,000+ Powerplant ..............Lycoming TVO-435-B1 Horsepower (takeoff only) ............... 270 hp Horsepower (max continuous) ........220 hp TBO ............................................1,000 hrs Overhaul cost (installed).............. $33,000 Seats ......................................................3 Cabin width ...................................5 ft 4 in Length........................................ 43 ft 3 in Width (storage) .............................9 ft 6 in Height ...........................................9 ft 4 in Main rotor diameter .....................37 ft 2 in Main rotor disc area..................1,081 sq ft Disc loading .......................... 2.73 lb/sq ft Power loading ........................... 10.9 lb/hp Tail rotor diameter .......................5 ft 10 in

Bell 47G-3B-1

Specifications

Max range (no reserve).................. 273 sm Rate of climb ................................880 fpm Hover ceiling (in ground effect) ... 16,100 ft Hover ceiling (out of ground effect) ..10,600 ft Service ceiling ............................ 17,200 ft Max gross weight ....................... 2,950 lbs Empty weight (standard)............. 1,819 lbs Usable fuel (57 gal) ....................... 342 lbs Payload with max fuel .................... 789 lbs For more information, see the website (www.scottsbell47.com). All specifications are based on manufacturer’s calculations. All performance figures are based on standard day, standard atmosphere, sea level, gross weight conditions unless otherwise noted.

Performance

Next came autorotation. Obi twisted off the power, and I immediately lowered the collective. Holding up the collective without power would result in losing needed rotor speed, and the helicopter would begin falling like a stone instead of gliding. I was grateful for being in a Bell 47 because it has high-inertia (heavy) rotor blades. It is more difficult to lose rotor rpm in a 47 than when flying other small helicopters with lighter blades. The flip side of this coin, however, is that if you do get sloppy and allow rotor speed to decay below limits, it is more difficult to recover lost rpm. Helicopter pilots are supposed to manipulate the cyclic control with their fingertips. Only light control movements are required to fly a helicopter well. At the end of my first flight, though, my hands were dripping with sweat. Restoring proficiency will require practice—lots of it. In December 2009, Scott’s Helicopter Service in Le Sueur, Minnesota, purchased the type certificates and tooling for the venerable Bell 47 from Bell Helicopter and formed Scott’s Bell 47. The new company is now responsible for providing technical support for the Bell 47 and will be manufacturing replacement parts. Its long-term goal is to obtain a production certificate from the FAA and begin manufacturing certain models of what will be called Scott’s Bell 47. Visit the author’s website (www. barryschiff.com).
AOPA PILOT • 55 • FEBRUARY 2011

VNE............................................... 105 mph Cruise speed ................................. 86 mph

http://www.scottsbell47.com http://www.barryschiff.com http://www.barryschiff.com

AOPA Pilot Magazine - February 2011

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