Need a little more speed than the BLS-43a? Then the BLS-37a is a great choice and again staying under 100 bucks to keep that big plane budget in check. It is packed with features that only the highest end servos have. An all metal cnc machined construction, loads of torque and as much speed as you could want in this class of servo.
 
Soft Start Protection
Over Voltage Protection
Low Voltage Protection
Locked Rotor Protection 
Temperature Protection
Includes Aluminum Servo Arm
 
 
Applications
Fantastic for 3D Airplane, Large Jet & 1/8th Buggy, Truggy, Crawler, Monster & Helicopter.  (EP / Gas / Nitro)
 
Specifications
Torque At 6.0V
     31.3 kg-cm / 434.8 oz-in
Torque At 7.4V
     37.8 kg-cm / 525.1 oz-in
Torque At 8.4V
     43.2 kg-cm / 600.1 oz-in
Speed At 6.0V
     0.10 sec / 60°
Speed At 7.4V
     0.08 sec / 60°
Speed At 8.4V
     0.07 sec / 60°
 
Power Supply
Operating Voltage
Range
 4.5V ~ 8.5V ( 4 ~ 6 Cell Ni-MH or 2S Li-Poly / 2S Li-Fe)
 
Standard Full Aluminum Servo
Control System
   Digital Controller / AD 12-Bits Resolution ( 4096 Steps )
   Frequency：333Hz / Neutral：1520us
Dead Band Width
   0.001ms ( Default：1us)
 
Mechanical Specifications
Ball Bearing
   Dual
Gear
   Titanium Alloy Gears
Motor
   Premium Brushless Motor
Horn / Gear Spline
   25 Teeth ( Same as F-Type )
 
Physical Specifications
Dimension (mm)
    40.5 x 20 x 39 mm / 1.59 x 0.79 x 1.54 in
Weight (gram)
    78.5 ± 1 grams / 2.77 oz