Shortcoming of Common Anti Torque Tail Rotor Helicopters

The tail rotor helicopter needs a tail with a small rotor to balance the torque generated by the main rotor system. Even though tail rotor helicopters are the most popular rotorcraft Many drawbacks come along with this type of chopper.   Common problems are listed at following  :

1. Tail rotor assembly of an anti torque helicopter does not produce lift in the vertical.  The tail rotor takes over 30% of engine power and consumes extra 30% fuel burn for anti torque without contribution to lift nor forward flight propulsion.
2. Instead, it produces drag and lousy noise due to the 2000-3500 RPM at which it spins  (approximately 5-6 times faster than the main rotor RPM). This high RPM, makes the blade tips turning near to the speed of sound.
3. During high-speed forward flight, the tail rotor produces a cylindrical airflow that is perpendicular to forward flight. The perpendicular airflow and the dimensions of the tail rotor assembly are immoveable barriers to high-speed forward flight. 
4. There is only one rotor producing lift, the total helicopter weight (with loads) is hanged under the main rotor single point.  (From a physics point of view, a single point hook-up compared to a dual point hook-up has less stability,  and has more tendency to swing or to oscillate. Therefore, using dual tandem twin rotors for vertical lift will has better stability, and more efficient.
5. Tail rotor style helicopters take extremely high fuel consumption and cost for operation, due to its low efficiency of power distribution.
6.  At  high speed level flight, common tail rotor helicopters are usually nose down tail up to obtain a back angle. Overturning back angle to increase high speed level flight might force rotor blades retrieving angle near to stall angle and burden the risk of  rotor system stall and lose control.
7. Low forward flight speed, fixed RPM rotor system. No matter hovering or high speed flying, the rotor spins at a fixed RPM. During high speed forward flight,  long rotor blades tips spin near to danger speed of sound. And blade retrieving angle is near to stall angle. Thus, it makes rotor blade tips easily self oscillating, and blooming. and lead to the the threshold of blades stalling. 
8. Less multi fault tolerant capability. Have to do instant auto-rotation emergency landing if engine or mechanical happened to fail . What about if taking mission critical tasks on water surface ?  fire fighting on blazing mountain ? fighting on enemy control area ? In where, no auto-rotation landing is allowed !

To summarize above points , a tail rotor helicopter characters less efficient aero-dynamics, using less available engine power for vertical lift, and slow forward flight speed.

Versatility      

Problem of Gyro-crafts and Gyroplanes !

 Advantage:  High speed, light weight, low fuel consumption, simple airframe, cost effective, low maintenance cost, long life, easy to fly.

Disadvantage :

(a)       Can not fly like helicopter to hover at 0 speed.

(b)       They are not VTOL, but STOL. Need short runway to take off. It’s classified as STOL,

(c)       Over speed will cause rotor blades flip over and cut its tail stabilizer.

(d)       Over speed might bend or break the auto-rotation  free swing gimble head.

(e)       Can not make reverse fly like helicopter.

(f)         Small payload, good for recreation only.

(g)      High noisy from high RPM speed propeller. blades pitch are no variable.

Technologies Breakthrough

World's First 3 Rotors Compound Gyro-Helicopter

It combines all  advanced features of common tail rotor helicopters and gyroplanes. 

Vertical take off and landing, fly faster beyond the speed limit of existing rotorcrafts !