(1)
The single rotor design
This is
the most common helicopter design that has a main and a small tail rotor, made
famous by Sikorsky & Bell by selling thousands to the U.S. Government.
(2)
The coaxial design
This
design has two rotors mounted one on top the other on a single axis and
rotating in opposite directions. Both Peter
Papadakos of the U.S., and Kamov Design Bureau of Russia perfected this design
primarily for military applications. Russian Kamov KA-50 was produced as a
counter force for the U.S. Apache with this design.
(3)
The tandem twin rotor design
This
design also has two rotors, one in the front and one in the rear of the
aircraft. This designed was pursued by Frank Piasecki and finally purchased by
and made famous by the Boeing
Aircraft Company.
(4)
The side-by-side twin rotor design
This
design also has two rotors arranged side-by-side and V-12 was built
in early Russia. Not much is known what happened to
the aircraft but many similar aircraft seemed to have been designed around the
concept.
(5)
The
intermeshing rotor design
This
design utilizes two intermeshing rotors, one located on each side of the
aircraft. Charlie Kaman of Kamax Corporation, USA, was the pioneer for this design. His aerial trucks have been sold around the world.
Advantages
of the YOSHINE Coaxial Configuration
YOSHINE EZYCOPTER incorporates the best features for a small coaxial design with
distinct engineering innovations as described below:
1. Ultimate Compactness:
The
EZYCOPTER presents the ultimate in compactness and demonstrates its capability
in operating with a high payload while requiring a minimum amount of power.
Under the same payload condition, the EZYCOPTER is smaller and lighter than
either a single rotor or tandem rotor configuration. This reduces,
significantly, the amount of space required for vehicle storage and permits
operations from anywhere where there is a small takeoff and landing area
available.
2.
Higher
Useful Load:
With
the absence of a tail rotor, the EZYCOPTER allows all of its engine power to
be used by the coaxial rotor system for lifting purposes. Therefore, in
comparison with a tail rotor configuration, the useful load of the EZYCOPTER
is higher, with a similar power rating. Also the lower weight of the coaxial design and
the less power loss due to shorter shaft power transmission provide the
EZYCOPTER a higher
useful load advantage over the tandem or any other multi-rotor configuration.
3. Safer VTOL
Characteristics:
In
cross winds, or on a rolling pitching takeoff, or when landing, the control of
the EZYCOPTER is much easier due to the following:
(a)
The
inherent torque neutralization characteristics of the single coaxial rotor
system eliminate dangerous inertia and torque and cross wind effects during
takeoff and landing;
(b)
The
use of the collective and the cyclic makes precision flight controls possible;
(c)
The
use of the correlation between the throttle and the collective makes automatic
flight
control
easier and safer.
4. Lower Empty Weight:
The
design of the fuselage is strictly functional and independent of the lifting
system. Accordingly, it can be made smaller in size than other designs resulting in
lower fuselage weight:
Consider
other weight savings:
(a)
The
weight of the coaxial transmission system for a given horsepower is lighter
than the total weight of the two or more transmission systems utilized in
either the anti-torque tail rotor or tandem rotor configurations;
(b)
The
total blade area of the coaxial rotor is essentially equal to the blade areas
of the main rotor of a comparable single rotor. The area is more when compared
to other multi-rotor high-disk loading systems.
(c)
The total combined weight of the fuselage, transmission, and rotor system of
the coaxial rotor helicopter is lower than that of a tail rotor configuration
with an equivalent power source, yet substantially lower than that of the
tandem or other multi-rotor configurations.
5. Complete Symmetrical Rotor System:
The
symmetry of the EZYCOPTER
coaxial rotor system permits the same aerodynamic efficiency and control for
flight in any direction; a feature found only in true coaxial helicopters with
precision collective and cyclic controls.
6. Freedom from control
cross-coupling:
Control
cross coupling exists in all other rotor configurations, causing control
complexity and unexpected vibration. Lack of control cross coupling in the
EZYCOPTER coaxial helicopter yields the following advantages:
(a)
Only
ONE control is required for transnational flight along any axis;
(b)
Control
along each axis is powerful, symmetrical, and unaffected by the controls along
the other axes;
(c)
Comparable
transitional accelerations in all directions are obtainable;
(d)
Precision
handling ability with excellent control; even under adverse cross wind conditions and;
(e)
Exact
and excellent hovering positioning is excellent due to the symmetry of the
coaxial rotor system.
7. Lower Manufacturing
Cost:
The
EZYCOPTER coaxial has an
advantage over the other configurations because of its lower empty weight; the
following two features further amplify this advantage:
(a)
The
symmetry of the rotor system and the transmission reduces approximately by one
half the number of critical individual components as compared to single rotor
configuration;
(b)
The
freedom of torque reactions of the fuselage allows for simpler fuselage
structural design.
8. Optimal Transmission
Design:
In
a coaxial configuration, the inherent feature of splitting the power input
into two paths results in a transmission design internally balanced, compact
and capable of handling greater horsepower per engine input than other
configurations. This design is naturally suited for multi-engine inputs
without creating external torque reaction problems.
This
unique feature of the coaxial transmission achieves greater significance as
the size of engines can be increased as required.
9. Modular Construction:
The
torque-free coaxial rotor system eliminates torque reactions to the fuselage,
making the fuselage independent from the rotor-transmission-engine
combination.
And
in the case of the EZYCOPTER, all four controls - longitudinal and lateral
cyclic controls, collective and directional yaw controls - are fully
independent and wholly incorporated into the lifting mechanism.
This
feature makes it possible to consider the engine, transmission, rotors, and
their controls as a major subassembly package, yielding the following
advantages:
(a)
Design
and Manufacturing Flexibility
(b)
Lower
Structural Weight
(c) Growth
Potential
(d) Modular
Construction
10. Growth Potential
This
is an area that the coaxial helicopter promises the most. As stated above, the
fuselage of the coaxial system is purely functional and independent to the
lifting system. Therefore, an increase in size of one of the major
subassemblies does not affect the other. The coaxial transmission is suited,
naturally, for multi-engine operations, as stated previously, without creating
external torque reaction problems.
Also,
there is, only, a small weight increase per additional engine. This feature
permits various other helicopter designs to be considered when using the
YOSHINE coaxial transmission system and without any major modifications or
associated costs. It is believed that this unique feature will encourage many
helicopter enthusiasts to seek out the YOSHINE Coaxial Design System as a
component part of their own helicopter development program.
11. Reduction &
Elimination of Common Helicopter Flight Hazards
The
U.S. Department of Transportation has published a “Basic Helicopter
Handbook”. One of the chapters in it is titled, “Some Hazards of
Helicopter Flight”. Ten items of hazards have been listed to indicate that a
typical single rotor helicopter has to deal with. The unique EZYCOPTER
coaxial design either reduces or eliminates these hazards:
The
following list indicates which:
