Moore Fans LLC Class 5000 Series 49 Engine Drive

Class 5000 fans are specifically designed for heat exchanger and cooling tower service and other efficiency-critical applications. They may be specified as original equipment or for replacement of existing obsolete or inefficient fans. Class 5000 fans are available in eight hub sizes (series) in fan diameters from 3 ft (.91 M) to 16 ft (4.9 M) of all aluminum construction.

CLASS 5000 FANS FEATURES

• INDIVIDUALLY BALANCED BLADES: Blades are balanced to astandard moment making them freely interchangeable between fans of the same series and diameter, even between manual or automatic units.
• ODD OR EVEN NUMBERS OF BLADES: Because blades are individually balanced, the exact number may be selected to provide the correct blade surface for the required performance, avoiding the inefficiency and additional cost of excess blades.
• ADJUSTABLE FAN DIAMETER: Minimizing the clearance between the tips of the blades and the fan ring is essential if a fan is to operate efficiently and satisfy the performance requirements of the installation. Most Moore hubs provide a means of increasing or decreasing the fan diameter by as much as1-1/2" (38 mm) an important feature in "fitting" the fan precisely to an existing ring.
• IDEAL FOR VARIABLE SPEED DRIVES: Varying fan speed is the mostefficient means of modifying air flow. Because of the dynamics ofthe resilient blade mounting, fan resonance are virtually eliminated, ideally suiting Moore fans for use with variable speed drives. There are no critical speeds to be avoided.
• RESILIENT BLADE MOUNTING: Like the blades of a helicopter, Moore fan blades are attached to the hub by a pivot. In operation, centrifugal force causes the blades to rise to their working position. The pivot itself is surrounded by a vibration-absorbing resilient material. Two of the major advantages of this designare:

1. Compared to fans with rigidly mounted blades, only 1/4 to 1/2 of the stresses caused by the air load are transmitted to the hub and drive, substantially increasing the life of the fan driving mechanism.
2. Resonant frequencies are virtually eliminated.

• LOW WEIGHT - LOW COST - LOW INERTIA: The stressed-skin construction of the jig-formed aluminum blade produces a very rigid, yet light weight member. Light weight reduces material costs and installation costs. One man can easily carry two Moore blades. The all-aluminum hub is more easily installed than steel hubs. Low weight also results in lower inertia, reducing the possibility of damage to the fan and drive during sudden stops.
• MANUAL OR AUTOMATIC: Hubs with either manual or automatic blade adjustment are standard (except Series 19 and 27) complete with QD bushings. Remote actuators are also available. Upon air failure, blades can revert to either last position, maximum pitch or minimum pitch.
• LOW NOISE: As part of Moore's ongoing noise research, fans can be provided with substantially reduce fan noise levels. Blade-end winglets (patent pending) may be provided to reduce the fan noise level by as much as 3 dB.
• UNIFORM VELOCITY FROM HUB TO TIP: Uniform velocity over the entire blade area is the most important criteria of efficient axial flow fan design. To produce a uniform velocity throughout its length, a fan blade must vary from a thin, narrow tip to a thick, cambered root. Each point on the blade must have the proper combination of chord (blade width) and angle. This results in a great deal of twist in a properly designed blade, a shape impossible to produce by extrusion. Moore fan blades are jig-formed to provide the complex contour needed for high aerodynamic efficiency.

Class 5000 fans are specifically designed for heat exchanger and cooling tower service and other efficiency-critical applications. They may be specified as original equipment or for replacement of existing obsolete or inefficient fans. Class 5000 fans are available in eight hub sizes (series) in fan diameters from 3 ft (.91 M) to 16 ft (4.9 M) of all aluminum construction.

CLASS 5000 FANS FEATURES

• INDIVIDUALLY BALANCED BLADES: Blades are balanced to astandard moment making them freely interchangeable between fans of the same series and diameter, even between manual or automatic units.
• ODD OR EVEN NUMBERS OF BLADES: Because blades are individually balanced, the exact number may be selected to provide the correct blade surface for the required performance, avoiding the inefficiency and additional cost of excess blades.
• ADJUSTABLE FAN DIAMETER: Minimizing the clearance between the tips of the blades and the fan ring is essential if a fan is to operate efficiently and satisfy the performance requirements of the installation. Most Moore hubs provide a means of increasing or decreasing the fan diameter by as much as1-1/2" (38 mm) an important feature in "fitting" the fan precisely to an existing ring.
• IDEAL FOR VARIABLE SPEED DRIVES: Varying fan speed is the mostefficient means of modifying air flow. Because of the dynamics ofthe resilient blade mounting, fan resonance are virtually eliminated, ideally suiting Moore fans for use with variable speed drives. There are no critical speeds to be avoided.
• RESILIENT BLADE MOUNTING: Like the blades of a helicopter, Moore fan blades are attached to the hub by a pivot. In operation, centrifugal force causes the blades to rise to their working position. The pivot itself is surrounded by a vibration-absorbing resilient material. Two of the major advantages of this designare:

1. Compared to fans with rigidly mounted blades, only 1/4 to 1/2 of the stresses caused by the air load are transmitted to the hub and drive, substantially increasing the life of the fan driving mechanism.
2. Resonant frequencies are virtually eliminated.

• LOW WEIGHT - LOW COST - LOW INERTIA: The stressed-skin construction of the jig-formed aluminum blade produces a very rigid, yet light weight member. Light weight reduces material costs and installation costs. One man can easily carry two Moore blades. The all-aluminum hub is more easily installed than steel hubs. Low weight also results in lower inertia, reducing the possibility of damage to the fan and drive during sudden stops.
• MANUAL OR AUTOMATIC: Hubs with either manual or automatic blade adjustment are standard (except Series 19 and 27) complete with QD bushings. Remote actuators are also available. Upon air failure, blades can revert to either last position, maximum pitch or minimum pitch.
• LOW NOISE: As part of Moore's ongoing noise research, fans can be provided with substantially reduce fan noise levels. Blade-end winglets (patent pending) may be provided to reduce the fan noise level by as much as 3 dB.
• UNIFORM VELOCITY FROM HUB TO TIP: Uniform velocity over the entire blade area is the most important criteria of efficient axial flow fan design. To produce a uniform velocity throughout its length, a fan blade must vary from a thin, narrow tip to a thick, cambered root. Each point on the blade must have the proper combination of chord (blade width) and angle. This results in a great deal of twist in a properly designed blade, a shape impossible to produce by extrusion. Moore fan blades are jig-formed to provide the complex contour needed for high aerodynamic efficiency.

Class 5000 fans are specifically designed for heat exchanger and cooling tower service and other efficiency-critical applications. They may be specified as original equipment or for replacement of existing obsolete or inefficient fans. Class 5000 fans are available in eight hub sizes (series) in fan diameters from 3 ft (.91 M) to 16 ft (4.9 M) of all aluminum construction.

CLASS 5000 FANS FEATURES

• INDIVIDUALLY BALANCED BLADES: Blades are balanced to astandard moment making them freely interchangeable between fans of the same series and diameter, even between manual or automatic units.
• ODD OR EVEN NUMBERS OF BLADES: Because blades are individually balanced, the exact number may be selected to provide the correct blade surface for the required performance, avoiding the inefficiency and additional cost of excess blades.
• ADJUSTABLE FAN DIAMETER: Minimizing the clearance between the tips of the blades and the fan ring is essential if a fan is to operate efficiently and satisfy the performance requirements of the installation. Most Moore hubs provide a means of increasing or decreasing the fan diameter by as much as1-1/2" (38 mm) an important feature in "fitting" the fan precisely to an existing ring.
• IDEAL FOR VARIABLE SPEED DRIVES: Varying fan speed is the mostefficient means of modifying air flow. Because of the dynamics ofthe resilient blade mounting, fan resonance are virtually eliminated, ideally suiting Moore fans for use with variable speed drives. There are no critical speeds to be avoided.
• RESILIENT BLADE MOUNTING: Like the blades of a helicopter, Moore fan blades are attached to the hub by a pivot. In operation, centrifugal force causes the blades to rise to their working position. The pivot itself is surrounded by a vibration-absorbing resilient material. Two of the major advantages of this designare:

1. Compared to fans with rigidly mounted blades, only 1/4 to 1/2 of the stresses caused by the air load are transmitted to the hub and drive, substantially increasing the life of the fan driving mechanism.
2. Resonant frequencies are virtually eliminated.

• LOW WEIGHT - LOW COST - LOW INERTIA: The stressed-skin construction of the jig-formed aluminum blade produces a very rigid, yet light weight member. Light weight reduces material costs and installation costs. One man can easily carry two Moore blades. The all-aluminum hub is more easily installed than steel hubs. Low weight also results in lower inertia, reducing the possibility of damage to the fan and drive during sudden stops.
• MANUAL OR AUTOMATIC: Hubs with either manual or automatic blade adjustment are standard (except Series 19 and 27) complete with QD bushings. Remote actuators are also available. Upon air failure, blades can revert to either last position, maximum pitch or minimum pitch.
• LOW NOISE: As part of Moore's ongoing noise research, fans can be provided with substantially reduce fan noise levels. Blade-end winglets (patent pending) may be provided to reduce the fan noise level by as much as 3 dB.
• UNIFORM VELOCITY FROM HUB TO TIP: Uniform velocity over the entire blade area is the most important criteria of efficient axial flow fan design. To produce a uniform velocity throughout its length, a fan blade must vary from a thin, narrow tip to a thick, cambered root. Each point on the blade must have the proper combination of chord (blade width) and angle. This results in a great deal of twist in a properly designed blade, a shape impossible to produce by extrusion. Moore fan blades are jig-formed to provide the complex contour needed for high aerodynamic efficiency.

Class 5000 fans are specifically designed for heat exchanger and cooling tower service and other efficiency-critical applications. They may be specified as original equipment or for replacement of existing obsolete or inefficient fans. Class 5000 fans are available in eight hub sizes (series) in fan diameters from 3 ft (.91 M) to 16 ft (4.9 M) of all aluminum construction.

CLASS 5000 FANS FEATURES

• INDIVIDUALLY BALANCED BLADES: Blades are balanced to astandard moment making them freely interchangeable between fans of the same series and diameter, even between manual or automatic units.
• ODD OR EVEN NUMBERS OF BLADES: Because blades are individually balanced, the exact number may be selected to provide the correct blade surface for the required performance, avoiding the inefficiency and additional cost of excess blades.
• ADJUSTABLE FAN DIAMETER: Minimizing the clearance between the tips of the blades and the fan ring is essential if a fan is to operate efficiently and satisfy the performance requirements of the installation. Most Moore hubs provide a means of increasing or decreasing the fan diameter by as much as1-1/2" (38 mm) an important feature in "fitting" the fan precisely to an existing ring.
• IDEAL FOR VARIABLE SPEED DRIVES: Varying fan speed is the mostefficient means of modifying air flow. Because of the dynamics ofthe resilient blade mounting, fan resonance are virtually eliminated, ideally suiting Moore fans for use with variable speed drives. There are no critical speeds to be avoided.
• RESILIENT BLADE MOUNTING: Like the blades of a helicopter, Moore fan blades are attached to the hub by a pivot. In operation, centrifugal force causes the blades to rise to their working position. The pivot itself is surrounded by a vibration-absorbing resilient material. Two of the major advantages of this designare:

1. Compared to fans with rigidly mounted blades, only 1/4 to 1/2 of the stresses caused by the air load are transmitted to the hub and drive, substantially increasing the life of the fan driving mechanism.
2. Resonant frequencies are virtually eliminated.

• LOW WEIGHT - LOW COST - LOW INERTIA: The stressed-skin construction of the jig-formed aluminum blade produces a very rigid, yet light weight member. Light weight reduces material costs and installation costs. One man can easily carry two Moore blades. The all-aluminum hub is more easily installed than steel hubs. Low weight also results in lower inertia, reducing the possibility of damage to the fan and drive during sudden stops.
• MANUAL OR AUTOMATIC: Hubs with either manual or automatic blade adjustment are standard (except Series 19 and 27) complete with QD bushings. Remote actuators are also available. Upon air failure, blades can revert to either last position, maximum pitch or minimum pitch.
• LOW NOISE: As part of Moore's ongoing noise research, fans can be provided with substantially reduce fan noise levels. Blade-end winglets (patent pending) may be provided to reduce the fan noise level by as much as 3 dB.
• UNIFORM VELOCITY FROM HUB TO TIP: Uniform velocity over the entire blade area is the most important criteria of efficient axial flow fan design. To produce a uniform velocity throughout its length, a fan blade must vary from a thin, narrow tip to a thick, cambered root. Each point on the blade must have the proper combination of chord (blade width) and angle. This results in a great deal of twist in a properly designed blade, a shape impossible to produce by extrusion. Moore fan blades are jig-formed to provide the complex contour needed for high aerodynamic efficiency.

Class 5000 fans are specifically designed for heat exchanger and cooling tower service and other efficiency-critical applications. They may be specified as original equipment or for replacement of existing obsolete or inefficient fans. Class 5000 fans are available in eight hub sizes (series) in fan diameters from 3 ft (.91 M) to 16 ft (4.9 M) of all aluminum construction.

CLASS 5000 FANS FEATURES

• INDIVIDUALLY BALANCED BLADES: Blades are balanced to astandard moment making them freely interchangeable between fans of the same series and diameter, even between manual or automatic units.
• ODD OR EVEN NUMBERS OF BLADES: Because blades are individually balanced, the exact number may be selected to provide the correct blade surface for the required performance, avoiding the inefficiency and additional cost of excess blades.
• ADJUSTABLE FAN DIAMETER: Minimizing the clearance between the tips of the blades and the fan ring is essential if a fan is to operate efficiently and satisfy the performance requirements of the installation. Most Moore hubs provide a means of increasing or decreasing the fan diameter by as much as1-1/2" (38 mm) an important feature in "fitting" the fan precisely to an existing ring.
• IDEAL FOR VARIABLE SPEED DRIVES: Varying fan speed is the mostefficient means of modifying air flow. Because of the dynamics ofthe resilient blade mounting, fan resonance are virtually eliminated, ideally suiting Moore fans for use with variable speed drives. There are no critical speeds to be avoided.
• RESILIENT BLADE MOUNTING: Like the blades of a helicopter, Moore fan blades are attached to the hub by a pivot. In operation, centrifugal force causes the blades to rise to their working position. The pivot itself is surrounded by a vibration-absorbing resilient material. Two of the major advantages of this designare:

1. Compared to fans with rigidly mounted blades, only 1/4 to 1/2 of the stresses caused by the air load are transmitted to the hub and drive, substantially increasing the life of the fan driving mechanism.
2. Resonant frequencies are virtually eliminated.

• LOW WEIGHT - LOW COST - LOW INERTIA: The stressed-skin construction of the jig-formed aluminum blade produces a very rigid, yet light weight member. Light weight reduces material costs and installation costs. One man can easily carry two Moore blades. The all-aluminum hub is more easily installed than steel hubs. Low weight also results in lower inertia, reducing the possibility of damage to the fan and drive during sudden stops.
• MANUAL OR AUTOMATIC: Hubs with either manual or automatic blade adjustment are standard (except Series 19 and 27) complete with QD bushings. Remote actuators are also available. Upon air failure, blades can revert to either last position, maximum pitch or minimum pitch.
• LOW NOISE: As part of Moore's ongoing noise research, fans can be provided with substantially reduce fan noise levels. Blade-end winglets (patent pending) may be provided to reduce the fan noise level by as much as 3 dB.
• UNIFORM VELOCITY FROM HUB TO TIP: Uniform velocity over the entire blade area is the most important criteria of efficient axial flow fan design. To produce a uniform velocity throughout its length, a fan blade must vary from a thin, narrow tip to a thick, cambered root. Each point on the blade must have the proper combination of chord (blade width) and angle. This results in a great deal of twist in a properly designed blade, a shape impossible to produce by extrusion. Moore fan blades are jig-formed to provide the complex contour needed for high aerodynamic efficiency.

Class 5000 fans are specifically designed for heat exchanger and cooling tower service and other efficiency-critical applications. They may be specified as original equipment or for replacement of existing obsolete or inefficient fans. Class 5000 fans are available in eight hub sizes (series) in fan diameters from 3 ft (.91 M) to 16 ft (4.9 M) of all aluminum construction.

CLASS 5000 FANS FEATURES

• INDIVIDUALLY BALANCED BLADES: Blades are balanced to astandard moment making them freely interchangeable between fans of the same series and diameter, even between manual or automatic units.
• ODD OR EVEN NUMBERS OF BLADES: Because blades are individually balanced, the exact number may be selected to provide the correct blade surface for the required performance, avoiding the inefficiency and additional cost of excess blades.
• ADJUSTABLE FAN DIAMETER: Minimizing the clearance between the tips of the blades and the fan ring is essential if a fan is to operate efficiently and satisfy the performance requirements of the installation. Most Moore hubs provide a means of increasing or decreasing the fan diameter by as much as1-1/2" (38 mm) an important feature in "fitting" the fan precisely to an existing ring.
• IDEAL FOR VARIABLE SPEED DRIVES: Varying fan speed is the mostefficient means of modifying air flow. Because of the dynamics ofthe resilient blade mounting, fan resonance are virtually eliminated, ideally suiting Moore fans for use with variable speed drives. There are no critical speeds to be avoided.
• RESILIENT BLADE MOUNTING: Like the blades of a helicopter, Moore fan blades are attached to the hub by a pivot. In operation, centrifugal force causes the blades to rise to their working position. The pivot itself is surrounded by a vibration-absorbing resilient material. Two of the major advantages of this designare:

1. Compared to fans with rigidly mounted blades, only 1/4 to 1/2 of the stresses caused by the air load are transmitted to the hub and drive, substantially increasing the life of the fan driving mechanism.
2. Resonant frequencies are virtually eliminated.

• LOW WEIGHT - LOW COST - LOW INERTIA: The stressed-skin construction of the jig-formed aluminum blade produces a very rigid, yet light weight member. Light weight reduces material costs and installation costs. One man can easily carry two Moore blades. The all-aluminum hub is more easily installed than steel hubs. Low weight also results in lower inertia, reducing the possibility of damage to the fan and drive during sudden stops.
• MANUAL OR AUTOMATIC: Hubs with either manual or automatic blade adjustment are standard (except Series 19 and 27) complete with QD bushings. Remote actuators are also available. Upon air failure, blades can revert to either last position, maximum pitch or minimum pitch.
• LOW NOISE: As part of Moore's ongoing noise research, fans can be provided with substantially reduce fan noise levels. Blade-end winglets (patent pending) may be provided to reduce the fan noise level by as much as 3 dB.
• UNIFORM VELOCITY FROM HUB TO TIP: Uniform velocity over the entire blade area is the most important criteria of efficient axial flow fan design. To produce a uniform velocity throughout its length, a fan blade must vary from a thin, narrow tip to a thick, cambered root. Each point on the blade must have the proper combination of chord (blade width) and angle. This results in a great deal of twist in a properly designed blade, a shape impossible to produce by extrusion. Moore fan blades are jig-formed to provide the complex contour needed for high aerodynamic efficiency.

Class 5000 fans are specifically designed for heat exchanger and cooling tower service and other efficiency-critical applications. They may be specified as original equipment or for replacement of existing obsolete or inefficient fans. Class 5000 fans are available in eight hub sizes (series) in fan diameters from 3 ft (.91 M) to 16 ft (4.9 M) of all aluminum construction.

CLASS 5000 FANS FEATURES

• INDIVIDUALLY BALANCED BLADES: Blades are balanced to astandard moment making them freely interchangeable between fans of the same series and diameter, even between manual or automatic units.
• ODD OR EVEN NUMBERS OF BLADES: Because blades are individually balanced, the exact number may be selected to provide the correct blade surface for the required performance, avoiding the inefficiency and additional cost of excess blades.
• ADJUSTABLE FAN DIAMETER: Minimizing the clearance between the tips of the blades and the fan ring is essential if a fan is to operate efficiently and satisfy the performance requirements of the installation. Most Moore hubs provide a means of increasing or decreasing the fan diameter by as much as1-1/2" (38 mm) an important feature in "fitting" the fan precisely to an existing ring.
• IDEAL FOR VARIABLE SPEED DRIVES: Varying fan speed is the mostefficient means of modifying air flow. Because of the dynamics ofthe resilient blade mounting, fan resonance are virtually eliminated, ideally suiting Moore fans for use with variable speed drives. There are no critical speeds to be avoided.
• RESILIENT BLADE MOUNTING: Like the blades of a helicopter, Moore fan blades are attached to the hub by a pivot. In operation, centrifugal force causes the blades to rise to their working position. The pivot itself is surrounded by a vibration-absorbing resilient material. Two of the major advantages of this designare:

1. Compared to fans with rigidly mounted blades, only 1/4 to 1/2 of the stresses caused by the air load are transmitted to the hub and drive, substantially increasing the life of the fan driving mechanism.
2. Resonant frequencies are virtually eliminated.

• LOW WEIGHT - LOW COST - LOW INERTIA: The stressed-skin construction of the jig-formed aluminum blade produces a very rigid, yet light weight member. Light weight reduces material costs and installation costs. One man can easily carry two Moore blades. The all-aluminum hub is more easily installed than steel hubs. Low weight also results in lower inertia, reducing the possibility of damage to the fan and drive during sudden stops.
• MANUAL OR AUTOMATIC: Hubs with either manual or automatic blade adjustment are standard (except Series 19 and 27) complete with QD bushings. Remote actuators are also available. Upon air failure, blades can revert to either last position, maximum pitch or minimum pitch.
• LOW NOISE: As part of Moore's ongoing noise research, fans can be provided with substantially reduce fan noise levels. Blade-end winglets (patent pending) may be provided to reduce the fan noise level by as much as 3 dB.
• UNIFORM VELOCITY FROM HUB TO TIP: Uniform velocity over the entire blade area is the most important criteria of efficient axial flow fan design. To produce a uniform velocity throughout its length, a fan blade must vary from a thin, narrow tip to a thick, cambered root. Each point on the blade must have the proper combination of chord (blade width) and angle. This results in a great deal of twist in a properly designed blade, a shape impossible to produce by extrusion. Moore fan blades are jig-formed to provide the complex contour needed for high aerodynamic efficiency.

Class 5000 fans are specifically designed for heat exchanger and cooling tower service and other efficiency-critical applications. They may be specified as original equipment or for replacement of existing obsolete or inefficient fans. Class 5000 fans are available in eight hub sizes (series) in fan diameters from 3 ft (.91 M) to 16 ft (4.9 M) of all aluminum construction.

CLASS 5000 FANS FEATURES

• INDIVIDUALLY BALANCED BLADES: Blades are balanced to astandard moment making them freely interchangeable between fans of the same series and diameter, even between manual or automatic units.
• ODD OR EVEN NUMBERS OF BLADES: Because blades are individually balanced, the exact number may be selected to provide the correct blade surface for the required performance, avoiding the inefficiency and additional cost of excess blades.
• ADJUSTABLE FAN DIAMETER: Minimizing the clearance between the tips of the blades and the fan ring is essential if a fan is to operate efficiently and satisfy the performance requirements of the installation. Most Moore hubs provide a means of increasing or decreasing the fan diameter by as much as1-1/2" (38 mm) an important feature in "fitting" the fan precisely to an existing ring.
• IDEAL FOR VARIABLE SPEED DRIVES: Varying fan speed is the mostefficient means of modifying air flow. Because of the dynamics ofthe resilient blade mounting, fan resonance are virtually eliminated, ideally suiting Moore fans for use with variable speed drives. There are no critical speeds to be avoided.
• RESILIENT BLADE MOUNTING: Like the blades of a helicopter, Moore fan blades are attached to the hub by a pivot. In operation, centrifugal force causes the blades to rise to their working position. The pivot itself is surrounded by a vibration-absorbing resilient material. Two of the major advantages of this designare:

1. Compared to fans with rigidly mounted blades, only 1/4 to 1/2 of the stresses caused by the air load are transmitted to the hub and drive, substantially increasing the life of the fan driving mechanism.
2. Resonant frequencies are virtually eliminated.

• LOW WEIGHT - LOW COST - LOW INERTIA: The stressed-skin construction of the jig-formed aluminum blade produces a very rigid, yet light weight member. Light weight reduces material costs and installation costs. One man can easily carry two Moore blades. The all-aluminum hub is more easily installed than steel hubs. Low weight also results in lower inertia, reducing the possibility of damage to the fan and drive during sudden stops.
• MANUAL OR AUTOMATIC: Hubs with either manual or automatic blade adjustment are standard (except Series 19 and 27) complete with QD bushings. Remote actuators are also available. Upon air failure, blades can revert to either last position, maximum pitch or minimum pitch.
• LOW NOISE: As part of Moore's ongoing noise research, fans can be provided with substantially reduce fan noise levels. Blade-end winglets (patent pending) may be provided to reduce the fan noise level by as much as 3 dB.
• UNIFORM VELOCITY FROM HUB TO TIP: Uniform velocity over the entire blade area is the most important criteria of efficient axial flow fan design. To produce a uniform velocity throughout its length, a fan blade must vary from a thin, narrow tip to a thick, cambered root. Each point on the blade must have the proper combination of chord (blade width) and angle. This results in a great deal of twist in a properly designed blade, a shape impossible to produce by extrusion. Moore fan blades are jig-formed to provide the complex contour needed for high aerodynamic efficiency.