Thermatic® / Electric Fans
In 1971, belt-driven fans were the only option for automotive cooling. Searching for a more efficient method, Australian engineers Daryl Davies and Bill Craig created the Thermatic® / Electric Fan. Davies, Craig was formed to manufacture the new electric fans, and has since developed a comprehensive range, covering most makes of vehicles. Its innovation in electric cooling has now become a standard feature on most of the world's new cars.
A Davies, Craig Fan is suitable for both condenser and radiator cooling and provides constant air flow, increased fuel economy, better air conditioning performance, cooler engine running, and increased engine power. Our fans are fully reversible blades and polarity for mounting either side of the heat exchanger. (Except 11" & 14" Brushless Fans)
All Davies, Craig Thermatic® / Electric Fans are packaged with fan assembly (motor, fan blade, shroud and mounting feet). Fan fitting / mounting hardware sold separately. (See below)
When a fan leaves our factory it is set up for upstream applications. For downstream applications the fan blade must be removed and turned over, always check that the fan blade rotates in the direction shown by the arrows on the blade before making a permanent wiring connection.
Davies Craig backs the quality of its fans with an unprecedented 2 Year Manufacturer Warranty
THERMATIC® / ELECTRIC FAN RANGE
UNIVERSAL FAN FITTING KIT (SOLD SEPARATELY]
The Davies, Craig Universal Fan Fitting Kit includes all parts necessary for mounting and wiring any 12- and 24-volt electric fans
– all Davies, Craig Thermatic® Fans and other electric fan models.
What size Thermatic® Fan do I need?
If your car make is not listed in our Model Selection Guide (see the Davies, Craig website, www.daviescraig.com.au/catalogues) we suggest the following:
- Measure your radiator core dimensions (width, depth and clearance - refer diagram below) and refer to “Fan Models” to check which fan/s will fit your core.
- Davies Craig Thermatic® Fans are reversible (Ex: Brushless models) which means they can be mounted upstream or downstream, as illustrated below.
- In general, one large fan will have better airflow than two smaller fans. Where radiator is rectangular there may be no choice but to fit two smaller fans; choose the largest that can be accommodated in space available. The fan can also be mounted offset from centre to clear engine components when mounted in the downstream position.
Note: Fans should not be fitted on opposite sides of radiator core unless these are offset such that the airflow of one is not interfering with the airflow of the other.
- If you require advice, please contact Davies, Craig for assistance.
Fan Mounting Direction
BENEFITS OF A DAVIES CRAIG THERMATIC® FAN
As a primary cooling source electric fans provide:
- Economical replacement for failed original equipment.
- 5-10% increase in engine power and fuel saving when replacing fan clutch and fan assemblies
- Reversible blades for pusher (upstream) or puller (downstream) applications
- Compatibility with all electric fan controls
- Coverage for a wide variety of applications
As an add-on cooling source electric fans provide:
- Constant air flow regardless of vehicle speed constant air flow across the condenser
- Increased air conditioning performance due to constant air flow across the condenser
- With the conversion from R12 to R-134A refrigerant there is a need for additional condenser cooling to ensure the overall improved efficiency of the cooling system
- Increased fuel economy All of our electric fans kits are packaged complete with instructions and mounting hardware for quick and easy installation
CAUSES OF OVERHEATING IN ORDER OF LIKELIHOOD
- Fan facing wrong direction.
- Fan rotating wrong direction.
- Fan wired to coil or alternator (only 8 Volts.)
- No condenser fan.
- Temperature gauge faulty - disagrees with thermometer in radiator.
- Towing a heavy caravan.
- Inadequate kit fitted.
- Oil cooler obstructing ram air.
- Insect screen obstructing ram air.
- Driving lights obstructing ram air.
- Number plate obstructing race air.
- Battery not up to 13 Volts.
- Insufficient water in radiator.
- Radiator need5.cleaning.
- Radiator cap faulty allowing water to boil at 100°C.
- Thermostat faulty.
- Electric motor faulty.
- Fan not in hot corner of radiator.
- Engine out of tune or idling too fast.
Straight vs. Curved Fan Blades - Dispelling the Myth!
The relative merits and technology of curved vs. straight fan blades, has been debated for some time. Davies, Craig conducted an extensive research program to formulate the design of fans in which several design types including curved blades with and without a ring were considered. Curved blades generated less noise but at the expense of a significant loss in performance caused by the fact that curved blades stall at a lower static pressure than straight blades. If a fan moves less air, then, simply you can expect less noise. As shown in the performance curves below, Davies, Craig Thermatic Fan outperforms its competitor across the full pressure range:
Noise Control: Most fan noise is generated from a blade passing a shroud strut. The noise level is higher when the whole length of a blade overlaps/passes a shroud strut and if all the blades pass all the struts of a shroud at the same time, NOISE IS AT ITS WORST. Some manufacturers have chosen to curve the blades and keep the struts straight. Since this approach significantly affects performance, Davies, Craig has proven it's best to adopt the reverse approach of having straight blades and curving the struts.
Our investigations also found that when air flowed in layers (laminar flow), it breaks up into counter rotating airflow vortices (whirlwinds): Figure 2
These vortices consume energy and therefore reduce the airflow. It was found that by inserting triangular protrusions near the leading edge of the blade, the air is tripped into going into vortices earlier but they were much smaller and removed much less energy therefore making the blade more efficient (Figure 3).
The idea of a ring around the blade tips was also researched and rejected since the performance suffered due to the increased energy required to propel the blade with the extra weight at the tips. While the purpose of a ring is to reduce losses from air passing from the high-pressure side of the blade to the low-pressure side as shown, Davies, Craig managed to achieve this by adding winglets to the blade tips without energy loss.
When all aspects of blade design are considered, straight blades with trips, winglets and the correct shroud is the optimum, test-proven combination for efficient fan operation.