It looks big but its very light and hollow. It takes air moving towards the rear and forces it through the motor. Fans have a limited pressure they can work with so depending on the ventilation through the motor there is a vent to relieve pressure to keep the fan at optimal pressure. Significant air moves diagonally from the top front of the motor to the rear back of the motor. Hot air exits the chassis from underneath and the passenger side of the motor to keep the rotor bearing temperatures down.

Better pictures with an easier color to see.

I run this shroud all the time now. I run 5 minute races and pull the car off at 153. Same everything without the shroud was 168.Yea, Thermistors are in the motor instead of measuring from the outside so my temps are very accurate.. This is a winner and has probably 10 races in.

This is an adaption of the air cooling systems you find on servo motors. Its a hybrid Axial/Radial fan to stay within rules and still use pressure through the motor. The trick is to get the air moving through the motor and out the bottom and front and still circulate air around the outside of the can. These fans are sensitive to pressure so if there is too much pressure you get very little flow. You adjust pressure and flow by using the wide slit in the front of the fanshroud. The slit allows you to adjust the pressure by ear to keep the flow high (if the motor screams you blocked too much of the slit). Depending on the amount of holes in the can and front of the motor and flow obstructions through the motor the slit is used to tune the flow. For example once you assemble it block off the slit and fan speed will skyrocket. This is too much pressure and the fan cavitates. Block half of the slit and the rpms remain constant. This means you are under the pressure limit of the fan and will have max flow and pressure. This is the best fan setup ive used. The front flange of the motor and bulkheads conduct heat very quickly because they are metal. There is so much air flowing through the motor the bulkheads are staying much cooler which means more acceleration and prolonged bearing life.

a tricky part of the design is the OD interference with the top plate and sealing the wires that run through the shroud. If i were to guess i would say this is the area that has to change for different chassis but maybe not if the top deck heights are about the same center distance from the rotor.

it has come off in 1 of 10 crashes but a piece of tape solved that. I’ll eventually get a crash clamp designed in but its not really necessary.. At some point i will also run a duct from the pressure zone on the windshield to the inlet of the fan to see if clean air helps.

this is also done in pla which is temperature sensitive. There has been 0 problems with deformation.

Im not sure if it will fit anything but an awesomatix with a trinity monster but my son would probably ebay these if someone was interested. Adding timing is possible if you believe in that but I dont need nor can I use more motor. In fact I should probably take more heat out of the motor. Im not getting beat in the straights with my 21.5.

all of my motors are stock class and the shroud fits. including the new fixed timing usgt.

Its looks like this duct fits 36mm cans without an issue. I havent had interference with any top decks on about 5 cars like the 419, express, tc7. It rotates around the can. I ended the duct on the backside in a way that you have probably 10 degrees of rotation to clear the top deck.

Wow, that’s a lot of great info. Great to know more about how to get the most out of these fans!