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Q-talk 112 - Dual Pass Radiator

These drawings and pictures are based on a design by Joe Holland for a Subaru or Mazda rotary installation, about 200 HP max. The side flanges can be trimmed to mount as required and the core can be tilted into or away from the airflow (shown tilted into the flow as this allows more space for the exit). Joe designed this for a Mazda installation for Quickie. So far it has not been tried, but based on my 80HP radiator of similar design it should do the job very well.

The more common method to cooling is to follow the P51 Mustang setup using a tapered duct to a fairly thick core. It is a well proven method provided the duct dimensions produce the right pressure gradient, but that is not so easy to do. Getting back to the basics, we are looking for effective heat transfer from the core. In comparing the Mustang method with the Joe Holland setup, he designs for max unimpeded airflow, but the traditional/Mustang approach is to manage the intake to maximize air contact with the core by slowing the airflow as the ducting widens.

I tried this approach with the Quickie but finished up with a bulky looking pod under the belly. Instead, I happily accommodated the Holland core in the cowl under the engine.

You can order a printed copy of Q-talk #112 by using the Q-talk Back Issue Order Page.