Monty Roberts wrote:

Hello all,

Here is the cooling concept that I have been working on for an EZ type aircraft. This particular model is a Vari, but Herb has talked me out of building a Vari. He suggests a Long EZ. This Idea will work for any canard. The primary goals here are to minimize the base drag, and minimize cooling drag. This is a problem with all of the canard designs. By reducing the abrupt cross section change on the aft end of the fuselage, I hope to reduce the base drag substantially. I also have done away with the large fairings needed to clear the cylinders on an opposed 4 cyl aircraft engine. To minimize cooling drag I have elected to use the conventional snorkel type scoop, in order to get the maximum pressure recovery. The radiator will be arranged in an oblique manner with a streamline diffuser as per Kucheman and Webber. After the air passes through the radiator, it goes into an exhaust driven ejector. This further heats and energizes the air. It then is passed out the rear of the cra!

ft through a nozzle for maximum energy recovery. Cowl flaps will be used to increase the exit area of the nozzle as needed. To reduce the drag of the scoop further, I plan to take the engine intake air from the boundary bleed area between the fuselage bottom and the top of the scoop. This is not shown in this model. The P-51 had the cabin air intake in this area.

Note that this is only a rough conceptual model. I have made sure that the engine, mount and radiator will fit. I did not spend much time making sure that all the surfaces faired out true or all of the fillets were done properly. This model was done in about 6 hours. The big advantage is now I can play around with the placement of components etc.and refine the design before I start to build. When I get the cowl like I like it, I will plot some templates and cut them out of foam, then knock the edges down and glass the cowl. Isn't 3D great!

Monty Roberts
RMI
1795 Berry St.
Fayetteville, AR 72701
tmrbrts@swbell.net

 
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