Let me throw a few things into the mix. 1.) About compression and temperature. There isn't enough pressure to make a difference. The fan in the K3 is not running at 40 PSI, or even at 0.4 PSI. I would bet the static pressure is less than 0.1 inches of water (.0036 PSI). It takes a pretty big centrifugal blower to make .036 PSI (1 inch of water), and the heating from that pressure is negligible.
2.) We really don't want laminar flow across a heatsink. We want some turbulence so the air isn't stagnant along the fins. The AL600 and ALS1300 have deflectors that add turbulence because the fins are 6" long, straight, smooth, flat, and far from the fans. Adding deflectors to create turbulence almost doubled the cooling. I doubt this is the case with the K3. 3.) I would not blow hot air from a heatsink or high dissipation area into the more sensitive electronics, nor would I do anything the engineers at Elecraft didn't suggest or approve. Generally people designing air systems know far more about the systems than casual observers. If I wanted a cooler heatsink and was left to my own devices, I would change to a higher airflow fan of the same style. I can see all sorts of problems that might occur from reversing, and even a few from adding a "blow into the case" helper fan. The heatsink is probably warming the air with 150 watts of heat dissipation at times. I haven't looked at current drawn by the rest of the radio, but I doubt the other components in the radio dissipate 25 watts total. Why would I blow a 150 watt heater into a 25 watt heated area? It would make a whole lot more sense to draw the slightly heated air across the heatsink than bake the rest of the radio. 73 Tom ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
