Bud Davidson
04-26-2017, 07:08 PM
FWIW: I am following closely these discussions. Learning a lot and applying to my Kitfox project ( 4-1200 ). I have noticed photos of planes with radiators hung in the open under the fuselage.
My last project had a Ford V6 engine using a Taurus radiator. Many assumed I had cooling problems. NEVER!! I followed 2 principles, that heat rises and it is necessary to PULL air through the radiator, not try to push air. Air will dam up on the radiator and flow around. Auto makers you will note pull the air out from behind with the fan.
My Ford was flown out of Deer Valley, AZ, and Lakeland , FL in the heat of summer. After a flight I never over heated even if sitting long periods after flight at an idle.
In AZ I was based at the Mogollon Airpark in Overgaard where it could be 5 degrees for a morning flight. I needed a flap but had none... mistake.
My Kitfox cowl has an opening in front with a flap to enhance warmup in cold weather and an exit downwind at least three times the front opening area. I strongly recommend at least a 3:1 relationship.
I am attaching pics.
I suggest the cowl for the radiator supplied by the kit supplier probably enhances cooling as well as reducing drag for the reasons I propose. I tried to convince auto conversion aircraft builders of this with little success. I do not expect Rotax drivers to be any easier to convince, but if your having heating problems with an uncowled radiator, I recommend you consider this.
Bud
My last project had a Ford V6 engine using a Taurus radiator. Many assumed I had cooling problems. NEVER!! I followed 2 principles, that heat rises and it is necessary to PULL air through the radiator, not try to push air. Air will dam up on the radiator and flow around. Auto makers you will note pull the air out from behind with the fan.
My Ford was flown out of Deer Valley, AZ, and Lakeland , FL in the heat of summer. After a flight I never over heated even if sitting long periods after flight at an idle.
In AZ I was based at the Mogollon Airpark in Overgaard where it could be 5 degrees for a morning flight. I needed a flap but had none... mistake.
My Kitfox cowl has an opening in front with a flap to enhance warmup in cold weather and an exit downwind at least three times the front opening area. I strongly recommend at least a 3:1 relationship.
I am attaching pics.
I suggest the cowl for the radiator supplied by the kit supplier probably enhances cooling as well as reducing drag for the reasons I propose. I tried to convince auto conversion aircraft builders of this with little success. I do not expect Rotax drivers to be any easier to convince, but if your having heating problems with an uncowled radiator, I recommend you consider this.
Bud