- Oct 18, 2003
- Saline Michigan
The big thing you have been missing is respect for folks who have actually done or know the stuff you have been so blithely dismissing. That we voluntarily try to help with understanding should be worthy of respect as well.I'll post my thoughts and see if anyone has a coherent response:
Full cooling flow at taxi/climb - most auto conversions struggle with cooling.
Lighter weight - every pound counts.
Reduce belt routing - having an alt and water pump would require an idler.
Will not last as long - easily fixed, assign a 1000 or 2000 hour replacement interval. Its only $170
Electric motor will stick out farther - might have a fitment issue, motor is taller than stock pulley.
Not done before in AC - extensive ground testing should give an indication of suitability. Swapping back is 30 minutes of work.
If I am missing something please let me know.. but I can't see a real downside.
An example comes to the fore here. You seem to think that ground cooling is a coolant flow issue.
Ground cooling of water cooled airplane engines has been problematic. I have never heard of a case where coolant flow changes mattered one iota. It is all about getting enough delta P across the radiator to drive air through the core with nothing but the prop at idle moving the air. The WWII V-12's all had very large thick radiator cores to get adequate cooling at flight speed and power for the level of waste heat from 1200 to 1700 hp engines at 300+ mph in cruise and at over 100 mph in climb) and then well designed expanding ducts to minimize drag for speed. On the ground, they had engine idle thrust which means they had a gentle breeze wafting - they basically ran with zero air flow through the rads until approaching takeoff speed. We do have the advantage in smaller engines of being able to run thinner radiator cores. Look up Ross' posts on radiators and cooling for how he SUCCESSFULLY solved water cooling for the EJ22 engine in an RV6 as well as how others have SUCCEEDED. With Ross' schemes, the idle level propwash has always given enough rad airflow to maintain temps against idle power heat rejection. With decent airflow, the underdrive pulleys will still move way more coolant than needed in all airplane modes, while greatly reducing accessory power use over stock in flight modes.
Could you stick electric cooling fans on the rad for ground cooling? Sure. Your airplane will be lighter and lower drag without it. WEIGHT IS THE ENEMY more than anything else in little airplanes, drag is #2 on the enemy list. Electric cooling fans are both more weight and more drag. A scheme that will ground cool without a fan is better on all counts.
I still have strong issues with the idea that an electric coolant pump is both effective and energy efficient in an airplane dutycycle. It may be viable in the airplane and that can have value over routing belts for one more accessory...
Once you go with an electric coolant pump, you must consider dual battery or dual alternator or both. But then running EFII, you probably should do at minimum one anyway. Bob Nuckoll's AeroElectric Connection should be required reading. Another guy who has SUCCESSFULLY done this stuff. His perspective on stuff breaking and being able to manage anyway should be mandatory...