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RJohn15183@aol.com wrote:

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<<This is absolutely true.  It is also a very good reason to leave the thermostat in the engine... the idea that running without a thermostat will somehow result in lower temps is a great fallacy.>>

Huh? That's funny, all this time I thought the primary purpose of a thermostat was to maintain a *minimum* coolant temp?

<<It seems to me that regulating cooling via the use of cowl flaps is a much better approach. Size your cooling system (radiator, oil cooler, inlets, and outlets) for the highest demand situation (climb) and then restrict the airflow through the system as required via the cowl flap in other situations.>>

This approach is not sufficient for air cooled engines in production aircraft so why would anyone assume it would work any better for a liquid cooled engine? All the piston airframe manufactures sell "winterization kits". These are essentially sheet metal plates that cover about half of the cowl intakes and a portion of the oil cooler. Now for operators in Alaska these are a pretty good alternative because he will take off and land in cold temps. However, for your operator in Nebraska taking off in 0-degree F temps and flying to Sunny San Antonio where it will be 70 degrees F when he flies home the next day these "kits" are a pain in the patoot. This is not just some BS example as I live in Dallas and fly home to see family in Lincoln Nebraska at Christmas time.

<<  Ive discussed the cooling system of the 13B with a couple of guys on Paul"s list who do cooling system analysis for a living. Consensus opinion>>

Hmmmm, let me make sure I understand this. On the group where "If it's not good engineering it does not get posted" they are advocating replacing a simple, light weight, inexpensive, reliable thermostat with a system of hinged flaps (note 1) having sometimes complex linkages (note 2) running from the cockpit to the engine bay? Additionally, you are going to have to fabricate a winterization kit for your plane and then be faced with deciding weather or not to use it when flying from warm weather to cold weather and vice versa. Also, on my Velocity XL I will need about a 15-foot run of cowl flap control cable. This cable is usually pretty good diameter steel case cable. With the hinging, pushrods, flaps, cockpit lever arm and 15 foot of cable I would guess we have added 15 pounds to my plane. On a tractor call it a minimum of five pounds. By the way this stuff your adding to the plane is not free! This solution also increases (albeit minimally) cockpit workload. One last facto!

r,!

 building and installing this stuff is going to add oh, say, at least 6 weekends of build time to the project. (Note 1 again)

So, to sum up, we have made the plane more complex, more expensive, heavier, with a longer build time, while increasing pilot workload and it STILL does not work as well as the simple thermostat? We still need a "winterization kit" !

I just love "Good Engineering". :-)

#Note 1: For most homebuilts cowl flaps will have to be designed and scratch built
#Note 2: Ever check out the cowl flap system on a Cessna 337?

The evil, cynical one,
Rob Johnson

We all know your stupid attitude about engineers Rob. 

"I ain't one so they don't know shit."

If you want to fly around at five knots slower and get 5 MPG less mileage
have at it. It is a free country to be stupid in.

Paul Lamar
 
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