Almost all car engines are water cooled. Water mixed with radiator fluid (= coolant) is pumped by the water pump (wow!) through the radiator. There it is cooled by the air passing over the fins, goes into passages in the engine where it absorbs engine heat, and then circulates back to the radiator to be cooled again. The thermostat - a flap that opens or closes to allow or block the flow of the coolant - keeps the engine temperature within the proper range. If the engine is cold the flap is closed so the coolant can't go to the radiator to be cooled. As the engine warms the thermostat's flap opens. Ta-da!
An air-cooled engine doesn't have any coolant or radiator. It has fins all over it which, because of their surface area, dissipate the engine's heat directly into the air as that air passes over the fins.
That's why motorcycles have dominated the air-cooled engine biz. Their engines are out in the open so the air can pass over them. Except that now even most motorcycle engines are water cooled and have radiators.
BMW is one of the few exceptions. My 2002 BMW motorcycle is air cooled, as are most BMW motorcycles.
All of that leads up to my question.
My air-cooled BMW has a temperature gauge on the "dash." It registers oil temp, but that's an accurate indicator of engine heat. (A water cooled engine's temp gauge measures water temp.) My motorcycle's temp gauge goes up as the engine warms and then stays within a very narrow range. On a 100-degree summer day it will register slightly higher than on a 50-degree "winter" morning, but the difference is minimal.
How does that work? Without a thermostat to control the flow of coolant, how does my motorcycle know it needs to be warmer until it reaches that optimal temperature range and then get no hotter?
We were thrilled the Cardinals made it into the playoffs. Nobody here expected them to win that game, never mind the next one. We're already giddy with success. Can they beat the Steelers? Who can say no, given the last two week's surprises?
Does size matter? And if it does, is bigger really better?
The standard assumption is that every church can and should be bigger. The field of church growth, with its seminars, books and gurus, assumes numerical growth is the sine quo non, the measure of success of a healthy church. Enlarge the facility, add a service, whatever is necessary to increase numbers. Authors write about pastors who shepherd a flock as oppossed to "ranchers" who administer an assembly sufficiently large so as to require several pastors. The assumption is that pastors can and should become ranchers. Those who don't - can't - serve ever growing congregations serve humbly (read: weakly), restricted by either their flock's limitations or their own.
I wanted to be a rancher. I enjoy administration, the challenges of creating and overseeing the infrastructure that keeps a sizeable organization functioning efficiently. And to be honest, being the pastor of a large and growing church is good for the ego. That's why pastors often ask each other, "How big is your church?" That question is a not-so-subtle bit of professional sparring, the questioner hoping to learn that his church is larger.
[My standard response to that question is, "Between three and four hundred." I smile on the inside, knowing that we're a lot closer to three than we are to four hundred.]
If occupied seats are any measure we had a good morning at Pathway, with several visitors. The preacher isn't happy with his morning's work, but since his sermon included a section on the critical nature of the Holy Spirit's ministry as the Word is preached he dare not complain too much.
While we want Pathway to grow, I've come to the place where I have no desire to be a rancher. Know why?
Because the people are the best part. Yes, administration is fun and challenging, but there comes a point where that activity comes at the expense of ministry to individuals. The pastor of a church of 3,000 people cannot interact with the joys and struggles of his people. He sees them on Sunday morning from 50 feet away as he preaches his sermon. He might shake their hand after the service but if he ran into them at the supermarket he'd be lucky to recognize them, never mind know the names of their kids. He can't know who is hurting, who is afraid, who is rejoicing.
I want to know their kids and their kids to know me. This morning I kneeled down and tickled 2-year old Brooke playing on the floor. She giggled freely because she knows me, she sees me every Sunday. She giggled and I did too.
I don't know how big is too big, don't have that number in my head. Maybe it's when Brooke wonders about the strange guy who just walked into the room. At that point I'll be disatisfied. Because I suspect that's the same point at which I will be separate from the lives of the people God has graciously given me to shepherd in his name.
FWIW
2 comments:
Re Oil Temp:
One of the things I learned in a series of classes I had to take on high pressure boiler maintenance and operation, is that water is one of the most efficient means of transporting and exchanging energy.
My speculation is that while motor oil is a good lubricant, it is probably much less suited for the task of exchanging heat. Therefore, any contact the oil (does your BMW have an oil cooler?) has with air temperature does not affect its measured temperature as much as it does water. Therefore, measured water coolant temp. is more drastically impacted by variances in air temperature passing through a radiator.
Also entering into play here is that an engine's water jacket is in contact with a MUCH larger surface area of the engine than is the lubrication system, making the water coolant more measurably responsive to engine and environmental conditions.
My two cents.... I bet an engineer somewhere is rolling his eyes at my gearhead answer.
Mike
Steelers? Try beating the Eagles first.
Now that we understand who we are playing, let us know the wager with Jason.
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