nose bowl question

[N43617]

why would someone block the air inlet below my prop
my plane is running a little warmer than id like
my baffling doesn't look to bad
can't find detailed info on what that hole actually was designed for
any ideas appreciated
plane runs around town fine 180-190 to
on climbs to 3500' ill get up to 225 it seems to stabilize then cool on descent after 10 mi straight and level
but once it gets warm it doesn't seem like it takes much to warm back up

[Dick Smith]

Re: nose bowl question

The comment, below this paragraph, was lifted, shamelessly, from the BackCountryPilot website. I believe it was posted by Bill Berle. Reading it will give you an idea of how things work. Included at the bottom is a picture of the baffle(painted black) which channels the incoming air across the bottom of the crankcase. I would remove the cover plate/tape (or whatever covers your cowl opening) and note the changes in running temps compared to what you saw before. I have mine covered right now and with the cool weather, it's fine...especially since I have'nt been doing any sustained climbs. During typical AK winter wx, if you don't cover the opening, you will immediately see why it's done...everything is cold...the engine and you! Dick

Re: Baffling subject C85-12
The Continentals came with a soft aluminum baffle that was sandwiched between the intake spider and the bottom of the crankcase. It fits over the two long studs that mount the spider. This baffle forms a channel underneath the engine, where air (from a hole in the nose cowl underneath the crankshaft) flows along the bottom of the engine. This baffle is important and has a large effect on the oil temp.

The Continentals use the bottom of the case as the oil return path. It drips down the inside of the case, then runs along the bottom, and pours back into the oil tank. So the entire bottom of the crankcase on the Continentals is the primary oil cooling method. If you blow cool air on that aluminum crankcase, the oil transfers its heat into the aluminum, then the aluminum gets cooled. Result: lower oil temperature without the hoses and cost and complexity of a small oil radiator.

The problem is... this lower case baffle needs to seal against the sides of the crankcase so the air does not just squirt out the sides. So the edges of this baffle must fit tightly against the engine, and it is a weird shape because of the shape of the lower engine case. So you need to make sure that baffle is there, and then make sure it is sealed against the sides of the engine. THEN, you need to make sure this air passage is sealed to the front of the engine and the inside of the nose bowl. THEN you need to make sure there is a small "roof" section to this duct just in front of the engine case. Some airplanes have this upper duct, some don't. But putting the roof on the duct (so that air coming in from the dedicated oil cooling hole in the nose cowl cannot just come in and then go upward into the main upper cooling plenum chamber) is a sure way to lower the oil temp. If you need further explanation and/or photos, let me know. But right now, most of the country is not exactly having high oil temp problems

[astjp2]

Re: nose bowl question

The c-140 also has a baffle that goes around the kidney tank with a C-85 that used the air that flowed along the bottom of the case. Tim

[N43617]

Re: nose bowl question

thinking about cutting a hole in my bowl any thoughts

[astjp2]

Re: nose bowl question

Get with Dick Smith in Kenai, look at his, that may help you decide. If you dont have the baffling between the spider and the case, then its pointless to cut the hole. You would then disrupt the flow of air going over the cylinders because you would lose the low pressure below the engine....and get it even hotter. Airforms up in Wasilla has new baffling, that is also an option depending on your finances...

Do you have a mechanic that knows taylorcrafts? Most know cubs but few know taylorcrafts and they try to treat them the same but they are not even close.

If you want a taylorcraft knowledgeable mechanic in the Matsu valley, give me a shout. Tim

[astjp2]

Re: nose bowl question

Hey Dick, is that lower baffle on your engine now? I would love to get a good pattern to make a mold from. Tim

[Dick Smith]

Re: nose bowl question

thinking about cutting a hole in my bowl any thoughts

Don't cut anything yet...! Give me a call. Dick 398-6943

[Dick Smith]

Re: nose bowl question

Tim, The lower baffle is installed on the engine. Let me do some checking and ask around among the Tribe up here. Dick

[N43617]

Re: nose bowl question

thanks you guys hit the nail on the head here. I'm in a cub world as far as the knowledge and experience around me. Dick, ill call you tomorrow we live right down the street from each other.