Winterization w/ STC'd cowl

[Bruce Fenstermacher]

What I was trying to suggest is that without modification take some sample temperatures of the sump. Then block the blast tubes. Note the rise in temperature on the gauge. Take samples at the same area of the sump and I would think you would see a rise in the sump temperatures if blocking the blast tubes is effective.
It would also interesting if any temperature rise would closely follow that of the gauge.

[mod cessna]

Install some of these. They are a Cessna part. I would not "live" with low oil temps and turn my engine into a ball of rust.

I bet you can't even get a 10F degree rise out of covering those blast tubes.

[jrenwick]

What I was trying to suggest is that without modification take some sample temperatures of the sump. Then block the blast tubes. Note the rise in temperature on the gauge. Take samples at the same area of the sump and I would think you would see a rise in the sump temperatures if blocking the blast tubes is effective.
It would also interesting if any temperature rise would closely follow that of the gauge.

Sorry, Bruce, I misunderstood where you were going with that. Corey already said that he can see a difference on his gauge, which has a probe mounted externally to the engine, on the oil filter. You might be right that the oil in the sump might not change much, because it holds the heat removed from the rest of the engine, and it has considerable thermal mass. But the point is that the oil we're sending into the engine is cooler with the blast tubes, so it's going to be more effective at cooling the bearings, etc. than without the tubes.

[Abe]

Install some of these. They are a Cessna part. I would not "live" with low oil temps and turn my engine into a ball of rust.

I've been interested in a Cessna winterization kit since I've owned 04D, but can't find where to find one and I've never seen the ones you show here...

Do you have a part number and a vendor? Because I've heard stories of the rust problems one can get into if you don't bring the oil up to temp...I use duck tape over the oil cooler inlet and both of the blast tubes ( I have a stock O-300) and I only get a minimal temp rise on my gauge. The other day the only way I could get an acceptable oil temp was to point the nose in the air and hold the AI at 70mph...It was cold out that day..13-degrees on the ground and 8-degrees at 8000'...I love flying in the winter here in NE Oregon, but I'm a bit hesitant to, due to the thought of creating more moisture than I can get rid of...

Thanks,

Bill

[Bruce Fenstermacher]

You might be right that the oil in the sump might not change much,......

Wouldn't if follow that if we are raising or cooling the oil at the temp probe to in order effect the overall temperature of the oil that the temperature in the sump would follow. If it doesn't then adjusting the blast from tubes is not an effective means to adjust the overall oil temperature other than to adjust the temperature probe point.

In this case we are interested in raising the oil temperature to boil off the condensed water. I'd think we would want that temperature rise in the sump and not just at the temperature probe.

I don't know the answer but as I said before my gut feeling is the overall oil temperature won't be effected as much as the temperature at the probe. John by your comment above you seem to have doubts as well.

What we need is a test. I think W has the perfect test conditions right now and I'll bet with all that methane monkey business he's into he's got an IR temperature gun. Further more he's got a 172 which is a nice tie-in to this 170 with the 172 cowl.

[rydfly]

So back to my original question regarding winterization with my cowl setup...

By the STC data instructions for my cowl, it comes from a Cessna 172 (C-model, I believe 1959-1060) with s/n36966-47746. My though is, wouldn't it be possible to utilize at least part of the winterization kit that was standard for that model of 172?

I've been looking through the online parts manual for pre-'63 172's and have found where winterization kits are described, but I can't determine from the text or pictures what the kit would look like for the 'C-model', or if one even existed. Is there something I'm not seeing here?

-Kennet

[n2582d]

By the STC data instructions for my cowl, it comes from a Cessna 172 (C-model, I believe 1959-1060) with s/n36966-47746.

I've been looking through the online parts manual for pre-'63 172's and have found where winterization kits are described, but I can't determine from the text or pictures what the kit would look like for the 'C-model', or if one even existed. Is there something I'm not seeing here?

-Kennet

Kennet,
Cessna led you astray in the way they index their parts manual. Look at the second page you copied. You circled "C --- 172 s/n 36966-47746" That "C" is not for the C model Cessna 172, it is for the "useable on code" column on the right side of the page. In this case it is for the Cessna 172A.

Then you said "C-model ...." That should be s/n 48735-49544. which was made in 1962. You went on to say, "... I believe 1959-1060 (sic) with s/n 36966-47746." Those years line up correctly with the serial numbers you listed but are for models earlier than the "C" model.

So, I believe you want the winterization kit shown for the C-172B (AK172-40) which would be usable on code "E" which covers both the 1961 and 1962 year models (172B and 172C). That plate (p/n 0552011-2) is made from gold-plated unobtainium for the price is $457 from Cessna.

[rydfly]

So, I believe you want the winterization kit shown for the C-172B (AK172-40) which would be usable on code "E" which covers both the 1961 and 1962 year models (172B and 172C). That plate (p/n 0552011-2) is made from gold-plated unobtainium for the price is $457 from Cessna.

I see what you mean regarding my error in assuming the "C" that I circled meant a 172C... but as I read it now, it would appear that I'm looking for parts to go with a 172A (matches my cowl from 172 s/n's 36966-47746)

...and, if I'm seeing the parts diagram correctly, the 172A kit would not help me anyway as it does not appear to have a plate to cover the square hole between the prop and the air filter screen. It appears only to restrict the openings to the cylinders, which wouldn't work for me since I have a belt-driven vacuum pump poking through one side.

(sigh)

[GAHorn]

[...I see what you mean regarding my error in assuming the "C" that I circled meant a 172C... but as I read it now, it would appear that I'm looking for parts to go with a 172A (matches my cowl from 172 s/n's 36966-47746)

...and, if I'm seeing the parts diagram correctly, the 172A kit would not help me anyway as it does not appear to have a plate to cover the square hole between the prop and the air filter screen. It appears only to restrict the openings to the cylinders, which wouldn't work for me since I have a belt-driven vacuum pump poking through one side.

(sigh)

When you first said "C" model, I thought you were talking about the 170-C...which was a straight-tailed 170. (Never marketed to the public, converted back to a round-tail and sold as a '56 170-B, I believe.)

The 172-A kit would be identical to the later 170-B kit, and you are mistaken about the oil sump baffle. It is depicted at the upper-right of the page.

The 175 winterizatin baffles are not appropriate for a 170 or a 172 due to the higher stance of the upper cowl of the geared GO-300 engine of a C-175.

RE: Oil temps: The blast tubes do indeed cool the oil at the oil inlet (where this engine's oil temps are supposed to be measured....not the sump. Sump temps are not specified for this engine,...although that appears to be the concern of those worried about internal rust.)
I submit that the oil sump temp is relatively unimportant (as this thread discusses it.) If the oil temp is elevated sufficiently during it's travels thru the engine, then most water (a by-product of combustion) will be vaporized and exit overboard thru the breather tube. The cold air introduced at the sump cooling opening below the prop hub, ordinarily chills the forward area of the sump and may encourage condensation at that point. A running engine will circulate that condensation and will re-heat it at the next travel through the engine. (Which is at the rate of 2-4 gallons per minute!)
Therefore I believe that installing an oil sump winterization baffle is adequate for most operators, and if your cylinder temps are not sub-normal the cylinder winterization baffles are unnecessary. (Operations sub-zero might require them, as might training flights wherein frequent periods of descents with low power are made. Otherwise, I believe this is a lot of imagined problems.)
I believe it is far better to change oil more frequently than it is to install unapproved and unproven baffles which might cause local hot-spots and engine damage. The damage from water condensation is easily addressed with oil changes and anyway, is a long-term-storage problem. A local hot-spot is a near-term failure problem.

Go to the Bar-B-Que supply house (Academy, etc.) and obtain a long-probe meat thermometer. They cost about $5. Next time you land, shut down and plunge that thing down your dipstick tube and see if it agrees with your cockpit gauge. I've done this many times and it is a simple and quick check of cockpit gauges as long as you perform the check immediately after shut-down.

One more thing: Relocation of the oil temp probe to the end of the (F&M Enterprises) oil filter adaptor does not change the way the blast tubes cool the oil. The oil travels thru the outer sheath of the adaptor similar to the original screen, where it is cooled before it passes the filter media. The probe measures the oil on it's path back into the inlet of the pump gears just as it does in the original set up.

[rydfly]

This is how I read it... am I still incorrect?

[GAHorn]

If you have the later "round" 172 cowl then your cowl is not original and may need seperate approval basis. None of the 170-B models were equipped with that cowl.
Is it possible your upper-cowl only was replaced? Do you still have the original lower cowl with the square hole? (That would have been a lot of work and then the square hole baffle should fit, right?)

[Bruce Fenstermacher]

George his very first post points out that he has a later 172 cowl and he has included pictures of his 170.

Kennet the area you circled in blue is your cowl and those are the winter plates. Off course you can't use the right one because of the vacuum pump. I would not use the left one without something on the right side.

But right in the middle of that page is your answer I think. If you look at the cowl that you circled the round inlet in blue you will see the exit baffle for the bottom of the cowl. Since all air entering the cowl must pass out the exit restricting the exit with this baffle or one like it is as good as blocking the inlet. Air can't get in if it then it can't get out and it then can't pass over the cylinders and through blast tubes.

[GAHorn]

George his very first post points out that he has a later 172 cowl and he has included pictures of his 170....

Yeah, that was prior to my last nap and on a previous page, so when I clicked on "new posts" it did not register with me.

It still appears he has the square hole and it shouldn't be a big deal to mfr a cover, as long as "approval basis" is not a concern. (In which case the entire cowl is also.)

According to my books this is the late 170-B and 1956 thru 1958 172 cowls. (Late '53 170B and 1956/57 cowls were the same.)

click to ENLARGE

And this is the 1959 172B cowls:

[W.J.Langholz]

I ran across this pic from last year, seemed to work fine

This is the hole up front it is not square on my 57 c-172 it is a 3x4. one guy told me and inspection plate from a rag plane pops right in there, I haven't tried that yet


Blast tube.....well I'll tell I don't know much about airplanes but I will tell you in the modern dairies they have this little 14 inch square chill plate that will cool 10,000 gal of milk from about 101F down to 36-38 degrees in less than 24 hours. Now to get a visual that is a little more than a semi load over that small plate. Now if I was gifted like my friend Miles he would get out his little ruler inside a ruler and start talking about pie squared and all that stuff......all I know is it works so I would think the blast tubes certainly would effect your oil temps.....besides I don't mind if my pie is squared as long as it comes with icecream


W.

[W.J.Langholz]

I dug this out and maybe it will help you also.
Here again it is a 1957 c-172

W.