Winterization w/ STC'd cowl

[GAHorn]

I was wondering if anybody had a winter kit for a 48 or pictures for one. As for temps here in Indiana I think we are now stuck in the teens and I need to do something other than duct tape.
Thanks, Aaron

The kit for the '48 ragwing is exactly the same as that for the A-model and early B. (See pg 101 of your IPC.)

[GAHorn]

While on the subject of early/late winterization kits, be advised that an old Service News Letter (SNL-72) dated 1-18-50 was issued by Cessna correcting an error in the last few pages of the aircraft Operators Manuals for the 1950 and prior aircraft.

Te 1948-1950 Operation Manual contained illustrations of the winterization kit with the plates behind the cowl grille installed on the outboard sides of the cowl opening in front of the cylinders. That was wrong. The plates are to be installed on the inboard ends of the openings.

Small, gummed pictures were made available to owners and dealers to be pasted into the manuals over the incorrect illustrations.

[hilltop170]

Yep, you're right, George. Cessna must have had some of those corrected Operation Manuals left over into 1951 because I have one of those that came with my '51 A-model, always wondered about it but it's glued too tight to look under the patch to see the differences.

Looking thru the options, where did the passenger's feet go with the ambulance installation for a patient over 5' tall? Another option was a small Southwind gasoline-fired heater attached to the firewall at the heat valve. I bet the pilot's left foot got REALLY hot with that one! The last option was a pneumatic tail wheel. Guess what George, the chains are just taut/springs not stretched with the weight on the tail. Also, the back two pages have pictures of the C-140 and C-195. Kinda fun to look thru the original Operation Manual again.

[GAHorn]

Yeah, it's fun to re-discover ....or discover....(as the case may be), all the documentation and info provided over the years.

Another interesting SNL is that the factory specifically warned about using C-190/195 elevators on the early 170's. They admitted they were made on the same jig, but gave stern warnings about substitutions based upon counterweighted 190/195 elevators versus non-weighted 170's. They warn about flutter due to the difference.

Another is about a tool-mark on late 170-B and early 172 aircraft, right wing, rear spars. Cessna provided a doubler and paid 100% of the labor* to add the doubler to prevent future-cracking of that spar.

*- The SNL required addition of a lower-skin inspection hole and cover and hole-coubler and tinnermans....and the rivetting of the doubler onto the lower angle of the aft spar...and the factory would pay the ENTIRE expense by shipping the doubler no-charge and paying the huge sum of $3 (three dollars) for all the labor! That's how Del probably got so rich!

[Bruce Fenstermacher]

Looking at the Service Information Summary page 6-8:

Date 11-11-60 S.L. 170/172-25 A new winterization kit has been prepaired which is considerably different fro winterizations kits previoulsy used. This kit consists of a baffle which covers the opening at the lower rear of the engine cowl, thereby reducing the amount of cooling air which can pass through the cowl. This kit, AK172-40 is available from the Cessna Part Department, priced at $17.50

Is this not a service letter covering a 170?

If so it would be an approval to use this kit on a 170 or even a 170 with a later 172 cowl. This would be a solution to this or another airplane with the vacuum pump mounted in the front cowl opening.

[GAHorn]

Technically anytime an STC is installed, the installer and/or operator/owner must determine how the STC is affected/affects other airworthiness matters and/or installation.

The front-mount vacuum pump STC must either accomodate the existing winterization kit... or it must provide an alternative kit...or a new kit and basis of approval must be found.

[mit]

Oh for Pete's sake! George..... sigh The Congress is suppose to follow the Constitution too.

[Bruce Fenstermacher]

...or a new kit and basis of approval must be found.

This kit and basis of approval must be found by the aircraft owner. On initial reading I thought George was saying the STC producer needed to find this. (I had composed a lengthy and eloquent reply to George,..... then I reread his post. )

[GAHorn]

Oh for Pete's sake! George..... sigh The Congress is suppose to follow the Constitution too.

Technically anytime an STC is installed, the installer and/or operator/owner must determine how the STC is affected/affects other airworthiness matters and/or installation.

The front-mount vacuum pump STC must either accomodate the existing winterization kit... or it must provide an alternative kit...or a new kit and basis of approval must be found.

In case anyone is confused about my post.... My point is that the front-mount vacuum pump STC does NOT have to accomodate the standard winterization kit. It also means that the standard Cessna winterization kit was not intended for use with the front vacuum pump ... and the owner of the aircraft will have to find a basis of approval to use one with the other.

(Taking a standard winterization kit and whacking it up to fit around that pump is not an authorized alteration. Sorry...but neither is duct tape.)

To put all this in perspective... which would be the more legal method of dealing with oil temps in cold weather.... duct tape and/or whacked up/Ad Hoc "winterization kits".... or more frequent oil changes?

[hilltop170]

I made the mistake of installing the Cessna blanking plate winterization kit on my C-180 many years ago. The riv-nuts work ok for awhile but eventually lose their grip and spin-out which makes them useless. Nut plates would have been a better attach hardware but many of the screw holes in the plates are in areas with compound curves in the cowl and not condusive to nut plates. I have not seen a good solution to this.

I now use duct tape whenever I need to restrict cooling air to the engine. It is installed for the ambient conditions and removed immediately after the flight while the engine is still hot and the tape adhesive is still soft. It comes off with no residue and will not affect the next flight which might very well be in different conditions. If left to get cold and harden, duct tape can be very difficult to remove.

As far as being legal, it's an owner produced part duplicating the function of the Cessna Service Kit. No STC involved.

[GAHorn]

...As far as being legal, it's an owner produced part duplicating the function of the Cessna Service Kit. No STC involved.

Purely in the interest of argument for argument's-sake: Since when does substitution of materials (tape for metal) and change of attachment methods (adhesive instead of clips and fasteners) meet the duplication-criteria for "owner produced" parts? That would be like using aluminum foil to make mufflers and heaters.

[Bruce Fenstermacher]

I use aluminum to make mufflers and heaters all the time. No big deal.

Actually the Duct Tape method was approved in the 1001 things you can do with duct tape book.

[hilltop170]

...As far as being legal, it's an owner produced part duplicating the function of the Cessna Service Kit. No STC involved.

Purely in the interest of argument for argument's-sake: Since when does substitution of materials (tape for metal) and change of attachment methods (adhesive instead of clips and fasteners) meet the duplication-criteria for "owner produced" parts? That would be like using aluminum foil to make mufflers and heaters.

Merry Christmas George!!! I was wondering how long it was going to take you to reply to that one. OK, how about this then, it's temporarily installed equipment not permanently attached to the airplane, like your GPS mount.

In all seriousness, I have never heard of the feds EVER questioning anyone using duct tape for a winterization kit. The pilot is obviously going to be watching the CHTs and if he got too agressive with the tape, he'll land and take off a couple of strips.

On the other hand, some air taxis do not use any winterization kits at all on their 206s and 185s in Alaska and they fly down to -40F and sometimes below. Their contention is as long as power is kept in the green, CHT will be high enough no matter what the OAT. They have the experience to show it works. They also never pull the power out of the green until the last second, no prolonged power-off descents. Add full flaps on downwind and hold power to the ground.

I have found that the plane does just fine with duct tape down to the temp where I'm not willing to fly anyway, below minus 10F. Anything less than that and things stop working like they should. If you have an emergency and you just sprain an ankle, it could be fatal. Not worth it anymore in my book.

[GAHorn]

Ha! "Loose Equipment!" Now THAT is a definition we can all live with!

...I have found that the plane does just fine with duct down to the temp where I'm not willing to fly anyway, below -10F. Anything less than that and things stop working like they should. If you have an emergency and you just sprain an ankle, it could be fatal. Not worth it anymore in my book.

Those are wise words! (And something we all are probably guilty of ignoring.) Even a springtime flight over forested hills can result in death by exposure. How many times have we flown in shirt-sleeves with not so much as a bottle of water, a jacket, blanket, or a serious First Aid Kit aboard?

[rydfly]

Okay, since I opened this can of worms a month ago feel obligated to give an update...

I experimented with some aluminum tape by just covering the square hole in the cowl to keep the airflow off the oil pan. At 20-deg OAT, my operating oil temp stabilized in the 140-150 degree range. That's a lot better than what I had.

Now to pursue a more permanent and FAA-pleasing way to continue cold-weather operation...