Overhaul time-so we are upgrading the c85 to c90 , my AP/IA says we need a cowl bottom doubler P/N 0452208 or equivalent. Have not able to identify this in our illustrated parts catalog. Anyone out there know what this is ,where we can find one or sketch to fabricate one. We are converting the exhuast system as well to the Hanlon-Wilson system , however no mention of this doubler in the STC. AP picked this up in the specs for c-90. Thanks for any info that someone has.
I believe there are three things you need. Change prop, add the doubler and a blast tube for the oil sender. The doubler may refer to the the summer kit? I do not have my parts book here so can't look up the number. I have a C90 in mine but will most likely change to the 0200 at time of major. As for the mufflers there is no mention on the Aircraft Certification A-768. Read note 5 it explains items needed. Aircraft Cert can be found in the library on this site under aircraft docs.
Bob
I am pretty sure that you can change to the c-9012f without much changing at all.You would keep the same engine mount and not have to change the cowl. You could keep the same prop as long as it could be pitched to maintain the proper static rpm. The c-90 12f is just like the c-8512f as far as outside size goes, and the engine mounts are the same. The thing I have been looking at is the advantages of the c-90. Most us fly around turning around 2300-2400 rpm most of the time. With the 0200 you get 75hp at 2400 rpm. With the c-85 you get about 70hp at 2400 rpm. With the c-90 you get about 82 hp at 2400 rpm. I think the c-90 is most likely the best engine to go with for our airplanes. The main difference between the c-90 and the 0200 is the cam. the cid is the same, the crank is the same, the pistons and cylinders are the same. I hope to someday put a c-90 in mine. JMO The c-9014f is like the 0200 mount.
I think the doubler they are referring to is a doubler that reinforces the air cleaner opening. Without the doubler a crack will appear if the skin is single layer. Most cowls have already had this doubler installed. As Don says the blast tube is important, also.
Thanks for the info coming in regarding my quest for help on this doubler conern, We have the blast tube ,it was already installed so we are good there, our lower cowling does have doubler installed around the opening for the aircleaner. It also has a second doubler installed ,from the lower edge of the aircleaner opening doubler, 6 inches by 12 inches . Looking at 1947 140 with c-90 with two openings for exhasut pipes there are doublers around each opening and doubler around the aircleaner opening but does not have the doubler in the center below the aircleaner opening as ours does. Interesting
Keep the thoughts coming, they are very helpful.We will get this resolved yet eyecrazy
Carl, So If we put the 0200 crank ,rods, pistons and a C-90 cam in our C-85's we would have the best of all worlds?? I wonder if anybody has STC'ed this??
John Warren wrote:
Carl, So If we put the 0200 crank ,rods, pistons and a C-90 cam in our C-85's we would have the best of all worlds?? I wonder if anybody has STC'ed this??
John
I think from what I have been able to learn, that the c-9012f engine, or the c-8512f with the 0200 crank stc would be very close in power. The c-90 has a somewhat stronger case from what I can find out but with the stc on the c-85 (0200 crank) you put in some through bolts that make the c-85 case stronger than it was. The cams on the two are made different, Forged vs cast. I have learned most of this from studying the Overhaul manual.
Bob,
The "doubler" your're looking for is in the parts book, I do not have my parts book here. However I'm fairly certain I've seen it in there. This part is actually a little "lip" that extends down into the airstream on the bottom of your cowling where the air exits after passing over and down through your engine area. If you can find an 0-200 powered c120/140 most of them have it. Look at almost any C-170 and they have a fairly large one. Kinda of a "crescent moon" shaped thing. Fits right in the air exit on the bottom of the cowling. What I've found is that on a 47 and later you need a bigger lip than on a 46 cowling since a 46 extends downwards into the air stream more than later model cowlings. Marty Lochman, our Sec/Treas. was kind enough to provide me with a pattern for mine when I needed to make one. (since at the time there were none available) I'll be happy to send it to you if you are unable to locate one for sale.
The joys of older airplanes. In the TC (type cert)it lists p/n 0452208 or equivelant, allowing you to make one.
It's spelled out in the TC what you need for different engines, and in my STC for the 0-200 I had to put this "lip (doubler)" on. (and change engine mount)
I'm pretty sure you will need another engine mount for your C-90. Depends on the (-) designation. A -14 will need it, since it uses the same mounts as the 0-200. This moves your engine back an inch. Other wise it will protrude into the cowling in the front. The engine TC will state what the diff's are between (-) engines.
P/N for the new engine mount is 0451111, it is note 5 of the TC.
Carl Webster wrote:
Bob
With the 0200 you get 75hp at 2400 rpm. With the c-85 you get about 70hp at 2400 rpm. With the c-90 you get about 82 hp at 2400 rpm. I think the c-90 is most likely the best engine to go with for our airplanes.
We have been trying to work the thrust HP equation for a C-90. We agree that a C-90 is best for a 140. Is the 82 HP you mention a C-90 with a 71/52 prop? Is that static thrust HP?
Could we use a 71/54 to get the reasonable 80 static thrust HP at an even lower RPM? Please let us know. tia, Don
Thanks for any info that someone has.
Thanks for the info coming in regarding my quest for help on this doubler conern, We have the blast tube ,it was already installed 
so we are good there, our lower cowling does have doubler installed around the opening for the aircleaner. It also has a second doubler installed ,from the lower edge of the aircleaner opening doubler, 6 inches by 12 inches . Looking at 1947 140 with c-90 with two openings for exhasut pipes there are doublers around each opening and doubler around the aircleaner opening but does not have the doubler in the center below the aircleaner opening as ours does. Interesting 
