The International Cessna 170 Association

Thanks Gene. Kind of sways us toward Gary's flat sheet being a repair. One thing for sure, it is another part I'll be looking closer at on '52 and prior to come to some conclusion what should be.

Bruce, you are in luck. I already bought my replacement baffle set from Airforms, but have not installed them yet. Here are some measurements and pics. If you need other measurements, let me know. The rivet rows for the ribs are spaced 4 1/8" apart with each row 2 3/16" from its side edge. (All measurements on centers.) The rivets in each row are spaced 1" apart with the first rivet in each row beginning 3/16" from the aft edge. (Note that each rib overhangs the aft edge about 3/32".) That first rivet in each row has a flush head and is driven the opposite direction of all the other rivets in the row. The others have universal heads. The ribs are 1/2" W x 1/4" H x 16 11/16" L with the forward end beveled about 20 deg and the aft end beveled about 45 deg. See the pics.

Gene, this is fantastic info and more than I imagined. could you venture a guess to the thickness of the sheet aluminum used? I know it is powder coated and hard to tell.

Always amused to see PMA replacement parts that don't look exactly like the original. I wonder if a PMA's 170 tail would be more square like a 180 than round as it is?

Those parts look nice.

Thanks

Bruce

Yeah, no kidding. Airforms does a nice job with those sets. Much nicer than the originals. I measured it at .045" including the "hammered" paint finishes on both sides of the sheet. I'll let you guess at the thickness of the paint finishes. The ribs are the same. Have fun with it!

Here are pictures of an Airforms center section of the inner cowl with support blocks I fabricated to prevent the cowl from wearing into the center section. The upper cowl hinge support angles started wearing into the brand new center section immediately uppon installation. Those angles had been wearing into the center section forever but I never understood what was causing it.

I finally determined the downward sweep of the upper cowl in flight causes downward force due to air loading. That downward force is what is wearing the cowl hinge angles against the inner cowl center section. Two Monadnock fasteners with round head scrwes were installed directly under the cowl hinge support angles with teflon blocks over the screw heads which bear against the angles keeping the cowling from touching the inner cowl center section. Safety wire is used to secure the teflon blocks to the Monadnock fasteners after the screws have been properly adjusted. This has totally solved the problem.

Bruce Fenstermacher wrote:Thanks Gene. Kind of sways us toward Gary's flat sheet being a repair. One thing for sure, it is another part I'll be looking closer at on '52 and prior to come to some conclusion what should be.

Bruce, I agree that mine is a repair. Someone in the last 65 years salvaged and repaired the front sheet metal piece that I pictured earlier and replaced the corrugated plate with a flat sheet of .032" aluminum.

About 6 hours give or take and I have practically a new center pressure cowl piece. Decided not to use original diamond corrugated skin material and to use .032 3003 H14 instead. Built it to the measurements Gene gave me of the Airforms piece and used the original engine mount piece with repaired legs the length that Gary and Steve confirmed. Unlike the Airforms I decided to install some anchor nuts for the baffle stops so they can be removed and the door removed without removing the cowl. There never where stops on the back as the Airforms has and unlike the front the back really can't come off with the dzus fasteners latched because of the vertical back of the baffle.