The International Cessna^® 170 Association

I am getting ready to purchase a new system. It appears the sources are Wag-Aero and Hanlon Wilson. This is my first experience with this engine's exhaust system. I would like an understanding of what would be best. I plan to extend the exhaust pipes to preclude the staining as the paint job is new this year. Also, is AWI an acronym or is it the name of the vendor. If not, could I have the full name. Thanks for your time in helping me. Mike

AWI = Aerospace Welding, Inc.

https://awi-ami.com/cessna-aircraft-exh ... ms-by-make

Hanlon Wilson is the name of the manufacturer who made the original parts. I do not believe Hanlon Wilson is still in business and if they are that you could buy direct. The name Hanlon Wilson in many cases is used to identify the type of exhaust ie a Hanlon Wilson system vs "pancake" style exhaust on a 170. Hanlon Wilson made exhaust systems for many models of airplanes over the years.

Wag Aero is the parent name of a "Manufacturer and Distributor of Quality Aircraft Parts & Services". They make lots of parts, some under PMA, some not. A subsidiary of Wag, Aero Fabricators, makes exhaust parts and is a small part of Wags overall business. Wag, or Aero Fabricators might make Hanlon Wilson style exhaust parts under PMA.

AWI or Aerospace Welding, Inc. is a company that specializes in manufacturing aircraft exhaust components under PMA. Some of their components are of the Hanlon Wilson style. From what we've seen they do an exceptional job manufacturing parts and assembling systems.

PMA - Parts Manufacturing Authority, given by the FAA. With out a PMA, for the most part, one can't manufacture and sell aircraft parts. Having a PMA is often equated to the thinking the part will be exactly like the original. In some cases it often appears what some think to be exactly like original has a wide latitude.

I recommend AWI. I recently installed 2 new mufflers from AWI on my A-model replacing, what I assume to be, original Hanlon-Wilson mufflers purchased from John Benham years ago. They fit directly onto the exhaust risers without having to loosen them from the cylinders, which surprised me. Also a neighbor recently replaced his A-model pancake system with a complete AWI kit and the only issue he ran into was having to enlarge one tailpipe exit hole in the cowling.

I do not recommend the "extended tailpipes" from Wag-Aero. I purchased a set of these and they don't fit well at all. The geometry is all wrong.

What are you replacing?

I am doing an extensive restoration of a 1948. The engine is being done by Signature Engine in Cincinnati. Upon completion, it will get a new exhaust system. I am reluctant to get into the cowling but can do the metal work if absolutely required. I realize we are saying AWI is supporting the Association, but Wag-Aero doesn’t require cowling fabrication, other than allegiance why wouldn’t we buy the Wag-Aero product? Are there quality issues? Regarding extended tailpipe, Aircraft Spruce offers a bolt on. Any experience/thoughts regarding this tailpipe? Discussion welcome and appreciated. Thanks, Mike

Saw this on a T-6 at OSH 2015.

melcessna wrote:I am reluctant to get into the cowling but can do the metal work if absolutely required.

I completely understand. This is the reason I didn't install the Wag-Aero tailpipes, installing them would have required that both exit holes in the cowling be enlarged. I wasn't willing to do that.

As for the Spruce exhaust parts, I believe they are made by AWI.

melcessna wrote:I realize we are saying AWI is supporting the Association, but Wag-Aero doesn’t require cowling fabrication Thanks, Mike

Mike. no correct Hanlon Wilson system, including from AWI, should require any cowl work.

The correct system for your '48 is the system for a '52 170B model.

Now if you buy the incorrect Hanlon Wilson system meant for a later 172 from any source, then you will have to put bumps in the cowl as that system uses larger diameter mufflers.

As for the cowl exit holes, I wouldn't be surprised you might have to open them a pinch and you may have to do this no matter the source. One the cowlings are 70 years old and not pristine in shape and mounting. Second you are replacing system design, the pancake system, for which the original cowl holes where placed, for another completely different system in the Hanlon Wilson.

Thanks, I will chat with AWI. Very helpful!

If a new exhaust system is being installed and it appears the cowling tailpipe exits need to be altered.... FIRST INSPECT YOUR ENGINE MOUNTS.
If your Lord Mounts are old and have settled...OR if your dynafocal mount has been tweaked.... OR if your fiewall attachment has settled.... THAT could explain the problem and should be corrected first.