The International Cessna^® 170 Association

I just visited with Mr. Felds at AWI, Inc., in Minneapolis who has agreed to expand their manufacture of replacement exhaust parts for Cessna 170s.
Included in the expansion will be the exhaust shroud parts for the right side (cabin heater) for later serials, post 25372, PN 0550157-52, and the "shark mouth" adaptor, officially known as PN 0550157-53, and the inlet, PN 0713019-32.
These last items, Inlets and Adaptors, have been particularly difficult to locate as these airplanes age. They are not simple parts and everyone should appreciate AWI's willingness to develop and produce these hard-to-find parts.
Mr. Felds also will study the feasibility of producing the Adaptor Shields, PN 0550157-23 which seal the "shark mouth" adaptor to the muffler's inlet pipe.
With these parts soon available, hopefully we can begin to get some of our old worn parts off the airplanes and return our cabin heaters to full blown service!

These later improvements should help older pre-serial 25373 airplanes improve their cabin heat performance as well, when coupled with the later muffers, PN 0550157-32. This is a larger Hanlon-Wilson type muffler than the earlier models, and is capable of producing lots more heated air when the associated parts are installed. They may be installed on earlier airplanes by virtue/approval of the type certificate which allows them on all 3 model 170's.

AWI is Aerospace Welding Inc.,
12124 12th Ave. South
Burnsville, MN 55337

952-890-1511 or toll free, 800=597-4315
Website: http://www.awi-ami.com/prodexhaust.htm

George Does that mean that those of us who have pancake style mufflers will be able to switch to the Hanlon Wilson style using all new parts including new muffs?

You can already do that. The exhaust outfit in west virginia was selling complete H-W systems several years ago. Trouble was,they wanted about $1400. It's probably more like $1700 now ( or more) for the whole works--remember,you'll need muffs and everything.
In The 170 Book,there's an article about an exhaust shop that was thinking of investing in the necessary dies to stamp out new pancake mufflers. as far as I know,no one ever took the plunge,eh? I kinda like the pancake style,I wouldn't mind replacing mine with new units if I could get them. I really like the Swift exhaust system--3 straight pipes on each side. Man,they sound great! Got a mean snarly tone to them.

Eric

Yes, the type certificate allows all the 170's to use the Hanlon Wilsons.
I receive a call every once in a while from someone who "used to work for an exhaust manufacturer" and who plans to go into business for himself ......(This is an imaginary, generic version of each caller's story)....
Anyway, the idea is they want my input on going into production making pancakes.
I always try to support the idea, but the same thing always happens. They figure out before too long that only a few airplanes per year actually wish to repair their pancakes, (patch-ups, not complete replacements) and that to produce the pancakes and all the necessary accessories for them, due to the relatively few airplanes that use them, the even fewer that need them in any given period of time, and the even fewer than that who actually wish to obtain new systems or even a portion of a new system, ....is so small as to make it unprofitable except at exhorbitant (even for aviation) prices. The price to take an existing pancake system and completely overhaul it would approach $2500, and they don't think it's worth the effort, especially since the existing fleet can simply convert to HW's lots cheaper than that.
I agree with Eric. I think it'd be nice to have a simple system without mufflers that merely "Wyed" together with slip-fittings similar to the Navajo and Baron systems. A small sheet-metal oven a la Aeronca for carb heat, and a large one for cabin heat and fly on down the road. Sounds simple. It's not.
I'm told the cabin heat so designed would have inadequate output due to lack of surface area. It's hard to believe, but that's what they say. Then, on top of that , there's a push now to put noise restrictions on reciprocating propeller driven aircraft similar to the jets. Getting rid of the muffs on a certificated design might become an issue in the future.
Even if one were to go to the trouble, how many of you really are in a position to order a complete new system which involved a new STC, this year or next? Not enough to make it profitable. Full circle, again.