oldtrucksrule wrote:So, I have a '48 with a C-145-2 with the "new" exhaust ie, not the pancake. Anyway, the aircraft left, pilot side, seems to hang a couple inches shorter than the other side. It's barely, I mean barely, clears the cowling. I purchased it from AWI so, I assume they sent the correct part. What are your thoughts?
Thanks, Cory
I only quoted the “originating” post to introduce addt’l comments:
There are significant differences between the “Original” or “Straight” Cessna 170 (also unfairly/diminutively known as the “Ragwing”) …and the 170-A…. and Versus the 170-B (which is further split into at least two groups based upon cabin-ventilation differences that occurred about the “1953” year-model ….(and which is further complicated by the FAA system of year-model registrations VS actual Design Year Model differences.) This latter situation is a significant example of why aircraft SERIAL numbers are important when discussing actual differences and when identifying Part Numbers.
The 170 and the 170-A, when first mfr’d, used the so-called “Pancake” style of mufflers/exhausts. This system is NOT interchangeable with the later “Hanlon-Wilson” mufflers/exhausts…. and further, based upon 170-B airframe serial number….the Right-Hand side exhaust changed further when the cabin-ventilation/heating system was modified/improved about 1953.
Further complicating this issue is the introduction in late 1955/56 of the C-172 which outwardly appears to mimic the late 170-B… but makes a subtle change of exhaust design almost immediately with the 172-B and continuing for several years until the mid-to-late 1960s. (An example of this is the “studded mufflers” of the 170s versus the “smooth” mufflers of the 172 series….with the accompanying “bent” versus the “straight” tailpipes. (This creates a complication when hodge-pod “data-plate re-builds” are found that may mix parts of fuselages of 170s with firewall-forward of 172s. Until repair parts are needed some owners can remain unaware of the modifications their airplane may have undergone in a prior life.)
This becomes a real problem for owners of Cessna 170, 170-A, and 170-B aircraft that have undergone alterations that may pass completely unnoticed and in many cases UN-recorded…. which used cowlings, engines, and ventilation/heating components “borrowed” from airframes of different/later Serial Numbers.
The most obvious change occurred with the switch from Pancake to H-W mufflers. (And BEWARE…. It is not unheard of to see an early 170/170-A with one Pancake and one H-W muffer…. different designs on each-side which is NOT approved.)
When the early Pancake system is found to be un-repairable the simplest solution is to convert the entire exhaust system to the HW system…..and when that conversion occurs the 170/170-A engine installations require that TWO LEFT-HAND mufflers be installed from the early HW system.
When THIS DISCUSSION-THREAD popped-up the first thing I thought of was that a botched conversion may have occurred in the airframes’ past that utilized a mis-match of tailpipes….or utilized a “customized” tailpipe system that does not conform to approved systems. Of course, it’s also possible that verbally-ordeing replacement parts that did not directly refer to applicable part numbers of approved conversions may have resulted in the incorrect parts being shipped/installed.
Then, of course, unlikely tho’ it might be, it’s possible a packaging/shipping error has occurred….or even more unlikely a mfr’g error.
Using the following illustration….when converting from a Pancake system to HW… Two LEFT HAND mufflers are used on all 170/170-A models prior to Serial Number 25373….later serials will utilize the differently designed RH Muffler. (Notice the different RH muffler has large “Rings” moulded into it’s ends to accommodate the post-1953 cabin heating system.) Notice also the “bent” tailpipes.
- Hanlon-Wilson System for all 170s thru early 172-A aircraft.
In the 70-plus years since the 170 was introduced many of the airplanes (if not ALL of them) have “borrowed” parts/designs from later models and from the very different 172 model aircraft. To the untrained eye they may sit on the ramp and appear to be the same aircraft…but they are actually very different. The following illustration is the 172 system which is sometimes found to have been “borrowed” into 170s and which is not “correct”.
Notice the “smooth” mufflers and straight tailpipes.
What may encourage such improper mixing of system is the commonality of the engines used on all those airframes.
