When I see a C-170 sitting on a ramp or in a photo such as on the November calendar, its always interesting to me to attempt to identify what year model it is. I know the '48 is easiest of all. The A models are pretty easy except I haven't learned what outside, physical differences there are between the '49 - '51 models. The pressure cowling aids on later models, but the one I still have to work on the most is the differences in the '55 & '56 models. I know the rear windows will identify it as either a 55 or 56 and if the cowling is original, the 55 has two doors while the 56 has only one. The 55 has an opening window on the right side while the 56 does not (Cessna should have been castrated for that cheap shot ). Are there some other, easily noted differences? I can't remember if the 56 went to the plastic covering on the instrument panel as did the 56 172 and forward models or not. The November calendar C-170 either doesn't have the original cowling or the air inlets have had the cross bars removed. Just curious
The November 170 on floats does not have the original nose bowl (not sure about the rest of the cowling). This change was usually made to accomodate the belt driven vacuum pump, but I don't know if the Nov. 170 has that mod or not (it would be visible in the opening of the co-pilot's side of the nose bowl ).
'49-'51 A modela are all the same on the outside except for the paint job and the lip on the bottom cowl (and associated opening) which on the early A models (through s/n 19200) was the same as the ragwing.
The '56 models incorporated plastic interior panels rather than metal. (Doorpost covers were also plastic.)
I don't think any '56 models were actually mfr'd without right-side cabin doors, but many were without openable windows and a few were without right-side flight controls.
The external tailwheel steering cables on serials subsequent to 26505 is also pretty obvious. (I don't recommend too much emphasis on "year-models" since the FAA muddied up that water pretty well by using a combination of production-dates and airworthiness issuance dates as methods of identification. Actual model-year modifications are better identified by serial numbers.
'53 B-model N146YS SN:25713
50th Anniversary of Flight Model. Winner-Best Original 170B, 100th Anniversary of Flight Convention. An originality nut (mostly) for the right reasons.
You are correct George, except no one mentioned the lack of right side "doors", only right side openable windows. You also mentioned door posts covers being plastic, but I don't recall seeing those. Will have to have a look. I know the 56 172 had the plastic on the instrument sub panel and the area forward of the door post (where the ashtray's are located) are plastic.
Speaking of the '56 with the co-pilots window that doesn't open, , I pulled the pins on both door hinges so I could repair the latch mechanisms in my shop. Got to thinking it would be a good time to replace the glass on the co-pilots side. After studying it for a half hour, I came to the conclusion that the design engineer must have had his head where the sun doesn't shine ... What were they ever thinking??? I know the 170 doors have windows that open (and why not?). I think my best bet would be to locate a right door from a '55 170 and paint it to match mine. Anybody replace the glass in one of these 'non-opening' windows before?
Joe Craig
'56 C172 Taildragger N6915A
'46 Aeronca Champ N65HM
If you're really thinking of replacing that door with the non opening window, good luck. I've never seen a replacement door that fit the opening worth a damn. I rally believe they're all custon fitted to a given airframe.
'53 B-model N146YS SN:25713
50th Anniversary of Flight Model. Winner-Best Original 170B, 100th Anniversary of Flight Convention. An originality nut (mostly) for the right reasons.
When I bought my 56 172 TD a former owner had hired Rube Goldburg to fashion an opening window for the RH door. It worked (?) in that it was a sliding arrangement that would open about the front half of the window area. It did let in fresh air, but in the winter it also let in a lot of fresh air. I had my IA install the fixed window at the first opportunity. I looked, thought, etc. for several years about how one could install an opening window in that factory door and gave up. Later I purchased two later model C-172 doors and had them installed. I like them. However, I agree with BL that Cessna must have hand fitted each and every door on their various aircraft. The later model doors needed a lot of work to make them acceptable and I am not sorry I made the change, but one of them still doesn't fit as well as it should, but I'm gonna keep it. I think the idea of finding a 55 C170 door might be worth a try.
I've replaced the springs in my door latches and I'm going to put the doors back on. Too many irons in the fire right now to attempt to align and repaint a door. I'll just keep my eyes open for a door and deal with it when I find one. My fuselage is pretty straight and I don't anticipate too many alignment problems. (But who would...) Thanks for the input.
Joe Craig
'56 C172 Taildragger N6915A
'46 Aeronca Champ N65HM
). Are there some other, easily noted differences? I can't remember if the 56 went to the plastic covering on the instrument panel as did the 56 172 and forward models or not. The November calendar C-170 either doesn't have the original cowling or the air inlets have had the cross bars removed. Just curious 
... What were they ever thinking??? I know the 170 doors have windows that open (and why not?). I think my best bet would be to locate a right door from a '55 170 and paint it to match mine. Anybody replace the glass in one of these 'non-opening' windows before?
