The International Cessna^® 170 Association

On page 45 of the book Cessna Wings for the World is a picture of a “Cessna 170C”. This pictures caption reads: (C170C, Forerunner of the 172 (Fully developed but never Produced). The “N” is clearly visible in the photograph as N37892. The N number is listed on the FAA’s web site as having been Deregistered.
It is listed as a Cessna 170B Serial number 609. Owned by a John A Yingst. This is curious as the serial number is way too low for a Cessna 170B. The Histories of the 170C that I have read tell me that the prototype 170C was converted to the prototype 172.
Cessna 170B Serial number 609. Owned by a John A Yingst is listed as destroyed and there is a NTSB report to go along with it. Does anyone have any information on this aircraft as to why had such an unusual serial number and was it possibly in fact the actual 170C sold or surplussed as a Cessna 170B?
It appears to me that the aircraft pictured in the photo also has a tubular tail wheel spring similar to the 180’s. However the picture in the book is not very clear

Maybe Cessna had a serial number series just for prototypes?

Metal Master...(as you are a certificated repair person I can't let this one pass by)... ....

Have you ever read a Type Certificate?

For the B-models: "Serial Nos. eligible 609, 19401 20267 through 20999, and 25000 through 27169"

(I.E. Cesnna reserved a few serials purely for prototypical testing purposes, including 609. They were used to develop certain features to be incorporated (or abandoned) in future models.)

gahorn wrote:Metal Master...(as you are a certificated repair person I can't let this one pass by)... ....

Have you ever read a Type Certificate?

For the B-models: "Serial Nos. eligible 609, 19401 20267 through 20999, and 25000 through 27169"

(I.E. Cesnna reserved a few serials purely for prototypical testing purposes, including 609. They were used to develop certain features to be incorporated (or abandoned) in future models.)

Yes but the type certificate does not tell us what the shape of the tail was. The serial number 609 is peculiar because Cessna used similar serial and numbers for their prototypes and research numbered aircraft such as 305 for the L-19 and the C-309 C-319 boundary layer control research aircraft. I think the 609 serial number had to be for some special purpose in any case.

I've no evidence to back these thoughts.

I'd taken note of these serial numbers before and this is I think the logical answer is. Serial 19401 was assigned to an A model fuselage made to the B model standard for testing then sold to the public. Serial 609 was an arbitrary number from a block of numbers given to a B model airframe taken off the line before a B model serial was assigned then used for C model testing but ultimately returned to meet the TCDS. So 609 would have to have had the round tail feathers when if was owned by the public or it wouldn't meet the TCDS.

John was my fathers best friend and my first170 ride, many years ago. I don't remember any differences in the aircraft from standard 170. That ride gave me my interest in 170's.
He was a very memorable person, mail pilot, WWII, lifetime in aviation. Never could figure out what happened when he wrecked the airplane.
I will try to find some pictures.
Scott

Perhaps it was not HE who wrecked it.

I want to find this thing haha