JT8D-200's
 

So I was trying to figure out how each differs:
JT8D-217
JT8D-217A
JT8D-217C
JT8D-217A/C
Could someone tell me the difference between the four?

http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgMakeModel.nsf/0/72dd9633752df29c86257346004a1cbf/$FILE/E9NE.pdf

Short answer, different thrust ratings. I believe they basically kept upping the thrust for different (longer, heavier) MD-80 variants. Hope this helps!

Its been a while,but I remember the "A" being short for APR. Auto Power Reserve. Lose one and the other two automatically go to max. (727 of course).

Same on the Mad Dogs. One blows up, the other adds a little boost. Then it blows up ;). Seriously, with the -219 they tweaked the JT8 about as far as it could go.

But Valsans only have 200 series engines on the pods. Most of them were 100s with a -9 in the center. I know of one 200 Valsan, it's got a -17 in the center but I don't know if it's a 17AR.

Fit form and function, the -217C is the same as a -219.

And yes, the Valsan conversion didn't apply to the #2 hole on a 727, just the 1 and 3 positions

On a side note, the Aerion concept SSBJ is to use -219s. P&W doesn't make the JT8's any more. Kind of weird...to buy a new jet with used engines.

Fedex at one point had 13 Valsans, all conversions of 727-2S2F -17 engined 200s. Also, Express One International had 2 727-221 -17 Valsans that were converted by Ultra Air, a charter company that folded. The original engines on the -221s as ordered by Panam were -17Rs, which had the APR performance reserve system. After conversion, they were plain -17s with no reverser.

Yeah this is odd but there must be a huge supply of used JT8's on the market. Perhaps the critical parts for repairs are still being made also. The other thing is I doubt Aerion plans to make more than a couple hundred of them. Personally I will be surprised if they ever make a single jet because the only thing it can do well is go fast over open sea.