Hey Pete,

Thanks once again for taking the time to help. I have an Evolution .61 NX and thought about using it, a so called friend of mine traded it to me for a K&B .61, said he needed a lighter engine for his plane. I haven't used the engine yet, but I have read about people having issues with this engine. The other reason for not using it is the need for the special muffler they sell to fit inside of the cowl on the D-VII, I'm sure it cost a few bucks. Since you are using the OS .61 FX what are you using for a muffler, I have a couple of those engines in stock, good runners. Your right about the age of the OS .90, I just checked on the one I have N.I.B. that I bought in 1984 from Indy R/C. I couldn't find the paper work on the .90, but I was buying one of each size 4 stroke OS made back then. I have the sales slip for the OS .120 dated Sept. 15,1984, price $165.00 + $6.50 shipping, $2.50 handling, $1.65 COD, for a total of $175.65 and the sales slip for the OS 61 dated Dec.11, 1984 was $119.95 + $2.50 handling, $1.65 COD for a total of $124.10, this one didn't have shipping because it was back ordered. I also bought an OS .40 4 stroke from them, but that's the only one out of the 4 that I ever used, I built a Nick Ziroli Eindecker and used the OS .40 in it. The 1.20, .90, and .61 are still in there boxes. The Eindecker is waiting to fly again, last flown about 25 years ago!

Bill