<div>Troy,</div> <div> Thanks for the info. </div> <div> I have one 120 NC and one 120 SC, the NC will go on an Aires and the SC will be a backup. Both required a rebuild, looks like they were left with some fuel in them and left that way for years. All the bearings needed replacement, including the camshaft bearings. The SC has a piston with a concave top, (dished ?). Of the two engines the SC is in the best shape, the crosshatch tooling marks are visable in the cylinder. The NC compression could be better. Any suggestions for running the NC ? How do I know when I need to replace the cylinder sleeve. </div> <div>Thanks again for the info, in this case more is better.</div> <div>Paul</div> <div><BR><B><I>"Troy A. Newman" <troy_newman@msn.com></I></B> wrote:</div> <BLOCKQUOTE class=replbq style="PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #1010ff 2px solid"> <META
content="MSHTML 6.00.6000.16587" name=GENERATOR> <STYLE></STYLE> <DIV><FONT size=2>15-10 is an excellent prop on the 120SC, if its a strong one you can with the 15-11</FONT></DIV> <DIV><FONT size=2></FONT> </DIV> <DIV><FONT size=2>Of special note the 120SC likes Nitro. It is a fairly high compression engine and can be a little finicky. It was the strongest of the 120's In fact I had one that gave the 140FZ a run for the money.</FONT></DIV> <DIV><FONT size=2></FONT> </DIV> <DIV><FONT size=2>Being this soupped up highly tuned 120...the extra nitro broadens the mixture settings. The other thing it does is higher nitro require richer settings to get the mixture correct and as a result they will run a bit cooler and better. More fuel flow means more oil flow and better cooling also.</FONT></DIV> <DIV><FONT size=2></FONT> </DIV> <DIV><FONT size=2>I strongly recommend the Cool Power 30% heli fuel.</FONT></DIV> <DIV><FONT size=2></FONT> </DIV>
<DIV><FONT size=2>By the way, on the 120SC because its more a higher compression soupped up version, don't run it out of fuel. If you are flying and too long and the engine runs dry it can backfire and can cause damage. Its never a good idea to run any of the pattern engines 2 or 4 stroke out of fuel, however the 120SC, 120AC, and the 140DZ tend to be a little brutal when this happens. Try to run the 120SC at the higher end of rpms. I would say the goal rpm for that engine would try to be up at 8600-8800 maybe as high as 9000. On the 15" props it will make noise with ease in most cases(read exhaust systems)</FONT></DIV> <DIV><FONT size=2></FONT> </DIV> <DIV><FONT size=2>The 120SC is an awesome engine. Like I said it was the king the of the 120's. There were some folks that had issues with them, but my experience was always good with the SC. There were some piston of the month changes to the 120SC. Namely they had a dished piston, and some magnesium pistons. The
goals behind these were to get more power out of the 120 case. Back then the FAI rules had not changed to allow larger than 120 displacement. So YS was trying to lighten the piston, and get the engine making max power from the little box. At the time there were a few models that were getting bigger than the 2 meter box as the 2m box didn't exist. No size limit just the engine limit and the weight limit existed at the time. On the piston front just stick any ole 120 piston in it....the 120SC piston could be a little fragile if run lean (meaning running it out of fuel). The original 120SF piston was bullet proof and works in the 120SC. The dished and designer pistons are really able to change the behavior of the engine. I have played with this "super" or the "hyper" pistons on the current 160DZ and 170DZ engines. Its cool how changing the piston by putting a dished top and closing off the bottom of the piston can change the way the engine reacts to certain prop
loads, or it will change the noise. Some of the things they can do make more power and some of the pistons make it run super smooth and quiet. Yamada doesn't do the testing in production like they once did with the pistons. I have been fortunate to try some of the super cool, "hyper" pistons they have played with on the DZ's. I wish I had the knowledge back then that I have now. Some of the smallest changes in a piston can really totally change the way an engine performs. Its kinda neat. I remember the need was for more power more power back then and now I know which piston designs would have done it better. </FONT></DIV> <DIV><FONT size=2></FONT> </DIV> <DIV><FONT size=2>Any of the current exhaust systems will work very well on the engine. Even the short hatori 821 pipes and the NMP header will work excellent on that engine.</FONT></DIV> <DIV><FONT size=2></FONT> </DIV> <DIV><FONT size=2>I have a couple of 120AC's that we carved up the heads to get more
power...I wish I still had the 120SC as it would be a really good engine for my war bird project I'm planning. I actually need a pair of the 120SC's for it. Right now the 120AC's are a little heavier than I would like and have been considering putting a pair of 140 Sports in the model.</FONT></DIV> <DIV><FONT size=2></FONT> </DIV> <DIV><FONT size=2>I know this was likely way way more information than you needed to know. But its a good engine and you'll love it.</FONT></DIV> <DIV><FONT size=2></FONT> </DIV> <DIV><FONT size=2></FONT> </DIV> <DIV><FONT size=2>Troy Newman</FONT></DIV> <BLOCKQUOTE style="PADDING-RIGHT: 0px; PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #000000 2px solid; MARGIN-RIGHT: 0px"> <DIV style="FONT: 10pt arial">----- Original Message ----- </DIV> <DIV style="BACKGROUND: #e4e4e4; FONT: 10pt arial; font-color: black"><B>From:</B> <A title=flyintexan@comcast.net href="mailto:flyintexan@comcast.net">flyintexan</A> </DIV>
<DIV style="FONT: 10pt arial"><B>To:</B> <A title=nsrca-discussion@lists.nsrca.org href="mailto:nsrca-discussion@lists.nsrca.org">NSRCA Mailing List</A> </DIV> <DIV style="FONT: 10pt arial"><B>Sent:</B> Saturday, December 29, 2007 8:53 PM</DIV> <DIV style="FONT: 10pt arial"><B>Subject:</B> Re: [NSRCA-discussion] YS 120 NC/SC prop recommendation</DIV> <DIV><BR></DIV> <DIV><FONT face=Arial size=2>Should be able to run a 16x8 on 30%...</FONT></DIV> <BLOCKQUOTE style="PADDING-RIGHT: 0px; PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #000000 2px solid; MARGIN-RIGHT: 0px"> <DIV style="FONT: 10pt arial">----- Original Message ----- </DIV> <DIV style="BACKGROUND: #e4e4e4; FONT: 10pt arial; font-color: black"><B>From:</B> <A title=paul.horan@sbcglobal.net href="mailto:paul.horan@sbcglobal.net">Paul Horan</A> </DIV> <DIV style="FONT: 10pt arial"><B>To:</B> <A title=nsrca-discussion@lists.nsrca.org href="mailto:nsrca-discussion@lists.nsrca.org">NSRCA Mailing List</A>
</DIV> <DIV style="FONT: 10pt arial"><B>Sent:</B> Saturday, December 29, 2007 6:09 PM</DIV> <DIV style="FONT: 10pt arial"><B>Subject:</B> [NSRCA-discussion] YS 120 NC/SC prop recommendation</DIV> <DIV><BR></DIV> <DIV> Any suggestions for a YS 120 prop ? It will be on a Aires ?</DIV> <DIV>Thanks,</DIV> <DIV>Paul<BR></DIV> <div> <HR> <div></div>_______________________________________________<BR>NSRCA-discussion mailing list<BR><A href="mailto:NSRCA-discussion@lists.nsrca.org">NSRCA-discussion@lists.nsrca.org</A><BR><A href="http://lists.nsrca.org/mailman/listinfo/nsrca-discussion">http://lists.nsrca.org/mailman/listinfo/nsrca-discussion</A></BLOCKQUOTE> <div> <HR> <div></div>_______________________________________________<BR>NSRCA-discussion mailing list<BR>NSRCA-discussion@lists.nsrca.org<BR>http://lists.nsrca.org/mailman/listinfo/nsrca-discussion</BLOCKQUOTE>_______________________________________________<BR>NSRCA-discussion mailing
list<BR>NSRCA-discussion@lists.nsrca.org<BR>http://lists.nsrca.org/mailman/listinfo/nsrca-discussion</BLOCKQUOTE><BR>