Long time no fly...

...the Stinger II!  I checked this blog, and the last time the Stinger flew was in Sept 2013!  Holy Moly that is a long time ago, but I left it alone due to my growing interest in helis and my worsening long distance vision due to cataracts, which have since been removed. In addition the YS 63 was not running real great.

Over the past few days, I took the engine off the plane and was going to replace it with either a OS40 two-stroke or a OS70 four-stroke.  After seeing how much work that is to mount different engines on the mounts, I said humbug and looked at how to fix the YS 63 instead, lol.  So I reset needle valves to factory settings, both high, and idle.  I opened the regulator and found small debris in it, which can plug the fine holes in there and make it run inconsistently...I was happy to find that and remove it.  Also checked the fuel lines in the tank but they looked ok.  I replaced some external fuel lines that looked loose or worn.  Next up was the engine had no compression from laying unused so long.  Turns out the valves were ok, but the push rods were not moving.  Upon further dismantling, I found the little pushrod sleeves that contact the cams were stuck in place from not running for about 2.5 years!  I was able to force them out.  Used the Dremel and some polishing compound to shine the sleeves up, then they slipped in and out of the engine block real smooth again.  Since I had the pushrods out and they were looking stained, I polished them too.  Next I reset the gaps at the rockers.  I don't know how much 0.1mm is, but for the OS engines I just use a slip of paper as the gap feeler gauge, so I did the same on the YS.  And finally, the flight battery pack was dead so I put a new 6V 2000mAh pack into the plane.

 I took the Stinger to the field today, and after flying the X5 four times and the Logo 690SX three times, I went to work on the Stinger.  The factory settings were decent as starting points, but my xmitter throttle was set too low to maintain idle.  Changed the control rod length at the servo connection, and that helped.  Next I ran up the engine and she held high idle and I took a flight with a rich high needle setting.  She ran the whole time but was weak, so for the next flight I leaned it out half a turn and also opened the low end, which is also equivalent to leaning the low end so that the idle was smoother, lower, and did not die.  Seemed to do the trick as the engine really pulled the plane fast, with a slight smoke trail.  Felt like a new plane and engine...lots of speed and authority.  Gonna be fun flying this bugger again!  Feeling satisfaction that I got that engine to run well again.

The Logo spooled up much better with the main blades loosened a little.  The shaking is less, but still there.  My throttle curve adjustment did not do the trick...the heli still jumps up when switching to IU mode, and it drops when I go from IU to normal, so that is not good.  It must be pitch curve differences, so I am going to adjust those to get a smooth transition between IU and normal mode.  Other than this, the Logo 690SX really is amazing for how smooth and quiet it runs and flies!  It is light on its toes like the X5, very spritely performance.