Thanks for the kind words! The stinger engines are made with new gravity castings for the cylinders. My old version had casting imperfections. So this is an improvement. Angled plugs are nice for fitting in a cowl, but actually produce a little less power than strait plugs.
As far as vibration, there wasn’t a huge noticeable difference if I remember correctly.
I hope yours doesn’t cause you any grief. Sure is a neat little twin!
Yeah, I'm not that crazy about the angled plugs either, like going with the tried and true, it's good to hear the casting is improved, but to be honest if the older version like yours were still available, I'd probably get one of those. "Improvements" always kinda worry me a little. The angled plugs do make it slightly narrower, but the plug ends are now ending up at a lower spot in the cowl, so the inward curve of the cowl makes the width in that spot a little less, and it seems like the engine to cowl clearance isn't much more than it was before as a result.
I think they did away with the external vacuum line for the carb pump too, at least I don't see a line on the new version, so maybe they are using internal carb suction for the carb pump like many other Walbro carbs do.
Your 21T setup just looked and sounded amazing in the video, even if the vibration may not be much less, the twin engine just looks so much more "realistic" and scale like than any other engine, and definitely than an electric motor. I'll try to post some pics as soon as I get that far.
I had some standard size analog servos, Hitec HS-311, I am using those for ail/flaps, just to avoid having to spend $25-30 on each servo. Do you think there will be any problem with those servos since everyone and the manual seem to suggest high torque or digital servos? They seem like they have enough torque, at least if I run them on 6V. I might use something a little more heavy duty on the elevator and rudder since those surfaces might see a little more load due to their larger areas/deflection.
Thanks again!