Props for a Stels .049

Mark, the side exhaust is one of the highest turning rpm.049 engines I owned aside from the VA MKII. The Stels didn't come with plugs initially, the recommended plug at the time was the Cox 1702.  Eventually, Stels did make their own plugs and I do own a few. These are two piece plugs similar to Glo Bee plugs. I generally would run 45% nitro, Doug Galbreath told me to use 65% nitro. You will see better longevity using Nelson plugs and a slight rpm gain. The fact that the venturi insert is still in the engine is quite surprising as these are always missing. The stock needles are far too sensitive and generally require replacing. Your prop choices should be small and lower than a 4 pitch. A Cox rubber ducky cut down to 4" will work but I've even settled on props just a tad smaller. I don't use the safety style, I prefer the older non safety tip when I trim them down and then round the tips. A Russian green will work as well as these are approximately the equivalent of a 2.75 pitch. Even the Russian prop can afford to be cut down a bit. Stay away from the blue if you find one as the pitch is too much. The purple Russian prop will also work.

       AME made engines, today AME is known as the porting designation in the Norvel engines. Seeing your engine on the left it appears to be a AME as it has what I refer to as AERO with the Cyrillic backwards E. None of my Stels which look identical with the exception of a few things had anything cast on the case. The only indication of Stels manufacturing has only been on my twin horns. I have about 6 new in the box examples of these engines. The importance of this is because the Stels piston liner was quite different then ANY of the AME versions and runs a lot stronger.  I don't know this factually but it seems to me that Stels used the AME cases and ground that logo off because that's what all of my new examples look like.

   AME engines can be pretty strong themselves. Unfortunately, many of these were more or less teaching implements. It could take 10 or more to achieve finding a strong one. One way I can usually tell Stels apart from others is that the cylinders of the Stels are not plated in anyway. The AME usually has a nickle plating whereas the Stels is just brass.

    If your looking for easier obtainable props, go with the APC 4.4x2 you can also use the APC 4.6x3 and knock a little off of the tips. The engine on the right the (Twinhorn) is the perfect engine to burn your fingers off. Right when you go to adjust the needle it feels great you must try it.

       Seeing the twin horn on the right, I see the stock slotted screws are still retaining the cylinder. The screws are dead soft and the heads usually pop off and the cylinder blows off. This usually damages the cylinder. I highly suggest replacing those screws with socket heads. I usually don't worry about this with the side exhaust version because you have 4 screws vs 3 holding the cylinder down.