Setxws6,
If I recall correctly, you are already flying this combination in your F-20, but as a review and reference for others.....
The budget alternative: the Thunder Tiger .46 engine with a Jett-Stream muffler installed is a good powerplant. Use a 9x7 or 9x8 on the SA F-20 application and you will get performance that will impress you - performs a bit short of the SJ-46, and it is a good combination to consider. In this case, yes, you will see the TT46 turn up 16,000-17,000 rpm. With this engine combination I recommend to prop it for peak ground rpm of around 16,000, and launch about 400-500 down from that. Unloads up into the mid 16K range in the air.
As for the Jett Engines.... thanks for the support in those posts above.... [&:]
Any of the Jett "40" size engines will make you smile
The SJ-46, SJ-50 or a SJ-60LX are ideal choices for the Sportsman F-20.
The performance goes up about 500 rpm per engine size. And you get a proportional increase in smile size.
[8D]
If I were to suggest an engine here, I would suggest the SJ-50. Just a good running engine with a ton of power, reliable, easy to operate, outstanding throttle response.
As noted, the numbers published on the Jett website are the actual performance rpm with a specific prop. The engines are pre-run before they are shipped to ensure they hit Jett's minimum performance standards. After proper break-in and a bit of flight time, most engines will exceed these performance figures.
In the case of the engines listed above, the baseline prop is an APC 10x6 and 15% fuel is used.
For the SA F-20 you are inquiring about, a 10x6 is a good prop to start with. Eventually an 9x7, 9x8 or 9x9 would be suitable as well.
The Jett engines have the same mounting pattern and installation footprint as the OS46/TT46/Mag46 et al
I hope this is helpful.
Bob