I have two Baby Streaks. One has a TEE Dee .051 and the other has a Revlite Big Mig .061, but an earlier one than the later NV Engines company. Both fly very well and my usual prop for 40' or 45' of line is an Master Airscrew GF series 6x3 cut back to 5.5" or 5.25". With the MA props I usually fly the 45' on breezy days. I do use the muffler on the Norvel. I've also used the APC 6x2 to tame the Big Mig slightly and use the 40' lines. But the APC is the only 6" prop that
I feel lets the engine turn up to it's most useful high RPM power band. Bob Z. occasionally brings 1/As to play with and claims my Norvel powered Streak is the best flying streak he's ever seen. I took that as a big compliment coming from him.
The Tee Dee powered Streak is no slouch either, not quite as fast, and it'll also handle the longer lines on a calmer day. Both are run on bladder pressure with 25-35% fuel.
Here's a video of each... back before I new how to fly a real stunt pattern.
First is the Big Mig with an MA 6x3(too much load, bogging it in the tight turns). I later found with the 5.5x3 and even shorter, the engine doesn't slow nearly as noticeably in the turns, and it's much cooler after landing. I plan to fly this one at our club's 1/2A Day in Huntersville next Saturday
And here's the Tee Dee, don't recall which prop, probably the MA 5.5x3. I fly it on a 5.25x3 these days.
The engine has lately started burping out when I turn inverted. The compression is shot too and I wonder if that's why. The cylinder is sideways mounted. I'm open for suggestions on what might be wrong with it.
If you decide to use the Norvel, I did a how-to on RCG about how to retro-fit it with a 128 tpi needle valve. The TD fine NVs are easily available. I get that and the Cox type fine thread spraybar NVAs from Texastimers.com. They also supply all of my bladder making supplies. If you want to use a radial mount firewall they sell a backplate for the TD that screws into the back of the engine and has a round collar with holes all around it so you can bolt it to a flat faced engine mount.
Here's the tutorial on RCG:
http://www.rcgroups.com/forums/showthread.php?t=1863251There's also a Norvel break-in post I wrote here on SH:
https://stunthanger.com/smf/12-a-building/cox-12a-engine-question/msg324763/#msg324763Hope that helps,
Rusty