I am about to set up a OS25FX.
Curious whats being used in the APC line for best speed and reasonable pull.
Thanks

For flying combat, a 9x4 is about right. I actually prefer the Master Airscrew GF/2 prop, since it allows the engine to rev a bit more and not bog down in a tight turn. The APC 9x4 is ok, and will run well, but in a really tight turn, the engine will load up a bit, so you can't hold quite as tight of a turn.

(btw, the GF/2 is the old style master airscrew. The new props, the GF/3 load the engine more, somewhat like the APC, so I don't like them. You can still get GF/2s if you order direct from MAS.

Good tip on the new props, thanks Kirk. I was wondering if there was any difference in the new series. Those originals sure do work well, but I haven't tried the new ones yet for combat.

Did you notice any difference in durability between the GF/2 and GF/3?

Durability? No, I didn't, but I didn't fly the new ones much. I bought a package, but wound up selling most of them to another guy here, since I don't like them much.

The folks at MAS know combat guys buy a ton of props, so they are keeping the GF/2 in production in some sizes. I just got a dozen 10x4's for limited B, and 2 dozen 9x4s for example. But I doubt you'll see many hobby stores trying to carry both types.

I like the APC Combat 9x3. It seems to me that the MAS 9x4 flexes flat to maybe a 9x2, makes noise and doesn't go anywhere..IMO.

r

I also use the APC 9x3 combat, but only my Webras, and only when they are getting up on the pipe and putting out enough power to keep the rpm up in the turns. On my OS's I use the MAS isntead. I find that the MAS 9x4 just pulls through the turns better, even if it does flex a little. Now, with the Webras, when they are turning up, the MAS is just not designed to handle that RPM, so I use the APC. However, at least one of my Webra's is getting tired, and doesn't always rev up (depends on the weather mostly). During the morning test flights, I try it on the APC 9x3combat. If it doesn't perform, I put on the MAS 9x4, which does allow the engine to spin up in to it's power band.

I should also note that prop selection does depend at least some on the airframe, envrionment, fuel, and flying style. What works best for one guy might not be best for another.