what the difference between the master air screw and the APC props. I'm useing MAS props now on my trainer and tiger60 but I have a tower uproar that I'm about to maiden and I'm looking for a good prop for it. I have a OS46fx on it. Would an APC prop change how my tiger flies?

APC is more efficient. It will increase some performance on your trainer but not enough to really make a difference.
Where the real difference comes into play is with more aerobatic planes.
Master Airscrew has a assortment of styles. I assume you are using a K series. They also make a Scimitar blade that is very similar to the APC.
I personally like Graupner props.

Yes I have the K series right now.

What Missleman says is right on the money. In addition, the Master Airscrew props you are using tend to take abuse better than the APC props. This is one reason why I recommend them for beginners, because prop strikes when learning to fly is pretty much a given.

Ken

Quite a few guys fly the Uproar 40 at our field. With a 46AX on it , it will be very quick indeed. I'd start with a 12x4 MAS to tame it down a bit and give you some more torque vs. speed to start with. After you get used to it, you can drop down to a 11 or 10" dia. with more pitch for speed if that is what you are looking for. Several guys have increased all the control surfaces 1" and that really makes for some nice 3-D like slow acrobatics. Enjoy! DG

Would any prop change how your Tiger flies? Yeah. But you're really not going to have any rules of thumb that'll insure your picking a better prop based on the brand of prop.

The brand of prop is no more important than the shape of the blades. And that's often the only difference between brands. And lots of brands have different lines that differ in blade shapes, so that blows blade shapes as the answer.

If guys at any field fly Uproar 40s with 46FXs and use 12x4s then buy whatever 12x4 is cheapest. And any other brand 12x4 as well. Then try them both. If you see a huge difference, then you forgot to adjust your needle valve after you swapped props, but you might actually see a slight difference. If that difference is good, keep running that prop. If it isn't good, put the other one back on. If neither pleases you, go get two more props. If the first two were too fast, the next two should have less pitch. If the first two didn't pull good enough, same deal. When you go for less pitch, consider if you could also go for larger diameter. But don't sweat the brand of prop until YOU see something that seems worthwhile to YOU.

A bunch of us really screw ourselves with brand loyalty. And there really isn't much reason to have brand loyalty with props. Not only do the mfg's not give us bulk discounts, but the differences between brands isn't predictable.

There are no magic props.

Basically you buy all the different props you can find around the size you think you need and then fly and try. When you find the best one or two, you set the others aside and maybe one of them will be the best for the next airplane/engine combo.