I am flying a Phoenix Topstar60 with a OS FS91SII and MAS 15x4 prop. The airplane flies exceedingly slowly with it. Though it remains fully controllable, I want to try out a different prop that has more airspeed and pull that I can still 3D with. So a few questions:

1) Should I get APC or MAS? The 15" is the largest prop this airplane can take. But it tends to hit the ground once in a while. I dont want to break a tip on a APC

2) Recommended prop range as per the manual is 13x9, 14x7, 15x6. So would a 14x6 fit the bill or should I get a 14x8. Basically, 14x7 isint available, I dont want to get too high a pitch as I dont want to reduce static pullout out of hover. Also, in the 14" range ground strikes are not likely. So should I get a APC then?

Ameyam

For doing 3D you want a low pitch prop. Probably the best for the 91 is an APC 16x4W, but if that is too big, you'll have to drop down to something in the 15" range.

Now, the higher the pitch, the more speed you'll get, but at a cost of losing power to pull out of a hover with.

It's a trade off. 3D planes are not meant to fly fast and fast planes are not meant to do 3D

In either case, I would go with the APC over a MAS

15x4 apc is a good 3d prop or 14x6 or7 apc for sport 13x8 or 10 for speed

This is the airplane. As you can see the 15" just about clears the ground. In APC, if I hit the ground I will break the prop. Therefore considering 14x6/7

Ameyam

You'll break a MAS if you hit the ground with it too. If the 3D thrust is good enough with the 14 inch prop, then just go up in pitch a bit. A 6 pitch is a good all around aerobatics prop, although you will lose some of the vertical grunt with it.

Use larger foam wheels and use a 16x4W.

Actually, I already hit the ground a couple of times with the MAS on Sunday. I realised you need to keep a bit more power on the 4C engine as its idle is so low there is no thrust at all at idle. So when the airplane stalled a couple of feet off the ground, I gave both power and elevator but hard landed regardless a couple of times. Then in the last landing of the day I kept a couple of clicks of power and touched down so softly I couldnt have kept it down softer myself by hand. Regardless, the MAS is quite OK even after the ground strike, an APC in its place would have broken

I am putting in an ordred for 2.75" PUF wheels and a 15x6MAS and 14x6APC at my LHS, will test this weekend if possible

Ameyam