What's the best 3D prop for a Tower.61 and a Tower.75? Any ideas?

.61- 13*4 to 14*4 range
.75- 14*4 to15*4 range

I havn't actually flow those motors, and it is all dependant to what airframe and the amount of thrust you are wanting.
I run an 11.5*4 APC wideblade on a .46pro, and a 12.25*3.75 APC wideblade on an xls .52.
A good general rule is to look at manufacturers prop chart and go to theLargest diameter prop and use a pitch of half the diameter (or a little less).

I use the 13/5 MA K series on my OS 61fx APC doen't make this size. The 14/4W doen't allow for prop clearance.

What airplane will it go on? gwsdrgnfly gave some solid advice. For 3d the APC's wide series seem to work well, but many like the narrow 13X6, depending on what flavor of 3D you are doing, and with which airplane. I am comparing this to my Magnum and OS .61 engines, and Magnum .75 engine. Won't own any more Tower engines, bad experience with them, but their mufflers rock, exspecially on .46's.

My Tower engine is the best running engine ever. If you follow the instruction booklet. I had a lot of trouble with mine 'till I read it. My problem was that I wasn't running the high-end starting with 4.5 turns out. My .61 will go on maybe a funtana, or a 3D plane of my own design.