Whats the best propeller for YS63 pattern flying using 15% or 20% fuel. I mounted YS 63 engine in my MK Alliance, plane tracks good but it's a bit under power. Im using 12x7 APC and 15% coolpower fuel. Any suggestions what propeller to use or engine that can give more pulling power than YS 63.

I used a 13X6 APC on mine on a Matt Chapman Cap580 and it seemed to be the perfect match. Lots of pull, 2 vertical snaps and it still kept climbing, excellent straight line vertical speed.

It should do well on your plane.

If that is the cool power 15% green fuel then that is not enough oil content. The green stuff is 17% synthetic. CoolPower does make a 15% heli blend that is 20% oil though.

YS engines work best on a minimum of 20% nitro and 20% fully synthetic oil and if you really want to wake that engine up give it 30% heli fuel from CoolPower (I think it's pink, I haven't used it in a while as I went to mostly gas). Also, even though the YS manuals tell you a castor blend of oil is fine, I found that castor tends to gum the regulator which will give you mid range problems so try to use all synthetic oil

i'd reccomend at least a 20% heli from cool power and a 12x7 or 13x6

Thanks guys, My fuel is cool power heli 15%. How about 12x8 APC?

I once did a little more digging over in the YS forum and it appears the 63 likes to turn around 11,000rpm. When I went to the 13X6 APC I got 10,600 on 30% CoolPower.

I would think the 12X8 is going to load the engine too much on 15%.

What rpm's are you seeing with your current set?

I used to own a 6 pound Javelin II with YS63S, which performed well with 13 X 6 APC on 25% Morgan Cool Power plus 3.75 ounces of synthetic oil added to increase percentage of oil to 20%.

My experience has been with both the Javelin and the Oxalys models using a YS .63S. With YS 20/20 fuel the .63 liked the APC 13x6 the best. The APC 12x8 just didn't have any grunt. As of late I've been burning Magnum 30% Heli fuel and using a APC 13x7. The setup has run flawlessly for me. I'm turning 11200 on the ground at WOT.

Clay

I preferred an APC 12x7 on my Zen-50 YS-63FZ combo. Tuned just a tad over 11K, no problems- great vertical uplines, a bit fast but hey!

Graupner G-Sonic 13x7 is perfect for the small YS for pattern flying. A little bit more pull than with 13x6 APC, wider speed envelope and less noise. And it is also quite light.