Hey guys what prop would you use for good 3D performance with an OS 91 FS?

I'm using an APC 15/6 on my UCD which works fine. I understand the 14/6 W which is noted as a wide blade design works well. Haven't located one yet.

EXCAP232

Not relating to the 91 engine, but to the "w" prop you mentioned. Just for a comparison, I just tried a "w" prop and here is what the rpm relationship was in case you want to judge which props you're trying to compare.

With my Saito .72, I was running a 13x6 at about 9800-10100 and when I went to the 14x4W it gave me about the same but closer to the lower end. That "w" affected it quite a bit considering "in theory" the 13x6 would produce similar results to a 14x5 which would conclude that a 14x4 would then have higher rpms but it didn't so the "w" comes close to consuming the same rpms as one jump in diameter or pitch.

Thought this may help you judge the 14x6W you are seeking and how it relates to your current prop. I found my "w" at Horizon but didn't see the size you're after.

-shaun

I have tried 15x4W & 16x4W APC for my FS90 powered Flip 3D. Both gave tremendous vertical pull but the 15x4W spool up faster. Mind u it is hot n' humid here so engine performance will degrade. Fuel is 15% coolpower. AUW of Flip 3D is 5.5lbs. Sorry no tach reading .

Hisham

GAGAK

If you can get a tach reading of 15x4W, I would be spooked. I would like to see how the 91 Surpass does with the 15x4W. Also, can you time the throttle response time going from idle to full throttle on this prop?

I run the 15-4W on my 91FS UCD and it is fine.The only other one I tried is a 14-6 APC,the 15-4W was much better.
Mike

Ditto on the spooling up. When I went from the 13x6 to the 14x4W, there was definitely a slower spool up. But with the increased pull, it's not like the plane fell out of the air.

-shaun

EXCAP,you should try the 15X4W,The 6 degree pitch for 3D is way too much on the .91FS.
Mike

seanychen

If you can get a tach reading of 15x4W, I would be spooked. I would like to see how the 91 Surpass does with the 15x4W. Also, can you time the throttle response time going from idle to full throttle on this prop?

Wellll.....! so far no tach reading yet (read no tachometer need to borrow one again) but from my MKII EARDRUM it sounds right. Maybe on the higher Rev but definitely not floating the valves. Will try to get a tachometer by next week (read buying one) .

As for throttle response there seems to be no noticeable delay from idle to full almost like my FZ63. I forgot to mention that my 91FS is the pumped version.

Happy Flying
Hisham