Setting Whirlwind GA-RW3B pitch on 912ULS

[jrevens]

I think I might have seen something from Kitfox which recommended a higher initial setting for the angle. Of course you set it at whatever it takes. Whirlwind may even be aware that the recommendation is a little too fine and just haven't gotten around to changing it in their installation documentation. Wish it wasn't so, but that is not unusual for many companies, in my experience. Just out of curiosity, have you checked the accuracy of your tachometer?

[3kdscf]

I think I might have seen something from Kitfox which recommended a higher initial setting for the angle. Of course you set it at whatever it takes. Whirlwind may even be aware that the recommendation is a little too fine and just haven't gotten around to changing it in their installation documentation. Wish it wasn't so, but that is not unusual for many companies, in my experience. Just out of curiosity, have you checked the accuracy of your tachometer?

Hi John,

I must have missed the Kitfox recommendation. As far as checking the accuracy of my tach, yes and no. I have both the Grand Rapids EIS2000 which gives the RPM in digital format as well as the analog AviaSport Rotax 912 tach and they both agree. Because they both trigger off the same signal provided by the engine, its not a true validation like as would be provided by a handheld laser RPM meter.

[desertdave]

Reviving this thread. I installed a Whirlwind prop, replacing my IVO and feel I lost quite a bit of airspeed. What are you guys finding as the sweet spot with your 100hp 912 ULS?

[efwd]

Okay, I'm back in the air. Fixing to fly to Phoenix today. I set up my pitch a bit more coarse than I had previously. I am currently 100 rpm less than what I had earlier (5250). So, at 5150 static WOT gives me about 10mph faster cruise than I had earlier. I took it out over the ocean where the air was very smooth and at 5500rpm I am now achieving 123mph TAS. If I run it at 5100 cruise I am now getting the speeds I once had while at 5500 rpm, about 110mph TAS.

[jrevens]

I’m kinda’ late to the game here, but I just rechecked what I have mine set at… 21 deg. measured in level attitude. Same engine & prop as you. I’m at a higher field elevation than you Dave, but at 7,500 msl and 5350 rpm I cruise at a little over 120 mph. I’ve easily taken it up to 18,000’. Like Eddie, any finer pitch & it’s too easy to over-rev, & over-all performance is compromised. That’s just my experience, FWIW.