Talk about airplanes! At last count, there are 39 (and growing) FAA certificated S-LSA (special light sport aircraft). These are factory-built ready to fly airplanes. If you can't afford a factory-built LSA, consider buying an E-LSA kit (experimental LSA - up to 99% complete).
I have a Sling 2 that I love. It does everything I want, except go a little faster. I get 109 TAS at 5450 rpm on 912ULS.
My mechanic suggested upgrading my propeller from the stock Whirlwind 3-blade to a new DUC 3-blade pitched for speed first, and then, try a Zipper Big Bore upgrade to 114hp. He thinks I could get into the mid-120 knot to close to 130 knots. ?
I am just starting research. I see Sling Academy did some Cato prop testing. Does anyone have any experience with these props or big bore upgrades?
As a rule of thumb it takes 4 times the power to double the speed. So figure the percentage of power increase and divide by 4 for your percentage of speed increase. I would expect at most a 4-5 knot in speed increase due to the horsepower increase. You will notice it more in climb performance.
The prop can certainly make a difference. I have heard good things about the DUC Swirl propeller, but have not swapped one out to see the change in performance. I have installed a few EProps, and there has definitely been an increase in both climb and cruise performance. On the plus side its light weight is also nice for the Rotax engine, especially the gearbox.
Cam, did you look into the adjustable Airmaster prop? I think it rings out some more power at the top end. I wanted one, but being an S-LSA, wasn’t gonna happen. Good luck, let me know how you make out. My Sling is finishing inspection, not sold yet.
Thanks guys. Sorry for MY slow reply! I think I might try a DUC prop. After discussing with others, I hear the DUC prop will run smoother, be better for the gearbox, and maybe get some knots (5 knots?). I live close to Sebring and I hear I could try the prop before buying.
Or, change my GX3 to indicate mph!
Or, I may just lose momentum and be happy at 109 knots. I am retired and in no hurry anyway!
I did an upgrade from a Woodcomp to a DUC on my Sting S3 and saw 5+ knot increase in TAS. Climb improved as well but don’t remember the exact number. This was way back when DUC just came out and they were very competitively priced. I did the upgrade when the Woodcomp needed to be serviced so the delta increase wasn’t that much. Things are a little more spendy these days so I don’t know that 4-5% increase in speed would be a material change.
Now then if it’s performance you want, I’d suggest waiting for the rules of MOSAIC to be turned into regs. This was due this summer but is likely delayed with the current administration’s pause on new regulations. But MOSAIC will allow for a constant/variable speed prop. eProps has a nice one that will likely run around $10K installed but will give you more top end and more climb.
My Sting S3 with the 912ULS would do 127KTAS at 5500RPM and 5500 feet, lightly loaded. I think I did around 115KTAS at 5000rpm. It’s been awhile since I sold the S3.
I get 109 TAS at 5450 rpm on 912ULS.
