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Some innovative propellers and the performance they provide:
Pretend "Constant Speed"
The innovative instant adjustable propeller
Carbon Fiber Forged Propeller Hub
How about in-flight adjustable?
Setting that Propeller pitch on a ground adjustable prop
Balancing the beast
PATRICK IS REPORTING A MAX SPEED OF 152 MPH USING A 3 BLADE WHIRLWIND SET AT 21 DEGREES ON HIS CH-601XL. HE IS ANTICIPATING CRUISING AT A LOWER SPEED BUT THE TESTING IS VERY USEFUL AND PROVIDE BASELINES TO COMPARE PERFORMANCE DATA.
This Viking / DUC STOL propeller is designed for serious STOL performance. The combination Viking 130 or Viking 180 Turbo with the 5 bladed carbon fiber blade AND hub propeller provide the ultimate in performance, thrust, looks, light weight and price.
Take a look at the design HERE
The propeller will be on the 2018 Viking 180 Super Duty STOL aircraft flyinhg the Valdez competition in May 2018
Here's some initial data from my testing, which is as yet incomplete. Weather has kept me on the ground for a few days, so I thought I'd just go ahead and share what I've got. Airframe is a 601XL with 650 canopy, with no aero improvements other than Step Fairings which have been on there for a couple of years already.
Pitch MPH at 4800 MPH at 5100 MPH at 5400 MPH at WOT WOT RPM
19 x 111 x 126 6000
20 x 118 x 144 6000
21 115 122 133 152 6000
22 122 133 144 Untested (>Vne?) Untested
23 135 138 Untested Untested Untested
I've got more testing to do at 23 degrees pitch, as the air wasn't as smooth as I'd have liked and so the data at that pitch isn't very good.
All speeds are "Indicated". Altitudes are around 2-3000 feet. Temperatures are around 50 degrees. Data is as written on my kneeboard, and so is "in the ballpark". Somebody with the ability to programatically log airspeed data would be able to get much better data. Still dialing in the Pitch of the prop. When I settle that, then I'll start doing some tuft testing and aero mods based upon that.
What propeller are you testing?
3 bladed Whirlwind, 68 inch blades, in front of a Viking 130.
For those of us who are still in the building stage, this kind of information is very helpful, thank you for posting this.
It would be interesting to me what RPM you get, on the ground. I.E. at what pitch, does it begin to limit RPM. Hope that makes sense....
I have been looking your numbers. I am curious if you plan to try higher pitch settings? Also, can you comment or provide numbers on how the climb rate was reduced at the higher pitch settings? Thanks again.
I'm at 23 degrees pitch right now, and am thinking about establishing that as my new "baseline", and then making aero improvements followed by re-testing. As my airplane stands right now, being "dirty" (no wheel pants or fairings, etc) the "sweet spot" looks like it would be around 22.5 degrees pitch.
No hard data on takeoff run or climb rate, right now. Less pitch equates to better takeoff/climb, and any pitch less than 22 degrees can redline the engine. Part of what I want to do is run at WOT at lower RPM's, and log engine data (I have a data logger) after having made aero changes. For example, if WOT yields 5,000rpm and I make a change, after which the new WOT rpm is 5,100, then I'd say "good". Looking further down that path, it's possible that I would also make further changes to pitch.
Rain has kept me on the ground all week, and I'll be out of the country for most of the next couple weeks, after which I'll be back at it. My intent here (besides just having fun doing this) is to get the highest speed with the lowest rpm.
Very helpful information. One thing I have read, (if I read your post correctly) is that it is a good place to start (on a new engine and prop combo) is to set the pitch at the point where it keeps the engine at or slightly below red line, and then adjust accordingly as beneficial.