Yes, worse. The X4 has a 150 cm cage and the motor’s and prop’s are more outward. The positive is the props are getting better undisturbed air… The yellow circle would be a 130cm single prop.
I said 2 years ago that 22x10 props are not optimal. The 10 pitch is good for fast power and gaining altitude, but for 36 km/h level flight just not the optimal pitch.
The 22x10 props need for level flight 5100 rpm and at climbing 6700 rpm.
The tip speed from the 22x10 props is at level flight 537 km/h and at climbing 706 km/h.
That would be 73 db at level flight and 81 db at climbing. This is loud.
Maybe next April I will show my newest Propeller progression. Theoretically they produce less
noise pollution as a single prop.
For level flight under 3100 rpm and climbing under 4250 rpm.
The tip speed for level flight would be 347 km/h and at climbing 468 km/h…
Level flight under 57 db and at climbing under 65 db. This is actually my main goal to have a
really quiet eppg with the least noise pollution possible. I think this is even more important than
increasing flight time, less noise will actually help gaining efficiency and increasing flight time as well.
Changes of 1db are not perceptible. A 3db change can be heard. A 5db change is noticeable,either up or down. Although an increase of 3db doubles the sound energy, it takes a change of 10db to be judged as twice as loud. Each similar decrease of 10db is considered as half as loud as the original sound.
in the picture the cage is 150 cm and the yellow line is 118 cm. therefore it looks unusual and I immediately noticed that it cannot be a 130 cm circle. this can be checked very easily with a drawing program.
So, thanks to this informative discussion, and fear of turning myself into a torque twizzler, I will nix the idea of preliminary testing on 4 identical carbon props, and wait on a response from Mejzlik.
Does anyone have a lead on where to purchase CW CCW sets of 22 x 12?
You need 2 x regular and 2 x pusher prop’s. The carbon prop’s are only available in 22x12.
They do have wooden 22x14, but the 14 pitch could already stall at start up with zero forward
movement. The forum member had the engel carbon prop’s in 22x10.
The problem from what I understand is locking them in place so they don’t slip on the prop shafts. The carbon is too slippery, the nut isn’t strong enough to keep them from slipping from what others have posted on this forum who have tried carbon props
Yep, I saw that others had issues with the single post mounts. Thanks to those guys sharing I took a different approach and am using the standard (non-extended) mount. Hopefully this will hold up.
Currently, I’ve got about 30mm clearance. When my frame build gets further along I’ll have a better feel how much flex there is in the system and may add more clearance.
As for the prop being in more turbulent air, I essentially traded the long prop mount you guys use for a long motor mount, so the position of props relative to the airframe should be about the same.
Battery case clearance grew to ~70mm after accepting some feedback from other designers and moving the motor arms back from 5° to 15°. Here are a few screen shots of my drawing (both the design and prototype unit are still in process).
As a reminder to those interested, Mejzlik now does have CW and CCW 22x12 props available, altho I’m starting out with the Engle carbon props referred to me on here. Also, a quick “Thank you very much!” to Paul and Zack for their help and inspiration, and just as importantly all the great feedback from members on this forum. - Chris
