FR certainly also used CFD to optimize his propeller. He does really have good performance + blades are not more than 2mm thick, which adds greatly to the overall performance like you said.
The 7.5x8 plastic prop also has very thin blades, down to 2mm, and runs really well and effectively with me.
Price 12, -
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What cnc are you using? I’m guessing you using Delrin/Acetal?
This is a nice work Frank 
However, you are missing 2 nuts on top i think 
DIY costs totally depends on what material you are using. We are talking about brass CNC and aluminium 5083 or 7075-t6. Nylon or plastic grade is indeed another option.
Do you have a Link to this Prop?
Material is POM…
Handmade, no CNC
CNC only makes sense with larger quantities.
POM is expensive than aluminum, but well suited for prototyping and such applications.
Mother does not need it, thread is cut, the last courses self-locking.
There is no link to it …
Is my drawing.
Only give them free if it works well.
Best regards Frank
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The knife in Aluminium.
It’s just a prototype, but it works very well.
Has become a 7x8 …
Let’s see when I can test while driving.
Greeting Frank
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Looks good. POM is Acetal, a variation of Delrin. Fantastic material!
Which gearbox is that? Is that the shaft or a bolt I can see?
Did you use the sand moulding technique for the blades?
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Ok Frank, this is a nice work
You cut the blades from a working prop to weld them on the folding part right ? It’s clever lol, nice one
It is easy and fast for Prototyp building, not clever 
Aluminium welding is not o problem for me.
Now someone would have to draw CAD, because I can not do that to have a print version.
Pitch can then be slightly varied over the number of degrees.
Thanks
Greetings Frank
I will hopefully draw something if I get the time to
Frank, you have to consider the fact that both blades need to open & close at the exact same moment. You need to add gears on the folding parts to allow this, otherwise you are going with crazy dangerous prop.
Why do you feel that it’s dangerous without the gears?
Lift’s prop seems to be working very well without gears.
My biggest concern would be how well its balanced using Franks technique.
Balancing is importent.
The knifes brought no gear!
Many faltalbe Prop without gears, is not necessary!
Greetings Frank
I can do CAD for the hub if you like, but not for prop curves.
KUff.
Acetal ( Polyacetal) is Delrin and both are POM.
Delrin is nothing but a Name created by DuPont
All is POM. Polyoxymethylene. A nice engineering plastic. Too bad you can not glue it.
As long as we are not riding waves, the folding prop is not necessary.
I was also refering to balacing. What if a blade does open more than the other ? (perhaps if you have a little stone blocked there,…). I’m not a pro, just wondering
as long as you do not lose a blade, nothing happens.
The blade always aligns itself as far as the slightest resistance permits.
Even if they could swing forward without a mechanical stop, they would not do it
best regards Frank
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