Hi, just want to share, in my view, a miracle fixing method used by my senior Russian Mechanical Engineering friend.
So, I have travelled to south of China with a 240 sized Quad and gear to get photos of a new apartment environment.
First just wanted to to get proper Home location and new Mag calibration done and then try it.
Next days supposed to film.
However, when all mag calibration done, AltVario working, PosHold in AttEstAlg INS13 is working rock steady, then flipping switch to RTB and had a crash that damaged the legs, GPS pole but also one of the cheep CW props like this.
I discovered that all the 20 spare props I brought to this trip was CCW 
A terrible mistake.
No filming, and many weeks of preparations down the drain - a very low moment.
However, my friend Valery said, "from an engineering point of view, I can fix this".
Since he has no prior experience on flying anything RC or others, I was just thanking him for trying to offer comfort and explained the high speed of rotation and the forces working at root of blade.
He insisted, and we had a go at it.
First using super glue to ge the lost blade in the right pitch angle. Did that okay but we later found the whole blade pointing upwards some 25 degrees (pitch okay though).
After that he took just a cotton string we found at home and twisted it so that it connected each blade both on top and below. Then just holding it very tight we added drops of super glue all around them.
Like this.
Its like welding metal, it became very stiff. Also, the weight added was evenly distributed over the three blades.
We found the damaged blade was pointing upwards too much and then used a cigarette lighter to heat up and bend it down. He got it down to just be off some 15 degrees (still, a lot!) but did not dare to continue without deforming the blade. So we tried to fly with it as that.
To our great surprise the pointing prop did not matter at all! No vibrations or oscillations, handles just like before.
And this is how it flies :
Just very impressed with his mindset; use what you have at hand, no one here to help, apply knowledge, apply skills, apply creativity - impossible is nothing!