Developer Comment by R_Lefebvre on June 18, 2012 at 4:10am

Gary, what does that make me? I've been bit twice. ;)

Developer Comment by R_Lefebvre on June 18, 2012 at 4:10am

Oh, and this is a terrible idea.

You could lose an eye people.

Comment by MC on June 18, 2012 at 4:14am

This is one and the same with Visual´s Basic ON ERROR RESUME NEXT.

Comment by R. D. Starwalt on June 18, 2012 at 4:53am

I see a science fair project here...

Really. To prove the obvious all it would take is a platform with a 3 axis piezo sensor mounted with a motor / ESC and servo tester (power supply/battery is assumed).

• Run a 'stock' prop, not balanced.
• Run a balanced prop.
• Run the 'school yard special' as seen above.
• Publish the graphs.

All props should be from the same manufacturer and the same pitch.

Ready,set, experiment!

My high school woodshop instructor was a member of a control line racing team. He made their props, wings, and upper body shells. The lower body was a cast aluminum pan. Rat Racing pushed the boundaries of materials and techniques.

There have been successful single bladed props though they were always balanced in all planes. This could be balanced in the plane of the diameter but certainly not in the plane of the motor shaft.

Comment by Ellison Chan on June 18, 2012 at 10:01am

One bladed has been successfully demonstrated, by Dave Herbert (Nightflyyer)  You need to counter-balance it.  It's much different and safer than the recycling method, used by Patrice. 

Developer Comment by R_Lefebvre on June 18, 2012 at 2:09pm

Ellison, that's awesome!  I'll have to look into it more.  I would have thought you'd have a problem with the center of lift wobbling around causing extreme vibration.

Comment by patrice.rance on June 19, 2012 at 7:47am

I will make a video for you guys ;) when the props are together they are like one. and the counter-balance work.

my method is when you don't have solution and you really want to fly. it's not perfect but it really works on my HEX6.

Comment by MC on June 19, 2012 at 10:04am

Patrice, I think the slight criticism embedded in the comments is just because most of us only have one set of eyes.

I totally understand this scenario, I've been grounded for weeks because I had no props. The ones I had were too  heavy for that engine, 10x6, so I cut them to make a 8x6, but the performance was still terrible.  

From what I've learned so far is, you have to take this hobby with a level of seriousness proportional to what you can afford to lose. As soon as something is spinning at several thousand's revolutions per minute and that is attached to something that is airborne, remote controlled, with hobby grade control systems, the space in time between its all fine to a disaster is unfolding is never more than a split second.

I tend to follow a GO-NO-GO procedure, which is far from a NASA like role-play, it is a safety procedure per-se... and propeller out of balance/chipped edges from biting the ground is a NO-GO. 

Sometimes its all fine, that small vibration you decided was "OK" when you where hovering 1 meter of the ground, might escalate quickly when you are 100 feet high and you have to push the throttle some more to beat a wind gust, vibration increases, gyros get upset.

I am in the process of developing a new composite airframe, whose prototype should be ready soon, then once the airframe is tested and stable, I will probably dive into propeller design, including a asymmetric propeller, with different pitch/lengths on each side.

If you really want to fly and all you have is broken propellers, exercise patience. That is a premise when dealing with such complexities as we do.

“Patience is passion tamed.”
Lyman Abbott

Comment by Ellison Chan on June 19, 2012 at 10:09am

Marcelo, yes I think that's a correct analysis of comments.  But I don't worry so much about my eyes, since I usually wear goggles, when flying close quarters.  However, I worry more about the precious eyes of bystanders. 

Robert, not according to people and Dave who's tried this.  In fact they claim that the turbulence from the opposing blade is reduced, since it's not there, and this results in more efficient flight.

Comment by patrice.rance on June 19, 2012 at 1:32pm

the video is ready ! i will post it tomorrow just to demonstrate that it works. i fly 10 mn with no probs.

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