Foldable propellers


#1

Hello
I’m new to the sport, but an experienced flyer in other forms. And modelist.
So i wonder if folding propellers could be interesting for freeflying with this electric paramotor ?
Since we use them in gliding ( radiocontroled or real )
Thanks for your work and input
Cheers
Alex


#2

I’m not against the idea, if we can find some decently priced ones I’m all for trying them out.


#3

Since the motors and props are not all that heavy they could be configured to swing behind the pilot. This would need to have independent prop guards. It would be more like a vertical H copter that swing back like a clam shell. In this type of configuration a second option could be to use just 2 props and motors giving it the equivalent of a 100 cc motor. Currently I fly a spyder 22 in free flight. I do have training for PPG and hope to go electric in Guam.


#4

Something like this would be great I think.

Especially when you are going to use Openppg for flying in thermals or hill soaring. But I have no idea if these kind of props are strong enough.

http://www.espritmodel.com/aeronaut-fiberglass-blade-stopper-for-folding-spinners-3blade.aspx


#5

Most of the drag comes from the cage and netting, not the props.
Adding foldable props would introduce more complexity (failure points) in the system.
Just my thought…


#6

I use foldable props on all my airplanes, and they are great: easy to balance, cheaper to replace. However, the chief problem is finding both CW and CCW versions. I don’t think you can get both.


#7

I think you are right.


#8

I used to have a foldable prop on my Doodlebg (powered hang glider). The Bug was secondhand and that was the prop it came with. I got a big chip in it and replaced it with the cheaper standard prop. I can’t say I noticed any real performance change between the two. I think CrypTunico has hit the major point in the cost / benefit sum. Apart from the drag of the Wing most of the rest of the drag comes from the netting, harness and the large lump of protoplasm steering the thing!


#9

Why not make 4 small cages with netting around each propeller? We really do not need one big cage do we?


#10

I’d say 4 small hoops are more complex to build than one large hoop.

Plus: If you have the need to forward launch, because you have 0 wind, you couldn’t!
Your lines would immediately be caught by your frame when your wing comes up, if you don’t have one large hoop surrounding the frame.