This prop saver was invented by Claus Urbach from Germany ! Thanks a lot for the idea !
It will save the propellar and motor shaft when landing harder than expected,
on some electric models landing gear is not an option so this saver is the only way.
This prop-saver can be used with brushless and normal electric motors, DANGER: NEWER WITH GLOW ENGINES !!!
Here is the idea sheet, approwed be the invertor him self.
remember to cover the M3 thread with some heatshrinking tube, to protect the rubber gasket that holds the prop.
The M3 screws I used are 10mm length
The top part where the prop is fitted is made so the prop fits exactly !
remember to make it so the prop is easy to bend over to the side
Note the bottom part is hollowed out so the edge can touch the motor base
This is also important in serious crashes.
See the plastic tube pressed over the screws, where the thick rubber gasket is mounted.
Mounted on small Speed 300 motor
make sure there is a gap from the saver to motor, about 0.2mm
Important: When you press on the saver, it will touch the motor base part, not the baring.
Little 5.7 x 3 prop mounted.
See this looks really prof.
Close up from top.
Using another rubber gasket type
The black type is a bit more strong, and not so elestic; compared to the red one.
25mm diameter, measured at center.
Prop mounting area is 13mm diameter.
Prop mounting area height is 5.6mm.
The propellar I use for this example is a Robbe 5.7 x 3 (cost about 5 EUR)
Motor shaft is 2.0 mm diameter.
Warning: When working with propellars extra caution must be taken !
if your prop does for fit perfectly or your rubber band is old, REPLACE and fix it !!
Else you might injure somebody with a flying prop or parts from it !.
Use the information found on this page at your own risk, it is your responsibility to make it safe.
Also make sure battery power is DISCONNECTED before you get yout fingers near a prop on a plane,
Just shutting OFF or GAS=None with your transmitter is NOT save.
Imagine what happens if a radio disturbance suttently gives a max speed code to your reciever !!
Think Think and Think again; about all the possible things that maybe can go wrong what ever you do.
Made June 2003 OZ2CPU.
Brushless 10 x 4.7 prop.
Made for a 10 x 4.7 prop and a 3.17mm gearbox shaft