Custom-made tail rotor

[Steve Shepard]

Over the holiday weekend our local rc club had it's 1st annual Christmas Bash. One of our members is an 85 year young retired watchmaker, jeweler, and aircraft designer. He is the kind of fellow that will build his own deisel engine for his rc copters from scratch. No design drawings or plans, etc. He just sits down at his mini lathe and milling machine and carves away everything that doesn't look like what he is trying to create. He expressed concern about the tail rotor (cat killer mod) function at full forward/backward position. It seems the blades flatten out at speed, reducing the pitch, and therfore the thrust. He took my rotor home Fri. eve and Sat morn he showed up with a 4-blade titanium rotor. Guess what?-- Now the BR has good fore/aft speed (faster than I can walk-maybe 5-6 mph (!)
On the matter of yaw/main rotor pitch-- I added more pitch to the top blades as described, to correct the ccw yaw, but after a couple flights, the yaw returned. Al suggested trimming .020" from the lower rotor blades' trailing edges. Now, no more yaw. Consistently.
I realize not everybody has access to guys like Al, but I think it might be worth while to experiment with making new rotors out of blister packs ( the kind that are welded together around the perimeter, and seemingly impossible to open, short of blasting with gunpowder) The plastic needs to be gently heated and held in place till it cools. Good luck !

[EvilVampire]

Where do you get the material to make the new rotors yourself. Im still having problems with mine breaking right where the shaft goes into the base. Lucky, NOT

[Steve Shepard]

EvilVampire : as I said, find something that comes in one of those dynamite-proof blister packs. Stores like WalMart, KMart, hardware stores, etc have all sorts of junk that comes in this kind of blister packs. Try to find something you need (maybe a set of small drill bits) so you can drill a hole for the motor shaft. To prevent breaking at the shaft hole you might try to reinforce the center by CAing a small disk over it and then drill the hole for the shaft. When you mount the rotor to the shaft maybe add some baking powder or microballoons to the CA to add a wee bit more strength to the assembly. Mind that you recheck your CG and be ready to add some forward weight (Iwrap a bit of scotch tape to the forward landing gear legs) Hope this helps .

[Stiznef]

Sounds like a firmer tale rotor could increase forward and backward mobility combined with triming lower rotor.

What about using some hardening fluid on the tail rotor instead of replacing the entire tail rotor?

Any ideas from anyone on what could harden the tail rotor and keep it from flattening out?

Stiz

[RiccoFX]

Over the holiday weekend our local rc club had it's 1st annual Christmas Bash. One of our members is an 85 year young retired watchmaker, jeweler, and aircraft designer. He is the kind of fellow that will build his own deisel engine for his rc copters from scratch. No design drawings or plans, etc. He just sits down at his mini lathe and milling machine and carves away everything that doesn't look like what he is trying to create. He expressed concern about the tail rotor (cat killer mod) function at full forward/backward position. It seems the blades flatten out at speed, reducing the pitch, and therfore the thrust. He took my rotor home Fri. eve and Sat morn he showed up with a 4-blade titanium rotor. Guess what?-- Now the BR has good fore/aft speed (faster than I can walk-maybe 5-6 mph (!)
On the matter of yaw/main rotor pitch-- I added more pitch to the top blades as described, to correct the ccw yaw, but after a couple flights, the yaw returned. Al suggested trimming .020" from the lower rotor blades' trailing edges. Now, no more yaw. Consistently.
I realize not everybody has access to guys like Al, but I think it might be worth while to experiment with making new rotors out of blister packs ( the kind that are welded together around the perimeter, and seemingly impossible to open, short of blasting with gunpowder) The plastic needs to be gently heated and held in place till it cools. Good luck !


You should get him to make more of those titanium tail rotors and sell them! I keep breaking mine - keeps snapping off!