Dual rotor /tiltup furl (revised)

[Stewart Corman]

After reviewing my design and feedback about how high the tiltback has to go to be effective and I could NOT even reach 45 degrees, I decided to modify the previous build by simply inverting the shaft bearings to below the frame, shortening the pillars holding up the servo, and remounting the pivot shaft to below the main shaft

304

The adjustable stops for the horizontal were extended up

305

note the shaft is still above the pivot but hanging below the frame, althought the new lever arm is measured at 1 1/4", whereas it had been 1 1/2"

306

here is the tilt at just shy of 60 degrees, the furl stops are fixed by the geometry of the two extended 2" x 3/8" C channel and a stop plate mounted to the base

307

closeup of the assembly when tilted

308

I have the means to allow it to tilt more than 60 degrees by using the pivot shaft mounting holes off centered, but I am not sure I want to, since there is a a gyroscopic effect caused by the spinning of the blades and I don't want the tail too far down and close to the tower where the wind stearing could be compromised.

Thanks to those here and from Otherpower who have given me constructive criticism.

Stew Corman from sunny Endicott

[Paul Bailey]

Nice flexibility in the design Stew....Since I have not followed the Math too much here ,How much power is available in the given swept area Vs. what you are planning on getting from the 1.3 Kw servo. ????? Also If you upgrade to the next size servo ( same outer dimension but just longer I think) ,do you have enough adjustability for correcting the Balance and Yaw , or if you installed larger blades??? Good job, I'm sure alot of thinking went into this . Paul:)

[Stewart Corman]

Paul,
thanks for your questions

a 10'8" turbine at 40% efficiency in a 20mph wind (at furl) can produce about 1.5KW ..so the entire setup is "balanced" and I am sure there is overspeed headroom

the next bigger servo is wider, not longer, so that is why I used 1" aluminum spacer blocks to mount the servo to the frame w/ uprights

there is a second set of mounting holes for the pivot shaft 1" forward, so between the +/- 1/4" slots and the other holes, I think I can accomodate any balance of the additional weights ...bigger/heavier blades, bigger/heavier servo

BTW, don't give me toooo much credit for designing this on paper ..much was done by fitting up the parts and seeing what fit where...I am a firm believer in the KISS principle ...

IMHO, I had thought the balance point would centered under the servo ...I was only wrong by about a foot!!! A Mark commented earlier about leverage ..that tail boom and tail weighing 30 lbs and sticking out 10 feet is a LOT of leverage

Stew