four bladed rotor dominator

[quadrirotor]

Who has info about the four bladed rotor that RFD claimed to be the best in the Rotocraft Mag of Dec-Jan 97-98?

[MikeBoyette]

What would you like to know? I maybe able to help since I am the author of that story. I will tell you this, it was an experiment that we decided to release the results of. The PRA magazine was about the only forum we had at the time.

[quadrirotor]

Why this configuration is not more widespread?
What are the advantages and drawbacks?
What are you gone a do with that experimentation?.
thanks.

[MikeBoyette]

1. Too expensive. Most people have a hard time justifing the cost of two sets of blades.
2. Advantages are dead smooth stick, smaller disk, larger payload, and increased top end speed. Disadvantages are increased control forces,storage of a machine with four blades, cost.
3. This idea was abondoned due to the cost and the fact that a rotor head confiqured like this will eventually fail due to the scissors affect. Dad had a mechinism in his rotor head that delt with this by allowing "in plane compliance". This worked great on a light two place such as our 618 powered Draggin two. We tried it later on Rusty Nance's Mazda powered Air Command. The results of this were not as promising. The "in plane compliance" was not enough for this amount of weight. After only a few flights Rusty felt a shake in the system . He came down and we discovered cracks in the same place on all four blades. They were on the inboard section of the blades on the trailing edge. The experiment was over. Dad decided to go in a different direction to solve the shaking inherent to a two bladed system. This was the slider head.
I hope this helps.

[quadrirotor]

Yes, thanks a lot. Can you explain what's the slider head?