Ideal blade design

[zeeoo]

Hello gentlemen, i'm shure you can help a poor worm like me.

What would be, on your opinion, the ideal blade design for :

- ultralight helicopter
- gyro capabilities
- tip jet capabilities
- 3 bladed semirigid rotor.

some basics : non linear twist, evolutive airfoil.
- root chord : 18 cm chord airfoil : S1020 , twisted 10 deg
- at 10 % : airfoil : VR7 , twisted 4 deg (CORRECTED)
- at 90 % : 16 cm chord airfoil VR9 , twisted 2 deg
- tip airfoil : super critical 0 deg twist.

tip shape : a mix of swept back and BERP tip, 2 % down dihedral, 30 degrees swept back.

weight expected : 3.5 kg (7lbs)

what would be on your opinions the limitations in a gyro mode use, a tip jet use, a classical powered use.

thank you

[bugdevheli]

How long do you expect the blade to be Zeeoo?.

[zeeoo]

Bug,
the blade will be 3 meters long from tip to last airfoil, the hub will be about 50 cm diameter, meaning a disk diameter of 6.50 meters.
Thank you.

[bugdevheli]

Thank you Zeeoo. A quick mental calc tells me your blades have to be about half the weight of r22 blades per foot lenght. Do I assume they would be of composite construction. Bug.

[zeeoo]

Thanks Bug
Yes they will be made of composites.
one precision about the weight : the blade grips will be molded with the whole blade, so, the extra weight for the blade, but weith save for the hub.
Thank you