Item 1057
DESIGN: UniCopter ~
Rotor - Blade - General - Material
Notes:
Material:
Core:
Spar: - Aramid fiber (Nomex) honeycomb core sandwiched between unidirectional carbon composite and pultruded carbon rods. May required some non-carbon fabric on upper surface to handle compression, if there is any.
Skin: - Bi-directional carbon cloth. 20/70/-70/-20. Or if the is to be separate root and tip control have the bi-directional cloth laid up with the threads running parallel to the span and \parallel to the chord, for the twist. Also, consider having spanwise tow of carbon and chordwise tow of fiberglass. This might add in-plane and out-of-plane strength and stiffness while still allowing active twist.
Leading edge weight: - Tungsten wire.
Method of Construction:
Too be added
.Tip Weight:
Consider not using one since the blades have a lot of mass already.
Approximate Weight of Blades:
Material for calculations: DA 4518U uni-graphite unidirectional prepreg tape.
Weight: 0.060 lbs/sq ft.
Thickness: 0.006 inch/ply
Weight per square inch: (0.060 / 144) / 0.006 = 0.0694333 lbs/sq in.
Cross sectional area of blade at tip [VR-7 w/ 5.25" chord]: 2.175 sq. in.
Assuming 25% of this area is core then area of carbon is 2.175 * .75 = 1.63125 sq. in.
If the amount of carbon does not change from tip to root and only the shape changes from flat at the tip to round at the root then the total weight of the carbon in an 8 foot blades is: 0.0694333 * 1.63125 * 8 * 12 = 10.87 pounds per blade.
The core will add approximately 1.0 lbs
The radius of the hub will cause a deduction of approximately 0.5 lbs.
The leading edge weight will add approximately 6 * 2 = 16 =1 sq in at .0694333 lbs for 6 ft = 4 pounds.
Each blade will weight about 15.5 pounds.
The six blades will weigh a total of approximately 93 pounds.
xxx
Back to top | UniCopter Home Page
Last Revised: May 5, 2006