B298

DESIGN: UniCopter ~ Rotor - Blade - NACA 00xx

Outside Helicopters

Some Outside Helicopters that use NACA 00xx Blades. Some with Large Thickness:

	Root	Tip
Bell 209 AH-1 Cobra	NACA 0009.3 mod	NACA 0009.3 mod
Bell 212 UH-1N	NACA 0012	NACA 0006
Vertol 76 VZ-2	NACA 0009 mod	NACA 0009 mod
Bell 48 YH-12	NACA 0018	NACA 0012
Bell 61 HSL low twist	NACA 0018	NACA 0012
Jovair J-2	NACA 0018	NACA 0018
McCulloch J-2	NACA 0018	NACA 0018
Bell 47G-2 H-13G wood blades	NACA 0017	NACA 0011
Bell 47J HUL wood blades	NACA 0016	NACA 0012
Texas Helicopter M74 Wasp	NACA 0016	NACA 0012
Texas Helicopter M74A Wasp	NACA 0016	NACA 0012

Move the following line to DESIGN: UniCopter ~ Rotor - Blade - NACA 230xx, when the page is produced.

Sikorsky S-69 XH-59A ABC

NACA 63(230)-224A

NACA 23012(64)

Polynomial for NACA 4-digit Symmetrical Sections:

See bottom of page [Source ~ PHA p.253]

UniCopter

Notes:

I thought that the ABC blades were NACA 0025 at the root.

There is the idea of producing the first blade for the UniCopter as an NACA 00xx symmetrical and thereby build only one mold for all 6 or 8 blades. This will not be that practical if the blades are required to have a built in droop (anhedral) to compensate for lack of absolute stiffness.

A symmetrical blade can be used on both the port and starboard rotor if there is

no twist (unless mold can be twisted when adding the skin)
no need to mold in anhedral.

Consider the ability to take the spar for a symmetrical airfoil and by machining a small amount off the bottom surface (flattening) this spar might work for an asymmetrical airfoil.

Look into the possibility of making the blade roots 2.25" or 2.0" diameter; particularly if there are 4-blade rotors where the blade carry 1/3 less loading.

Also consider the use of torsion-tension straps, if there are 4-blade rotors. This should reduce the overall height of the rotorhub.

Both of the above will reduce the drag of the rotorhubs and the blades, at a critical area because of the airflow to the propeller.

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Last Revised: January 12, 2007