1322

Item 1322

OTHER: Flight Dynamics - Control - Twin Vertical Stabilizers

Overview:

A simple means of improving the yaw authority of an intermeshing helicopter.

The thinking behind this idea is directed primarily at helicopters that have relatively weak yaw authority during hover (rigid rotor intermeshing etc.). The objective is to move the craft's center for drag forward, toward a central location, as the craft's forward velocity decreases.

This should allow for normal yaw stability during forward flight, while demanding less from the yaw device during hover.

An alternative method might be; OTHER: Flight Dynamics - Control - Variable Vertical Fin Concept

Idea:

The intermeshing helicopter has limited yaw authority. It may therefore be advantageous to have two smaller vertical stabilizer's, located side-by-side and in close proximity to each other.

The two should be sized and spaced to provide good stability about the vertical axis (yaw) during forward flight.
During hover, one rudder will reduce the effectiveness of the other and this could be utilized to balance the aerodynamic (drag) moments for and aft of the vertical axis.

Design Thoughts:

Having a small spacing between the two stabilizers will be advantageous during hover since the closer they are the less the aerodynamic force from side wind or craft rotation. This close spacing will result in drag during forward flight since the air must be compressed/accelerated as it passes between the two fins.

Perhaps the fins can have a thin profile such as NACA 0006 or 0009, or have a thinner profile on their inner surfaces and a NACA 0012 on their outer surfaces.

Make very thin to minimize profile drag and the compression then expansion in the gap between the two vertical stabilizers?

A low and a high HS to tie the two VS together?

Shape the fuselage behind and below the rotorhubs to minimize drag and impart a small swirl to the air , which is opposite to the swirl generated by the propeller. The VSs are located out of the rotor and propeller down/back wash

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Initially displayed: May 11, 2004 ~ Last Revised: January 22, 2007

The above application of reverse velocity utilization in a twin main rotor helicopter is openly and publicly disclosed on the Internet to negate an entity from patenting it, to the exclusion of all others whom may wish to use it. ~ Reference patent law 35 U.S.C. 102 A person shall be entitled to a patent unless - (a) the invention was known ... by others in this country, ..., before the invention thereof by the applicant for patent.