During hovering flight in windy conditions, the pilot's ability to maintain heading control is greatly enhanced by the addition of strakes horizontally mounted along the helicopter tail boom. Without the strakes, the tail boom "flies" in the winds from t....

How about having made a round tapered wooden rod the same size as the tail boom except a little longer (say 10 feet long). A (2 part or 1 part) glass female mold is made over this rod.

The rod is wrapped in plastic, a release material is placed over the plastic and the fiberglass (or later carbon) is laid up over this. A plastic sheet is then placed over the lay-up. This is then inserted into the female mold and with a screw device pressure is applied. The extra length is also to allow removal of excess boom after making. It is also to allow the male mold to extend out the small end of the female molded when pressing and curing.

A ring with pins is slid over the male mold before applying fiberglass. This ring is clamped to the female mold to compress the flange, which has additional fiberglass in it for strength.

The additional reinforcing/bracing for control surfaces are slid inside this tube and bonded with epoxy later.

Would this be of interest to Rick?

Consider having the male mold contain a air fitting at one end and a pipe running down its length. Dozens, if not hundreds of small holes would then be drilled from the outside cylinder wall into the central tube (porous). This method will not put as much pressure on the curing composite as the screw method but it will allow for an unequal wall thickness, for additional fabric at areas where holes are to be cut into the tube to attach control surfaces etc.

The screw system may allow for shaving away a little of the cylinder wall in places for additional fabric, as long as this cut-away has a taper in the direction of the small diameter end also.

The boom is not subjected to the same horizontal loading as it is on a conventional helicopter in full CCW yaw.

If large end diameter is 4.5" dia. then circumference is 14.1429"

If small end diameter is 2" dia. then circumference is 6.2857"

Consider if a unidirectional cloth was cut (14.1429" + 6.2857") 20.4286" wide. And a length of ??

Then cut diagonally from 6.2857" from one side to 6.2857" from the other.

Will this wrap properly around a tapered tube @ 45 degrees with no gap?

Look at the Xerox in the Composite folder {A029] for idea in wrapping aluminum tube in unidirectional tape then curing then removing aluminum tube with acid.

From Sun 'N Fun; - The composite propeller blade manufacturer uses a Teflon coated tapered tube that is removed after the cure. This results in a hollow center for the root end third of the blade.

 From Sun 'N Fun; - The company that produces carbon composite cowlings for older Cessna planes uses a Teflon coated straight aluminum tube for his carbon tubing. It expands for cure and shrinks for extraction.