Hi,

Any help would be appreciated with this. I am currently 70% through building a UH-18 SPW Hoverwing (I've attached a picture of a finished version). I am currently about to start work on the tail section, which consists of a horizontal tailplane with elevator, two vertical tailplanes each with a rudder (it differs slightly from the photo which has three). The thrust duct at the rear has four 38.1mm inner diameter aluminium tubes bonded/glassed in, which extend out the back of the duct by 9 inches. The idea would be that 6061 aluminium tubes with an outer diameter of 37.8mm would be a sliding fit into the 4 "sleeves" mentioned, which would then be pinned to stop any movement and allow them to be removable. The length of these tubes would be 1.5 metres, supported by the duct sleeves along 9 inches (230mm) at the duct end. There would be an extra stiffener as shown in the photo, running from bottom of thrust duct to the horizontal tailplane to prove some extra rigidity. My question is, would these roll-wrapped tubes provide the stiffness/strength required instead of using the 6061? The tail can obviously sag a little while at rest, but will provide lift during flight and therefore can't move a ridiculous amount... The tail surfaces probably add up to around 10-15kg total.

The reason for asking is that these craft have a tendency to be tail heavy, and if I can save weight by doing this it's worthwhile, as it's so far behind the centre of gravity.

Thanks, Oliver

PS sorry for switching between imperial and metric... the plans are imperial :@!

If you look at the Specification tab on the webpage listing, you will see the mechanical data for these tubes. You just need to compare to the mechanical data you have for the 6061 tubes and work from there.

Warren Penalver
Easy Composites / Carbon Mods - Technical Support Assistant