Auriga (oz14423)

About this Plan

Auriga. Radio control hand launch glider model, for 2 functions.

Quote: "Auriga. Try this neat V-tail chuckie by Matthew Jones.

The Auriga was designed about eighteen months ago as a lightweight glider with a conventional tail and an aluminium boom about 1/2 in diameter with an RG 15 wing. The trouble was that it came out at 22 ounces which is too heavy for a HLG (mostly lead to counteract the heavy tail) and produced an unacceptably high wing loading. However, it flew for a season and it did me well.

At the beginning of the year, I resolved to make myself a lighter version and looked at where I could save weight. A vee tail and a lighter boom were the way to go.

The first one flew well with the SD 70212 wing but there were some problems. The tail was too small which made the plane difficult to fly. It was also too flexible and prone to flutter from a hard hand launch.

I made several changes, including going back to at the RGI5 wing and it proved a pure delight to fly.

Tail: I always like to start here because it is quick and easy and gives encouragement to finish the rest. Start by cutting the inner and outer 'blocks; and pin to the board. Cut and glue the leading and trailing edge pieces and then the diagonals paying attention to the glue joints (see later). Repeat with the control surfaces.

Now, sand everything to the correct profile and the angle at the root join. Sand the control surfaces to shape and chamfer the hinge join.

Next, pin one side to the board and pack up the other until an angle of 110 degrees is made at the joint and glue. When set, remove from the board and add a strip of light glass cloth top and bottom with five minute epoxy.

Next, cut the boom to length and glue it to the tail with epoxy and strengthen with more glass cloth and epoxy. This may seem time consuming but so far, I haven't found a lighter/stronger way to hold a vee tail Any suggestions? Add the skid.

Make the control horn by squashing some 1/8 brass tube flat, cut to length and drill a hole 1 to 1.5mm diameter in one end and remove any burrs which may fray the wire trace. Bend to the right angle and roughen the other end to provide a better 'key' for gluing. Cut the slots in the control surfaces for the hinges and horns and glue them both in.

Make up the torque rods from the thinnest piano wire (22 swg). The trace pulls the surface down and when slackened, the torque rod forces the surface up. Painless wasn't it? Time for a tea break.

Wings: These are your standard spar and rib assembly so there are no problems there - are there?

Cut the spars to length and pin the bottom ones to the board. Make the ribs (either free cut or sandwich method) and glue in place. Now add the top spar leading edge, LE and TE sheeting, inner sheeting if applicable and capping strips. remember that the two inner ribs need to be trimmed to accept the wing locating dowel.

Next repeat for the outer sections remembering the tip blocks. When all four panels have been built and sanded to shape, join them by butt gluing together first and then reinforcing the joints with lightweight glass cloth (best to do this at the same time as glassing the fuselage, it saves mixing up two batches). Now add the ply sub ribs either side of the root ribs for the wing locating dowel. Add the ply support for the wing bolt.

As can be seen, I have omitted the 1/16 shear webs and ply braces, this is a personal choice but go ahead if you feel that the extra strength and rigidity merit them.

Fuselage: This can be built in two ways, either with 1/8 balsa sides or with 1/16 balsa, glass reinforced. Start by cutting out and laminating the formers (you will need to trim 1/16 off each if using 1/8 balsa sides) - remember to drill the holes for the boom and wing locating dowel.

Cut the main side panels and glue F1 to F4. When set, plank around the bottom up to F4 and add the nose block and hatch.

Slide the spare half of the boom into F3 and F4, slide F5 down the boom into its position and plank around the rear end. This ensures that all the holes line up, then add the tail piece.

Make up the wing nut former, drill the hole and insert the nut and glue the former in. Do not push it down too far or it will block the holes for the boom. Glass reinforce if you wish. The boom can then be glued in with thin cyano..."

Auriga from Silent Flight, August 1995.

Direct submission to Outerzone.

Supplementary file notes

Article pages, thanks to RFJ.

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