MOOgallo (oz14351)

About this Plan

MOOgallo. Radio control sport model, for electric power. A micro RC Rogallo wing.

Quote: "Construction: Begin by checking your servo against the servo notch shown on the plan; you should adjust the size of the servo notch to fit your servo. Having checked the notch, cut the main fuselage piece out of light, C-grain balsa; don't forget those two big holes in the pylon! Cut two strengtheners out of 1/4x1/2-inch basswood to accept the servo screws.

Now cut out all six 1/64-inch-thick ply pieces so that you have two pylon braces, two nose plates and two pylon plates. Epoxy these pieces to both sides of the fuselage, holding them with clamps until the epoxy has cured. Make the landing gear by bending 1/16-inch music wire, and install it over the fuselage and the ply nose plates. To strengthen the assembly, wrap the gear with thread and glue. Now bend the tailskid and install it, this time using a piece of nylon tape for reinforcement.

Make the motor mount out of 1/16-inch ply and balsa quarter stock that's shaped to 'saddle' the motor. When installing the motor mount, be sure to incorporate right thrust as shown on page 2 of the plan. Drill a small hole beneath the motor mount to accommodate the tie-wrap that will secure the motor. Cut the battery plate out of 1/16-inch plywood and attach it to the bottom of the fuselage. Strengthen the plate with quarter balsa stock, as shown. Set the fuselage aside.

The sail is shown on page 2 of the plan. Cut three pieces of 1/8 x 1/8 x 22-inch basswood. In the keel plate, make a notch for the spreader, then epoxy the keel plate to the keel so that the spreader notch is 10 inches behind the nose (the keel is the bass-wood piece that runs along the middle of the sail).

Make a paper pattern of the sail and place it on your building board. Tightly tape a 24x40-inch sheet of sail material (HDPE, high-density polyethelene) over the pattern, smoothing away as many wrinkles as you can (use HDPE of the kind that makes a 'crinkly' noise when shaken; don't use the soft stuff). Clean the sail material with rubbing alcohol and let it dry. Spray the keel strip (the edge that goes against the sail) with 3M 77 spray glue: let the glue get tacky, then press the keel down along the center of the sail material from A to B as indicated on the plan. Now spray the leading-edge pieces and glue them down to the sail. Let the sail dry before going on.

While the sail is still taped down, trim it. Using a new no.11 blade. first cut the material from C to B and from B to D. Then cut from D to A and A to C. Now you are ready to create the 'billow' in the sail. Put weights on the keel, and move C and D toward B until the trailing edge measures 19 inches (the sail will be wrinkled, but don't worry). Weight the leading edge and add the spreader (a 25-inch piece of Yax1/8-inch basswood or spruce). Slide the spreader through the keel plate at G, making sure the spreader is perpendicular to the keel - then glue the spreader to the keel at G, and at points E and F only. Do not glue the spreader to the sail. Cut away the sail material at the nose, and glue two nose braces cut out of 1/64-inch plywood to the top and bottom of the nose.

After the nose braces have set, bevel the keel plate and the 1/8 x 1/4-inch strip on the top of the pylon as shown in the 'Sail Hinge Detail' on page 1. Slit the wood and install three Sig Easy Hinges with thin CA. Add the wheels, install the servo and fasten the motor to the mount with a tie-wrap. Epoxy the plywood horn to the spreader bar (5/8 inch out from the keel plate) and construct the sail pushrod (adjust its length to fit). Glue the 1/56-inch dowel into the hole in the top of the pylon. Glue on one side of Velcro to the battery plate and its other side to the battery. The receiver and ESC are fastened on either side of the fuselage with thread sewn through the wood. Glue a Deans base-loaded antenna to the top of the pylon and parallel to the keel.

Trimming and Flying: Balance is very important in this design: there is no way to trim the glide except by adjusting the balance! With all the equipment installed. support the model by the 1/16-dowel under the wing. The keel should be level with the horizon: if it isn't, move the battery pack until it is.

This design is just like any other rudder-only flyer: there is only right and left. The servo pushes the spreader bar and causes the sail to tilt from one side to the other. This motion also shifts the weight laterally, and the plane accordingly banks toward the heavy side.

Up and down are controlled by the throttle. If the nose pitches up during climb, apply left or right to bleed off lift. Too much throttle will pitch the nose up, but the MOOgallo will not stall: just throttle back. This is one of the beauties of the Rogallo design; of course, the downside is its poor glide angle, but you can't have it all! Adjust the sail throw at the wingtips so that each wingtip travels 2 inches up and 2 inches down from neutral.

Always launch and land your MOOgallo directly into the wind! It doesn't like crosswinds; gusts can cause you to lose control. When hand-launching, be sure to tip the nose up and allow the breeze to fill the sail: then lower the nose and gently launch. If you don't fill the sail first, the plane will drop until the sail is filled, and you might not have enough altitude to recover. It will take off from smooth surfaces, but be ready to throttle back or turn on takeoff.

This is a very draggy design. so don't expect flashing performance. It doesn't like wind because the wing is flexible and gusts bounce it around, but it does love to fly indoors!"

Direct submission to Outerzone.

Supplementary file notes

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