Chiribiri N5 (oz15023)

About this Plan

Chiribiri N5. Radio control scale model, for electric power, with Speed 400 geared motor.

Quote: "Chribiri N5, by Peter Rake. A 45 in wingspan model, designed for small electric motors and 3 function mini R/C.

I've always had something of a soft spot for some of the more obscure pre-1914 aircraft (some would say between my ears), so when I saw a peanut plan for the Chiribiri N.5 (oz4116) I was hooked. With our local clubs main annual competition coming up, the plan was drawn and construction started, despite being unable to find any more information on the aircraft. All I am able to say about the prototype is that it's from 1912 and is Italian. So the colour scheme is highly researched pure guesswork. But I think it looks the part, and you must admit it is pretty.

In order to keep the weight and size down I opted for 600ma. nicads, a Speedgear 400 7.2v motor and Hi-Tec mini Rx. and servos. Motor control is via a Westbury speed controller. All of which means you should be looking for an all-up weight of around 28-30 ounces. Since the model is so straightforward to build, an in depth construction article is hardly necessary. This being the case I'll just cover some of the more important points in each stage. The most important thing is to keep it all as light as possible, since there isn't that much reserve of power. Do not, however, omit the rigging. It may only be monofilament fishing line, but it really is functional and does it's job well. I used 30 lb, breaking strain on the wings and 12 lb. bs on the tailplane, cyano'd into the blocks, once everything is finally lined up.

Fuselage: If you've built a Flair kit this will all be old hat to you. Build the front (sheet) section and the rear framework and join them inverted over the plan.

All the wire parts should be bound and cyano'd in place, as should the skids. Assemble the leg with the axle etc, before it is bound in place (unless you're feeling masochistic). Also worth noting is that if you fly from a tarmac strip you'll need to reinforce the tailend of the skids with wire. They act as a tail skid and the rudder would be the next thing to get ground away.

Motor mounting is to a 1/8 Reply plate & can be with either 'shell' mounts or a rolled ply tube. If you're using the cheaper 2.33/1 geared Speed 400, this has mounting lugs fitted.

Wings: I like to start with these whilst I'm still filled with enthusiasm. The tips are laminated from three strips of well soaked 1/16 x 3/16 balsa PVA'ed together and formed around card templates. The root rib bay sheeting and the reinforcing at the rigging points and wing tips are important. Don't omit them.

Tail surfaces: Nothing in the least difficult here. Just build them as drawn and don't be tempted to 'beef' them up. The rigging will provide all the strength needed.

Finishing: The models open structure is covered with Litespan whilst the sheeted areas are covered with veneer, sanded very smooth and then stained and varnished. The method used to make the louvres in the lithoplate panels is as follows.

Mark the louvre position and drill a small hole at each end. Now cut between the holes with a knife (score and flex). Make a 3/16 wide slot in a piece of scrap ply and round-off the end of a piece of 3/16" diameter dowel. Position the litho over the slot and use the dowel to form the louvre. Do a few practice runs first. The bottom litho panel is screwed in place, in case you need to get to the motor at some stage. Rib tapes are narrow strips of masking tape.

Flying: Well, I wish I could say it flew straight off the board, but it almost did. As I said earlier it was built for a club competition and time was pressing. So, even though the weather was less than perfect (quite windy & cold), I decided to test fly the model. Hand launched into the wind, she actually managed to make some headway, and a circuit was flown. Much relieved to have it back on the ground again, I left it at that and went home; where re-equipped with 8x600AE cells and a Master Airscrews 12 x 8 wooden prop, I was all ready to try again.

I only live about two minutes walk from our local cricket field, so when the sun rose on a dead flat calm morning, it was too much to resist. Hand launched (again), she climbed away beautifully, nice and slow and steady. Not wishing to push my luck, she was brought round in a nice gentle circuit and lined up for a landing. However, she decided that she didn't want to stop flying, so the landing was well overshot (150 ft), but at least she was down safely.

The competition went quite well, with perfect weather, and a second place for my little model, with lots of character, which performs faultlessly.

A smashing little plane to fly, low & slowly. So get building."

Direct submission to Outerzone.

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