The Wing Pivot
The tube of the head of the pylon is the axis on which the wing will pivot. For that, a bolt made of screwed rod of 10-mm. material 200 mm. long goes through the wing and holds to it the metal piece which is bent into a U and welded on to a tube made of rolled strip of 2-mm. thickness.
The pivoting is assured by these two tubes revolving one on the other, one being fixed on to the pylon and the other fixed to the wing. In case it is impossible to weld, one can arrange a metal fitting without a tube, but doubled. The tube will be so arranged that the metal piece moves freely on it, but without lateral play. Perfect adjustment of these two tubes is useless; whether there is 1 mm. or 2 mm of play is of little importance, provided that they are approximately round. A drop of oil is all that is necessary.
Choice of span
The wing span should be adapted to to the space in which it is to be constructed.
The ideal is a room or apartment of metres x 4 metres. The machine itself is small, but this room should suffice for it . The wing is the largest part and has a span of 4 metres.
The plane was first tried with a 5 1/2 metres span, but it was decided to try 4 metres as a test. The first profile, with a flat lower side and the tail turned up, showed itself perfectly stable, but it did not lift well. The machine meandered across country, but it wanted the full power of the motor, and it scarcely climbed at all.
If one only wants to flutter so to speak, to learn to fly on little journeys of two or three kilometres above a flat open plain, where one can land anywhere, then this span of 4 metres is possible. It is better than a machine which only rolls on the ground; better than a "penguin" because it really flies " in the air and the principle incorporated in the " Flea " will permit faults of piloting which in an ordinary aeroplane would lead to catastrophe. Its lateral stability is immense.
Commence in that way if your room will not allow you to make a bigger wing. This wing of wing of 4 metres for the standard model will be suitable for the rear wing of another "Flea," or perhaps will be the the means of doing a kindness to a pal.
If you are light (10 stone) and are only thinking of short journeys, then a span of 5 metres will suit you very well, but on 6 metres you can weigh 12 stone, and you can carry with you enough petrol for three or four hours' flight.
Whether on 4-, 5-, or 6-metre span, the construction is identical. You only have to elongate, at your discretion, the ends of the wings (which means a few extra normal ribs to nail) and alter the attachment of the bracing wire. The central part remains unchanged.
This last wing of 6 metres, longer and deeper, and better arched, is definitely superior.
The Front Wing
The framework of the wing (Fig. 20) is made up of 18 ribs threaded to the main spar which is 6 metres long. A small rear spar of 5 metres 20 mm. is inserted into the tails of the ribs, which are all of the same pattern.