wonwinglo

Most of the small rubber kits have a simple nose button,this is quite useless in many ways as for one thing it does not give you any latitude to adjust the thrustline of your model when trimming,as this is a most essential operation the best thing is to resort to a proper nose block,this can be made up from laminations of hard balsa in a square shape with a balsa nose glued into place,putting rubber through a tiny nose button is near impossible and not practical so the nose block is a good practical alternative,once the balsa nose block is in place and sanded to the contours of the fuselage this can be bushed with brass tube and the ends flared over either side,next place the piano wire shaft into position and slip on a thrust bearing or even cup washers if you dont have a bearing to hand,make a suitable free-wheeling device for the prop so that it does not just stop 'dead' when the motor cuts,there are various ways of doing this the simplest of which is to embed a spring washer into the nose block and bend the motor shaft at right angles finishing into a neat loop,this is where a visit to Old Warden is well worth it to steal ideas from other modellers ! take your notebook and camera to record these small but vital details.
When forming the motor hook always slip some plastic tubing onto the wire shaft,this stops the rubber motor cutting into the wire,a wider nose block also stops that dreaded problem, the motor bunching up especially if you stretch wind the rubber.
Once you have found the proper downthrust,and side thrust you can then dispense with the paper packing and take the model home to make the thrustline permanent.
To understand the thrustline adjustment imagine the initial torque from the prop will try and twist the model the opposite direction,as the rubber power decreases the nose will straighten out but the model must be first trimmed for that initial biurst of power,same with the downthrust a high wing design will try and rotate around the axis of the centre of gravity,so we need to place the noseblock facing down a little to stop the model from power stalling,once again it is all about a compromise as are all free flight creations flying under their own devices,but boy you will learn about trimming fast !
Above all make the nose strong and sheet the sides in that area,the chances are that you are going to need weight in that area anyway so why skimp here ?
To be continued...

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'And there I was oil on my goggles from a broken pipe,then I looked at the altimeter,all I could see was the makers name !'
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