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Super Junior model aircraft, a conversion of the Junior 60
Aileron conversion of the Junior 60 vintage model aircraft
This model aircraft is a standard radio control converted junior 60 fuselage and tail surfaces fitted with a modified aileron equiped wing.
What you see here is the second attempt at this modification. The first was very successful until the wing folded, sending the plane by express route to Austraila.
This time I'm using an existing Junior 60 model and a just a new wing.
The wing has the same planform as a standard issue Junior 60. I've changed the wing section to a flat bottom one by removing the undercamber from the original aerofoil, and the wing is built flat with no dihedral angle.
Construction of the new wing is very similar to the standard Junior 60. Inboard ailerons are built into the wing and local reinforcement is added around these. Joining the two panels and centre section are two long 1/8 inch x 3/4 inch spruce braces which run either side of the main spar. These are of different lengths to avoid a local stress area where they end. The last one of these I built used a ply brace which failed under load.
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This version of the wing is fitted out with a servo for each aileron, these being mounted local to their respective control surfaces. Wires are run through the wing and soldered to a servo lead. The first one of these I built had a single centre mounted servo and piano wire pushrod running through the wing which moved the ailerons via bellcranks. Both systems do the job well, but the twin servo method is quicker to build and a bit more positive.
To mount the servos hardwood blocks are fitted to the wing. The servos are mounted into SLEC aileron wing servo mounts and these are then screwed into the blocks. Instead of the standard self tappers I used countersunk 3mm machine screws on this model, the holes for these being drilled and tapped into the blocks. This gives a very secure job.
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Before fixing on the ailerons to the aircraft's wing the underside of both the wing and ailerons were covered in solartex. Doing this job before hinging on the control surfaces avoids having to paint the part between the wing and ailerons. For hinges I used some barb hinges, these are quick to fit and have been proven over many flights in my camera plane.
I used some old pre-supershrink solartex on this wing. This stuff had been knocking about the workshop for a long time waiting for an aircraft to stick to.
As this was the old solartex a coat of dope was applied and then the wing spayed with some tuf coat. This is not really required but I just felt like it. Gives I nice glossy finish which stands out from the grubby old fuz and tail.
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The OS20 FS engine was replaced with a brand new SC36 heli engine which needed running in. This is a ringed engine so I wanted a model aircraft which could fly easily with the engine running rich while the ring beds in. The helicopter silencer from a Century Hawk was fitted which makes the plane look like a Kenworth (the exhaust jet should give plenty of downthrust!).
This engine is a compact powerhouse, I was able to use the existing engine plate, just needing to file some extra side clearance and drill new holes. The one plate can now be used for this engine or the OS20FS.
The plate is screwed down with woodscrews into hardwood bearers, rubber grommets being used to give the required down-thrust as well as damping out much of the engine vibration.
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More information on this model aircraft on page 2
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