RC Conversion - MK/4 Endeavour.
PART 3 - The Rudder Assembly.
Two routes for the rudder, either make your own as I have done on this example or buy a ready made modern nylon equivalent from a hobby supplier. Lower down the page is an alternative MK/4 conversion fitted with a ready made rudder.
If you make your own, this will be the hardest part of the conversion and will consist of a rudder blade, a shaft, an outer tube, two washers, two seals and a tiller arm. I used 2.5mm brass rod, 3mm O/D brass tube with 0.5mm brass plate for the blade. The shape was made from a smaller SB series version, cutting out the blade shape requires cutting the straight edges with metal sheers first, followed by nibbling away at the round profile, finally putting a smooth curve on with a straight file, take your time and you will get a good result. Next is putting the hinge like tube section on the opposite end to take the brass rod, you may have your own way of fabricating this but for me it was easier to bend the brass using a pair of silversmiths duck billed pliers which have wider jaws than ordinary pliers. Start at the very edge and bend up the brass just a little to start the tube shape, then go further in and repeat a couple of times until you can bend the brass right the way over.
Keep checking the brass rod for the right profile. Insert the brass rod into the brass sheet and by gripping the sheet and rod together you can slowly bend the sheet around the rod until it completes the tube shape. When this is completed, you can use the pliers to put an opposite angle on the tube to the blade to centralise the tube.
To make a permanent join, I soldered the blade to the rod but modern day epoxy glues may do the same for you. To do this, I removed the rod from the blade, then after rubbing the end of the rod with some abrasive paper to clean it up, coated it with some solder flux paste and inserted the rod back into the tube. Laying down the rudder onto a brick with the open joint of the tube uppermost, I placed a couple of small lengths of solder along the join, with a gas blowlamp, I heated first the brass rod close to the blade then the blade itself and the solder melted running into the join and around the tube. It was then left to cool.
Assembling the rudder.
Perform a dry run first. First push you brass tube or sleeve into the drilled hole in the hull from the top downwards until it pokes out of the hull 2mm. Then mark a point 5mm above the hull recess, trim the tube and finish the cut end with a fine file as a nitrile sealing ring will be fitted to both ends. The final trimming of the tube depends on the next step.
Taking the rudder, fit a brass washer to the shaft followed by a nitrile seal, push the rudder up into the tube all the way, then fit another seal followed by another washer. Fit the tiller arm so that the arm points to the side of the hull (Some tiller arms have more than one arm, cut off any unwanted ones with a hacksaw. Tighten the securing allen key. Place a straight edge across the hull top edges over the rudder and make sure that you have enough clearance, at least 3mm, for the rudder to move when the linkage wire is finally attached, trim the tube if you do not have enough clearance. If all is okay, mark the rudder shaft, disassemble the rudder assembly and the trim the rudder shaft to length using the mark made. It helps if you can file a small flat on the top of the shaft where the tiller arm grub screw tightens up.
Fitting the rudder tube.
Rough up the tube side with rubbing paper to make a key for the glue. Mix the epoxy glue putting some down the drilled hole and also around the outside of the tube, then push the tube into the hull so that it extends the required 2mm underneath, wipe away any excess glue. While the glue is soft, place the rudder shaft into the tube and adjust the tube in the hull so that it is vertical from a front to rear and a side to side view, somehow brace the rudder so it sets in this position, I used masking tape. When cured, remove the rudder from the tube.
Final assembly.
Taking the rudder, fit a brass washer to the shaft followed by a nitrile seal, get a small dab of grease, push the rudder up into the tube and apply the grease to the lower half of the shaft as it enters the tube, push the shaft all the way, then fit another seal followed by another washer. Holding the rudder blade in a straight ahead position, fit the tiller arm so that the arm points 90 degrees to the side of the hull (Some tiller arms have more than one arm, cut off any unwanted ones with a hacksaw if necessary). Tighten the securing allen key grub screw, it sometimes helps if you are able to file a small flat on the shaft to locate the grub screw. Make sure there is no up / down play and not too tight to restrict a smooth movement, when happy, add a drop of glue to where the shaft protrudes the tiller arm to hold everything in place.
Fitting A Shop Bought Rudder.
Above: Ready made rudders come in different sizes, I have chosen one with a blade depth of 48mm, a maximum width of 38mm and a shaft diameter of 3mm with a 6mm sleeve. The kit comes with a nylon washer seal which I would suggest add on above this a 3mm I/D nitrile seal and another one at the top of the tube under the tiller arm.
To fit, after marking the position of the rudder shaft, drill a 6mm hole making sure that it is vertical in both planes, you may need to open out the hole a tiny bit to provide a sliding fit. Position the tube into the hull so that the bottom protrudes about 4mm and mark the top of the tube 4mm above the deck cut out, remove the tube and with a hacksaw shorten the tube to the required length. From the off cut portion of the tube, knock out the top bearing and press into the piece you are using. Roughen up the outside of the tube, apply some epoxy glue and refit into the hull to the required overhang. It helps to replace the rudder whilst doing this so that you can hold the tube into a vertical position as the glue cures, use masking tape to secure in place. Dry fit the rudder assembly, take the rudder, fir the nylon washer, then a 3mm nitrile seal, fit into the rudder tube, then fit another nitrile washer followed by the tiller arm, check for clearance below he deck level, if all is okay, mark the rudder shaft, disassemble the rudder assembly and the trim the rudder shaft to length using the mark made. It helps if you can file a small flat on the top of the shaft where the tiller arm grub screw tightens up.
Final assembly.
Taking the rudder, fit the nylon washer provided to the shaft followed by a 3mm nitrile seal, get a small dab of grease, push the rudder up into the tube and apply the grease to the lower half of the shaft as it enters the tube, push the shaft all the way, then fit another seal. Holding the rudder blade in a straight ahead position, fit the tiller arm so that the arm points approx. 90 degrees to the side of the hull (Some tiller arms have more than one arm, cut off any unwanted ones with a hacksaw if necessary). Tighten the securing allen key grub screw, it sometimes helps if you are able to file a small flat on the shaft to locate the grub screw. Make sure there is no up / down play and not too tight to restrict a smooth movement, when happy, add a drop of glue to where the shaft protrudes the tiller arm to hold everything in place.
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