The Jackal Submarine: May 2015

Here's a few pics on the progress of the rudder cables running from the pedals, under the seat and out to the rudder. It's being tested with string at the moment, though once it's done it'll have a 4 mm thick nylon cord. A few problems have been found, but it's nothing that can't be fixed with a bit of time.

How it works is; a string runs in a loop from one pedal, all the way to the rudder shaft, and from the rudder shaft back to the other pedal. So if one pedal goes forward, the rudder turns and pulls the other pedal back, ready to be pushed so the rudder turns the other way. But due to the pedal being so heavy (almost five kilos) the force required to pull it back is so much that it instead it stretches the string and the pedal doesn't move! I'll upload a few pics of it being fixed later this week.

Here's both pedals in place and wired up. You can see the nylon cord running from each pedal. If you've got good eyes you might just be able to see the cable running between the pedals at the back. The cord runs from the pedals to two arms that pivot on the hull. This is so the pedal moves through a greater distance before turning the rudder through its full angle of movement; and it makes it easier to push by increasing the leverage. The cable will run from the points on the arms closest to the hull, out to the rudder.

Without the arms, the cable has to be pulled a mere 16 mm for the rudder to turn 78° - with the arms the cable has to be pulled about 90 mm for the same angle. This will give better control over turning.

Fig. 1.
19/05/2015

The rudder shaft arm. The left side has a cable that runs to the left pedal and the right side to the right pedal. The arms on this shaft are a lot smaller than the arms from the pedals (about five times smaller) which is why it's so hard for it to pull the pedal back. (For the pedal to pull the rudder is five times easier, for the rudder to pull the pedal is five times harder)

Fig. 2.
17/05/2015

The cable hub that sits under the seat and directs the cables from both the rudder pedals and elevator controls toward the rear of the sub.

Fig. 3.
21/05/2015

It's been a few weeks and the back end is taking shape. The rear has almost been completed and right now I'm in the process of welding it to the back of the sub and strengthening it up.

One of the most time consuming parts to make were the bearing and water seal brackets. Each one was designed to scale on the computer to be sure that it would fit, and work, inside the 65 mm by 65 mm square tube (blue steel in the back of the photo).