Control Systems

Not being the greatest welder, building the control system was the first steel work I attempted. I attended a TIG welding course at our local college. Not easy but I suppose by the time I finish the Piet, I may have some idea as to how to weld.

IMG_0313_JPGThis is the first attempt at rudder pedals/bar and control sticks

IMG_0329_JPGI then welded the streamline tubing for the elevator control horn

IMG_0392_JPGDue to the size of the torque tube bearing (pictured above) I had to modify the elevator control cable routing. The pulley position on the torque tube was too low to allow the control cables to go over the rear bearing enroute to the elevator control horn. I tried designing a way for the pulleys to sit inside the torque tube so that the cables exited the tube from the center. I scotched this idea because I could not install the control cables already made up and tested. They would have had to be made up in-situ. I eventually decided to follow others on the net and used push rods to move the control horn.

IMG_0379_JPG IMG_0378_JPGDuring all this time making the control system I was thinking about how I was going to cut all the steel needed for the plane. After much deliberation and research I decided to purchase the steel in reasonably small quantities and have it all laser cut.

I went though all the plans and pencil drew all the bits I could find. I then used the pencil drawing to transfer all the data to Visio. I sorted all the drawing pieces into their relevant steel sizes and and produced a drawing for each steel thickness. Laser Cutting shops generally use ACAD *.dwg files so I created a zip file with the Visio drawing files redrawn in the ACAD format.

Juggling around for hours trying to get the most pieces per sheet of steel. I sent one of the most complicated drawings to a local Laser cutting shop and asked for a quote. They came back with AU$250.

I though that was pretty reasonable being that a small bandsaw would have cost AU$750 to AU$1000 and I still could not get the same amount of pieces from a given size of steel sheet.

I then went and purchased the steel from a welder at one of our Regional Airports. It was more expensive per sq foot than a steel supplier but I got what I needed without any wastage.

I took all this to the Laser cutter only to find that he could cut a minimum of 18 inches square. I had some bits as small as 6 inches square. Home again to rearrange the drawings once more.

When redrawn and laser cut I was very impressed with the result.

IMG_0330_JPGAll cut and it only cost AU$350!

IMG_0335_JPGShowing the laser cutting route

IMG_0336_JPGAll the bits laid out on printed copies of the Visio drawing.

I still have some small pieces to do and have found another laser cutter that can do small sizes, no doubt at a greater cost.

I assembled the new rudder pedal with toe brakes (thanks to John Dilatush for the photos of his rudder bar). It was almost like using a Meccano set. The pieces were all a tight fit.

The completed control system now looks like this (some mounting hardware is not of the correct type. I was awaiting an order from AS&S).

IMG_0390_JPGElevator control horn and swing arm behind rear seat.

IMG_0389_JPGSwing arm behind pilot’s seat. I have since reinforced the seat back to take the bolts

IMG_0388_JPGRear control column and aileron horn

IMG_0387_JPGRear control column and aileron horn showing rod ends inside control column

IMG_0386_JPGRudder bar and toe brake levers

IMG_0384_JPGFront control column and rudder bar

IMG_0383_JPGFront rudder pedals (I may redo these, they are still the originals!!!)

IMG_0397_JPGThe completed control system parts awaiting painting