How To Build Your Own Cockpit

Parts 4 - 8

by Kev Saker

Part 4

It's now time to decide if you are going to build the full cockpit or a smaller set up. If you decide to build a smaller set up all you require is a simple wooden base for your flight controls and centre consul. If you wish to build the full cockpit please refer to diagram part 4.

This shows how I constructed my base. You will see this is designed around the sliding monitor display system. The drawing shows dimensions for my sim, however you can make the base to your own dimensions if you wish. Materials used were 6 inch x 1 inch floor boarding and one inch ply for the top.

The workstation is made of white faced melamine board. All the dimensions are approximate.

Part 4A

Next we need to build the control column. I started by cutting a length of aluminium tube; cut a hole in this for the cables from the yoke to exit in to the centre consul. This is fixed to the base using two pieces of alum plate bent to the shape of the tube and fitted with plasticard inserts which provide bearing surfaces.

Finally, the control column is cut from 3-inch plastic drainpipe and bolted to the alum tube. The top of the column has an alum plate bolted in position as shown this is the bearing plate for the yoke.

Part 4B

This section shows how the yoke is attached to the column. The diagram is looking down on to the column and you will see there is an aluminium plate bent and fitted inside the tube, the yoke centre pin is pushed through this and secured with a split pin.

Also it is necessary to push all the cables from the yoke through and down the control column and alum tube into the centre consul.

Below this diagram is a simple drawing on the layout of the joystick pots which shows how the controls are attached to the pots. The aileron pot is secured at the base of the control column and the elevator pot is fixed on the base in the centre consul in front of the alum tube. Both linkages use model aircraft snap on ball and socket connectors. It is important that there is no free play in any of the flight control linkages.

Part 5

Part 5 shows a simple wooden frame for the centre consul. Attached to this are two metal plates which the throttle bar uses as shown in the lower drawing. This bar is steel with an aluminium sleeve cut into segments which are used as spacers between the stab trim lever, the two throttles and the flap handle. The bar is held in place with split pins.

Also on this page you will see a tray which has two sliding lead weights attached to the throttles. This provides the throttles with feel and is also part of the auto throttle system.

Part 5A

The auto throttle system is a basic unit that will move the throttles via micro-switched commands from the control column and from the auto throttle control panel.

It is a simple system, which can be added to at a later date. In this form when the control column is pulled back the auto throttle will add power, when the column is pushed forward slightly the auto throttle will move the throttles back towards idle. Also a simple E.P.R. reduced thrust mode for take off can be included and a descent mode which will retard the throttles slowly.

The system is easy to build and requires a small amount of electrical knowledge. The metal tray with the lead weights forms part of the system. Simply attach 4 wheels to the tray and fit aluminium guide rails at each side. All this fits under the radios pedestal. If you move the tray with your hand you will see that the throttles move forward and backward, so now we fit a geared down motor to drive the tray. (The best place to obtain a motor for this job is your local car breakers yard, a car windscreen wiper motor is ideal being 12 volt and lots of power to move the tray.)

To do this cut a length of threaded rod and attach it to the motor. Next cut a piece of metal and bend it to an "L" shape, weld a nut to this plate that the threaded rod will screw through, bolt this assembly to the under side of the tray.

If you apply 12 volts to the motor you will see the throttles move nice and slowly forward and if you reverse the polarity to the motor backwards.

Naturally you need to fit cut out micro switches to each end of the assembly to stop the tray over running. The wiring diagram for this is on the page. The beauty of this system is at any time you can move the throttles manually, as the lead weights will just slide along the tray.

Inputs for this device can be as simple as two micro switches that will detect small movements of the column. The E.P.R. system is a switch on the auto throttle panel to start the throttles moving forward. By fitting a micro switch to one of the throttles with a piece of nylon cord attached, running forward through a pulley to a small drum fitted to the back of the temp selector on the auto throttle panel. So when the throttles move forward the nylon cord is pulled back until the micro switch is activated to cut the power to the motor.

The temp selector can have a scale on the panel so by rotating the selector the cord length is increased or shortened to adjust the selected thrust setting. You can also fit a descent switch to the panel that can activate the motor to slowly return the throttles to idle.

Parts 6 And 6A

Make up the throttle tops as shown in the drawing, use alum bar and plasticard with micro switches to activate the reverse thrusters. Cutting a piece of alum tube, glue two plasticard disks to each end. This makes the throttle handles. Next mix up some two component epoxy putty (Milliput modelling putty) and clad the handles as shown.

When completely dry put the handle in an electric drill on slow speed, glue some course sandpaper to a piece of alum tube to use as a sanding tool. Carefully sand the Milliput down until you get the concave shape of the throttles. This method will also produce the thrust reverser handles also.

Part 7

The flap lever is built using aluminium bar and a selection of nuts and bolts plus a couple of micro switches.

To set the flaps, a lever is pulled up and moved to the next detent position. The method I used to accomplish this is as follows: first cut two pieces of alum bar, bolt them together with a washer so that they can move as in diagram. Fix two micro switches to the lower bar as indicated; this lower bar then fits on the throttle bar across the centre consul. You will see that there is a control cable fitted to the bottom of the lever, this goes to the flap position gauge on the centre instrument panel. (These plastic control cables are used with radio controlled model aircraft).

When the lever is moved for example backward, the micro switch is depressed once for each detent; also the flap indicator gauge shows the corresponding flap position.

The micro switches can be connected directly to the joystick cables for the flaps up / down function.

It is necessary to fit a tube to the top bar. This has a rod with a spring at the lower end, the lever is lifted and the flap handle moved to the next de-tent, as in diagram.

Finally, the flap selector plate is cut from a piece of aluminium and bolted to the side of the throttle housing.

Part 8

The manual stab trim lever is perhaps not needed on the simulator as we have a very good electrical trim system on the yoke, however I thought it would be better if I could build a simple system if possible. The diagram shows my idea. The stab trim lever has a friction plate which makes the movement quite firm. This is attached to the stabilizer upright bar inside the centre consul via a nylon line and two springs.

Basically this adjusts the centre stop position of the control column. So by moving the stab trim lever back the column centre stop is commanding a slight climb, push the stab trim forward and a slight descent will be held hands off. It's quite effective when used.

Below this is a diagram of the speed brake set up. The lever is attached to a toggle switch which turns the speed brake deployed light on. When the lever is pulled back this momentarily activates a micro switch that deploys the speed brakes. It works the same way to lower them. Also there is a diagram showing how to wire up the speed brakes so that they will automatically deploy when reverse thrust is engaged provided the speed brake lever is in the armed position.

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