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In order of connection:
My initial assesment of the simplicity of the throttle was a bit skewed. Its construction won't be impossible, but not a walk in the park, either. I found two outstanding sources for my throttle construction, one by Gustavo de Coro and Harry Crowell, the other by John D. Yarrow (see 9.4.1). I am not entirely certain about the workings of a C-130, but one would assume that it would have one throttle control for each engine, possibly even one set per pilot. That's four axes of motion, or one analog joystick port. We'll get more in depth on the electronics side of it in a bit. But, my thought is, since a 4-throttle unit would take up one port, the yoke and rudders would need a second. So, I'll probably have to get something like a Gravis Game Card, a PCI card put in your computer to offer you more joystick ports (two, if I remember correctly). Also, Mr. Yarrow's explanation showed the possibility of having 14 buttons, vice the 4 that Mr. de Coro demonstrated. If you'll notice the bank of switches on the throttle encasement, there are many assorted switches. I figure it'll be easiest to attach some of them through the throttle box.
Shelving rails...........: 1/2" (12.7mm) x 1/4" (6.35mm), length TBD Potentiometers...........: 4x 100K, linear taper Wood for cover...........: Balsa wood, 1/8" (3mm) Threaded rod.............: 1/8" (3mm) d, 4' (1219mm) l [at least] Screws...................: RHMS #10, 1/2" (12.7mm) (Round Head Machine Screws) Nuts.....................: to fit screws (above) Nuts.....................: to fit threaded rod Wire.....................: asst. colors, #22Ga (pref. shielded) DB15M Connector..........: one (for conn. to computer) Jacketed Wire 8 conductor: 9' (3m) (for conn. to computer) Terminal strip (8 terms).: one Plastic gears............: 4x large, 4x small -------------------------- 1N914 Diodes.............: 25x (approx) perfboard................: 1.25" x 2" x 0.1" (circuit board)
Super Joy Box 8 - Okay, it sounds wrong, but it'll be used to connect 15 pin things to USB things. Quite helpful if you ask me!
| Just about every resource you look at will have a map of the PC's joystick port. This is for good reason, one always consults map before one begins on a journey, unless one hopes to get hopelessly lost.
The map goes like so ==> Explanation [as I understand it]: As for what these modifications are, that's where potentiometers and buttons come in. Potentiometers are basically variable resistors. They impede the flow of electricity, just not all the way. They are also adjustable as to how much resistance there is, and the computer can determine how much resistance is there and translate it to an axis value. All clear? Now, one joystick port has the means to support 4 axes - Joystick 1's X and Y axes, and Joystick 2's X and Y axes. What we are going to do is use J1X (Joystick 1 - X axis) as throttle one, J1Y as throttle two, J2X as three, and J2Y as four. The port also has four inputs for buttons. Each of these inputs can have one of two values, off or on (0 or 1). This would make it very simple to have four buttons, as explained in Mr. de Coro's procedures. OR, you could set up a matrix, and have the four inputs act as a binary counting system, allowing up to 16 values instead of 8, and therefor allows for scads of buttons! (an interesting note on binary-did you know you can count to 1023 on your fingers? Assuming of course you have ten fingers, and each is given two values, down and up [off/on, 0/1]) |
Your joystick port: .---------------------------------. \ o o o o o o o o / \ / \ o o o o o o o / '---------------------------' Numbered like so: .---------------------------------. \ 1o 2o 3o 4o 5o 6o 7o 8o / \ / \ 9o 10o 11o 12o 13o 14o 15o / '---------------------------' 1 - +5v 9 - +5v 2 - Btn 0 10 - Btn 2 3 - Joystick1, X 11 - Joystick2, X 4 - Ground 12 - MIDI 5 - Ground 13 - Joystick2, Y 6 - Joystick1, Y 14 - Btn 3 7 - Btn 1 15 - Midi 8 - +5v |
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Wiring:
Most of this info comes from John Yarrow's site, he's got some other good stuff there, too.
14----------------.-------.-----------.-----.
| | | |
10----------.-----|-----.-|-----.---. | |
| | | | | | | |
7----------|-----|---.-|-|---.-|---|-|---. |
| | | | | | | | | | |
2--------.-|---. | | | | | | | | | |
V V V V V V V V V V V V V
^ - - - - - - - - - - - - -
Pin | | | | | | | | | | | | |
' ' ' ' ' ' ' ' ' ' ' '
_|_ _|_ _|_ _|_ _|_ _|_
Buttons-> 5 6 7 8 9 10
.-----. .-----.
| V | | |
| - | = 1N914 diode | _|_ | = Button
'-----' '-----'
(created by AACircuit v1.28.6 beta 04/19/05 www.tech-chat.de)
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I plan to base the majority of this construction on Gustavo de Coro's How to: Dual Throttles For Your Flight Simulator. This is an excellent resource for this procedure, so I would advise you to check it out. His yoke, though, only utilizes four buttons, so we'll be making a couple other modifications.
I did a bit of inquiring on the ole' newsgroups, and this is what I found out: The C-130 has 4 throttle levers on the pilot's side, and a feathering lever, defeathering lever, and 2 sync levers on the copilot's side (see this photo). These are all very important when flying the actual aircraft, but I'm not certain [at this point] whether their functionality will be required in the sim. If they are, I can always set up another set of levers using the last gameport (remember, with the GameCard we have three ports, so far we've used two).
This is what I got from the AOPA website:
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[preceeding concerns propeller types] "Constant Speed "Before there were constant-speed props, there were adjustable-pitch models. By altering each blade’s angle of attack, the prop can be better optimized for both climb and cruise performance. Early models used manual adjustment of the prop pitch, while a few pioneer inventors played with automatic pitch-change mechanisms. "As soon as aircraft developed wide speed ranges -- the difference between the slowest climb and the fastest cruise -- it was clear that a better system was needed. By the early 1930s, the groundwork for the constant-speed prop had been laid, in large part by Ercoupe and Piper Cherokee designer Fred Weick. "A separate mechanism is used to alter each blade’s angle of attack, with the goal to maintain a constant engine speed. In a fixed-pitch prop, as the airplane accelerates, the engine, given a fixed throttle position, will follow suit. With a constant-speed arrangement, the blades’ angle of attack increases as the engine tries to accelerate, loading the engine and maintaining the set speed. "This setup provides two main benefits over fixed-pitch propellers. First, you get a more optimum blade pitch setting, and second, the engine can be made to run at a set speed, greatly reducing pilot work load and making precise power settings possible. "Feathering props are found on most twins. "Feathering "A feathering propeller is simply a constant-speed unit that can rotate the blades until they are nearly aligned with the relative wind. This provides reduced drag in the event of an engine failure. Feathering props are found on most twin-engine airplanes." |
Feathering as I understand it: The blades of the propeller are like so =-(/)-= during flight (assuming a top-down view, ^that way being forward). When they are feathered, they become like so ==(|)== . That way, the wind will just pass by and not slow down the aircraft any further than it has to, should the engine die.
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