747 TQ Question

[IPG1939]

I have a quick one, As i tear down my TQ im finding a wealth of treats. As in these pics i see the Flap lever has 5 switches built in to it. My question being, Have any of you guys used these as your input instead of a slider pot? I would much rather because of the engineering they put into it. Im just missing a switch for flaps 20, That wouldn't be hard.

searched and found some guys adding switches them self, But couldn't find anything on using the OEM switches.

Also, what were the purpose of these switches? I see there were also cables. Where these just for the indicators?

Man, Boeing sure built these things tuff!

http://i255.photobucket.com/albums/hh121/tugengineer/PA210014.jpg
http://i255.photobucket.com/albums/hh121/tugengineer/PA210013.jpg
http://i255.photobucket.com/albums/hh121/tugengineer/PA210012.jpg

[rjvcarvalho]

Hello,

By the photos the individual switches are activated by the flaps 2 5 and 10 positions by the part attached to the flap wheel, they must serve as an indication of take off flaps warning.

[IPG1939]

Also if you look to the lower flap setting range there are 2 more switches for 25 and 30 deg

[wledzian]

If you want to fake a potentiometer, you can do it with a series of resistors. As you can hook up a pot as a variable resistor or as a voltage divider, I've included circuits for both.

http://www.mycockpit.org/photopost/data/500/flapswitches.JPG

In variable resistor mode, the switches are treated as single-pole single-throw. Full resistance is measured with all the switches open. Each switch that closes cuts the resistance by the value of one of the resistors.

In voltage divider mode, you sense through each switch in turn, with the switches wired as single-pole, double-throw. The capacitor to ground may be necessary to avoid spikes or dips during each transition.

[IPG1939]

Very good idea ^^^^^^!

This is why i love the site