start switches...

[Efe Cem Elci]

past 300 now.

[RadarBob]

Out of my range I'm afraid - So I was looking at making my own.

Does anyone know how the real switch behaves when it is placed into the 'GRD'
position ? - Is there any spring resistance - Or is it just the resistance of the
switch mechanism ?

Rob

[dnoize]

Push in to turn to left or right.

Solenoid held to GRD.

There are some very nice designs to be found on this forum.


Stef



.

[RadarBob]

Thanks Stef - I hadn't realised it was necessary to push the control in before turning.

When you turn it, does it feel as if it's spring loaded ?

What I'm getting at is:

Could the switch be spring loaded such that it latches when at GRD, and the solenoid just releases the latch to allow it to spring back - Or does the solenoid need to push the switch back ?

Also, can the switch be put back to the OFF position manually once it has been put into GRD ?


Rob

[dnoize]

When you push them in, you feel a spring tension.

When the solenoid is not powered, its not possible to completely turn the switch into ground position.

Not sure if you can pull it out of the grond position manually. i can try that tonight.

stef



.

[tomenglish2000]

Ah, that explains the recess in the panel around the start switch knobs on the 767 engine start panel I have!

One of lifes little mysteries solved. Thanks!

Tom E.

[RadarBob]

Thanks Stef.

I don't think the 737 has the recess around the start knobs - But I have noticed that the knob shafts seem to stick out quite a way forward of the panel, and I did wonder why that was.

Rob

[Efe Cem Elci]

Yeah no recess on the 737s I've seen. Just the knob sticking out further than usual to allow for the push down and turn operation. Pops up when you get to OFF but rotates from CONT to FLT and back depressed.

[RadarBob]

Thanks for that Efe.

Do you know whether having pushed in the knob, it turns under spring pressure
towards GND - Or is it just the usual force required to operate the switch mechanism ?

Rob

[Efe Cem Elci]

I'll take a look tonight but the ones we have are custom made. Worst case, I'll ask the pilot