Parking Brake Lever Won't Stay Latched

[emerydc8]

I am not able to get the parking brake lever to stay latched when I try to set the brakes. I noticed that my right toe brake only goes to 996 when fully pressed. I am using the Precision Flight Controls Cirrus rudder pedals and the PSX virtual parking brake lever to set the brakes, once both brakes are fully applied.

I put a voltmeter on the right pot and couldn't get it to go all the way down to zero voltage like I could with the left. Also, when I removed it from the brake assembly and turned the pot by hand it still only went to 996 -- not 1000.

I just got off the phone with PFC and they are saying that because the tolerance on this 10K Ohm pot is +/-20% it is within tolerance and not defective just because I can't get it to show zero volts at the outer limit. I ordered a new pot for $30 and will see if this fixes the problem. I have my toe brakes set to -30 on each side and they work fine to stop the airplane -- no notable asymmetric pulling to either side.

Would only getting to 996 on one side cause the parking brake not to latch?

Thanks,
Jon D.

[Hardy Heinlin]

950 is the limit, i.e. 95% of max travel. I think that agrees with the real Boeing mechanics.

+/- 20% error tolerance on a pot -- e.g. 8k Ohm instead of 10k Ohm -- is rather poor quality, I would say (typical 2$ toy).

How high does the pedal indicator go up (magenta hooks in the upper left corner of the PSX frame)?


Cheers,

|-|ardy

[emerydc8]

The hooks go all the way up on both sides when I press the brakes. When I hold them down, I pull the virtual parking brake lever back and release the toe brakes while holding the lever back. I see parking brake set on the EICAS; but the lever just snaps forward when I take my finger off of it. Maybe it's a touchpad issue. 

[Hardy Heinlin]

950 is the limit, i.e. 95% of max travel. I think that agrees with the real Boeing mechanics.

+/- 20% error tolerance on a pot -- e.g. 8k Ohm instead of 10k Ohm -- is rather poor quality, I would say (typical 2$ toy).

However, even with 20% tolerance, the pot should be good enough to contact the outer pins, so that in a voltage divider circuit the middle pin is 100% closed with the one or the other outer pin. Whether the 135° angle (on a 270° pot) produces exactly the half voltage, is not that important indeed.

The hooks go all the way up on both sides when I press the brakes.

So your USB pedals are OK.


I'll search the forum ... I think Nico had a similar problem some months ago.


Cheers,

|-|ardy


Looks like Nico's problem was something different, just the Neutral zone not being set to zero:
http://aerowinx.com/board/index.php?topic=2657.0

Jon, while you're holding the park brake lever:

When your pedals are fully depressed, the magenta hooks should go up to the max.
When your pedals are fully released, the magenta hooks should fall back to the 95% position.

When you now release your finger from the park brake lever, the lever should hold itself in the pulled position, and the magenta hooks should keep staying at the 95% position.

[emerydc8]

Thanks for looking at this, Hardy. No matter what I do, as soon as I release the toe brakes, both magenta hooks go all the way down, even with the parking brake lever being held by my finger on the touchscreen. I can live with using the keyboard spacebar on this one though. Is there supposed to be a yellow vertical bar on the right and white on the left where the magenta hooks rise up during toe brake application?

[Hardy Heinlin]

The vertical bars are rudder pedals, not toe pedals. Yellow means the rudder trim is out of center.

[emerydc8]

Okay. Thanks. I'll check that out.