737 OEM TQ Parking Brake conversion

[paulnd]

Hello,

I'll be very grateful if someone can suggest a good parking brake mechanism/setup that mimics the OEM park brake.

I've searched this forum and others although there are a number of threads about the parking brake, I have yet found one suitable for an OEM TQ that is close to the real thing.

There is a very detailed write up here http://www.flaps2approach.com/journal/2015/7/1/throttle-quadrant-rebuild-parking-brake-mechanism-replacemen.html which is a very interesting read but doesn't go into detail on the mechanism between the actuator and control rod except explaining what it does but not how. Unfortunately it is also obscured in the photo and it's this bit that I'm having difficulties with.

I'll be very grateful for any advice, photos etc

thanks in advance

Paul

[Gallie]

Hi Paul,

Axel has som very clear pictures on his website.
http://www.famgrau.com/N737AG/Controls/Pages/Installing_Flight_Controls_%28Nov.2010%29.html#7

Push toe brakes, pull parkbrake handle and the toe brakes are then locked in the pushed position.
In the picture you can see the linkage from the throttle quad postition towards the rudder linkage.
The mechanism is spring return, the spring is located above the toebrake interconnect linkage (captain side).

A link to a other forum where i shared some pictures of my cockpit that shows some of the linkage
https://prosim-ar.com/forum/viewtopic.php?f=17&t=9491

Michael

[paulnd]

Hi Michael,

Thank you for the links.

I unfortunately don't have the space for under floor linkages so I have to compromise, I was thinking of engaging the parking brake control rod with an actuator and then when I get round to designing a pedals/rudder unit, I'll design a mechanism to hold the toe brakes when the parking brake is engaged. The link will be virtual rather than physical, or at least that's my ambition!

In the meantime, I'll be happy to have a "as real as possible" action for the parking brake lever.

Paul

Sent from my Nexus 7 using Tapatalk

[Aerosim Solutions]

Hi Paul,

I have used a 12 volt actuator from a car central locking system. My custom built TQ is a true full-scale replica and the parking brake lever works in the same manner. My auto-throttle software was custom built by a friend who is a whizz at coding and I don't fully understand how my TQ works but I do know the principle. I have a Phidgets 888 board that energizes the actuator for half a second to release the parking brake. As you know, when both toe brakes are pressed, FS displays a red flag sign "BRAKES". My friend's software reads the offset that triggers this flag and it triggers the park brake release actuator, it works great!!
[smg id=1080]
Cheers Gwyn

[paulnd]

Thanks Gwyn, do you perhaps have any photos of the how the actuator links to the parking brake.

I'm fine with the software aspect but finding the mechanical design a bit of a challenge. I plan to CNC mill or 3D print required parts.

Paul


Sent from my iPhone using Tapatalk

[srisim]

Thanks Gwyn, do you perhaps have any photos of the how the actuator links to the parking brake.

Second that request. Looking for the same details.

Thanks in advance.

Srini

[Aerosim Solutions]

Thanks Gwyn, do you perhaps have any photos of the how the actuator links to the parking brake.

I'm fine with the software aspect but finding the mechanical design a bit of a challenge. I plan to CNC mill or 3D print required parts.

Paul


Sent from my iPhone using Tapatalk

Hi guys, this is how I did my park brake.
There is very little room inside my TQ under the parking brake, there is the gear drive for the speedbrake and numerous switches etc. The very bottom of my park brake lever has a hole drilled in it and this is tapped with an M3 thread. An M3 bolt secures a length of fishing trace wire which is made of stainless steel. This wire exits the TQs base plate then through a hole into the centre console, my actuator is mounted within the centre pedestal underneath the radio units. The actuator pulls on the wire via a small lever arm that increases the travel distance of the pull and the park brake handle flicks forward with a nice sounding clunk! It is really quite simple and this method doesn't take up any room within the TQ itself. If I ever had to remove the TQ I would just disconnect the wire from the actuator.

[smg id=1353]
[smg id=1354]

Cheers Gwyn

[paulnd]

thank you Gwyn