Brittain BI-805 valve substitution question.

[Mooneymite]

There are several iterations of the Basic Brittain wing leveler, or PC.  The one in my '74 C model is very different from others I have seen, though it seems to work pretty much the same.  My question pertains to PC's of my PC's vintage.

 

I would like to switch out the basic pneumatic control valve

which is mounted on the interior side of the firewall

with the BI-805 electric control valve .

 

Has anyone here on Mooneyspace made this switch?

 

Was it a worthwhile modification?

 

Do you have any pictures of the installation?

 

Where did you locate the BI-805?

 

Where did you put the "disconnect" switch?

 

Any other advice?

[Schinderhannes]

I believe you are on the wrong TRAK here  (pun intended)  The two valves serve a very different purpose, the top one disconnects the positive control, the BI-805 is part of the Accu-Trak autopilot.  It is connected to the control head and the electric valve open and close to relay the steering commands from the Accu-Trak to the servos.  In our M20C the BI-805 is mounted in between the eye-brows. I will try to take a picture later today.

[Mooneymite]

Yes, you are correct.  The BI 805 is part of an Accutrak II system.  I thought that the 805 valve controlled the vacuum to the entire PC system....

[scottfromiowa]

Is the first valve your yoke mounted valve? There is a replacement (electric) that eliminates the manual yoke valve. Need the new style yokes to make it work. A solenoid "cuts off" the PC vs. pushing the button on the yokes.

[Mooneymite]

Yes, the first valve is the original pneumatic pilot valve that is (on my plane) mounted on the firewall and contolled by the yoke button.  I thought (incorrectly, apparently) that the BI 805 was the electric replacement.  Do you know the nomenclature/part number for the electrical replacement valve?

 

I know the BI 805 is a very pricey part.  I'm hoping that the electical PC disable switch is a bit cheaper.

 

Is it absolutely necessary to upgrade to the new yokes, or can an electrical switch be added to the original style yoke?

[scottfromiowa]

The electric solenoid pc disconnect was about a .1AMU's. Cheap. Pretty easy to install. I don't think you could do it on the old yokes as it is not certified for them.

[Alan Fox]

Most people put a fish tank valve (aux static valve)  in series with the yoke buttons vacuum line to have a cutoff switch ,   It is real simple , the yoke switch is normally closed , when you push it in it opens the line to atmosphere and the main supply valve to the rate gyro closes and the system shuts down...... get a vacuum tee , tee it into the line coming off of the yoke going to the main valve , run the open port of the tee to the valve , and PRESTO its done , about 4 dollars in parts.......

[N601RX]

Here is the valve you need to replace the original pneumatic valve and button. It sold several months ago. I believe there are 2 routes for the approval paperwork. One is use the paperwork from the mooney yoke upgrade kit and I think I've heard someone say that Brittain has paperwork for just swapping the valve.

http://mooneyspace.com/topic/8672-for-sale-brittain-electric-wing-leveler-valve/

[Mooneymite]

Ah, so.....

 

Thanks.

 

Any idea what the part # is?

[N601RX]

4085