What Does Airspeed Switch Look Like?

[MBDiagMan]

In the next few days I hope to get my 67 F on jacks and check into an electric landing gear problem.  I am trying to get familiar with everything possible before getting in and under the plane.  One thing I need to know is what the “air pressure safety switch” looks like.  Some may call it an airspeed switch.  I am told it makes at about 80 MPH.  I expect it to be located near the ASI.

Any pictures or information is appreciated.  I don’t think the gear is coming up.  No red light, and it flies like a slug.

As a side note, I had to give up my wonderful Johnson Bar C due to a shoulder injury.  Now I have electric gear that must be kept working.  Bad deal.

Thanks in advance.

[Marauder]

In the next few days I hope to get my 67 F on jacks and check into an electric landing gear problem.  I am trying to get familiar with everything possible before getting in and under the plane.  One thing I need to know is what the “air pressure safety switch” looks like.  Some may call it an airspeed switch.  I am told it makes at about 80 MPH.  I expect it to be located near the ASI.
Any pictures or information is appreciated.  I don’t think the gear is coming up.  No red light, and it flies like a slug.
As a side note, I had to give up my wonderful Johnson Bar C due to a shoulder injury.  Now I have electric gear that must be kept working.  Bad deal.
Thanks in advance.

You sure you have an airspeed switch?


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[MBDiagMan]

No, but the wiring diagram shows a pressure safety switch in series with the up circuit.

Consider me at the level of first day of the Mooney Electric Gear 101 Class.

[Marauder]

Here is what a squat switch looks like just in case (left wheel).




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[Ragsf15e]

My 68F with electric gear installed at the factory has the airspeed switch right behind the airspeed indicator.  No squat switches at all.

what has your gear been doing, not coming up as expected?  What about the lights vs the floor window... is it retracting ok but the green light stays on? Has your airplane had the 20 to 1 gears installed instead of the original gears?  What about the required gear gears (yeah, that’s what I said) inspection/lube?

[Marauder]

They were switching between the two switches and I think others with pre-70 may have airspeed switches.


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[MBDiagMan]

Thanks guys, keep it coming.

The plastic window between the seats is so foggy I can’t see much.  Can I just cut a piece of plastic and how hard is it to replace?  I saw a screw on the top.

The gear was all put together sometime early this year by An MSC.  It has been flawless for about 15 hours of flying.  It has a 40:1 actuator.  

I am trying to start moving maintenance and repair to my own hangar.  The local, competent shop is straight across from my hangar.  I am wanting to get it on jacks so I can get familiar with the system myself with them doing the work.

Knowing that if it has the airspeed switch it is on the back of the altimeter is good information.  If it has the squat switch what does it do?  Does it have the limit switches inside?

[Guest]

Look for a disc about 3” in diameter, silver in colour, located behind the instrument panel near the ASI.  It will have a hose on one side and a pair of wires on the other.

Clarence

[Marauder]

Thanks guys, keep it coming.
The plastic window between the seats is so foggy I can’t see much.  Can I just cut a piece of plastic and how hard is it to replace?  I saw a screw on the top.
The gear was all put together sometime early this year by An MSC.  It has been flawless for about 15 hours of flying.  It has a 40:1 actuator.  
I am trying to start moving maintenance and repair to my own hangar.  The local, competent shop is straight across from my hangar.  I am wanting to get it on jacks so I can get familiar with the system myself with them doing the work.
Knowing that if it has the airspeed switch it is on the back of the altimeter is good information.  If it has the squat switch what does it do?  Does it have the limit switches inside?

Yes, you can make a replacement window for the floor actuator. I made one earlier this year. Once removed, I took it to Lowe’s and had them match it up with a piece of acrylic for thickness. They cut it to size for me and I used the original to match the holes in it.


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[MBDiagMan]

Okay guys!  As always you guys are tons of help!  Headed to the airport in a few minutes.

Now..... if it has the switch, it seems that once on jacks the switch will have to be bypassed to raise the gear.  Is there a provision for that?

[ziggysanchez]

@MBDiagMan, Here is a picture of the airspeed switch.

[Marauder]

48 minutes ago, MBDiagMan said:

Okay guys!  As always you guys are tons of help!  Headed to the airport in a few minutes.

Now..... if it has the switch, it seems that once on jacks the switch will have to be bypassed to raise the gear.  Is there a provision for that?

You will need to either use the bypass switch or disable it. Your F may not have this bypass switch installed. I had mine installed. It's the red button next to the gear switch. Post us a picture of your panel.

[Yetti]

What year F?   My 75 F works the gear fine on jacks.  No acrobatics required.

[MBDiagMan]

It’s a 67 model but shows up on some papers as a 66.  I expect it was built in late 66.

[MBDiagMan]

There is a brass disc shaped thing about 3 inches in diameter on the back of the asi that is no more than about a half inch thick with a pinto line to it.

[Guest]

13 minutes ago, MBDiagMan said:

There is a brass disc shaped thing about 3 inches in diameter on the back of the asi that is no more than about a half inch thick with a pinto line to it.

Should have said that newer ones are anodized gold colour.  I think you’ve found it.

Clarence

[MBDiagMan]

There is a brass disc shaped thing about 3 inches in diameter on the back of the asi that is no more than about a half inch thick with a pinto line to it.

[MBDiagMan]

It was dark when I took these pictures.  No bypass switch.

I am going to get some tubing to test the switch and be ready to swing the gear.  

My 94 year old Mom is going on hospice, so this project may get delayed, but please keep the discussion going.  I am getting an education and the thread will hopefully help others now or down the line.

Thanks to all.

[Yetti]

I would be careful with the Pinto line, they have been known to explode when rear ended.

[MBDiagMan]

Yeah, don’t you just love autocorrect?

[Marauder]

1 hour ago, MBDiagMan said:

It was dark when I took these pictures.  No bypass switch.

I am going to get some tubing to test the switch and be ready to swing the gear.  

My 94 year old Mom is going on hospice, so this project may get delayed, but please keep the discussion going.  I am getting an education and the thread will hopefully help others now or down the line.

Thanks to all.

Looks nice!

[MBDiagMan]

Thanks!  Now if I can just get that dial in the upper left to wrap around way past 135 again, it will all be good.

[Ragsf15e]

Got pictures of one in my ia shop today... this on a 76 F.

[Vance Harral]

12 minutes ago, Ragsf15e said:

Got pictures of one in my ia shop today... this on a 76 F.

Interesting how Mooney switched back and forth.  Our 1976 M20F has the squat switch, no airspeed switch.

[larryb]

My plane is in the shop right now for this. Last year at annual they replaced the airspeed safety switch. Ever since it has been off on its calibration. Sometimes it works fine. But most of the time I have to press the override button because the switch does not activate at the calibrated airspeed. The shop tried to adjust it once but it is just flaky. This time it is a warranty issue.