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Landing Gear Airspeed Safety Switch


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Hey Gang,

I'm curious about the minimum airspeeds that typical J/Ks will fold up its legs?  I recently had an airspeed switch replaced in my J and was surprised by the gear unsafe warning tone as I selected 'gear up' at my usual phase of take off.  That was a new one for me, so I put the gear handle back down, all was calm again, and I decided to land.

Today, I jacked her up, taped up the pitot drain hole, then ran 20 ft of flexible PVC tubing from the pitot tube through the vent window.  After closing off the opposite end, I put the gear switch up and gently squeezed the remaining coiled length of tubing . The beeping stopped and the gear transited as the ASI hit 80 kts.  

I'm guessing my previous switch was set at around 70-75 KIAS and just wanted to hear what other owners have for their minimum gear retract speed.  

v/r

Terry Winnett

84 M20J

Edited by TerryDubYa
take out duplicate info
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There is a lot written about max retraction speed...

https://mooneyspace.com/search/?q="Retraction speed"&updated_after=any&sortby=relevancy

There is plenty written about air speed switches... and there adjustment...

https://mooneyspace.com/search/?q="Airspeed Switch"&updated_after=any&sortby=relevancy

Take your pick... read up while waiting for a good response...  :)

Best regards,

-a-

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You need the correct adjustment. Mine was set to high, a high density altitude ,I could not retract the gear or, climb, shoving the nose down at 25’ agl is not fun, and when the runway disappears behind you, big pucker factor. Gear finally cycled and I climbed out as per book numbers. 

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58 minutes ago, TerryDubYa said:

Thank you, Skip.  I need rub together a pair of shekels and get one of them there magical maintenance manuals for myself! 

 

Terry

Ask and thou shall receive.  Of course there are more pages available.

Clarence

99A30C8A-DD08-4FA0-8FF7-32DA10ED1CB6.jpeg

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42 minutes ago, Ron McBride said:

You need the correct adjustment. Mine was set to high, a high density altitude ,I could not retract the gear or, climb, shoving the nose down at 25’ agl is not fun, and when the runway disappears behind you, big pucker factor. Gear finally cycled and I climbed out as per book numbers. 

How exciting!!!  NOT !!  :(

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2 hours ago, TerryDubYa said:

Thank you, Skip.  I need rub together a pair of shekels and get one of them there magical maintenance manuals for myself! 

 

Terry

The M20J manual can be downloaded online for free.     http://mooney.free.fr/Manuels M20J/M20J/Mooney Service Manuel M20J Vol. 1 of 2.pdf

Vol 2 has the electrical schematics and is also available if you search.

 

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2 hours ago, Ron McBride said:

You need the correct adjustment. Mine was set to high, a high density altitude ,I could not retract the gear or, climb, shoving the nose down at 25’ agl is not fun, and when the runway disappears behind you, big pucker factor. Gear finally cycled and I climbed out as per book numbers. 

A safer option is to press the little red button next to the gear switch to override the airspeed switch.

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3 minutes ago, PT20J said:

A safer option is to press the little red button next to the gear switch to override the airspeed switch.

I could be mistaken, but I don't believe Ron's F model was equipped with an override capability.  At least my 1967 F model was not equipped so.

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9 minutes ago, MooneyMitch said:

I could be mistaken, but I don't believe Ron's F model was equipped with an override capability.  At least my 1967 F model was not equipped so.

I think you are right. I thought the override was on all models after Mooney ditched the squat switch for the airspeed switch, but I looked at a F owners manual and don’t see it mentioned. Perhaps some other F owners can clarify if it was ever on the F, or got added at the J.

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On my 78 J model, on my initial takeoff of the day, I need to reach 100+ mph IAS for the switch to activate. On subsequent take-off, it activates at about 80 mph.  I use the red button to retract on my first flight of the day and listen to the beeping until reaching about 100 mph.  After that it is consistent at about 80 mph. Not sure why it sticks.  Anyone have any ideas?

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1 minute ago, PT20J said:

I think you are right. I thought the override was on all models after Mooney ditched the squat switch for the airspeed switch, but I looked at a F owners manual and don’t see it mentioned. Perhaps some other F owners can clarify if it was ever on the F, or got added at the J.

Perhaps because Ron’s post is under Modern Mooney’s, we assumed it was such......:)

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1 minute ago, PT20J said:

I think you are right. I thought the override was on all models after Mooney ditched the squat switch for the airspeed switch, but I looked at a F owners manual and don’t see it mentioned. Perhaps some other F owners can clarify if it was ever on the F, or got added at the J.

It got added after J production started.  SB M20-196a shows how to install one in aircraft that don't have it.   From the S/N application list, it wasn't stock on M20Js until S/N 24-0238.

Mine was converted from a squat switch to an airspeed switch and had the override switch installed not long after it left the factory.   

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I have been through 3 replacement switches from the manufacturer. The first replacement could not be adjusted to a stable and accurate speed. He others failed the switch itself. I have little confidence in the outfit that makes these things.

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