PA-28-200R Landing gear

[cessna_driver2]

P-28R-200 has
A.squatswich on left main gear.(disables gear operation on ground)
B.Microswitch on the throttle quadrant. (Activates horn Below 14" MP with gear up.)
C.Microswitch on flaps. (Activates horn beyond 10 degrees flaps with gear up.)
D You have three down-limit switches and obviously three up-limit switches.
These basically tell the hydraulic pump when to stop pumping hydraulic fluid to the actuator cylinders on all three gears.

One small problem with the up limit switch. On the arrow's the uplimt switch does not turn off the hydraulic pump. The Pump will maintain a positive pressure then shut off around 1500 PSI & maintains it. The up limit switchs turn off the Gear unsafe light. If for one reason the hydraulic system looses pressure, the gear will fall, Deactivating the Up limit switch & illuminating the gear unsafe light.

 

[JRSLim]

One small problem with the up limit switch. On the arrow's the uplimt switch does not turn off the hydraulic pump. The Pump will maintain a positive pressure then shut off around 1500 PSI & maintains it. The up limit switchs turn off the Gear unsafe light. If for one reason the hydraulic system looses pressure, the gear will fall, Deactivating the Up limit switch & illuminating the gear unsafe light.

OK, I dug out the Arrow manual, because I was thinking the same thing (about the motor pressure switch)
Referencing the Electrical Schematic in the Arrow Manual we have:
3 up limit switches.
3 down limit swiches
1 squat switch
1 pressure switch for the motor
1 throttle quadrant switch
On certain models, 1 switch for the Automatic Gear Down Actuator.
On certain models without the above AGDA switch, 1 flap switch that sounds the horn with 10 degrees flap and gear still up.

As a matter of interest -- during flight the gear may drop a little as the system loses pressure -- this trips the pressure motor switch which pumps the gear back up

 

[JonJohn82]

I'm just making sure I understand this correctly. The three "down" microswitches will stop the pump when the gear is down and locked. They will also cause the gear position indicator lights to show illuminate. The gear "up" microswitches do not stop the pump. The pump stops itself at a certain PSI. Is that correct?

 

[pilotmyf]

P-28R-200 has
A.squatswich on left main gear.(disables gear operation on ground)
B.Microswitch on the throttle quadrant. (Activates horn Below 14" MP with gear up.)
C.Microswitch on flaps. (Activates horn beyond 10 degrees flaps with gear up.)
D You have three down-limit switches and obviously three up-limit switches.
These basically tell the hydraulic pump when to stop pumping hydraulic fluid to the actuator cylinders on all three gears.

I've heard of the vertical stabilizer thing. Whether it's found on the Arrow? I don't know.

I've also heard mounting the engine at a slight angle off-sets torque.
Which manufacturers do this? I don't know.

Stand 10 feet back from the spinner and look at the spacing in relation to the cowling. The engine is obviously offset a bit.

 

[cessna_driver2]

I'm just making sure I understand this correctly. The three "down" microswitches will stop the pump when the gear is down and locked. They will also cause the gear position indicator lights to show illuminate. The gear "up" microswitches do not stop the pump. The pump stops itself at a certain PSI. Is that correct?

Ok direct from pa28r-200 information manual for s/n 28r-7435001 - 28r-7635545.

Some a/c incorporate a pressure sensing device in the system whech lowers the gear regardless of gear selector position, depending upond airspeed & engine power.

Now, if the pressure sensor notices a loss of pressure, it should activate the pump to increase the pressure. Positive pressure keeps the gear up. The sensor should notice a drop in pressure before there is enough movement in the gear to deactivate the micro switch.

So you are correct. The gear up switch does not shut the hydraulic power pack off.

 

[JRSLim]

So you are correct. The gear up switch does not shut the hydraulic power pack off.

Neither do the gear down microswitches as far as I'm aware.

 

[Pilotadjuster]

--as an aside, you should watch (listen) for a pump which does not shut off; usually indicates a leak in the system (and will wear out that expensive pump if not repaired). It will stay on to keep the gear (and pressure) up; the gear may stay all the way up, but the pressure will be too low for the pump to shut off.

 

[VNugget]

Neither do the gear down microswitches as far as I'm aware.

Then what shuts the pump off at the down limit? My manual shows a pressure switch only in the side of the system that's pressurized when gear is going up.

 

[Foxcow]

Then what shuts the pump off at the down limit? My manual shows a pressure switch only in the side of the system that's pressurized when gear is going up.

Three down limit switches will shutoff the pump going down. ~1800 PSI (not up limit switches) will shut the pump off on the way up.