Mailing List lml@lancaironline.net Message #18587
From: <Sky2high@aol.com>
Sender: Marvin Kaye <marv@lancaironline.net>
Subject: Re: [LML] Re: LNC2 Odd Gear Pump Behavior
Date: Wed, 23 Apr 2003 08:37:24 -0400
To: <lml>
Lee, Larry:

Larry's analysis is excellent. Lee, you must get your plane up on jacks for some tests. Some additional considerations are:

1.  With the gear in the down position, inspect the three actuator push rods for straightness.  It is possible that actuators not physically at full extension with the gear down and locked can be bent, thus adding to load and maybe slowing things down.

2. Retract should generally look like this:
a. one main should start to come up and then the other.
b. as both mains hit the "up door valves", the inboard doors should flick or partially close, depending on the strength of the nose gas strut.
c. the sound should indicate the pump starting to work harder and the nose gear should start up.
d. after the nose gear is tucked away, the doors will come up and the pressure will build as everything is held tightly.  If there is a stutter or stall in this step, it may indicate the shuttle valve problem or simply that the pressure switch needs adjustment or replacement.
e. shut off the master, go have lunch and on your return, check to see if there was any sagging of the gear.  If so, there is is a leak - see Larry's procedure.
f.  this is a good time to check the dump valve operation.  Put the gear switch in the down position, open it and watch the gear come down. The doors open immediately, the nose gear snaps down and the mains drop down more slowly.  Check to see how long it takes for each main to lock and if one or both are sloooow (more than 5 seconds) push the wheel gently outboard until it locks.  If this takes more than 5 pounds of pressure, check the overcenter locking springs. Close the valve, turn on the master and note that it should take only a second or two to pressurize the system.

Lee, find a builder in your area and have him take a look at it.

Finally, note that Larry can outrace you if it takes forever to get your gear up.

Scott Krueger
Sky2high@aol.com
LNC2 N92EX IO320 Aurora, IL (KARR)
Subscribe (FEED) Subscribe (DIGEST) Subscribe (INDEX) Unsubscribe Mail to Listmaster