X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Wed, 15 Apr 2009 18:35:30 -0400 Message-ID: X-Original-Return-Path: Received: from imo-d20.mx.aol.com ([205.188.139.136] verified) by logan.com (CommuniGate Pro SMTP 5.2.13) with ESMTP id 3581893 for lml@lancaironline.net; Wed, 15 Apr 2009 09:10:53 -0400 Received-SPF: pass receiver=logan.com; client-ip=205.188.139.136; envelope-from=Sky2high@aol.com Received: from imo-da01.mx.aol.com (imo-da01.mx.aol.com [205.188.169.199]) by imo-d20.mx.aol.com (v107.10) with ESMTP id RELAYIN3-449e5dc9e1aa; Wed, 15 Apr 2009 09:09:50 -0400 Received: from Sky2high@aol.com by imo-da01.mx.aol.com (mail_out_v40_r1.5.) id q.d39.4839d3f3 (42805); Wed, 15 Apr 2009 09:09:34 -0400 (EDT) From: Sky2high@aol.com X-Original-Message-ID: X-Original-Date: Wed, 15 Apr 2009 09:09:34 EDT Subject: Re: [LML] Gear Free Fall X-Original-To: lml@lancaironline.net X-Original-CC: domcrain@tpg.com.au MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="-----------------------------1239800974" X-Mailer: AOL 9.1 sub 5006 X-Spam-Flag:NO X-AOL-IP: 205.188.169.199 -------------------------------1239800974 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Content-Language: en Dom, Assuming you have not detecting any unusual binding and that you have lubricated all moving parts (including the rat trap springs), you may not= have a serious problem. Remember that when the dump valve is opened, that allow= s the fluid in the up-side of each actuator to transfer and fill the down= side. Restriction in flow and/or resistance in seals could affect the fre= e fall. If it takes no more than 2-4 lbs of outward hand pressure on the = wheel to get the over centers to lock, then things are good. The nose gea= r gas spring must be able to exert 100 lbs of pressure to get it down and lo= cked in flight and, if I remember correctly, 25 lbs pushed against the nose wheel when it is about half way down would translate to about 100 pounds= of gas spring pressure because of the geometry. However, after satisfying yourself of proper gear operation on jacks, the= only real test is that made in the air. Carefully slow to 87 Kts (100 mph), flaps optional (I use 10 or so degrees to keep the nose down a bit)= , motor breaker open, gear switch down, dump valve open and check for green= lights. Skid the plane appropriately to add air load to any main until it= locks. If the nose gear doesn't lock, the gas spring is not strong enough= - you may want to carefully try a G adding maneuver (without nibbling at a stall). If some gear doesn't lock, close the dump valve and the motor br= eaker. If all lock, land and kiss the ground - fix the sticky problem. If it still doesn't lock, oooops. Any further activity is left as an exercise= for the student. Blue skies, Grayhawk PS I often have to enter a mild skid to get my right main to lock. One= can wonder if the middle door provides an anti-load in some cases. PPS If you go below 87 KIAS, you have failed the test. In a message dated 4/15/2009 6:52:02 A.M. Central Daylight Time, domcrain@tpg.com.au writes: I=E2=80=99d like to draw on the opinion of listers regarding LNC2 gear fr= ee fall problem. The main gear is slow to free fall, and on the jacks (most likely in the= air) the RMG won=E2=80=99t lock in. Slight pressure on the wheel locks it in, which is handy if one wing walk= s upside down. Disconnected the actuator strut and it drops like a beauty and snaps into= position. I doubt the actuator struts are the problem because both main gear have= exhibited the same problem at the same time. The LMG does eventually lock= down on the jacks. One thing I=E2=80=99ve noticed is the NG is slower to lock down under nor= mal extension than it usually does. Until recently, it was always the first,= and quick to lock down. Under free fall the gas strut dives the NG down and= locks as it should quite quickly. Wondered if anyone might have a trouble shooting sequence I can draw upon= . Thanks Dom Crain VH-CZJ **************Great deals on Dell=E2=80=99s most popular laptops =E2=80=93= Starting at $479 (http://pr.atwola.com/promoclk/100126575x1220631252x1201390195/aol?redir= =3Dhttp:%2F%2Fad.doubleclick.net%2Fclk%3B213968550%3B35701427%3Bh) -------------------------------1239800974 Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Content-Language: en
Dom,
 
Assuming you have not detecting any unusual binding and that you have= lubricated all moving parts (including the rat trap springs), you may not= have a serious problem.  Remember that when the dump valve is opened, that= allows the fluid in the up-side of each actuator to transfer and fill the do= wn side.  Restriction in flow and/or resistance in seals could affect th= e free fall.  If it takes no more than 2-4 lbs of outward hand pressure on= the wheel to get the over centers to lock, then things are good.  The nos= e gear gas spring must be able to exert 100 lbs of pressure to get it down and lo= cked in flight and, if I remember correctly, 25 lbs pushed against the nose whe= el when it is about half way down would translate to about 100 pounds of gas= spring pressure because of the geometry.
 
However, after satisfying yourself of proper gear operation= on jacks, the only real test is that made in the air.  Carefully slow to= 87 Kts (100 mph), flaps optional (I use 10 or so degrees to keep the nose dow= n a bit), motor breaker open, gear switch down, dump valve open and check for= green lights.  Skid the plane appropriately to add air load to any main unt= il it locks.  If the nose gear doesn't lock, the gas spring is not strong= enough - you may want to carefully try a G adding maneuver (without nibbling at= a stall).  If some gear doesn't lock, close the dump valve and the moto= r breaker.  If all lock, land and kiss the ground - fix the sticky problem. If it still doesn't lock, oooops.  Any further= activity is left as an exercise for the student.
 
Blue skies,
 
Grayhawk
 
PS I often have to enter a mild skid to get my right main to lock.&nb= sp; One can wonder if the middle door provides an anti-load in some cases.
 
PPS If you go below 87 KIAS, you have failed the test.
 
In a message dated 4/15/2009 6:52:02 A.M. Central Daylight Time, domcrain@tpg.com.au writes:

I=E2=80=99d like to= draw on the opinion of listers regarding LNC2 gear free fall problem.

The main gear is sl= ow to free fall, and on the jacks (most likely in the air) the RMG won=E2=80=99t lo= ck in.

Slight pressure on= the wheel locks it in, which is handy if one wing walks upside down.

Disconnected the ac= tuator strut and it drops like a beauty and snaps into position.

I doubt the actuato= r struts are the problem because both main gear have exhibited the same problem= at the same time. The LMG does eventually lock down on the jacks.

One thing I=E2=80= =99ve noticed is the NG is slower to lock down under normal extension than it usually does.= Until recently, it was always the first, and quick to lock down. Under free fa= ll the gas strut dives the NG down and locks as it should quite quickly.

Wondered if anyone= might have a trouble shooting sequence I can draw upon.

Thanks

Dom Crain

VH-CZJ


Great deals on Dell=E2=80=99s most popula= r laptops =E2=80=93 Starting at $479
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