REFLECTOR: slow nose gear down indicator

Wed Feb 20 13:29:25 CST 2013

Scott,

What you are describing happened to me and this was the cause.  The 
hydraulic cylinder stopped pushing the link over center.  The reason was the 
lock nut on the end of the hydraulic cylinder shaft wasn't tight enough to 
prevent the shaft from turning  in the end fitting thus screwing it in 
gradually.  When I readjusted it I added Lock-tight and made sure the lock 
nut was nice and tight.  Since the gas spring is now pushing the link over 
center it is working against the wind force pushing on the gear which tries 
to hold the link ON center and explains why it doesn't happen in the hangar. 
The gas spring has less poop when it gets cold on top of that.

Larry Coen
N136LC

--------------------------------------------------
From: "Scott Derrick" <scott at tnstaafl.net>
Sent: Wednesday, February 20, 2013 10:33 AM
To: "Velocity Aircraft Owners and Builders list" <reflector at tvbf.org>
Subject: Re: REFLECTOR: slow nose gear down indicator

> I don't see how, the wind pushes it fully open?
>
> -------- Original Message --------
> Subject: Re: REFLECTOR: slow nose gear down indicator
> From: John Dibble <aminetech at bluefrog.com>
> To: Velocity Aircraft Owners and Builders list <reflector at tvbf.org>
> Date: 02/20/2013 09:25 AM
>
>> Yes.  As the gear goes over center, the gear leg moves forward (retract
>> direction).  The wind pushes the leg back toward the "neutral" point.
>> The Hydraulics will hold the gear in the over center position.  However
>> a strong spring will move it a tiny bit further.  Adjusting the
>> microswitch may do the trick.
>>
>> John
>>
>> On 2/20/2013 8:53 AM, Scott Derrick wrote:
>>> Whats odd is it always go quickly green doing a gear test on jacks, by
>>> releasing the the valve or using the hydraulic pump.
>>>
>>> So maybe the wind pushing on the gear is doing something?
>>>
>>> Scott
>>>
>>> -------- Original Message --------
>>> Subject: Re: REFLECTOR: slow nose gear down indicator
>>> From: Richard J. Gentil <richard at naples-air-center.com>
>>> To: Velocity Aircraft Owners and Builders list <reflector at tvbf.org>
>>> Date: 02/20/2013 07:23 AM
>>>
>>>> Scott,
>>>>
>>>> The gas strut is supposed to help the nose gear go over center during
>>>> free fall.
>>>>
>>>> Richard
>>>>
>>>> Sent from my iPhone 5
>>>>
>>>> On Feb 20, 2013, at 9:11 AM, Scott Derrick <scott at tnstaafl.net> wrote:
>>>>
>>>>>
>>>>>     I checked the micro switch a while back and it is mounted solid
>>>>> and looks like it works as designed.
>>>>>
>>>>>     I will do a thorough inspection of the mechanism, I do every
>>>>> annual and its coming up very soon.
>>>>>
>>>>>     So maybe I don't understand what the gas strut is for?  I
>>>>> thought the hydraulic ram pushed the gear strut to full extension
>>>>> but then the gas strut pushed the locking mechanism over center so
>>>>> so you are not relying on hydraulic pressure to keep the nose gear
>>>>> in the down position when the electric pump is not powered up and
>>>>> the pressure eventually leaks down internally.
>>>>>
>>>>>     What does the gas strut do?
>>>>>
>>>>> Scott
>>>>>
>>>>> -------- Original Message --------
>>>>> Subject: Re: REFLECTOR: slow nose gear down indicator
>>>>> From: Scott Baker <scottb33333 at gmail.com>
>>>>> To: Velocity Aircraft Owners and Builders list <reflector at tvbf.org>
>>>>> Date: 02/20/2013 05:43 AM
>>>>>
>>>>>> On 2/19/2013 7:38 PM, Scott Derrick wrote:
>>>>>>> Lately my nose gear down(green) light has take longer and longer to
>>>>>>> light up.   The main green lights up, the gear motor stops, 10-15
>>>>>>> seconds later I finally get a nose gear green. Actually today it 
>>>>>>> took
>>>>>>> maybe 25 seconds before the nose green lit up.  I was starting to
>>>>>>> wonder.
>>>>>>>
>>>>>>> I think my gas strut is getting old,  97 model strut. Maybe it just
>>>>>>> doesn't have the umphh to push it over center?
>>>>>>>
>>>>>>> Anybody see this type of behavior?
>>>>>>>
>>>>>>> Scott
>>>>>> Hi Scott,
>>>>>>
>>>>>> First check the nose gear down micro switch and its mount to
>>>>>> confirm the
>>>>>> switch is functioning as it should and the micro switch mount is
>>>>>> solid.
>>>>>>
>>>>>> Something other than the gas spring is the culprit.  If the nose gear
>>>>>> linkage is rigged as it should, the hydraulic ram (by virtue of
>>>>>> extending itself to its most outward travel) should push the
>>>>>> linkage to
>>>>>> its over-center position.  As you know, when the ram reaches its
>>>>>> furthermost travel, hydraulic pressure builds and ultimately turns 
>>>>>> the
>>>>>> pump off when the 'gear down' hydraulic pressure switch reaches its
>>>>>> set
>>>>>> pressure (about 550psi).  When this happens, the ram should not be
>>>>>> capable of any further travel.  This is a long winded way of saying
>>>>>> that
>>>>>> the strength of gas strut has no bearing on the travel of the nose
>>>>>> gear
>>>>>> linkage.
>>>>>>
>>>>>> Check the travel limits of the nose gear ram to make sure that it is
>>>>>> providing full travel and the gear linkage is over-center when the 
>>>>>> ram
>>>>>> reaches its furthermost travel.  Possible problem areas include loose
>>>>>> mounting screws at the base of the nose gear cylinder; ram rod end
>>>>>> bearing turning (though not likely); some sort of blockage inside the
>>>>>> ram that is limiting its full travel; or major slop in the nose gear
>>>>>> linkage pivot bolt bearing/bent bolt.
>>>>>>
>>>>>> Best,
>>>>>> Scott B.
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>>>>>
>>>>> --
>>>>> I do not want the peace which passeth understanding, I want the
>>>>> understanding which bringeth peace.
>>>>> Helen Keller
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>>>
>>
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>
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> He who know himself is enlightened.
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