REFLECTOR: Nose Gear Almost Up

[Dave Black]

Chuck,


> Most time, but not all the time, the XL RG nose gear  raises to its up
> position, then the mains come up, then the nose gear travels the last few
> inches into its 'up' resting position which triggers the nose gear doors to
> close.  The problem is, in the air, about 50% of the time the nose gear
> comes up, the mains comes up, but the nose gear never finishes its last few
> inches of 'up' travel, thus the nose gear doors never fully close.
> 
> I've tried cycling the gear and resetting the hydraulic system, but no
> change.  It rare that the hydraulic motor ever has to cycle on for a second
> or two to keep the hydraulics up to pressure.  Any ideas why the nose gear
> isn't popping up into its final resting position?

Absolutely. 

There are two issues at play here:

1) The sequence valve is extremely difficult to push, so prevents the nose
gear closing as it should before the mains go up. The fix for this is to
relocate the sequence valve to within 2" of a pivot point in the NG retraction
mechanism. In that location, the gear will retract and the doors will close
slick as grease BEFORE the mains come up. 

2) The hydraulic system shuts off before reaching high enough pressure to
activate the sequence valve at its present location. If you don't mind the
nose door slamming shut at the end of the retraction cycle, simply increase
the high pressure limit on your hydraulic pump until it always retracts the
nose gear. The extra hydraulic pressure probably won't damage anything, and
anyway this is how 98% of builders adjust it. 

Either of these two methods will get your nose doors to close. I prefer
relocating the sequence valve, as that's at the root of your problem. But most
builders look nervously for the nearest exit when I explain this...


Dave