REFLECTOR: Gear warning horn

[Ronnie Brown]

Hi Al, 

I would suggest using a microswitch on the throttle instead of relying on the airspeed switch.  The airspeed switch is only measuring about 4 inches of water pressure (approx 80 kts) which makes it pretty inaccurate for indicating airspeed.  My throttle switch is set fairly high so that it comes on when descending to the airport - well before high idle. On normal cruise descents from altitude it does not come on. It serves as a reminder that I need to decide when I'm going to lower the gear.  It is interconnected with the main gear up and locked switch.  I also incorporated a gear horn silence relay that I can engage but it automatically resets/rearms when either the throttle is advanced again or the main gear is extended.  I can send that schematic if anyone wants it.

My nose gear up and locked microswitch is mounted on the canard bulk head just above the where the gear protrudes from the pivot.  I mounted my main gear microswitch on the top of the over center linkage at the center pivot so that it closes only when the over center is all the way down..  I first mounted it on the secondary locking arm but that didn't indicate correctly. 

Again, my "gear not down" alarm works well, has a momentary nuisance silence button that will reset automatically any time the throttle is advanced again.  It works well.  But there's nothing like making CERTAIN you have two down green lights on the downwind or 5 mile final and AGAIN on short final.  

Ronnie
  ----- Original Message ----- 
  From: Al Gietzen 
  To: reflector 
  Sent: Wednesday, September 08, 2004 6:45 PM
  Subject: REFLECTOR: Gear warning horn


  The normal approach for wiring the gear warning horn is a low throttle position switch.  Having a liquid cooled engine, I think I may be less reluctant than otherwise to pull the throttle all the way back for slowing and descending when I have no intention of landing; and having the annoyance of having to reset the gear horn.



  I have an 'airspeed switch' to prevent gear up while on the ground; so I'm thinking of using a double throw relay circuit that activates the warning horn at the speed the air speed switch opens.  Then set that for a tad above final approach speed; and horn sounds if gear is not down.



  Is this re-invention of the wheel, or maybe not a good idea; or trading one set of annoyances for another.



  And while I'm at it; what's a good location for "Up and Locked" switch on the nose gear?



  Al





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