REFLECTOR: Need a topic... gear down check

[Mark Magee]

FIXED GEAR!

Mark B. Magee
Sent from IPhone 4S

On Jan 24, 2013, at 11:14 PM, Mike Dawson <medawson250 at yahoo.com> wrote:

> Has anyone mentioned a cheap alternative? It's call a landing checklist!
> 
> Michael E Dawson
> ATCI CFII
> N104DD
> 
> 
> On Jan 24, 2013, at 7:41 PM, "Darrell & Nora Kufalk" <kufalk at wi.rr.com> wrote:
> 
>> I have this landing gear warning system installed in my Velocity XL-RG.  It senses the ground just like radar or a laser except it uses microwaves instead.  Seems like it’s exactly what you are looking for.
>> http://www.flyingsafer.com/2037.htm
>>  
>>  
>>  
>> From: reflector-bounces at tvbf.org [mailto:reflector-bounces at tvbf.org] On Behalf Of Dave T Nelson
>> Sent: Thursday, January 24, 2013 3:48 PM
>> To: reflector at tvbf.org
>> Subject: Re: REFLECTOR: Need a topic... gear down check
>>  
>> I agree with everyone that a key shortcoming of my plan is in having to guess at the altitude (i.e., subtracting the destination airport altitude from the Dynon altitude).  Short of a laser based or radar altimeter, a better solution would be to find a north American elevation database referenced to lat/long.  A bit of background...
>> 
>> I researched homebrew radar systems, even going so far as to exchange emails with several experimenters.  Unfortunately, there was no simple, repeatable design to be had...  The other factor to consider is that the architecture of what I'm implementing is very highly configurable... there will be no big problem in retrofitting a better solution in the future.  
>> 
>> Keep the input coming!
>>   
>> Dave
>> 
>> Dave T. Nelson
>> T/L 553-4327, Voice 507-253-4327, Fax 507-253-3648
>> Program Director, ISC ECAT NPI & Test Engineering
>> 
>> ----- Message from James Lotspeich <jlotspeich34 at gmail.com> on Wed, 23 Jan 2013 22:28:08 -0600 -----
>> 
>> To:
>> Velocity Aircraft Owners and Builders list <reflector at tvbf.org>
>> Subject:
>> Re: REFLECTOR: Reflector Digest, Vol 94, Issue 37
>> It's been a while, but I believe Cloudcap builds laser altimeters for precision autopilot landings (UAV autopilot).  The cost six years ago was ~$1k.  Worked pretty well when wings are level up to maybe 1000ft.  With an IMU or AHRS unit, you can tell when you're level.  The laser will give a good height above ground.  Both units feed serial data or CAN bus.  I'd trust the laser over field elevation calculations.  Also could be used for an auto gear down if you're feeling really experimental.
>> 
>> James
>> 
>> On Wednesday, January 23, 2013, Richard J. Gentil wrote:
>> 
>> Hi Dave,
>> 
>> I'm sorry I didn't make myself clear. I was going on the premise of building your own because the topic had mentioned building a single PCB computer to do what you needed. My comment was on how Avidyne handled it with the information from the Garmin and it was something that if you were thinking of designing on your own could give you some ideas on how to implement it. And I should add if you did build it, I would be happy to take one off your hands. ;)
>> 
>> Richard 
>> 
>> Sent from my iPhone 5
>> 
>> On Jan 23, 2013, at 2:43 PM, Dave T Nelson <dtnelson at us.ibm.com> wrote:
>> 
>> I'll respond to Rich Ervin and Rich Gentil below...
>> 
>> From:
>> ----- Message from Rich Ervin <rich_ervin at hotmail.com> on Wed, 23 Jan 2013 13:54:25 -0500 ----- 
>> To:
>> <reflector at tvbf.org>
>> Subject:
>> Re: REFLECTOR: Need a topic... gear down check
>> Any way to build this based on altitude or distance to ground? Some simple range detecting device that can measure the distance to the ground?
>> 
>> What I'm planning is to use the Dynon altitude (referenced to MSL), and subtract the altitude of the destination airport (using the three letter identifier and a quick database look up)... to approximate the AGL altitude.  This is far from perfect... I've looked at trying to find an elevation database I could use and reference via lat/long... but so far no luck.  
>> 
>> From:
>> ----- Message from "Richard J. Gentil" <richard at naples-air-center.com> on Wed, 23 Jan 2013 14:22:12 -0500 ----- 
>> To:
>> Velocity Aircraft Owners and Builders list <reflector at tvbf.org>
>> Subject:
>> Re: REFLECTOR: Need a topic... gear down check
>> Rich,
>> 
>> You could use a radar altimeter. Also the Avidyne System in the Cirrus uses the GPS to give you TAWS terrain warnings when you are more then 5 miles from an airport and it calls out 500ft when you are on approach before landing at an airport. 
>> 
>> I would think that something like that would be what you are looking for in order to integrate with a gear warning if the gear is still up. 
>> 
>> Richard 
>> 
>> I've actually looked at homebrew radar altimeters for this application... complicated and expensive.  The Avidyne system in a Cirrus is quite different from my Garmin GNS-530W... my Garmin has terrain warnings, but unfortunately does not output anything usable regarding terrain warning or AGL altitude in the RS-232 data string.  As I'm not ready to by an Avidyne (or a Cirrus), I'm kinda out of luck on that front and working on my own solution.
>> 
>> To all - thanks for the input!
>> 
>>   
>> Dave
>> 
>> Dave T. Nelson
>> T/L 553-4327, Voice 507-253-4327, Fax 507-253-3648
>> Program Director, ISC ECAT NPI & Test Engineering
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