Ooops, I forgot to convert the air density to slugs – dang English units…   Here’s the table corrected.  The dynamic pressure expressed  in psi is lower than my intuition had it.  Looks like the pressure switches at the Automation Direct link are not at all in the range needed to use as a squat switch.

 

Valin

 

 

 

Bruce,

 

Thanks for the link to the pressure switches.  I’m looking at airspeed pressure switch options for possibly toggling in lower trim tab servo speeds at higher air speeds.  I did a quick spreadsheet to see if the pressures for the switches at the link were in the needed range.  If I did the calculations right, it looks like the lowest airspeed for the lowest pressure switch at that link (7.5-145 psi range) is for 100 kts.

 

 

Tom,

 

I can point you toward this 55 to 140 kts range airpseed switch offered by TCW Technologies – they make the Safety Trim product: http://www.tcwtech.com/usw-1.HTM   You get the switch and relay for $95.

 

 

 

Hope this helps.  Good luck,

 

Valin Thorn

Legacy project

Houston, TX USA

 

 

-----Original Message-----
From: Lancair Mailing List [mailto:lml@lancaironline.net] On Behalf Of Bruce Gray
Sent: Sunday, May 30, 2010 8:54 AM
To: lml@lancaironline.net
Subject: [LML] Re: Low Pressure Gear Switch Needed

 

This is what I use for up/down pressure control on my GIII. It's an adjustable solid state pressure switch. Last one on the page.

 

http://www.automationdirect.com/adc/Search/Search?searchquery=psd25&cmd=Search&fctype=adc.falcon.search.SearchFormCtrl&TxnNumber=-1

 

 

Bruce

www.Glasair.org

 

-----Original Message-----

From: Lancair Mailing List [mailto:lml@lancaironline.net] On Behalf Of

Tom McNerney

Sent: Sunday, May 30, 2010 1:09 AM

To: lml@lancaironline.net

Subject: [LML] Low Pressure Gear Switch Needed

 

I am helping with a new prototype that has a gear system similar to a

LNC2 or Legacy.  We are trying to get it flying so we can make Oshkosh

this year.  We recently ran into a bit of a holdup.  The PS550 low

pressure switch for the landing gear system is on back order with

Lancair for at least 1 month.  This would not leave us enough time to

test the gear system before the show.  Does anybody know of an alternate

source for this pressure switch?  Or, anybody have an extra to sell?

Rent? Loan for a month? :)

 

Thanks for your help.

Tom

dudewanarace@yahoo.com

www.N54SG.com

 

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