Mailing List flyrotary@lancaironline.net Message #49767
From: Mike Wills <rv-4mike@cox.net>
Subject: Re: [FlyRotary] mechanical gauges
Date: Mon, 18 Jan 2010 09:14:52 -0800
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Kevin,
 
 I used Autometer mechanical gauges for oil temp, oil pressure, and coolant temp. I installed them partly because I didn’t entirely trust my engine monitor manufacturer to deliver (since gone out of business) and partly to monitor effectiveness of the cooling system (they are mounted in different locations from the sensors for my monitor so I can measure delta temps across the coolers). I've used Autometers for 30+ years in a variety of cars and have never had a problem with one. The temp gauges require a little car with the capillary tube. I wouldn’t use the cheesy nylon line for the pressure gauge. Our local Earl's plumbing supplier provided a teflon lined -3 hose for that and I have no concerns about a hose tested to 1000psi failing.
 
 One advantage I didn’t see mentioned. Electric gauges typically have a meter movement with a sweep of 90 - 120 degrees where a mechanical has a sweep of 270 degrees. This provides much better resolution and an easier visual scan in an airplane cockpit.
 
Mike Wills
RV-4 N144MW

From: kevin lane
Sent: Thursday, January 14, 2010 8:41 PM
Subject: [FlyRotary] mechanical gauges

I was asking summit racing about their mechanical gauges, wondering if the price included all the necessary parts.  they told me that the oil pressure and water temp hook up directly with an 1/8th" line that I cut to fit.  I questioned whether the water temp would work that way since water wouldn't be circulating thru the line.  do mechanical temperature gauges work that way?  I assumed there must be a sealed , fixed length bulb/line arrangement that converts temp into line pressure?
what are the pros/cons of using mechanical vs. electrical gauges?  I have some of them currently in my plane but will need gauges to run the engine initially for ground tests, and hate to pay for duplicates, so leaning towards the cheaper mechanical gauges.     kevin
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