From: "Charlie England ceengland7@gmail.com" <flyrotary@lancaironline.net>
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Subject: Re: [FlyRotary] Re: Using the EM3's EGT/CHT inputs for reading MPX10
 pressure sensors
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
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Date: Wed, 8 Jan 2020 20:02:37 -0600
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On the subject of static source, are we talking about measuring cooling 
air *velocity* inside the ducts, etc? If so, I believe that you'll need 
to put the static source in the same air as the pressure ('pitot') source.

If you're looking for pressure ('piccolo tubes') differential, then I'd 
think you'd want a differential sensor with one port in the high 
pressure plenum area and the other in the exit plenum, which likely will 
also be at a higher pressure than the a/c's static pressure.

FWIW,

Charlie

On 1/8/2020 5:47 PM, Stephen Izett stephen.izett@gmail.com wrote:
> Thanks very much Finn
>
> Thats what I was a after.
> As you mention, I’m not needing hi res data to understand whats happening in the cowl and ducts at various speeds.
> Unfortunately I removed the data log option years ago (not enough space in that panel) and the Skyview logs the engine data well.
>
> Do you have the schematics for the EC2 and 3? & EM3?
>
> I thought it was just a question of whether I wanted to spend the extra time knocking up a string of amps for the 5 sensors I’ve got.
> But after thinking about it overnight, displaying the data in the cockpit is no where near as helpful as logging and analysing the data on the ground.
> I use a micromite system so the reading and writing to a mem card will be simple.
> The benefit of building a little batt powered unit as you suggested Matt is we could use it to diagnose other’s temp issues.
>
> So you guys have been helpful as usual.
> With my 5 MPX10DP sensors we could log airspeed and 4 pressure inputs referenced to the ships static.
> Perhaps temps for each press input would be helpful as Matt suggested.
>
> Being realistic, I’m a bit slow, so I would need a week to fab it all up.
> But it would be super helpful to me and possibly many others.
> Only over the weekend we had a first flight of a lyc powered machine put down in a field adjacent to our strip due to overheating. Fortunately both pilot and machine were unscathed.
>
> Cheers
>
> Steve Izett
>
>
>
>
>
>
>
>
>> On 8 Jan 2020, at 11:58 pm, Finn Lassen finn.lassen@verizon.net <flyrotary@lancaironline.net> wrote:
>>
>> I thought about 3D printing a pressure multiplexer to be driven by a stepper motor.
>>
>> Imagine an 8 point ignition distributor.
>>
>> You wouldn't have 8 real time pressure sensors, but I guess 1 second on each input should be enough for pressure to stabilize enough for measurement. So sampling all 8 inputs would take 8 seconds.
>>
>> Commercially available but much more expensive than buying 7 extra sensors.
>>
>> Should be a fun Arduino project.
>>
>> Finn
>>
>> On 1/8/2020 10:17 AM, Matt Boiteau mattboiteau@gmail.com wrote:
>>> Temp sensors are cheap, but pressure sensors are $15-20??each.
>>
>
> --
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