From: "Stephen Izett stephen.izett@gmail.com" <flyrotary@lancaironline.net>
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Subject: Re: [FlyRotary] Re: First engine run -- prop or not?
Date: Tue, 26 May 2020 06:50:08 +0800
References: <list-289754@logan.com>
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
In-Reply-To: <list-289754@logan.com>
Message-Id: <AF407B72-C782-47B8-A162-EA522A7E1B61@gmail.com>

Hi Finn

Its about the differential pressure across the injector when its =
switched on.=20
If the fuel rail  stayed constant pressure, but the pressure in the =
manifold/port varies, as it does with throttle position&rpm, the fuel =
flow will vary (not good).
With the regulator tracking manifold pressure then the injectors always =
pass the same amount of fuel per time open.

Steve Izett


> On 26 May 2020, at 6:44 am, Finn Lassen finn.lassen@verizon.net =
<flyrotary@lancaironline.net> wrote:
>=20
> I wish I knew what type my sensors are. I'm assuming absolute, but is =
there a way to tell?
> https://www.ebay.com/itm/272759060859
> Using the 80 psi one for fuel.
>=20
> Yes, MAP port on fuel regulator connected to MAP sensors in EC3 and =
then to intake plenum after throttle body.
>=20
> So, lower MAP =3D more air?
> More air, more fuel, higher fuel pressure?
>=20
> Seems I got the opposite from the brief log run.
>=20
> But the EC3 changes fuel flow based on MAP, so don't quite understand =
the need for varying the fuel pressure.
>=20
> Bear with me, I'm new to EFI.
>=20
> Finn
>=20
> On 5/25/2020 4:38 PM, Charlie England ceengland7@gmail.com wrote:
>> If the regulator has a MAP port and it's connected to the intake, =
then fuel pressure should vary with MAP. That's supposed to keep fuel =
flow proportional to airflow. But MAP is absolute; fuel pressure =
measurement will depend on the type of sensor (relative to atmospheric, =
or absolute).
>>=20
>> I wouldn't attach any significance to bubbles in the return line; the =
regulator is venting (spitting) fuel through what can be a tiny slit, =
into the relatively free air of the return line.=20
>>=20
>> Charlie=20
>>=20
>> On 5/25/2020 2:57 PM, Finn Lassen finn.lassen@verizon.net wrote:
>>> Don't have the wings on. Ran from a 6 gallon jug next to the =
fuselage. Can use a transparent line for the fuel return to inspect for =
bubbles.
>>>=20
>>> How is the fuel pressure regulator supposed to work? Looks like the =
fuel pressure dropped a bit as MAP dropped. Is that the way it's =
supposed to work?
>>>=20
>>> Finn
>>>=20
>>> On 5/25/2020 8:59 AM, Charlie England ceengland7@gmail.com wrote:
>>>>=20
>>>>=20
>>>> On Sun, May 24, 2020 at 10:34 PM Finn Lassen =
finn.lassen@verizon.net <flyrotary@lancaironline.net> wrote:
>>>> Good point. =46rom the log I think it was running lean. I'm =
temporarily using a narrow band O2 sensor. I think I'll hook a =
multimeter directly to it to bypass any errors from sensor to EC3 and =
EC3 to EM3 and its display. And I have to read the EC3 manual  :)
>>>>=20
>>>> Those o-rings were a bad idea. If I'd had a mill and could have =
milled recesses to retain them from expanding out under pressure they =
might work. But an o-ring between two flat surfaces is probably bad =
design. If sucking air, won't I see that in the return line as bubbles?
>>>> You won't if you use proper fuel line. ;-) The big issue is loss of =
power if it starts sucking air at a critical time. I've got a couple of =
friends who fly big-Continental powered Globe Swifts. They've both had =
forced landings (one of them multiple times) before they found that the =
ancient flex lines feeding the fuel pump had dried out and were porous =
to air but not fuel. Never leaked fuel, but would intermittently suck =
air and cause engine stoppage.
>>>>=20
>>>> Charlie
>>>>=20
>>>> Finn
>>>>=20
>>>>=20
>>>> On 5/24/2020 10:56 PM, Charlie England ceengland7@gmail.com wrote:
>>>>> Congrats on 1st run. Doubt that the issue is no prop; they idle ok =
in the car without one. ;-)
>>>>>=20
>>>>> Don't neglect the input side; those pumps will suck air even =
better than fuel.
>>>>>=20
>>>>> Charlie
>>>>>=20
>>>>> On 5/24/2020 9:01 PM, Finn Lassen finn.lassen@verizon.net wrote:
>>>>>> Probably too early to give you that. (Used 8.10 and PICkit2).
>>>>>>=20
>>>>>> Ran for the first time today (no prop).
>>>>>>=20
>>>>>> Over speeding not an issue. Ran like a Harley :( =20
>>>>>> No sure if because no prop or because not tuned yet or if =
something else wrong.
>>>>>>=20
>>>>>> Zero RPM readout on EM3. I must have misunderstood the =
instructions or the program. I thought the EM3 got RPM from the EC3, so =
I didn't wire the tach input to the EM3.
>>>>>> EM3 shows "NOP" until EC3 is turned on. Then shows "0".
>>>>>>=20
>>>>>> Only did a couple of runs. Fuel pumps started leaking badly =
around O-rings when I adjusted fuel pressure up to 37psi (engine not =
running). Pooled up in fuselage. Need to fix before I try running again. =
Gas is cheap, but not that cheap. I'll try copper washers on the =
pressure (output) side instead of the o-rings.
>>>>>>=20
>>>>>> Yes, I know, not pretty. Threaded the output fitting at an angle =
:(=20
>>>>>> Too lazy to redo the output block.=20
>>>>>> I also need to bend a new input tube without a kink.
>>>>>>=20
>>>>>> Max oil pressure only about 50 psi, hopefully because of low RPM.
>>>>>> Forgot to turn on master switch so alternator didn't come =
on-line.
>>>>>> Didn't log the run where that worked.
>>>>>>=20
>>>>>> Anyhow, can now say I've run the engine :)
>>>>>>=20
>>>>>> Finn=20
>>>>>>=20
>>>>>> On 5/22/2020 6:12 AM, Stephen Izett stephen.izett@gmail.com =
wrote:
>>>>>>> Great work Finn
>>>>>>> Could I get the MPLABs version your using and any more info for =
the build.
>>>>>>> I could build and program and confirm the burn but the EC3 ran =
like a dog.
>>>>>>>=20
>>>>>>> Steve
>>>>>>>=20
>>>>>>>=20
>>>>>>>=20
>>>>>>>=20
>>>>>>>> On 22 May 2020, at 9:16 am, Finn Lassen finn.lassen@verizon.net =
<flyrotary@lancaironline.net>
>>>>>>>>  wrote:
>>>>>>>>=20
>>>>>>>> Well, after several hours of Murphy working overtime, I finally =
was able to get the wiring on my EC3 chip programming board right, chips =
programmed and EC3 installed.
>>>>>>>>=20
>>>>>>>> Flux capacitor fluxing, injectors clicking and spark plug =
firing.
>>>>>>>>=20
>>>>>>>> Time to get the wheels on and roll it out and start the engine.
>>>>>>>>=20
>>>>>>>> Oh, wait, guess I need to finish and install the prop :(
>>>>>>>>=20
>>>>>>>> Finn
>>>>>>>>=20
>>>>>>>>=20
>>>>>>>> On 5/21/2020 9:23 AM, Finn Lassen=20
>>>>>>>> finn.lassen@verizon.net
>>>>>>>>  wrote:
>>>>>>>>=20
>>>>>>>>> 1) Without prop any vibration will be from engine and PSRU and =
can inspect engine (leaks, etc.) with no fear of prop.
>>>>>>>>>=20
>>>>>>>>> 2) With prop less chance of over rev and some cooling air =
through rads and oil cooler.
>>>>>>>>>=20
>>>>>>>>> What do you think?
>>>>>>>>>=20
>>>>>>>>> Finn
>>>>>>>>>=20
>>>>>>>>>=20
>>>>>>>>>=20
>>>>>>>>> --=20
>>>>>>>>> Homepage: =20
>>>>>>>>> http://www.flyrotary.com/
>>>>>>>>>=20
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