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Date: Sun, 22 May 2022 21:00:01 -0600 Message-Id: <51C35825-6F5A-4909-ACCF-D6950ED73955@uwyo.edu> References: In-Reply-To: To: Rotary motors in aircraft X-Mailer: iPad Mail (19E258) X-ClientProxiedBy: CY5PR13CA0036.namprd13.prod.outlook.com (2603:10b6:930:11::21) To CY4PR05MB3384.namprd05.prod.outlook.com (2603:10b6:910:57::35) Return-Path: SBoese@uwyo.edu MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-Office365-Filtering-Correlation-Id: 15894d80-3566-4943-1376-08da3c6855f3 X-MS-TrafficTypeDiagnostic: DM6PR05MB4635:EE_ X-Microsoft-Antispam-PRVS: X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0; X-Microsoft-Antispam-Message-Info: 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 X-Forefront-Antispam-Report: CIP:255.255.255.255;CTRY:;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:CY4PR05MB3384.namprd05.prod.outlook.com;PTR:;CAT:NONE;SFS:(13230001)(4636009)(366004)(8676002)(53546011)(86362001)(52116002)(33964004)(6666004)(6506007)(2906002)(6486002)(33656002)(75432002)(8936002)(508600001)(26005)(6512007)(6916009)(83380400001)(2616005)(5660300002)(36756003)(316002)(786003)(38350700002)(38100700002)(186003)(66476007)(66556008)(66946007)(45980500001);DIR:OUT;SFP:1102; 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charset=utf-8 Content-Transfer-Encoding: quoted-printable Finn, It seems to me that the problem you=E2=80=99re seeing is consistent with the= capacity of the pump not being sufficient for the max flow required by the e= ngine and the pump flow capacity is decreasing with use. You appear to have= checked everything but the flow capacity of the pump under normal system pr= essure which is what you really need to know. If you can divert the returni= ng fuel flow from the pressure regulator to a measuring vessel and and colle= ct that fuel for an accurately measured time, the pump flow rate can be calc= ulated. This flow rate should be greater than the maximum required by the e= ngine by a comfortable amount. =20 My apologies in advance if this is obvious. Steve Boese=20 > On May 22, 2022, at 8:05 PM, Stephen Izett stephen.izett@gmail.com wrote: >=20 > =EF=BB=BF > =E2=97=86 This message was sent from a non-UWYO address. Please exercise c= aution when clicking links or opening attachments from external sources. >=20 >=20 > Hi Finn >=20 > Thanks for the reminder of my pump issue.=20 > Yes, you chose more wisely the pump capacity. Mine were way overkill. >=20 > So I=E2=80=99m thinking options are: > 1. Fuel Pressure transducer fault - No - as this was confirmed by the mixt= ure monitor and tune going out. > 2. Power supply to pump via fault in termination or switch current path - U= nlikely, given the slow reduction - I would imagine a faulty connection woul= d create a less uniform symptom. > 3. Alternator Battery voltage/current reduction over time - No - You would= see this in the log. > 4. Significant Fuel leak - No - Would think this would have become obvious= on inspection and not intermittent.=20 > 5. Fuel Regulator - They are pretty simple but unsure if they can fail wit= h this symptom? > 6. Fuel filter blockage - Certainly this would have to be an obvious, but I= take it you swapped this out. > 7. Pump internal failure - > Electrical - ? > Mechanical breakage - ? > Flow Path - blockage - unlikely if filtered effectively >=20 > Where is your pressure transducer in relation to Reg/Any post pump filteri= ng/Flow Transducer/Rail? >=20 > If fuel regulator and filters can be discounted, I=E2=80=99m struggling to= trust the pump. But your test had it sounding in good shape and to spec. >=20 > So frustrating. >=20 > Cheers >=20 > Steve >=20 >=20 >=20 >=20 >=20 >> On 23 May 2022, at 8:44 am, Finn Lassen finn.lassen@verizon.net wrote: >>=20 >> Thanks Steve. >>=20 >> =46rom your March/April 2017 posts it was a GSL392 that failed (high curr= ent draw/low pressure, even after you removed the insect you found in the in= let). >>=20 >> So this afternoon I ran the pump for about an hour. Amp draw from 3.04 to= 2.86 depending on voltage. Pressure between 43 and 40 psi (also depending o= n voltage). No noticeable degradation. Of course the difference with this te= st is that no fuel went to engine -- all recirculated through pressure regul= ator and back to tank. But no signs of a failing pump in terms of higher cur= rent draw and less pressure. >>=20 >> I guess I should put a temp probe on the pump and see what it reads durin= g flight to see if that could be a factor. >>=20 >> Finn >>=20 >>> On 5/21/2022 9:01 PM, Stephen Izett stephen.izett@gmail.com wrote: >>> Hi Finn >>>=20 >>> I had from memory a 393 fail. Can=E2=80=99t recall the symptoms sorry. >>>=20 >>> I test before takeoff and then run both pumps below 2ooo ft incase of fa= ilure. >>> I plan to instal a comparator relay board in fuel pressure circuit to au= tomatically bring on backup pump and failure indicator. >>> So testing before flight becomes - switch off and back on main engine pu= mp. This will save amps and wear of backup pump. >>> When I switch off a pump at WOT the engine dies pretty much instantaneou= sly and don't want to be fiddling with a restart in the Glasair which glides= like a brick with the gear out in the breeze. >>>=20 >>> Regards =20 >>> Steve Izett >>>=20 >>>=20 >>>=20 >>>=20 >>>=20 >>>> On 21 May 2022, at 10:30 pm, Finn Lassen finn.lassen@verizon.net wrote: >>>>=20 >>>> Recently I noticed my fuel pressure being low. Noticed because engine d= id not come up in power when advancing to full throttle. Noticed mixture rea= l lean. Checking fuel pressure as low as 28 psi (normally 35 and up to 40 at= full throttle). >>>>=20 >>>> Going over my engine logs since first flight I now see that fuel pressu= re has been trending lower through each flight -- more pronounced on longer f= lights (40+ minutes). More and more pronounced over the months and became re= ally noticeable over last month. Could explain why mixture tuning appeared t= o have changed. Nice to have engine logs from practically each flight. >>>>=20 >>>> But why? Pump getting weaker? >>>>=20 >>>> My primary fuel pump is a GSL414. I figured it was wasted energy to pus= h way more fuel than needed through the pressure regulator back to the tank.= >>>>=20 >>>> My secondary (backup) pump is a GSL393. When turning that on, fuel pres= sure comes back up to where it needs to be. >>>>=20 >>>> Anyone have experience with failing or weak EFI pumps, particularly the= GSL414? >>>>=20 >>>> Finn >>>>=20 >>>=20 >>=20 >=20 --Apple-Mail-88E90DFE-7836-4BCD-9E79-30A6B84EB498 Content-Type: text/html; charset=utf-8 Content-Transfer-Encoding: quoted-printable
Finn,
=

It seems to me that the problem= you=E2=80=99re seeing is consistent with the capacity of the pump not bein= g sufficient for the max flow required by the engine and the pump flow capa= city is decreasing with use.  You appear to have checked everything bu= t the flow capacity of the pump under normal system pressure which is what = you really need to know.  If you can divert the returning fuel flow fr= om the pressure regulator to a measuring vessel and and collect that fuel f= or an accurately measured time, the pump flow rate can be calculated.  = ;This flow rate should be greater than the maximum required by the engine b= y a comfortable amount.  

My apologies in advance if this is obvious.

=
Steve Boese 

On May 22, 2022, at 8:05 PM, Stephen Izett stephen.izett@= gmail.com <flyrotary@lancaironline.net> wrote:

=EF=BB=BF

=E2=97=86 This message= was sent from a non-UWYO address. Please exercise caution when clicking li= nks or opening attachments from external sources.


Hi Finn

Thanks for the reminder of my pump issue. 
Yes, you chose more wisely the pump capacity. Mine were way= overkill.

So I=E2=80=99m thinking options are:
1. Fuel Pressure transducer fault - No - as this was confir= med by the mixture monitor and tune going out.
2. Power supply to pump via fault in termination or switch = current path - Unlikely, given the slow reduction - I would imagine a fault= y connection would create a less uniform symptom.
3. Alternator Battery voltage/current reduction over time -= No - You would see this in the log.
4. Significant Fuel leak - No - Would think this would have= become obvious on inspection and not intermittent. 
5. Fuel Regulator - They are pretty simple but unsure if th= ey can fail with this symptom?
6. Fuel filter blockage - Certainly this would have to be a= n obvious, but I take it you swapped this out.
7. Pump internal failure -
Electrical - ?
Mechanical breakage - ?
Flow Path - blockage - unlikely if filtered effectively

Where is your pressure transducer in relation to Reg/Any po= st pump filtering/Flow Transducer/Rail?

If fuel regulator and filters can be discounted, I=E2=80=99= m struggling to trust the pump. But your test had it sounding in good shape= and to spec.

So frustrating.

Cheers

Steve





On 23 May 2022, at 8:44 am, Finn Lassen finn.lassen@verizon.net <flyrotary@lancaironline.net> wrote:

Thanks Steve.

From your March/April 2017 posts it was a GSL392 that failed (high current = draw/low pressure, even after you removed the insect you found in the inlet= ).

So this afternoon I ran the pump for about an hour. Amp draw from 3.04 to 2= .86 depending on voltage. Pressure between 43 and 40 psi (also depending on= voltage). No noticeable degradation. Of course the difference with this te= st is that no fuel went to engine -- all recirculated through pressure regulator and back to tank. But no si= gns of a failing pump in terms of higher current draw and less pressure.
I guess I should put a temp probe on the pump and see what it reads during = flight to see if that could be a factor.

Finn

On 5/21/2022 9:01 PM, Stephen Izett stephen.izett@gmail.com wrote:
Hi= Finn

I had from memory a 393 fail. Can=E2=80=99t recall the symp= toms sorry.

I test before takeoff and then run both pumps below 2ooo ft= incase of failure.
I plan to instal a comparator relay board in fuel pressure = circuit to automatically bring on backup pump and failure indicator.
So testing before flight becomes - switch off and back on m= ain engine pump. This will save amps and wear of backup pump.
When I switch off a pump at WOT the engine dies pretty much= instantaneously and don't want to be fiddling with a restart in the Glasai= r which glides like a brick with the gear out in the breeze.

Regards  
Steve Izett





On 21 May 2022, at 10:30 pm, Finn Lassen finn.lassen@verizon.net <flyrotary@lancaironline.net>= wrote:

Recently I noticed my fuel pressure being low. Noticed becaus= e engine did not come up in power when advancing to full throttle. Noticed = mixture real lean. Checking fuel pressure as low as 28 psi (normally 35 and= up to 40 at full throttle).

Going over my engine logs since first flight I now see that f= uel pressure has been trending lower through each flight -- more pronounced= on longer flights (40+ minutes). More and more pronounced over the months = and became really noticeable over last month. Could explain why mixture tuning appeared to= have changed. Nice to have engine logs from practically each flight.

But why? Pump getting weaker?

My primary fuel pump is a GSL414. I figured it was wasted ene= rgy to push way more fuel than needed through the pressure regulator back t= o the tank.

My secondary (backup) pump is a GSL393. When turning that on,= fuel pressure comes back up to where it needs to be.

Anyone have experience with failing or weak EFI pumps, partic= ularly the GSL414?

Finn




= --Apple-Mail-88E90DFE-7836-4BCD-9E79-30A6B84EB498--