X-Virus-Scanned: clean according to Sophos on Logan.com From: "Charlie England" Received: from mail-pf0-f178.google.com ([209.85.192.178] verified) by logan.com (CommuniGate Pro SMTP 6.2c1) with ESMTPS id 9609141 for flyrotary@lancaironline.net; Sat, 25 Mar 2017 15:52:59 -0400 Received-SPF: pass receiver=logan.com; client-ip=209.85.192.178; envelope-from=ceengland7@gmail.com Received: by mail-pf0-f178.google.com with SMTP id p189so9084211pfp.1 for ; Sat, 25 Mar 2017 12:52:58 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:in-reply-to:references:from:date:message-id:subject:to; bh=AF3/AWmXcPV4u6v0s/Fhx2CvmlPjL+NVphhUyBt+vAc=; b=WZR/HdRUmnqdqce7z1QR5J3BzuN4CtEnK4UfrPYU3FP1qPsEpDjLbLNgsmZYrcR/7b ZYMJgXQpjNUyr6kZOc+MHVpEpGa/reZoV34veH3cuGBxGQ2tHYjJCBmsZtCzBffXD+In RFe9Sjc7+jZSYF9aIqeD3ONzr3mFIicR04f10PM95IEibp2PixUg1RWn/NFxiEQZpuPC 9r1PNirFhmaVQSwvUT1dXqs//G954i/C3P4QzCxyoBIgp5VQoPNQ+3pr+0BCUEDS0B9G Vi2R/cJnsjNN35+byz49Kcz+ptC7qi/jx0y6zcQ30TfdK61p4U/O/06JLhO0mBkcHQrb f9UQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:in-reply-to:references:from:date :message-id:subject:to; bh=AF3/AWmXcPV4u6v0s/Fhx2CvmlPjL+NVphhUyBt+vAc=; b=qVDM8IyqWWh0LytEwGTrpdcbv8yZ2JaW0FOkWyyNmSC7qGsUxoxDx4LIdDwFOahwfo f4QPvd2YeTKaHWT8yBKQA+bZJgIDtvkfGpv0aKRDIBtZoUPoujy42Pold7iooIDcERLN 1s3Y3BUd0SQGlaFYBqfjqKOWBJtFB6Sv6RCr4XqY2WUp3IrNHLydhlud81oZ5GzLYZiY uprDFj6z54j8tfF48RVyVLmfB5gb3BNKTgo4zNTcnkL8mH8Ov0ftOs+7cPa3BLZLj+Bt tKFl8R8fFCmn2IwXlXcjhX+ec9m3njlztTTEDrbUjJML3EI0j8qIEsquLBslq8Kev8yc l8ig== X-Gm-Message-State: AFeK/H01cuRb1YKDzFxIP6gj7ADwnMlbWT1c9JMpFifhzlGI6TX51Oo6PTKaUrtXgky0h6UWMDk6TiCCzWj9GQ== X-Received: by 10.98.36.81 with SMTP id r78mr16609166pfj.178.1490471559838; Sat, 25 Mar 2017 12:52:39 -0700 (PDT) MIME-Version: 1.0 Received: by 10.100.128.83 with HTTP; Sat, 25 Mar 2017 12:52:39 -0700 (PDT) In-Reply-To: References: Date: Sat, 25 Mar 2017 14:52:39 -0500 Message-ID: Subject: Re: [FlyRotary] Re: Fuel Pump current and pressures To: Rotary motors in aircraft Content-Type: multipart/alternative; boundary=001a11378a1edf41db054b9373ef --001a11378a1edf41db054b9373ef Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable I'd say the Walbro is the 'gold standard', but there are plenty of others out there. If you could get into your header tank, or have room for an additional small 'sump', you could try this type: http://www.ebay.com/itm/360843503639?_trksid=3Dp2060353.m1438.l2649&ssPageN= ame=3DSTRK%3AMEBIDX%3AIT (Not saying to use a $12 pump; just this style of pump.) I considered this style for my in-tank pumps, but they must be mounted vertically, and would have interfered with the float of the fuel level sender. Variations on this are in almost all new cars, but in the gas tank. That one is ~1.5 inches diameter & ~4.5 inches tall. Supposed to draw around 4 amps, so likely to be lower flow than any of the gerotor pumps. Walbro makes one that's about the same size, for typically around US $80-$90. They're turbine pumps, so the bottom must be in fuel to prime. No easy way to attach an input, except the purpose-made filter sock. There are complete after-market assemblies (single pump, filter sock, surge housing, 40-240 ohm fuel level sender, and cover plate with both fuel & electrical connections, for around US $30-$50. Charlie On Sat, Mar 25, 2017 at 7:31 AM, steve Izett wrote: > Thanks Steve > Really appreciate your helping me with this. > Is there an option other than the Walbro GSL393 or is this the recommende= d > inline pump at present? > > Thanks > Steve > > > > On 25 Mar 2017, at 3:11 pm, Steven W. Boese > wrote: > > Steve, > > It is quite likely that getting your fuel system to behave would not > involve looking at more than can be seen in the photo of the pumps that y= ou > posted. > > Your item 1 would most likely be resolved if pumps of lower flow ratings > were used. The stock RX7 regulator is very similar to the one you are > using and has worked well with those smaller pumps. > > Item 2 may be a result of the pump with the higher current draw having > more internal friction causing a load on the motor in addition to the loa= d > from pumping fuel. > The additional load would slow the motor down resulting in less flow and > lower pressure. It is possible that the decreased flow allows the > regulator to control the pressure at 44 psi. Otherwise there may be a > constriction either within the pump or in the flow path somewhere > before the point where the flow of the two pumps are combined. > > Item A is unlikely to be the case since if the seat in the regulator > hadn't been broken, there would be no flow, thus stalling the pump and > causing a current draw of over 20 amps. > > In item B, you are likely correct that the regulator cannot support the > flow from the high volume pump, thus causing the rail pressure to be abov= e > the regulator's pressure rating. It seems unlikely, however, that the > pressure would drop with the engine running since there is so much more > fuel circulating through the system (~70 gal/hr) than what the engine cou= ld > ever use (~20 gal/hr) even at full throttle. > > All this discussion is directed toward the pumps or the system downstream > of them. Consider also the system between the tank and the pumps. Tryin= g > to draw 140 gal/hr with the two pumps through a single -6 line, and also > through a 20 to 40 micron screen if one is installed as required by the > pump manufacturer, would have to involve a very low pressure at the inlet > to the pumps. This seems to be a very good recipe for vapor lock. > > Steve Boese > > > ------------------------------ > *From:* Rotary motors in aircraft on behalf > of steve Izett > *Sent:* Friday, March 24, 2017 6:19:23 PM > *To:* Rotary motors in aircraft > *Subject:* [FlyRotary] Re: Fuel Pump current and pressures > > I=E2=80=99ll remove the pumps to confirm the model and do some testing. > In old notes I see I thought they were GSL392=E2=80=99s. > The real obvious is as you show in your calcs, the volume of fuel heading > back to the tank with both pumps running is huge. > With a piddly little 150hp stock unit that probably has quite a small > orifice for bypassing regulation, quite large pressures are going to buil= d > up. > I have the two problems though. > 1. Flow capacity of the regulator if I want to be able to run both pumps > simultaneously. > 2. The difference between the pumps currently. Why does one draw more > current and produce less pressure? > > What is causing the 4psi pressure differential: > One of the pumps draws more current but the pressure has dropped from 48 > to 44psi. Now either one of two things could bring this about in my > thinking. > A. The higher current pump is delivering very low fuel flow and so > measures a rail pressure drop, meaning not enough fuel pressure/flow to > break the regulator seat. But I think I can remember hearing fuel returni= ng > to the tank when either pump is running. OR > B. The other pump is delivering at idle more fuel pressure/flow than the > the regulator can cope with so is higher than the regulation pressure. So > as the engine begins to use fuel the rail pressure would drop back to the > regulator pressure. (I cant remember seeing this during engine testing, b= ut > I wasn=E2=80=99t looking for it and Ive deleted some video of engine moni= toring). > > Have I missed something? > > Steve > > On 25 Mar 2017, at 3:11 am, Steven W. Boese > wrote: > > Steve, > > Examining the Walbro pump specifications at: > https://walbrofuelpumps.com/walbro-gsl-series-universal-inline-fuel-pumps > and looking at the data for the individual pumps enables the following > speculation. It is only speculation. > > If you have GSL392 pumps, as are almost all of the pumps listed now on > Ebay, they have a flow rating of 255 L/hr (70 gal/hr) at 40 psi and 8 > amps. If your engine could use 20 gal/hr, that would still leave 50 gal/= hr > returning to the tank. With two of those pumps running at 65 psi > they should be moving 60 gal/hr each with each drawing 10 amps. If your > engine was using 20 gal/hr, 100 gal/hr would be returning to the tank. > This would seem to be moving much more fuel than necessary. Depending on > where you are measuring the fuel pressure and the details of the fuel flo= w > path, the pressure at the pump outlet (and the current draw) could be muc= h > higher with flow rates this high. > > At these flow rates, your whole fuel system could be a constriction and > any fittings (tee's etc) may have significant effects. > > That is why it would be good to establish which pumps you are using eithe= r > by identifying them or measuring their flow rates. GSL393 pumps (45 > gal/hr at 40 psi and 5 amps) might be more appropriate for your > installation if your present pumps have high flow ratings. > > Steve Boese > > ------------------------------ > > *From:* Rotary motors in aircraft on behalf > of Charlie England > *Sent:* Friday, March 24, 2017 12:24 PM > *To:* Rotary motors in aircraft > *Subject:* [FlyRotary] Re: Fuel Pump current and pressures > > Hey Steve, > > Just re-read your post with the measurements, & I'm not sure which had > higher current draw. It was the bottom pump, right? > > Thanks, > > Charlie > > On 3/24/2017 8:06 AM, Stephen Izett wrote: > > Good idea Charlie. > That would clear it up as far as the manifold flow characteristics. > Just a pain in the but to get to. > Thanks > Steve > > > > On 24 Mar 2017, at 8:56 pm, Charlie England > wrote: > > Have you tried swapping the position of the pumps & making the same > measurements? It's hard to imagine it making that much difference, but th= e > bottom pump does have a tight right turn and then a sharp edged 'T' turn = to > the left. I couldn't guess how much, but that would account for at least > some pressure increase. > > Charlie > > On Fri, Mar 24, 2017 at 4:14 AM, steve Izett > wrote: > >> Hi Guys >> Hi Peoples >> >> Here is a photo of our parallel pumps plumbed with 3/8 aluminium lines >> feed from a 28 gallon header tank above to the right. >> Fuel then passes through the firewall and race filter before feeding the >> rail and returning via the pressure regulator (4cyl toyota reg) >> back through the firewall to the header tank, again in 3/8. >> >> I did further measurements today. >> >> 1. Bottom Pump only ~8A and 48psi - Turning both pumps on this pump draw= s >> 9.9A and produces a rail pressure of 65psi >> 2. Bottom Pump only ~9.9A and 44psi - Turning both pumps on this pump >> draws 14.8A and produces the same rail pressure of 65psi >> >> So bottom pump goes from 8.0 -> 9.9A (1.9A increase) under higher head >> pressure >> Top pump goes from 9.9A -> 14.8A (5.1A increase) under same head!! >> >> Clearly Pressure Reg bypass capacity is inadequate for both pumps, >> perhaps with even one pump running. >> (I don=E2=80=99t have data of fuel pressure under load to see if it drop= s as >> power is applied) >> I think I modelled the pump layout/manifold after seeing someone else=E2= =80=99s >> and not sure if it causes any problems? >> The pumps came from eBay stating that they were genuine Walbro and now >> I=E2=80=99m wondering. >> >> Cheers >> >> Steve Izett >> Glasair Super II RG Renesis 4 port RD1C EC3 EM3 >> >> >> >> >> >> >> > > --001a11378a1edf41db054b9373ef Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable
I'd say the Walbro is the 'gold standard', but= there are plenty of others out there. If you could get into your header ta= nk, or have room for an additional small 'sump', you could try this= type:

(Not saying to use a $12 pump; just = this style of pump.)

I considered this style for m= y in-tank pumps, but they must be mounted vertically, and would have interf= ered with the float of the fuel level sender.

Vari= ations on this are in almost all new cars, but in the gas tank. That one is= ~1.5 inches diameter & ~4.5 inches tall. Supposed to draw around 4 amp= s, so likely to be lower flow than any of the gerotor pumps. Walbro makes o= ne that's about the same size, for typically around US $80-$90. They= 9;re turbine pumps, so the bottom must be in fuel to prime. No easy way to = attach an input, except the purpose-made filter sock.

<= div>There are complete after-market assemblies (single pump, filter sock, s= urge housing, 40-240 ohm fuel level sender, and cover plate with both fuel = & electrical connections, for around US $30-$50.

Charlie

On Sat, Mar 25, 2017 at 7:31 AM, steve Izett <flyrotary@lan= caironline.net> wrote:
Thanks Steve
Really appreciate your hel= ping me with this.
Is there an option other than the Walbro GSL39= 3 or is this the recommended inline pump at present?

Thanks
Steve



=
On 25 Mar 2017, at 3:11 pm, Steven W. Boese = <flyrot= ary@lancaironline.net> wrote:

Steve,

It is quite lik= ely that getting your fuel system to behave would not involve looking at mo= re than can be seen in the photo of the pumps that you posted.

Your item 1 would most likely be resolved if pumps = of lower flow ratings were used.=C2=A0 The stock RX7 regulator is very simi= lar to the one you are using and has worked well with those smaller pumps.<= /div>

Item 2 may be a result of the pump wi= th the higher current draw having more internal friction causing a load on = the motor in addition to the load from pumping fuel.=C2=A0
The additional load would slow the mo= tor down resulting in less flow and lower pressure.=C2=A0 It is possible th= at the decreased flow allows the regulator to control=C2=A0the pressure at = 44 psi.=C2=A0=C2=A0 Otherwise there may be a constriction either within the= pump or in the flow path somewhere before=C2=A0the point where=C2=A0the fl= ow of the two pumps are combined.

Item = A is unlikely to be the case since if the seat in the regulator hadn't = been broken, there would be no flow, thus stalling the pump and causing a c= urrent draw of over 20 amps.

In item B,= =C2=A0you are=C2=A0likely correct that the regulator cannot support the flo= w from the high volume pump, thus causing the rail pressure to be above the= regulator's pressure rating.=C2=A0 It seems unlikely, however,=C2=A0th= at the pressure would drop with the engine running since there is so much m= ore fuel circulating through the system (~70 gal/hr) than what the engine c= ould ever use (~20 gal/hr) even at full throttle.

All this discussion is directed toward the pumps or the system d= ownstream of them.=C2=A0 Consider also the system between the tank and the = pumps.=C2=A0 Trying to draw 140 gal/hr with the two pumps through a single = -6 line, and also through a 20 to 40 micron screen if one is installed as r= equired by the pump manufacturer, would have to involve a very low pressure= at the inlet to the pumps.=C2=A0 This seems to be a very good recipe for v= apor lock.

<= div style=3D"margin-top:0px;margin-bottom:0px">Steve Boese=C2=A0=C2=A0=C2= =A0=C2=A0=C2=A0<= /span>


From:=C2=A0Rotary motors in aircraft <flyrotary@lanc= aironline.net> on behalf of steve Izett <flyrotary@lancaironline.net>= ;
Sent:=C2=A0Friday, March 24, 2017 6:19:23 PM
To:=C2=A0Rotary motors in = aircraft
Subject:=C2=A0[FlyRotary] Re: Fuel Pump current and pressures
=C2=A0
I=E2=80=99ll remove the pumps to confirm the mode= l and do some testing.
In old notes I see I thought they were GSL392=E2= =80=99s.
The real obvious is as you show in your calcs, the volum= e of fuel heading back to the tank with both pumps running is huge.
With a piddly little 150hp stock unit that probably has quite a small or= ifice for bypassing regulation, quite large pressures are going to build up= .
I have the two problems though.
1. Flow capacity of t= he regulator if I want to be able to run both pumps simultaneously.
2. The difference between the pumps currently. Why does one draw more cu= rrent and produce less pressure?

What is causing t= he 4psi pressure differential:
One of the pumps draws more curren= t but the pressure has dropped from 48 to 44psi. Now either one of two thin= gs could bring this about in my thinking.
A. The higher current p= ump is delivering very low fuel flow and so measures a rail pressure drop, = meaning not enough fuel pressure/flow to break the regulator seat. But I th= ink I can remember hearing fuel returning to the tank when either pump is r= unning. OR
B. The other pump is delivering at idle more fuel pres= sure/flow than the the regulator can cope with so is higher than the regula= tion pressure. So as the engine begins to use fuel the rail pressure would = drop back to the regulator pressure. (I cant remember seeing this during en= gine testing, but I wasn=E2=80=99t looking for it and Ive deleted some vide= o of engine monitoring).

Have I missed something?<= /div>

Steve
On 25= Mar 2017, at 3:11 am, Steven W. Boese <flyrotary@lancaironline.net> wrote:=

Steve,

Examining the Walbro pump specifications at:
<= div style=3D"margin-top:0px;margin-bottom:0px">https://walbrofuelpumps.com/walbro-gsl-series-universal-= inline-fuel-pumps
and looking at the data for the individual pumps= enables the following speculation.=C2=A0 It is only speculation.

If=C2=A0you have GSL392 pumps, as are almost all o= f the pumps listed now on Ebay, they have a flow rating of 255 L/hr (70 gal= /hr) at 40 psi and 8 amps.=C2=A0 If your engine could use 20 gal/hr, that w= ould still leave 50 gal/hr returning to the tank.=C2=A0 With two of those p= umps running at 65 psi =C2=A0
they should be moving 60 gal/hr= each with each drawing 10 amps.=C2=A0 If your engine was using 20 gal/hr, = 100 gal/hr would be returning to the tank.=C2=A0 This would seem to be movi= ng much more fuel than necessary.=C2=A0 Depending on where you are measurin= g the fuel pressure and the details of the fuel flow path, the pressure at = the pump outlet (and the current draw) could be much higher with flow rates= this high.=C2=A0

At these flow rates, your whole = fuel system could be=C2=A0a constriction and any fittings (tee's etc) m= ay have significant effects.

That is why it would = be good to establish which pumps you are using either by identifying them o= r measuring their flow rates.=C2=A0 GSL393=C2=A0 pumps=C2=A0(45 gal/hr at 40 p= si and 5 amps)=C2=A0might be more appropriate for your installation if your p= resent=C2=A0pumps have high flow ratings.

Steve Bo= ese

=C2=A0From:=C2=A0Rotary motors in aircraf= t <flyr= otary@lancaironline.net> on behalf of Charlie England <flyrotary@lancaironl= ine.net>
Sent:=C2=A0Friday, March 24, 2017 12:24 PM
To:=C2=A0Rotar= y motors in aircraft
Subject:=C2=A0[FlyRotary] Re: Fuel Pump current and p= ressures
=C2=A0
Hey Steve,=C2=A0

Just re-read your post with the measurem= ents, & I'm not sure which had higher current draw. It was the bott= om pump, right?

Thanks,

Charlie

On 3/24/2017 8:06 AM, = Stephen Izett wrote:
Good idea Charlie.= =C2=A0
That would clear it up as far as the manifold flow characteristi= cs.
Just a pain in the but to get to.
Thanks
Steve<= /div>



=
On 24 Mar 2017, at 8:56 pm, Charlie England <flyrotary@lancaironline.net&= gt; wrote:

Have you tried swapping the position of the pumps &= amp; making the same measurements? It's hard to imagine it making that = much difference, but the bottom pump does have a tight right turn and then = a sharp edged 'T' turn to the left. I couldn't guess how much, = but that would account for at least some pressure increase.=C2=A0

<= /div>
Charlie

On Fri, Mar 24, 2017 at 4:14 AM, steve Izett=C2=A0<= flyrotary@= lancaironline.net>=C2=A0wrote:
Hi Guys
Hi Peoples

Here = is a photo of our parallel pumps plumbed with 3/8 aluminium lines feed from= a 28 gallon header tank above to the right.
Fuel then passes thr= ough the firewall and race filter before feeding the rail and returning via= the pressure regulator (4cyl toyota reg)=C2=A0
back through the = firewall to the header tank, again in 3/8.

I did f= urther measurements today.=C2=A0

1. Bottom Pump on= ly=C2=A0~8A and 48psi - Turning both pumps on this pump draws 9.9A and prod= uces a rail pressure of 65psi
2. Bottom Pump only=C2=A0~9.9A and = 44psi - Turning both pumps on this pump draws 14.8A and produces the same r= ail pressure of 65psi

So bottom pump goes from 8.0= -> 9.9A (1.9A increase) under higher head pressure
Top pump g= oes from 9.9A -> 14.8A (5.1A increase) under same head!!

<= /div>
Clearly Pressure Reg bypass capacity is inadequate for both pumps= , perhaps with even one pump running.=C2=A0
(I don=E2=80=99t have= data of fuel pressure under load to see if it drops as power is applied)
I think I modelled the pump layout/manifold after seeing someone e= lse=E2=80=99s and not sure if it causes any problems?
The pumps c= ame from eBay stating that they were genuine Walbro and now I=E2=80=99m won= dering.

Cheers

Steve Izet= t
Glasair Super II RG Renesis 4 port RD1C EC3 EM3=C2=A0





<Fuel Pres Pumps.JPG>


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