X-Virus-Scanned: clean according to Sophos on Logan.com From: "Charlie England" Received: from mail-pg0-f47.google.com ([74.125.83.47] verified) by logan.com (CommuniGate Pro SMTP 6.2c1) with ESMTPS id 9610631 for flyrotary@lancaironline.net; Sun, 26 Mar 2017 10:05:24 -0400 Received-SPF: pass receiver=logan.com; client-ip=74.125.83.47; envelope-from=ceengland7@gmail.com Received: by mail-pg0-f47.google.com with SMTP id 81so2337353pgh.2 for ; Sun, 26 Mar 2017 07:05:24 -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=a/k+U33QIfc4fWISOFlvoEXN+Oto5LztZxXitcbikPg=; b=VJKO/VV0cd12Go94SznmehIRPxppunYFBkFaz9OBruTPhR+FNUsM0givqIgsvAfIvE 8Djge2dwg1JRruyMIRhIjTWOb5u6nkr4GTZuQSFhVXJk7AnK15U9JSRcFbaizuXDmcXx hwa+wtQ4eq6l6IfoSNgUqqLga4to9Y3Hw86aPJ+R/ux8JmwIOtSky6aa7+UKNjjnbAJ4 ViFRkfWCkpZi98oKxxttMua23iQ6M2il85BKIy8OJAOviI3xAea784f3hxDoDBVaLFTt CJtuOYfEgWgVZhboYkyb9+7kaXJbZiwIbUAVp8l8924f6uYPwU10ZxYV0QR9puw6f9i8 f16Q== 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=a/k+U33QIfc4fWISOFlvoEXN+Oto5LztZxXitcbikPg=; b=gYtfDbyE6fyMUFg0ZguE5IQp6N7BVF1Bsnz/A+UQzQD7XHh0CUEMoFY4H60QQstgRX gvUke+8H7uEg0yuXlGPJzvUma0snMt96PY2Qpmmy0qmIapy1NDDa/npujSWaVMBE/DVM qEdYaXVR54/F1ZH07ALSG+kOMtScmisYrz5wbBoCAN2vz+yDeMeoIAUvpDwbTTeo2Rj5 5QiKnQ5DBP6imU+1LUVHDW78ShY/MTQzic/He2fdSp+PzU3KTayaxSVv7keLpPIY88BF ZAnvUIvR2g1HzfmO9Tn5JdIEEdw9jIZo4klVSfeBSU6XZJ0MzN1//AjN8Aq90FIn6AwT kgcg== X-Gm-Message-State: AFeK/H2fNLb5vmtMh+ZyqYDS+D2m0U1ejDJwEWeCYf6XtSDZO0T+bmsqAriZRzkXk6jvD1zY2WYatphLG+Kh5g== X-Received: by 10.99.94.198 with SMTP id s189mr19284451pgb.211.1490537106872; Sun, 26 Mar 2017 07:05:06 -0700 (PDT) MIME-Version: 1.0 Received: by 10.100.128.83 with HTTP; Sun, 26 Mar 2017 07:05:06 -0700 (PDT) In-Reply-To: References: Date: Sun, 26 Mar 2017 09:05:06 -0500 Message-ID: Subject: Re: [FlyRotary] Re: Fuel Pump current and pressures To: Rotary motors in aircraft Content-Type: multipart/alternative; boundary=94eb2c0c7894c7a0e9054ba2b6f1 --94eb2c0c7894c7a0e9054ba2b6f1 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable I'm not aware of any made for inline use, since they won't self prime. If your existing tank has a flat side or bottom surface, could you just cut a port big enough for a pair, and mount them on a cover plate? That's what I'd have done in the RV-7's wing tank, but there just wasn't room because of the tank's shape (wing leading edge). Of course, the simplest thing is to 1st check that pump for proper operation, and then get a high capacity regulator. On Sun, Mar 26, 2017 at 8:16 AM, Stephen Izett wrote: > Hi Charlie > In retrospect I=E2=80=99d seriously consider building the 18 Gal header t= ank to > suit a couple of submerged pumps. > As my pumps live below the header tank perhaps I could use turbine pumps, > but does anyone make them for inline use. > > Cheers > Steve Izett > > > > > On 26 Mar 2017, at 3:52 am, Charlie England > wrote: > > 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&ssPageName=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 wa= y > 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 fu= el > & 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 >> recommended 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 = you >> 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 lo= ad >> 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 abo= ve >> 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 co= uld >> ever use (~20 gal/hr) even at full throttle. >> >> All this discussion is directed toward the pumps or the system downstrea= m >> of them. Consider also the system between the tank and the pumps. Tryi= ng >> 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 inle= t >> 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 headin= g >> 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 bui= ld >> 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 return= ing >> 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. S= o >> as the engine begins to use fuel the rail pressure would drop back to th= e >> regulator pressure. (I cant remember seeing this during engine testing, = but >> I wasn=E2=80=99t looking for it and Ive deleted some video of engine mon= itoring). >> >> 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-pump= s >> 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 o= n >> where you are measuring the fuel pressure and the details of the fuel fl= ow >> path, the pressure at the pump outlet (and the current draw) could be mu= ch >> 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 >> either 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 t= he >> 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 th= e >>> 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 >>> draws 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 dro= ps 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 >>> >>> >>> >>> >>> >>> >>> >> >> > > --94eb2c0c7894c7a0e9054ba2b6f1 Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable
I'm not aware of any made for inline use, since they w= on't self prime.

If your existing tank has a flat si= de or bottom surface, could you just cut a port big enough for a pair, and = mount them on a cover plate? That's what I'd have done in the RV-7&= #39;s wing tank, but there just wasn't room because of the tank's s= hape (wing leading edge).

Of course, the simplest = thing is to 1st check that pump for proper operation, and then get a high c= apacity regulator.=C2=A0

On Sun, Mar 26, 2017 at 8:16 AM, Stephen Izett <flyro= tary@lancaironline.net> wrote:
Hi Charlie
In retrospect I=E2= =80=99d seriously consider building the 18 Gal header tank to suit a couple= of submerged pumps.
As my pumps live below the header tank perha= ps I could use turbine pumps, but does anyone make them for inline use.

Cheers
Steve Izett




On 2= 6 Mar 2017, at 3:52 am, Charlie England <flyrotary@lancaironline.net> wrote= :

<= div dir=3D"ltr">I'd say the Walbro is the 'gold standard', but = there are plenty of others out there. If you could get into your header tan= k, or have room for an additional small 'sump', you could try this = type:

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

I= considered this style for my in-tank pumps, but they must be mounted verti= cally, 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. S= upposed to draw around 4 amps, so likely to be lower flow than any of the g= erotor pumps. Walbro makes one that's about the same size, for typicall= y around US $80-$90. They're turbine pumps, so the bottom must be in fu= el 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 Ize= tt <flyrotary@lancaironline.net> wrote:
Thanks SteveReally appreciate your helping me with this.
Is there an option= other than the Walbro GSL393 or is this the recommended inline pump at pre= sent?

Thanks
Steve

<= div>

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

Steve,
<= br>
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 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 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 th= e higher current draw having more internal friction causing a load on the m= otor in addition to the load from pumping fuel.=C2=A0
The additional load would slow the motor do= wn resulting in less flow and lower pressure.=C2=A0 It is possible that 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 flow of = the two pumps are combined.

Item A is u= nlikely to be the case since if the seat in the regulator hadn't been b= roken, there would be no flow, thus stalling the pump and causing a current= draw of over 20 amps.

In item B,=C2=A0= you are=C2=A0likely correct that the regulator cannot support the flow from= the high volume pump, thus causing the rail pressure to be above the regul= ator's pressure rating.=C2=A0 It seems unlikely, however,=C2=A0that the= pressure would drop with the engine running since there is so much more fu= el circulating through the system (~70 gal/hr) than what the engine could e= ver use (~20 gal/hr) even at full throttle.

All this discussion is directed toward the pumps or the system downstr= eam 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 lin= e, and also through a 20 to 40 micron screen if one is installed as require= d by the pump manufacturer, would have to involve a very low pressure at th= e inlet to the pumps.=C2=A0 This seems to be a very good recipe for vapor l= ock.

Steve Boese=C2=A0=C2=A0=C2=A0=C2= =A0=C2=A0


=
Fro= m:=C2=A0Rotary motors in aircraft <flyrotary@lancaironline.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 model and do some testing.<= div>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 reg= ulation, quite large pressures are going to build 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 be= tween the pumps currently. Why does one draw more current and produce less = pressure?

What is causing the 4psi pressure differ= ential:
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 abo= ut 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 hear= ing fuel returning 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 th= e engine begins to use fuel the rail pressure would drop back to the regula= tor pressure. (I cant remember seeing this during engine testing, but I was= n=E2=80=99t looking for it and Ive deleted some video of engine monitoring)= .

Have I missed something?

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

Steve,

<= div style=3D"margin-top:0px;margin-bottom:0px">Examining the Walbro pump sp= ecifications at:
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 of the pu= mps 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 would sti= ll leave 50 gal/hr returning to the tank.=C2=A0 With two of those pumps run= ning at 65 psi =C2=A0
they should be moving 60 gal/hr each wi= th 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 moving much = more fuel than necessary.=C2=A0 Depending on where you are measuring the fu= el 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 hi= gh.=C2=A0

At these flow rates, your whole fuel sys= tem could be=C2=A0a 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 either by identifying them or measur= ing their flow rates.=C2=A0 GSL393=C2=A0 pumps=C2=A0(45 = gal/hr at 40 psi and 5 amps)=C2=A0might be more appropr= iate for your installation if your present=C2=A0pumps have high flow rating= s.

Steve Boese

=C2=A0
From:=C2=A0Rotary motors in aircraft <flyrotary@lancaironline.net> on behalf of Cha= rlie England <flyrotary@lancaironline.net>
Sent:=C2=A0Friday, March 24, 2017 12:24 PM
To:=C2=A0Rotary mo= tors in aircraft
Subject:=C2=A0[FlyRotary] Re: Fuel = Pump current and pressures
=C2=A0
Hey Steve,=C2=A0

Just re-read your post with the measurements, & I= 'm not sure which had higher current draw. It was the bottom pump, righ= t?

Thanks,

Charlie

On 3/24/2017 8:06 AM, Stephen Izett= wrote:
Good idea Charlie.=C2=A0
Tha= t 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 <flyrotary@lancaironline.net> wrote:
Have you tried swapping the position of the= pumps & making the same measurements? It's hard to imagine it maki= ng that much difference, but the bottom pump does have a tight right turn a= nd then a sharp edged 'T' turn to the left. I couldn't guess ho= w much, but that would account for at least some pressure increase.=C2=A0
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 par= allel pumps plumbed with 3/8 aluminium lines feed from a 28 gallon header t= ank above to the right.
Fuel then passes through the firewall and= race filter before feeding the rail and returning via the pressure regulat= or (4cyl toyota reg)=C2=A0
back through the firewall to the heade= r tank, again in 3/8.

I did further measurements t= oday.=C2=A0

1. Bottom Pump only=C2=A0~8A and 48psi= - Turning both pumps on this pump draws 9.9A and produces 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 rail pressure of 65psi=

So bottom pump goes from 8.0 -> 9.9A (1.9A inc= rease) under higher head pressure
Top pump goes from 9.9A -> 1= 4.8A (5.1A increase) under same head!!

Clearly Pre= ssure Reg bypass capacity is inadequate for both pumps, perhaps with even o= ne pump running.=C2=A0
(I don=E2=80=99t have data of fuel pressur= e under load to see if it drops as power is applied)
I think I mo= delled 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 S= uper II RG Renesis 4 port RD1C EC3 EM3=C2=A0


<= /div>