X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from [97.64.187.19] (HELO dsmdc-mail-smtp.mcomdc.com) by logan.com (CommuniGate Pro SMTP 5.3.7) with ESMTP id 4340789 for flyrotary@lancaironline.net; Tue, 08 Jun 2010 18:18:20 -0400 Received-SPF: pass receiver=logan.com; client-ip=97.64.187.19; envelope-from=btilley@mchsi.com Received: from [10.14.204.137] ([166.137.137.237]) by dsmdc-mail-bxga3 with bizsmtp id TaMv1e00657W3r201aMyyp; Tue, 08 Jun 2010 17:22:16 -0500 X-Authority-Analysis: v=1.1 cv=tjA7BBGQGMWTpY/NJkPBZwf2yjWhb0GsfLEpP826H2g= c=1 sm=1 a=qDP2XmYWB9gA:10 a=GQCbJdZ--msA:10 a=Irtx+EaSSKYLT7sZ+A7spQ==:17 a=8pif782wAAAA:8 a=ayC55rCoAAAA:8 a=arxwEM4EAAAA:8 a=r1ClD_H3AAAA:8 a=QdXCYpuVAAAA:8 a=7g1VtSJxAAAA:8 a=ekHE3smAAAAA:20 a=UretUmmEAAAA:8 a=Ia-xEzejAAAA:8 a=k1mB9UNLAAAA:8 a=pedpZTtsAAAA:8 a=aK1lgdqGLhvnX50Xp98A:9 a=RcgxU4frIa5HfOkOp7QA:7 a=FOxnq9F05Rdjm0bEp9oOcoUxM4EA:4 a=QEXdDO2ut3YA:10 a=B0MEC-MkJC0A:10 a=Qa1je4BO31QA:10 a=VKpQBh4bLwwA:10 a=1vhyWl4Y8LcA:10 a=EzXvWhQp4_cA:10 a=eJojReuL3h0A:10 a=t5mxNg6ZAujzd5nm:21 a=f7GV5GKFLYCoJc9E:21 a=GzqvpU34Bo1_1ZEyEcEA:9 a=s_fWy9bjg5CIBRpe6OoA:7 a=WyEco5lZ3IvU_nxMCX-JglJQgR4A:4 a=7EUc7KqRjnVW0Jr0:21 a=bBeIIQh7m7psCOiN:21 a=Irtx+EaSSKYLT7sZ+A7spQ==:117 Message-Id: From: Bob Tilley To: Rotary motors in aircraft In-Reply-To: Content-Type: multipart/alternative; boundary=Apple-Mail-1--772134360 Content-Transfer-Encoding: 7bit Mime-Version: 1.0 (iPhone Mail 7E18) Subject: Re: [FlyRotary] Re: high/low pressure pumps question Date: Tue, 8 Jun 2010 17:14:51 -0500 References: X-Mailer: iPhone Mail (7E18) --Apple-Mail-1--772134360 Content-Type: text/plain; charset=utf-8; format=flowed; delsp=yes Content-Transfer-Encoding: quoted-printable Ed You are making us smarter every day! http://en.wikipedia.org/wiki/Clausius=E2=80=93Clapeyron_relation And the info we get from so manyon the list is what makes this list so =20= good!!! Bob Tilley Sent from my iPhone On Jun 8, 2010, at 2:15 PM, "Ed Anderson" =20= wrote: > Hi Al, > > > Everyone on this list ultimately makes up their own mind about what =20= > information to use and how to evaluate it, all view points are =20 > welcome on this list =E2=80=93 that is why it exists. There is no = moderator=20 > to make those judgment calls about what should or should not be dis=20= > cussed or mentioned =E2=80=93 it=E2=80=99s up to everyone to take the = input =20 > provided and make their own decision about it. That=E2=80=99s why = this lis=20 > t is great! > > > Onward indeed!! {:>) > > Ed > > > > > Rv-6A N494BW Rotary Powered > > Matthews, NC > > eanderson@carolina.rr.com > > http://www.andersonee.com > > http://www.eicommander.com/store.htm > > http://www.dmack.net/mazda/index.html > > http://www.flyrotary.com/ > > http://members.cox.net/rogersda/rotary/configs.htm#N494BW > > http://www.rotaryaviation.com/Rotorhead%20Truth.htm > > From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] =20= > On Behalf Of Al Wick > Sent: Tuesday, June 08, 2010 10:59 AM > To: Rotary motors in aircraft > Subject: [FlyRotary] Re: high/low pressure pumps question > > Hi Ed. You often make significant contributions that help improve =20 > flight safety. If you share your fuel design, at least do the =20 > calculations and let users know how close this is to vapor lock. =20 > We're talking about life risk here. You are glossing over my point =20 > and changing the topic. Returning fuel to pump inlet is very risky =20 > and should not be done unless you desire to operate on the threshold =20= > of vapor lock. > > I agree, there is one exception. That's if you have one of the new =20 > fuel pump controllers that measures fuel parameters and alters pump =20= > speed. I looked into that one years ago. Talk about added complexity! > > On with the good stuff! > > -al wick > ----- Original Message ----- > From: Ed Anderson > To: Rotary motors in aircraft > Sent: Monday, June 07, 2010 8:00 AM > Subject: [FlyRotary] Re: high/low pressure pumps question > > Points noted, Al. > > However, would like to point out that today many automotive fuel =20 > systems DO NOT return fuel to the tanks =E2=80=93 they use the =E2=80=9C= No-=20 > Return=E2=80=9D fuel systems whereby pump pressure is regulated to = prevent v=20 > apor lock. However, these are systems with the pumps generally embed=20= > in the fuel tank =E2=80=93 thereby minimizing (if not eliminating) = your con=20 > cern about the return being =E2=80=9CT=E2=80=9D back into the line = close to the =20 > high pressure pump intake. With millions of autos now using this sy=20= > stem =E2=80=93 it would appear to be a viable approach if done = correctly (al=20 > ways the caveat {:>)) > > That is one point that Charlie made - was the possibility of using a =20= > simple PWM circuit to control pump pressure similar to the no-return =20= > Auto systems. > > For those interested, here is a fairly good non-technical =20 > description of a no-return system used in automobiles. > > Ed > > http://www.picoauto.com/tutorials/fuel-injection.html > > Returnless Fuel Systems > Have been adopted by several motor manufacturers and differ from the =20= > conventional by having a delivery pipe only to the fuel rail with no =20= > return flow back to the tank. > The returnless systems, both the mechanical and the electronic =20 > versions, were necessitated by emissions laws. The absence of heated =20= > petrol returning to the fuel tank reduces the amount of evaporative =20= > emissions, while the fuel lines are kept short, thus reducing build =20= > costs. > Mechanical Returnless Fuel Systems > The =E2=80=98returnless=E2=80=99 system differs from the norm by = having the =20 > pressure regulator inside the fuel tank. When the fuel pump is activ=20= > ated, fuel flows into the system until the required pressure is obta=20= > ined; at this point =E2=80=98excess=E2=80=99 fuel is bled past the = pressure =20 > regulator and back into the tank. > The =E2=80=98flow and return=E2=80=99 system has a vacuum supply to = the pressure =20 > regulator: this enables the fuel pressure to be increased whenever t=20= > he manifold vacuum drops, providing fuel enrichment under accelerati=20= > on. > The =E2=80=98returnless=E2=80=99 system has no mechanical compensation = affecting =20 > the fuel pressure, which remains at a higher than usual 44 to 50 psi=20= > . By increasing the delivery pressure, the ECM (Electronic Control M=20= > odule) can alter the injection pulse width to give the precise deliv=20= > ery, regardless of the engine load and without fuel pressure compens=20= > ation. > Electronic Returnless Fuel Systems > This version has all the required components fitted within the one =20 > unit of the submersible fuel pump. It contains a small particle =20 > filter (in addition to the strainer), pump, electronic pressure =20 > regulator, fuel level sensor and a sound isolation system. The =20 > electronic pressure regulator allows the pressure to be increased =20 > under acceleration conditions, and the pump=E2=80=99s output can be = adjusted=20 > to suit the engine's fuel demand. This prolongs the pump=E2=80=99s = life as =20 > it is no longer providing a larger than required output delivery. > The Electronic Control Module (ECM) supplies the required pressure =20 > information, while the fuel pump=E2=80=99s output signal is supplied = in the =20 > form of a digital squarewave. Altering the squarewave=E2=80=99s duty = cycle a=20 > ffects the pump=E2=80=99s delivery output. > To compensate for the changing viscosity of the fuel with changing =20 > fuel temperature, a fuel rail temperature sensor is installed. A =20 > pulsation damper may also be fitted ahead of or inside the fuel rail. > Here is one rendition of such a system in an auto application > > > Ed Anderson > > Rv-6A N494BW Rotary Powered > > Matthews, NC > > eanderson@carolina.rr.com > > http://www.andersonee.com > > http://www.dmack.net/mazda/index.html > > http://www.flyrotary.com/ > > http://members.cox.net/rogersda/rotary/configs.htm#N494BW > > http://www.rotaryaviation.com/Rotorhead%20Truth.htm > > From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] =20= > On Behalf Of Al Wick > Sent: Monday, June 07, 2010 9:25 AM > To: Rotary motors in aircraft > Subject: [FlyRotary] Re: high/low pressure pumps question > > I'm really concerned for your life risk. This is a very high risk =20 > fuel design. Puts your fuel pressure at pump inlet very very close =20 > to the vapor pressure of fuel. This suddenly makes the design =20 > sensitive to a whole bunch of environmental factors. > > Ask this question: Millions of automobiles. When they designed =20 > automotive fuel systems, why did every single engineer return fuel =20 > to tank instead of pump inlet? So much more expensive to send to tank. > > You can bench test your design and prove how close it is to failure. =20= > Just need to measure fuel pressure at pump inlet, measure pump temp. =20= > Use hair dryer to force pump to higher temp. Put all the numbers in =20= > spreadsheet, then calculate distance between vapor pressure and your =20= > readings. Adjust for worst case, which would be high altitude =20 > airport, hot day sitting on tarmac for 1 hour, heat soaked engine =20 > compartment, car fuel containing ethanol. > > Marginal designs can fly for years without failure. This is the =20 > nature of failure. Use care, I'm concerned. > > -al wick > > > ----- Original Message ----- > From: Charlie England > To: Rotary motors in aircraft > Sent: Sunday, June 06, 2010 6:47 AM > Subject: [FlyRotary] Re: high/low pressure pumps question > > Hope this helps... > > On 6/6/2010 2:21 AM, Todd Bartrim wrote: > > > > Hi Charlie; > > Hmmmnn, I gotta say a picture (or drawing) is worth a thousand =20 > words. > > Todd (sent on my new-fangled google phone with a really damn small > > keyboard) > > > >> On 2010-06-05 8:46 PM, "Charlie England" >> > wrote: > >> > >> Hi Todd, > >> > >> My thought is to set up the fuel path thus: fuel source through a T > >> into injection pumps, through filters, through combining T, through > >> the regulator(in cockpit), through firewall to engine. The > >> regulator's bypass port (in the cockpit) would be plumbed just like > >> yours, except no heat exchanger since the bypass fuel would never =20= > see > >> the heat of the engine compartment. The bypass would still T into =20= > the > >> supply to the injection pumps, like your system. Obviously, a > >> manifold pressure line would be required through the firewall into > >> the cockpit to the pressure regulator. > >> > >> My original plan (different injection that didn't require a return > >> line) was similar to your selector setup: main tanks feeding stock > >> van's selector, with the 3rd port on it being fed by a 2nd vans > >> selector to select either of the 2 aux tanks. No transfer pump =20 > would > >> have been required, & no crossover valve. Failure of the primary > >> valve could have been a 'show stopper', but the newer valves seem =20= > to > >> be rock solid reliable. Going to this system using the gear type > >> pumps requiring a return line forced re-thinking. Using your idea =20= > to > >> return the bypassed fuel at the pump inlet effectively eliminates =20= > the > >> 'return' issue, & tempts me to return to the original fuel selector > >> layout, with the addition of a Facet boost pump. The fact that the > >> optical sensors will work looking into the side of a fuel line (the > >> T), instead of needing them in the tank & that they still give =20 > almost > >> a full minute's warning, is very encouraging. I'll start looking =20= > for > >> a convenient place to mount them. > >> > >> I hope that Tracy will chime in on how he plumbed the regulator on > >> his -8. > >> > >> Many thanks for the extra details. > >> > >> Charlie > >> > >> > >> > >> On 6/5/2010 12:32 PM, Todd Bartrim wrote: > >> > >> > > >> > Hi Charlie > >> > Not sure I understand correctly what you mean? Can you > >> sketch it out quickly? I'... > >> > >> > *From*: Charlie England >> > >> >> .. > >> > >> > *Subject*: [FlyRotary] Re: high/low pressure pumps question > >> > *Date*: Sat, 05 Jun 2010 08:38:09 -0... > >> > >> > >> > >> -- > >> Homepage: http://www.flyrotary.com/ > >> Archive and UnSub: http://mail.lancaironline.net:81/lists... > >> > > -- > Homepage: http://www.flyrotary.com/ > Archive and UnSub: = http://mail.lancaironline.net:81/lists/flyrotary/List.html --Apple-Mail-1--772134360 Content-Type: text/html; charset=utf-8 Content-Transfer-Encoding: quoted-printable
Ed

You are making us = smarter every day!
http://en.wikipedia.org/wik= i/Clausius=E2=80=93Clapeyron_relation

And the info we = get from so manyon the list is what makes this list so = good!!!

Bob Tilley
Sent from my = iPhone

On Jun 8, 2010, at 2:15 PM, "Ed Anderson" <eanderson@carolina.rr.com>= ; wrote:

=

Hi = Al,


 
Everyone on =
this list ultimately makes up their own mind about what information to =
use and how to evaluate it, all view points are welcome on this list =E2=80=
=93 that is why it exists.  There is no moderator to make those =
judgment calls about what should or should not be discussed or mentioned =
=E2=80=93 it=E2=80=99s up to everyone to take the input provided and =
make their  own decision about it.  That=E2=80=99s why this =
list is great!
 
 
Onward indeed!! =
 {:>)
 
Ed
 
 
 

   =

From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of Al Wick
Sent: Tuesday, June 08, = 2010 10:59 AM
To: Rotary motors in aircraft
Subject: [FlyRotary] Re: = high/low pressure pumps question

 

Hi Ed. You often make significant contributions that = help improve flight safety. If you share your fuel design, at least do the calculations and let users know how close this is to vapor lock. We're = talking about life risk here. You are glossing over my point and changing the = topic. Returning fuel to pump inlet is very risky and should not be done unless = you desire to operate on the threshold of vapor = lock.

 

I agree, there is one exception. That's if you = have one of the new fuel pump controllers that measures fuel parameters and = alters pump speed. I looked into that one years ago. Talk about added = complexity!

 

On with the good stuff!

 

-al wick

=

----- Original Message ----- =

From:= Ed Anderson

Sent: Monday, June 07, 2010 8:00 AM

Subject: [FlyRotary] Re: high/low pressure pumps question

 

Points noted, = Al.

 

However, would like to point out = that today many automotive fuel systems DO NOT return fuel to the tanks =E2=80=93= they use the  =E2=80=9CNo-Return=E2=80=9D fuel systems whereby pump = pressure is regulated to prevent vapor lock. However, these are systems with the = pumps generally embed in the fuel tank =E2=80=93 thereby minimizing (if not eliminating) your concern about the return being =E2=80=9CT=E2=80=9D = back into the line close to the high pressure pump intake.  With millions of = autos now using this system =E2=80=93 it would appear to be a viable approach if = done correctly (always the caveat {:>))

 

That is one point that Charlie made = - was the possibility of using a simple PWM circuit to control pump pressure = similar to the no-return Auto systems.

 

For those interested, here is a = fairly good non-technical description of a no-return system used in = automobiles.

 

Ed

 

http://www.= picoauto.com/tutorials/fuel-injection.html

 

Returnless Fuel = Systems

Have been adopted by several motor manufacturers and differ from the conventional by having a = delivery pipe only = to the fuel rail with no return flow back to the = tank.

The returnless systems, both the = mechanical and the electronic versions, were necessitated by emissions laws. The = absence of heated petrol returning to the fuel tank reduces the amount of = evaporative emissions, while the fuel lines are kept short, thus reducing build = costs.

Mechanical Returnless Fuel = Systems

The =E2=80=98returnless=E2=80=99 system = differs from the norm by having the pressure regulator inside the fuel tank. = When the fuel pump is activated, fuel flows into the system until the required = pressure is obtained; at this point =E2=80=98excess=E2=80=99 fuel is bled past = the pressure regulator and back into the tank.

The =E2=80=98flow and return=E2=80=99 = system has a vacuum supply to the pressure regulator: this enables the fuel pressure = to be increased whenever the manifold vacuum drops, providing fuel enrichment = under acceleration.

The =E2=80=98returnless=E2=80=99 system = has no mechanical compensation affecting the fuel pressure, which remains at a = higher than usual 44 to 50 psi. By increasing the delivery pressure, the ECM (Electronic Control Module) can alter the injection pulse width to give = the precise delivery, regardless of the engine load and without fuel = pressure compensation.

Electronic Returnless Fuel = Systems

This version has all the required = components fitted within the one unit of the submersible fuel pump. It contains a = small particle filter (in addition to the strainer), pump, electronic pressure regulator, fuel level sensor and a sound isolation system. The = electronic pressure regulator allows the pressure to be increased under = acceleration conditions, and the pump=E2=80=99s output can be adjusted to suit the = engine's fuel demand. This prolongs the pump=E2=80=99s life as it is no longer = providing a larger than required output delivery.

The Electronic Control Module (ECM) = supplies the required pressure information, while the fuel pump=E2=80=99s output = signal is supplied in the form of a digital squarewave. Altering the squarewave=E2=80=99s duty cycle affects the pump=E2=80=99s delivery = output.

To compensate for the changing = viscosity of the fuel with changing fuel temperature, a fuel rail temperature sensor = is installed. A pulsation damper may also be fitted ahead of or inside the = fuel rail.

Here is one rendition of such a system in = an auto application

 

 <image001.jpg>=

Ed Anderson

Rv-6A N494BW Rotary = Powered

Matthews, NC

eanderson@carolina.rr.com

http://www.andersonee.com<= /p>

http://www.dmack.net/mazda/index.html

http://www.flyrotary.com/

http://members.cox.net/rogersda/rotary/configs.htm#N494BW

http://www.ro= taryaviation.com/Rotorhead%20Truth.htm

=

From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of Al Wick
Sent: Monday, June 07, = 2010 9:25 AM
To: Rotary motors in aircraft
Subject: [FlyRotary] Re: = high/low pressure pumps question

 

I'm really concerned for your life risk. This is a = very high risk fuel design. Puts your fuel pressure at pump inlet very very close = to the vapor pressure of fuel. This suddenly makes the design sensitive to a = whole bunch of environmental factors.

 

Ask this question: Millions of automobiles. When they designed automotive fuel systems, why did every single engineer return = fuel to tank instead of pump inlet? So much more expensive to send to tank. =

 

You can bench test your design and prove how close it = is to failure. Just need to measure fuel pressure at pump inlet, measure pump = temp. Use hair dryer to force pump to higher temp. Put all the numbers in spreadsheet, then calculate distance between vapor pressure and your = readings. Adjust for worst case, which would be high altitude airport, hot day = sitting on tarmac for 1 hour, heat soaked engine compartment, car fuel containing = ethanol.

 

Marginal designs can fly for years without failure. = This is the nature of failure. Use care, I'm concerned. =

 

-al wick

 

 

----- Original Message -----

=

Sent: Sunday, June 06, 2010 6:47 AM

Subject: [FlyRotary] Re: high/low pressure pumps question

 

Hope this = helps...

On 6/6/2010 2:21 AM, Todd Bartrim wrote:
>
> Hi Charlie;
> Hmmmnn, I gotta say a picture (or drawing) is worth a thousand = words.
> Todd (sent on my new-fangled google phone with a really damn small =
> keyboard)
>
>> On 2010-06-05 8:46 PM, "Charlie England" <ceengland@bellsouth.net =
>> <mailto:ceengland@bellsouth.net= >> wrote:
>>
>> Hi Todd,
>>
>> My thought is to set up the fuel path thus: fuel source through = a T
>> into injection pumps, through filters, through combining T, = through
>> the regulator(in cockpit), through firewall to engine. The
>> regulator's bypass port (in the cockpit) would be plumbed just = like
>> yours, except no heat exchanger since the bypass fuel would = never see
>> the heat of the engine compartment. The bypass would still T = into the
>> supply to the injection pumps, like your system. Obviously, a =
>> manifold pressure line would be required through the firewall = into
>> the cockpit to the pressure regulator.
>>
>> My original plan (different injection that didn't require a = return
>> line) was similar to your selector setup: main tanks feeding = stock
>> van's selector, with the 3rd port on it being fed by a 2nd vans =
>> selector to select either of the 2 aux tanks. No transfer pump = would
>> have been required, & no crossover valve. Failure of the = primary
>> valve could have been a 'show stopper', but the newer valves = seem to
>> be rock solid reliable. Going to this system using the gear = type
>> pumps requiring a return line forced re-thinking. Using your = idea to
>> return the bypassed fuel at the pump inlet effectively = eliminates the
>> 'return' issue, & tempts me to return to the original fuel selector
>> layout, with the addition of a Facet boost pump. The fact that = the
>> optical sensors will work looking into the side of a fuel line = (the
>> T), instead of needing them in the tank & that they still = give almost
>> a full minute's warning, is very encouraging. I'll start = looking for
>> a convenient place to mount them.
>>
>> I hope that Tracy will chime in on how he plumbed the regulator on
>> his -8.
>>
>> Many thanks for the extra details.
>>
>> Charlie
>>
>>
>>
>> On 6/5/2010 12:32 PM, Todd Bartrim wrote:
>>
>>     >
>>     > Hi Charlie
>>     >    Not sure I = understand correctly what you mean? Can you
>>     sketch it out quickly? I'...
>>
>>     > *From*: Charlie England <ceengland@bellsouth.net >>     <mailto:ceengland@bellsouth.net= >
>>     <mailto:Charlie%2= 0England%20%3cceengland@bellsout.
>>     <mailto:Cha= rlie%2520England%2520%253cceengland@bellsout.>..
>>
>>     > *Subject*: [FlyRotary] Re: = high/low pressure pumps question
>>     > *Date*: Sat, 05 Jun 2010 08:38:09 = -0...
>>
>>
>>
>> --
>> Homepage: http://www.flyrotary.com/
>> Archive and UnSub: http://mail.lancaironline.= net:81/lists...
>>

--
Homepage:  http://www.flyrotary.com/
Archive and UnSub:   http:/= /mail.lancaironline.net:81/lists/flyrotary/List.html

=
= --Apple-Mail-1--772134360--