Return-Path: Received: from [24.25.9.100] (HELO ms-smtp-01-eri0.southeast.rr.com) by logan.com (CommuniGate Pro SMTP 4.2b5) with ESMTP id 149006 for flyrotary@lancaironline.net; Fri, 11 Jun 2004 13:42:15 -0400 Received: from EDWARD (clt25-78-058.carolina.rr.com [24.25.78.58]) by ms-smtp-01-eri0.southeast.rr.com (8.12.10/8.12.7) with SMTP id i5BHfffP014749 for ; Fri, 11 Jun 2004 13:41:43 -0400 (EDT) Message-ID: <000801c44fdb$5e44b610$2402a8c0@EDWARD> From: "Ed Anderson" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] Re: Cooling oil Date: Fri, 11 Jun 2004 13:41:46 -0400 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0005_01C44FB9.D6EBACD0" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2800.1409 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1409 X-Virus-Scanned: Symantec AntiVirus Scan Engine This is a multi-part message in MIME format. ------=_NextPart_000_0005_01C44FB9.D6EBACD0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Me thinks you are right, Al. Debating about a few % one way or the = other which can be easily swayed by a small difference in operating = parameters is probably not as good a use of our time as we could find. = Frequently differences are simply due to different assumptions or = starting points or viewpoint of which the real physical world could care = less{:>) Lets just say that the rotary does require more consideration of = rejection of heat through oil than the average reciprocating engine. Ed Ed Anderson RV-6A N494BW Rotary Powered Matthews, NC ----- Original Message -----=20 From: Al Gietzen=20 To: Rotary motors in aircraft=20 Sent: Friday, June 11, 2004 1:24 PM Subject: [FlyRotary] Re: Cooling oil Ed; I got my numbers from a plot of the distribution of heat shown as a = function of mixture (lambda) for a rotary that Paul Lamar posted years = ago. I think the difference in our numbers comes mostly from different = assumption on mixture, and accounting for unburned fuel. Your number of = 25% is correct for a rich mixture; lambda about 0.925. My number, 28% = corresponds to a lambda of about 1.10, more like leaned cruise. = However; for either condition it shows 6.5 to 7.0% (can't read the chart = with any more accuracy) of the fuel energy goes to the oil cooler. At lambda of 0.925 the graph shows: 25% to power out; 7% to oil; 12% = to the coolant; 35% out the exhaust; 17% unburned gas; 4% other. At lambda of 1.10 it's: 28% to power out; 7% to oil; 16% to coolant; = 42% out the exhaust; 5% unburned gas; 2% other. Are we maybe putting too fine a point on this? J Al Subject: [FlyRotary] Re: Cooling oil Well, my figures for 160Hp show fuel burn of 1.58 lbm/min, so a quick = sanity check shows 1.58*60 =3D 94.8 lbsm/hour/6 =3D 15.8 Gallons/hour = which sounds about right for 160HP with a "Best Power" A/F of 12.56 So 1.58 lbm/min *19,000 BTU/Lbm =3D 30020 BTU/Min Taking Al's apportionment we have Power =3D 28%*30020 =3D 8405.6 BTU/Min =3D 198.02 HP (I think this is = a bit high on HP for a 15.8 gallon/hr fuel flow, I would expect to see a fuel flow of around 18.5 gph for close to 200HP) Coolant =3D 18%*30020 =3D 5403.6 BTU/Min Oil =3D 7%*30020 =3D 2101.4 BTU/Min Exhaust the remainder. So using Al's figures, we are closer to the 1775 BTU figure for the = oil cooler. I use 25% for power and 25% for waste heat and 50% for = Exhaust, just to be on the conservative side. Also I allocate 2/3 of = waste heat to coolant and 1/3 to oil.=20 Al's percentages may be closer to reality than the ones I use, which = are pretty standard for a reciprocating engine. But, I have never found = any similar percentages for the rotary. If someone could direct me to a = credible source, I will revise my allocation of BTUs. Thanks Ed Ed Anderson RV-6A N494BW Rotary Powered Matthews, NC ----- Original Message -----=20 From: Dale Rogers=20 To: Rotary motors in aircraft=20 Sent: Friday, June 11, 2004 10:26 AM Subject: [FlyRotary] Re: Cooling oil Al, Perchance, did you forget that the 160 HP is *output*,=20 not the total produced from the fuel burn? Dale R. COZY MkIV-R #1254 >=20 > From: "Al Gietzen" > Date: 2004/06/11 Fri AM 12:46:45 EDT > To: "Rotary motors in aircraft" > Subject: [FlyRotary] Re: Cooling oil >=20 > =20 >=20 > Subject: [FlyRotary] Re: Cooling oil >=20 > =20 >=20 > =20 >=20 > ----- Original Message -----=20 >=20 > From: "Joseph Berki" >=20 > To: "Rotary motors in aircraft" >=20 > Sent: Thursday, June 10, 2004 12:39 PM >=20 > Subject: [FlyRotary] Re: Cooling oil >=20 > =20 >=20 > =20 >=20 > > It would be interesting to measure flow in both engines. I = thought that >=20 > > both Lycoming and Mazda engines rejected 2/3 heat load through = the >=20 > > oil that is why I started going down this road. If the engines = generated >=20 > > the same Hp than the heat load should be similar. >=20 > > >=20 > > Joe Berki >=20 > =20 >=20 > Joe, both engines may generate the same heat load, but the = proportion >=20 > rejected through the coolant in case of the Mazda is 2/3 of its = waste heat >=20 > while the oil rejects another 1/3 of the waste heat. Neither = engine rejects >=20 > anywhere near 2/3 of its waste heat through the oil. >=20 > =20 >=20 > Most aircraft engines reject on the order of 300-600 BTU/Min = through the >=20 > oil, the Mazda at 160HP rejects approx 2446 BTU/Min through the = oil. >=20 > =20 >=20 > Ed Anderson >=20 > =20 >=20 > Ed; >=20 > =20 >=20 > That number looked a bit high to me, so I went in to my file to = check. My > data shows 28% of the fuel burn energy in the rotary gets = converted to HP, > 18% goes to the coolant, and about 7% to the oil. Most of the rest = goes out > the exhaust pipe. For 160 HP output, I think that should be 1725 = BTU/Min > going to the oil cooler. So about 3 times the comparable powered = Lyc. >=20 > =20 >=20 > Double check me on this. >=20 > =20 >=20 > Al >=20 > =20 >=20 > =20 >=20 >=20 >=20 -------------------------------------------------------------------------= --- Subject: [FlyRotary] Re: Cooling oil ----- Original Message -----=20 From: "Joseph Berki" To: "Rotary motors in aircraft" Sent: Thursday, June 10, 2004 12:39 PM Subject: [FlyRotary] Re: Cooling oil > It would be interesting to measure flow in both engines. I = thought that > both Lycoming and Mazda engines rejected 2/3 heat load through the > oil that is why I started going down this road. If the engines = generated > the same Hp than the heat load should be similar. > > Joe Berki Joe, both engines may generate the same heat load, but the = proportion rejected through the coolant in case of the Mazda is 2/3 of its = waste heat while the oil rejects another 1/3 of the waste heat. Neither engine = rejects anywhere near 2/3 of its waste heat through the oil. Most aircraft engines reject on the order of 300-600 BTU/Min through = the oil, the Mazda at 160HP rejects approx 2446 BTU/Min through the oil. Ed Anderson Ed; That number looked a bit high to me, so I went in to my file to = check. My data shows 28% of the fuel burn energy in the rotary gets = converted to HP, 18% goes to the coolant, and about 7% to the oil. Most = of the rest goes out the exhaust pipe. For 160 HP output, I think that = should be 1725 BTU/Min going to the oil cooler. So about 3 times the = comparable powered Lyc. Double check me on this. Al -------------------------------------------------------------------------= --- >> Homepage: http://www.flyrotary.com/ >> Archive: http://lancaironline.net/lists/flyrotary/List.html ------=_NextPart_000_0005_01C44FB9.D6EBACD0 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Me thinks you are right, Al.  = Debating about a=20 few % one way or the other which can be easily swayed by a small = difference in=20 operating parameters is probably not as good a use of our time as we = could=20 find.  Frequently differences are simply due to different = assumptions or=20 starting points or viewpoint of which the real physical world could care = less{:>)
 
Lets just say that the rotary does = require more=20 consideration of rejection of heat through oil than the average = reciprocating=20 engine.
 
 
 
Ed
 
Ed Anderson
RV-6A N494BW Rotary Powered
Matthews, NC
----- Original Message -----
From:=20 Al = Gietzen=20
Sent: Friday, June 11, 2004 = 1:24 PM
Subject: [FlyRotary] Re: = Cooling=20 oil

Ed;

 

I got my numbers from = a plot of=20 the distribution of heat shown as a function of mixture (lambda) for a = rotary=20 that Paul Lamar posted years ago.  I think the difference in our = numbers=20 comes mostly from different assumption on mixture, and accounting for = unburned=20 fuel.  Your number of 25% is correct for a rich mixture; lambda = about=20 0.925.  My number, 28% corresponds to a lambda of about 1.10, = more like=20 leaned cruise.  However; for either condition it shows 6.5 to = 7.0% (can=92t=20 read the chart with any more accuracy) of the fuel energy goes to the = oil=20 cooler.

 

At lambda of 0.925 the = graph=20 shows: 25% to power out; 7% to oil; 12% to the coolant; 35% out the = exhaust;=20 17% unburned gas; 4% other.

 

At lambda of 1.10 = it=92s: 28% to=20 power out; 7% to oil; 16% to coolant; 42% out the exhaust; 5% unburned = gas; 2%=20 other.

 

Are we maybe putting = too fine a=20 point on this? J

 

Al

 

Subject:=20 [FlyRotary] Re: Cooling oil

 

Well, my figures for = 160Hp show=20 fuel burn of 1.58 lbm/min, so a quick sanity check shows 1.58*60 =3D = 94.8=20 lbsm/hour/6 =3D 15.8 Gallons/hour which sounds about right for 160HP = with a=20 "Best Power" A/F of 12.56

 

So 1.58 lbm/min = *19,000=20 BTU/Lbm =3D 30020 BTU/Min

 

Taking Al's = apportionment we=20 have

 

Power =3D 28%*30020 =3D = 8405.6=20 BTU/Min =3D 198.02 HP (I think this is a bit high on HP for a = 15.8=20 gallon/hr fuel flow, I would expect to

see a fuel flow of = around 18.5 gph=20 for close to 200HP)

Coolant =3D 18%*30020 = =3D 5403.6=20 BTU/Min

Oil =3D 7%*30020 =3D = 2101.4=20 BTU/Min

Exhaust the=20 remainder.

 

So using Al's figures, = we are=20 closer to the 1775 BTU figure for the oil cooler.  I use 25% for = power=20 and 25% for waste heat and 50% for Exhaust, just to be on the = conservative=20 side. Also I allocate 2/3 of waste heat to coolant and = 1/3 to=20 oil.

 

Al's percentages may be = closer to=20 reality than the ones I use, which are pretty standard for a = reciprocating=20 engine.  But, I have never found any similar percentages for the=20 rotary.  If someone could direct me to a credible source, I will = revise=20 my allocation of BTUs.

 

Thanks

 

Ed

Ed Anderson
RV-6A N494BW = Rotary=20 Powered
Matthews, NC

----- Original Message = -----=20

From: Dale = Rogers=20

To: Rotary motors in = aircraft=20

Sent:=20 Friday, June 11,=20 2004 10:26=20 AM

Subject:=20 [FlyRotary] Re: Cooling oil

 

Al,

   = Perchance, did=20 you forget that the 160 HP is *output*,
not the total produced = from the=20 fuel burn?

Dale R.
COZY MkIV-R #1254

>
> = From:=20 "Al Gietzen" <ALVentures@cox.net>
> = Date:=20 2004/06/11 Fri AM 12:46:45 EDT
> To: "Rotary = motors in=20 aircraft" <flyrotary@lancaironline.net>
>=20 Subject: [FlyRotary] Re: Cooling oil
>
> 
> =
> Subject: [FlyRotary] Re: Cooling oil
>
>  =
>
> 
>
> ----- Original Message = -----=20
>
> From: "Joseph Berki"=20 <joseph.berki@grc.nasa.gov>
>
> To: "Rotary = motors in=20 aircraft" <flyrotary@lancaironline.net>
>
> Sent: = Thursday, June 10, 2004 12:39 PM
>
> Subject: = [FlyRotary] Re:=20 Cooling oil
>
> 
>
> 
> =
>=20 > It would be interesting to measure flow in both engines.  = I=20 thought that
>
> > both Lycoming and Mazda engines = rejected=20 2/3 heat load through the
>
> > oil  that is = why I=20 started going down this road.  If the engines generated
> =
> > the same Hp than the heat load should be = similar.
>=20
> >
>
> > Joe Berki
>
>  =
>
> Joe, both engines may generate the same heat load, = but the=20 proportion
>
> rejected through the coolant in case of = the=20 Mazda is 2/3 of its waste heat
>
> while the oil = rejects=20 another 1/3 of the waste heat.  Neither engine rejects
> =
>=20 anywhere near 2/3 of its waste heat through the oil.
> =
> =20
>
> Most aircraft engines reject on the order of = 300-600=20 BTU/Min through the
>
> oil, the Mazda at 160HP rejects = approx=20 2446 BTU/Min through the oil.
>
> 
> =
> Ed=20 Anderson
>
> 
>
> Ed;
> =
> =20
>
> That number looked a bit high to me, so I went in = to my=20 file to check.  My
> data shows 28% of the fuel burn = energy in=20 the rotary gets converted to HP,
> 18% goes to the coolant, = and about=20 7% to the oil. Most of the rest goes out
> the exhaust pipe. = For 160=20 HP output, I think that should be 1725 BTU/Min
> going to the = oil=20 cooler.  So about 3 times the comparable powered Lyc.
>=20
> 
>
> Double check me on this.
>=20
> 
>
> Al
>
> 
>=20
> 
>
>
>

 

Subject: [FlyRotary] Re: = Cooling=20 oil

 

 

----- Original Message = -----=20

From: "Joseph Berki"=20 <joseph.berki@grc.nasa.gov>

To: "Rotary motors in = aircraft"=20 <flyrotary@lancaironline.net>

Sent: = Thursday, June 10,=20 2004 12:39 PM

Subject: [FlyRotary] Re: = Cooling=20 oil

 

 

> It would be = interesting to measure=20 flow in both engines.  I thought that

> both Lycoming and = Mazda engines=20 rejected 2/3 heat load through the

> oil  that is why = I started=20 going down this road.  If the engines = generated

> the same Hp than the = heat load=20 should be similar.

>

> Joe = Berki

 

Joe, both engines may = generate the same=20 heat load, but the proportion

rejected through the = coolant in case of=20 the Mazda is 2/3 of its waste heat

while the oil rejects = another 1/3 of=20 the waste heat.  Neither engine rejects

anywhere near 2/3 of its = waste heat=20 through the oil.

 

Most aircraft engines = reject on the=20 order of 300-600 BTU/Min through the

oil, the Mazda at 160HP = rejects approx=20 2446 BTU/Min through the oil.

 

Ed = Anderson

 

Ed;

 

That = number=20 looked a bit high to me, so I went in to my file to check.  My = data=20 shows 28% of the fuel burn energy in the rotary gets converted to = HP, 18%=20 goes to the coolant, and about 7% to the oil. Most of the rest goes = out the=20 exhaust pipe. For 160 HP output, I think that should be 1725 BTU/Min = going=20 to the oil cooler.  So about 3 times the comparable powered=20 Lyc.

 

Double = check me=20 on this.

 

Al

 

 

>>  = Homepage: =20 http://www.flyrotary.com/
>>  Archive:  =20 = http://lancaironline.net/lists/flyrotary/List.html

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