Return-Path: Received: from fed1rmmtao06.cox.net ([68.230.241.33] verified) by logan.com (CommuniGate Pro SMTP 4.2b5) with ESMTP id 148988 for flyrotary@lancaironline.net; Fri, 11 Jun 2004 13:24:40 -0400 Received: from BigAl ([68.107.116.221]) by fed1rmmtao06.cox.net (InterMail vM.6.01.03.02 201-2131-111-104-20040324) with ESMTP id <20040611172409.VIVM28972.fed1rmmtao06.cox.net@BigAl> for ; Fri, 11 Jun 2004 13:24:09 -0400 From: "Al Gietzen" To: "'Rotary motors in aircraft'" Subject: RE: [FlyRotary] Re: Cooling oil Date: Fri, 11 Jun 2004 10:24:21 -0700 Message-ID: <000001c44fd8$ef706fb0$6400a8c0@BigAl> MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0001_01C44F9E.431197B0" X-Priority: 3 (Normal) X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook, Build 10.0.6626 Importance: Normal In-Reply-To: X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1165 This is a multi-part message in MIME format. ------=_NextPart_000_0001_01C44F9E.431197B0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable Ed; =20 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. =20 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. =20 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. =20 Are we maybe putting too fine a point on this? :-) =20 Al =20 Subject: [FlyRotary] Re: Cooling oil =20 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 =20 So 1.58 lbm/min *19,000 BTU/Lbm =3D 30020 BTU/Min =20 Taking Al's apportionment we have =20 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. =20 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 =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. =20 Thanks =20 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 =20 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 _____ =20 =20 Subject: [FlyRotary] Re: Cooling oil =20 =20 ----- Original Message -----=20 From: "Joseph Berki" To: "Rotary motors in aircraft" Sent: Thursday, June 10, 2004 12:39 PM Subject: [FlyRotary] Re: Cooling oil =20 =20 > 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 =20 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. =20 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. =20 Ed Anderson =20 Ed; =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 Double check me on this. =20 Al =20 =20 _____ =20 >> Homepage: http://www.flyrotary.com/ >> Archive: http://lancaironline.net/lists/flyrotary/List.html ------=_NextPart_000_0001_01C44F9E.431197B0 Content-Type: text/html; charset="us-ascii" Content-Transfer-Encoding: quoted-printable

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. =

 

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 = -----

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

Subject: [FlyRotary] Re: Cooling oil

 

Al,

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

Dale R.
COZY MkIV-R #1254

>
> From: "Al Gietzen" <ALVentures@cox.net>
> Date: 2004/06/11 Fri AM 12:46:45 EDT
> To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
> Subject: [FlyRotary] Re: Cooling oil
>
> 
>
> Subject: [FlyRotary] Re: Cooling oil
>
> 
>
> 
>
> ----- Original Message -----
>
> From: "Joseph Berki" = <joseph.berki@grc.nasa.gov>
>
> To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
>
> 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
>
> 
>
> 
>
>
>

 

Subject: [FlyRotary] Re: Cooling = oil

 

 

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

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

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

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

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