X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from mail-bk0-f42.google.com ([209.85.214.42] verified) by logan.com (CommuniGate Pro SMTP 6.0.7) with ESMTPS id 6506103 for flyrotary@lancaironline.net; Mon, 07 Oct 2013 20:24:22 -0400 Received-SPF: pass receiver=logan.com; client-ip=209.85.214.42; envelope-from=msteitle@gmail.com Received: by mail-bk0-f42.google.com with SMTP id my10so3023727bkb.1 for ; Mon, 07 Oct 2013 17:23:48 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :content-type; bh=GWS6Tx2DefHdb4nfLAEqsnl5TBCNDRLktVsQdsWlWTc=; b=tQ28Ln0bRP5Uw3+84ooAyUDeBu8csXEqgkAZ2rqPzdLf6iUHWY32ykp7C/USyhxr89 sOZ/FxRYxZetvCtICd08Y0W3LA3B54xXlfqUDF8ym+BdLFAgB3k9mS4q5G33Z4fP9WUu scOuSPPfkPAr9cGMV5FwnYp6WxmoLomIGjnd7E4o9OtN56G6bekgTeV35aEvZwh0gtBc q9+v9n2Dpgqxoh3oOTSbZ7Y38wwPGVZBYOlU8Q6h6fOsbTBVxcOZ71zoSBlzOpPJZHwP GNCOfI6/db8fcIAh0Kc558l7mIrPr8D8KAwqh/qbgbozI1jKosP4KJbCU/lhGRRF0yel 70eQ== MIME-Version: 1.0 X-Received: by 10.204.234.8 with SMTP id ka8mr29005335bkb.5.1381191826558; Mon, 07 Oct 2013 17:23:46 -0700 (PDT) Received: by 10.204.102.195 with HTTP; Mon, 7 Oct 2013 17:23:46 -0700 (PDT) In-Reply-To: References: Date: Mon, 7 Oct 2013 19:23:46 -0500 Message-ID: Subject: Re: [FlyRotary] Re: Prop and PSRU efficiency From: Mark Steitle To: Rotary motors in aircraft Content-Type: multipart/alternative; boundary=20cf301cbdc830801604e82fc88e --20cf301cbdc830801604e82fc88e Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: quoted-printable Bill, I was getting at a defined standard so that your numbers could be compared to a certified a/c engine. Wikipedia defines SAE hp, depending on the configuration of the engine being tested, as follows: SAE gross power[edit ] Prior to the 1972 model year, American automakers rated and advertised their engines in brake horsepower (bhp), frequently referred to as SAE gross horsepower, because it was measured in accord with the protocols defined in SAEstandards J245 and J1995. As with other brake horsepower test protocols, SAE gross hp was measured using a stock test engine, generally running with few belt-driven accessories and sometimes fitted with long tube test headers in lieu of the OEM exhaust manifolds. The atmospheric correction standards for barometric pressure, humidity and temperature for testing were relatively idealistic. SAE net power[edit ] In the United States, the term *bhp* fell into disuse in 1971-72, as automakers began to quote power in terms of SAE net horsepower in accord with SAE standard J1349. Like SAE gross and other brake horsepower protocols, SAE Net hp is measured at the engine's crankshaft, and so does not account for transmission losses. However, the SAE net power testing protocol calls for standard production-type belt-driven accessories, air cleaner, emission controls, exhaust system, and other power-consuming accessories. This produces ratings in closer alignment with the power produced by the engine as it is actually configured and sold. SAE certified power[edit ] In 2005, the SAE introduced "SAE Certified Power" with SAE J2723.[20] This test is voluntary and is in itself not a separate engine test code but a certification of either J1349 or J1995 after which the manufacturer is allowed to advertise "Certified to SAE J1349" or "Certified to SAE J1995" depending on which test standard have been followed. To attain certification the test must follow the SAE standard in question, take place in an ISO9000/9002 certified facility and be witnessed by an SAE approved third party. So, if I understand you correctly, you are looking to determine "SAE Net HP", which is measured at the flywheel, and includes air filter, accessories, stock exhaust, etc. Without these "additions", you would be talking "SAE Gross HP". Mark On Mon, Oct 7, 2013 at 4:42 PM, Bill Bradburry wr= ote: > ** ** ** > > Based on the below statement, where would ****Tracy****=92s planet gear > system fall?**** > > ** ** > > PSRUs have losses inherent in their gearsets or belts. Lay people have > often speculated that these losses are up to 40 hp in the case of a 200 h= p > class drive. This is absurd as it would represent about 30,000 watts bein= g > dissipated as heat. If this was in fact true, the case or belts would mel= t > in just a few minutes. Typical losses for single mesh spur and helical > gears is around 2-2.5%. HTD belts run at 3-4%. Twin mesh helical gearsets > would then have perhaps a 6% loss as worst case including bearing losses.= * > *** > > The statement came from:**** > > ** ** > > http://www.sdsefi.com/air51.htm**** > > ** ** > > B2**** > > ** ** > ------------------------------ > > *From:* **Rotary motors in aircraft** [mailto:flyrotary@lancaironline.net= ] > *On Behalf Of *Bill Bradburry > *Sent:* Monday, October 07, 2013 3:42 PM > *To:* **Rotary motors in aircraft** > *Subject:* [FlyRotary] Re: Prop and PSRU efficiency**** > > ** ** > > Mark,**** > > ** ** > > They would be included if the engine was tested on a dyno, so I consider > them to be part of the engine. But not so the PSRU if measuring from the > flywheel.**** > > ** ** > > Ernest,**** > > ** ** > > I don=92t know what you mean by .98 to .99?? Certainly you don=92t think= it > would only be a loss of 1 or 2%!?? It would have to be in the range of 1= 0 > to 20 HP or even greater. That is 5 to 10% in our HP range. Just the lo= ss > due to prop efficiency is in the range of 30 HP!**** > > ** ** > > Bill **** > > ** ** > ------------------------------ > > *From:* **Rotary motors in aircraft** [mailto:flyrotary@lancaironline.net= ] > *On Behalf Of *Mark Steitle > *Sent:* Monday, October 07, 2013 1:26 PM > *To:* **Rotary motors in aircraft** > *Subject:* [FlyRotary] Re: Prop and PSRU efficiency**** > > ** ** > > Bill, **** > > **** > > While you're at it don't forget to account for the water pump and > alternator(s). **** > > **** > > Mark S.**** > > ** ** > > On Mon, Oct 7, 2013 at 12:18 PM, **Bill Bradburry **< > bbradburry@bellsouth.net> wrote:**** > > I have asked this question a couple of times and no one has hazarded a > guess. > > How much HP is lost from our engines due to the PSRU? I have been > interested in determining what the HP output of my engine is and that inf= o > would be needed for that estimation. > > They tell me that most props are about 80-85% efficient, so to calculate > the > hp, you take the difference between your climb rate and your glide descen= t > rate at the same airspeed, multiplied by the weight, and then divided by > 33000. > > Wt * V / 33000 =3D HP > > This would be the prop HP, so to get the prop flange HP, you would divide > by > the prop efficiency, between .8 and .85. > > To get the engine flywheel HP, you would have to add something for the lo= ss > of the PSRU. > > Is anyone willing to take a shot at that number?? Third or forth chance! > :>) > > Bill B > > > > > -- > Homepage: http://www.flyrotary.com/ > Archive and UnSub: > http://mail.lancaironline.net:81/lists/flyrotary/List.html**** > > ** ** > --20cf301cbdc830801604e82fc88e Content-Type: text/html; charset=windows-1252 Content-Transfer-Encoding: quoted-printable
Bill,=A0

I was getting at a defined sta= ndard so that your numbers could be compared to a certified a/c engine. =A0= Wikipedia defines SAE hp, depending on the configuration of the engine bein= g tested, as follows:

SAE gross power[= edit]

Prior to the 1972 model year, Am= erican automakers rated and advertised their engines in brake horsepower (b= hp), frequently referred to as SAE gross horsepower, because it was measure= d in accord with the protocols defined in=A0SAEstandards J245 and J1995. As with other brake hors= epower test protocols, SAE gross hp was measured using a stock test engine,= generally running with few belt-driven accessories and sometimes fitted wi= th long tube test=A0headers=A0in lieu of the=A0OEM=A0exhaust manifolds. The atmospheric correcti= on standards for barometric pressure, humidity and temperature for testing = were relatively idealistic.

SAE net power[edit]

In the United States, the term=A0b= hp=A0fell into disuse in 1971-72, as automakers began to quote power in= terms of SAE net horsepower in accord with SAE standard J1349. Like SAE gr= oss and other brake horsepower protocols, SAE Net hp is measured at the eng= ine's crankshaft, and so does not account for transmission losses. Howe= ver, the SAE net power testing protocol calls for standard production-type = belt-driven accessories, air cleaner, emission controls, exhaust system, an= d other power-consuming accessories. This produces ratings in closer alignm= ent with the power produced by the engine as it is actually configured and = sold.

SAE certified power[edit]

In 2005, the SAE introduced "SAE= Certified Power" with SAE J2723.[20]=A0This test is voluntary and = is in itself not a separate engine test code but a certification of either = J1349 or J1995 after which the manufacturer is allowed to advertise "C= ertified to SAE J1349" or "Certified to SAE J1995" depending= on which test standard have been followed. To attain certification the tes= t must follow the SAE standard in question, take place in an ISO9000/9002 c= ertified facility and be witnessed by an SAE approved third party.


So, if I understand you correctly, you are l= ooking to determine "SAE Net HP", which is measured at the flywhe= el, and includes air filter, accessories, stock exhaust, etc. =A0Without th= ese "additions", you would be talking "SAE Gross HP". = =A0


Mark



On Mon, Oct 7, 2013 at 4:42 PM, Bill Bradburry <= ;bbradburry@b= ellsouth.net> wrote:

Based on the below statement,= where would Tracy=92s planet gear system fall?

=A0

PSRUs have losses inherent in their gearsets or belts. Lay people have often speculated that these losses are up to 40 hp in the case of a 200 hp class drive. This is absurd as it would represent about 30,000 watts being dissip= ated as heat. If this was in fact true, the case or belts would melt in just a f= ew minutes. Typical losses for single mesh spur and helical gears is around 2-2.5%. HTD belts run at 3-4%. Twin mesh helical gearsets would then have perhaps a 6% loss as worst case including bearing losses.

The statement came from:

=A0

http://www.sdsefi.com/air51.htm=

=A0

B2

=A0

From: Rot= ary motors in aircraft [mailto:fl= yrotary@lancaironline.net] On Behalf Of Bill Bradburry
Sent: Monday, October 07, 20= 13 3:42 PM
To: Rotary motors in aircraft
Subject: [FlyRotary] Re: Pro= p and PSRU efficiency

=A0

Mark,

=A0

They would be included if the= engine was tested on a dyno, so I consider them to be part of the engine.=A0 But not s= o the PSRU if measuring from the flywheel.

=A0

Ernest,<= /font>

=A0

I don=92t know what you mean = by .98 to .99??=A0 Certainly you don=92t think it would only be a loss of 1 or 2%!??=A0 It would have to be in the range of 10 to 20 HP or even greater.=A0 That is 5 to 10% in our HP range.=A0 Just the loss due to prop efficiency is in the range of 30 HP!

=A0

Bill

=A0

From: Rot= ary motors in aircraft [mailto:fl= yrotary@lancaironline.net] On Behalf Of Mark Steitle
Sent: Monday, October 07, 20= 13 1:26 PM
To: Rotary motors in aircraft
Subject: [FlyRotary] Re: Pro= p and PSRU efficiency

=A0

Bill,

=A0

While you're at it don't forget to account f= or the water pump and alternator(s).

=A0

Mark S.

=A0

On Mon, Oct 7, 2013 at 12:18 PM, Bill Bradburry <bbradburry@bellsouth.net> wrote:

I have asked this question a couple of times and no = one has hazarded a
guess.

How much HP is lost from our engines due to the PSRU? =A0I have been
interested in determining what the HP output of my engine is and that info<= br> would be needed for that estimation.

They tell me that most props are about 80-85% efficient, so to calculate th= e
hp, you take the difference between your climb rate and your glide descent<= br> rate at the same airspeed, multiplied by the weight, and then divided by 33000.

Wt * V / 33000 =3D HP

This would be the prop HP, so to get the prop flange HP, you would divide b= y
the prop efficiency, between .8 and .85.

To get the engine flywheel HP, you would have to add something for the loss=
of the PSRU.

Is anyone willing to take a shot at that number?? =A0Third or forth chance!=
:>)

Bill B




--
Homepage: =A0http:/= /www.flyrotary.com/
Archive and UnSub: =A0 http://mail.lancaironline.net:81/lists= /flyrotary/List.html

=A0


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