X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from ms-smtp-02.southeast.rr.com ([24.25.9.101] verified) by logan.com (CommuniGate Pro SMTP 5.0.9) with ESMTP id 1184115 for flyrotary@lancaironline.net; Mon, 19 Jun 2006 20:53:19 -0400 Received-SPF: pass receiver=logan.com; client-ip=24.25.9.101; envelope-from=eanderson@carolina.rr.com Received: from edward2 (cpe-024-074-111-186.carolina.res.rr.com [24.74.111.186]) by ms-smtp-02.southeast.rr.com (8.13.6/8.13.6) with SMTP id k5K0qW9X002384 for ; Mon, 19 Jun 2006 20:52:34 -0400 (EDT) Message-ID: <001a01c69403$d0864130$2402a8c0@edward2> From: "Ed Anderson" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] Ivoprop Date: Mon, 19 Jun 2006 20:52:32 -0400 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0017_01C693E2.492855F0" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2900.2869 X-MIMEOLE: Produced By Microsoft MimeOLE V6.00.2900.2869 X-Virus-Scanned: Symantec AntiVirus Scan Engine This is a multi-part message in MIME format. ------=_NextPart_000_0017_01C693E2.492855F0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Dave, I have absolute no experience with any prop other than the fixed = pitch wood Performance Propellers. Several guys on this list, however = do have in-flight adjustable IVO props, so they will probably respond. Ed ----- Original Message -----=20 From: hoursaway1@comcast.net=20 To: Rotary motors in aircraft=20 Sent: Monday, June 19, 2006 6:58 PM Subject: [FlyRotary] Ivoprop Ed; This is Dave Cook, we met at several Sun-n-Fun flyin's including = this year. Do you (or anyone else reading) know anything about the = Ivoprop magnum inflight adjustable, am still shopping for a prop, will = need to make a choice VERY soon. Application will be; RV6A 13B = Turrentine build w/mods done, RWS EC2, EM2 & PSRU-B, 3.5" throttlebody. = Thanks, David. -------------- Original message --------------=20 From: "Ed Anderson" =20 > Thanks Charlie, I'll read the Low Flow Articles.=20 >=20 > Its no secret that you reduce exit airflow drag by accelerating it = to the=20 > outside airstream velocity. We also know that if we make an area = smaller=20 > that the air velocity will speed up. I will be very interested in = how they=20 > do it without incurring drag. It would take a higher pressure area = in front=20 > of the narrow exit in order to force the hot air through a smaller = area.=20 > Since mass flow will remain constant, you can increase the = velocity and get=20 > the same amount of air through a smaller exit area or increase the = area and=20 > get a larger volume of air through at a slower velocity.=20 >=20 > But when you decrease the exit area you generally will experie nce = pressure=20 > increase in front of the narrow area (which in this case is inside = the=20 > cowl). That pressure increase in back of a core or fins would tend = to=20 > oppose the air flow coming in to the determent of good cooling. If = they had=20 > exhaust augmentation then I could see how that would work.=20 >=20 > But, I should stop speculating and read the articles and see if = that=20 > improves my understanding of how a smaller exit improves cooling.=20 >=20 > Ed=20 >=20 >=20 > ----- Original Message -----=20 > From: "Charlie England"=20 > To: "Rotary motors in aircraft"=20 > Sent: Saturday, June 17, 2006 9:00 PM=20 > Subject: [FlyRotary] Re: Exit area smaller than intake was = External=20 > Diffusion=20 >=20 >=20 > > I've read several articles that talk about making the exit = smaller than=20 > > the inlet. The key was not exhaust augmenta tion, but exit = ducting that's=20 > > effectively the reverse of the 'pressure recovery' of the inlet. = Think of=20 > > the P-51. IIRC, the CAFE Foundation articles talk about it.=20 > >=20 > > http://cafefoundation.org/v1/research.htm=20 > >=20 > > Try the 'local flow' articles (BTW, look at the most efficient = exit shape;=20 > > it's not gills or a 'reverse NACA').=20 > >=20 > > I think that the old 130% of inlet ideas gained popularity = before=20 > > homebuilders really understood how to get air in & out of a = cowling=20 > > efficiently. If you look at that Mustang II in the exit area you = will=20 > > almost certainly see some significant changes from 'stock' below = the=20 > > cylinders & around the bottom of the firewall. I talked to Tracy = Saylor=20 > > (sp?), owner of the 180 hp, 230+ mph RV-6 about how he does it, = & his mods=20 > > to guide the air after it cools the cylinders & oil are pretty = impressive.=20 > >=20 > > Charlie=20 > >=20 > > Ed Anderson wrote:=20 > >=20 > >> Ok, thanks, Thomas.=20 > >>=20 > >> I understood correctly 135% OF the exit - just conveyed my = understanding=20 > >> improperly. Yes, if you have them already scanned I would like = a copy.=20 > >> I hope there are a few photos as I am interested whether or not = they may=20 > >> be using exhaust augmentation (whether they realize it or not). = > >>=20 > >> Ed=20 > >>=20 > >> ----- Original Message ----- From: "Thomas y Reina Jakits"=20 > >>=20 > >> To: "Rotary motors in aircraft"=20 > >> Sent: Saturday, June 17, 2006 4:30 PM=20 > >> Subject: [FlyRotary] Re: Exit area smaller than intake was = External=20 > >> Diffusion=20 > >>=20 & gt; >>=20 > >>> Ed,=20 > >>> there is a mistake as the intake is not 135%bigger than, but = 135% of the=20 > >>> exit.=20 > >>> It still makes it 1.35 times bigger than the exit.=20 > >>>=20 > >>> I posted this last in April 2005, the latest response to the = subject was=20 > >>> on=20 > >>> 14th of december by Monty Roberts.=20 > >>> It always starts with a question to verify the intake bigger = than exit=20 > >>> claim,but "no mistake" that's what it is!=20 > >>>=20 > >>> Please search the archive or let me know if you want me to = repost the=20 > >>> post!=20 > >>> It was about Brian Schmidtbauers Mustang II being the fastest = around!=20 > >>> Also menetioned is Dave Anders' RV-4, details in the CAFE = report.=20 > >>> I have the essential pages of the Kitplanes article scanned, = let me know=20 > >>> if=20 > >>> you want them emailed....=20 > >>>=20 > >>> It just shows that rules of thumb are not always the best = solution. Most=20 > >>> likely just the most economic one to build.....=20 > >>>=20 > >>> Thomas=20 > >>>=20 > >>> PS: Search "Kitplanes" and go for the 14th Dec.,2005 posts!!=20 > >>>=20 > >>>=20 > >>> ----- Original Message ----- From: "Ed Anderson"=20 > >>>=20 > >>> To: "Rotary motors in aircraft"=20 > >>> Sent: Saturday, June 17, 2006 6:35 AM=20 > >>> Subject: [FlyRotary] Exit area smaller than intake was = External=20 > >>> Diffusion=20 > >>>=20 > >>>=20 > >>>> That's very interesting, Thomas. I too recall seeing in = several places > >>>> reference to=20 > >>>> exit area being some multiple of the inlet with the ratios = varying from=20 > >>>> 1.2 -1.7.=20 > >>>> There certainly could be some kind of phenomena I have not = hear of or=20 > >>>> read about, but seems strange you would ever have your intake = area more=20 > >>>=20 > >>> than=20 > >>>=20 > >>>> the exit area. But assuming no error then it would appear to = me that=20 > >>>> external diffusion is taking place.=20 > >>>>=20 > >>>> What that indicates to me is that the exit area (what ever = size=20 > >>>> it was) provides adequate airflow for cooling flow through = the engine=20 > >>>> compartment.(assumption is the engine did not get cooked). = Enough air=20 > >>>=20 > >>> mass=20 > >>>=20 > >>>> ; HAD to leave the cowling sufficient to carry away the = necessary BTUs of=20 > >>>> heat. That said, then if the inlets were 135% larger than the = exit=20 > >>>> area,=20 > >>>> then air HAD to be spilling around the inlet or area of = external=20 > >>>=20 > >>> diffusion.=20 > >>>=20 > >>>> The air molecules in this part of the airflow (external to = the cowl)=20 > >>>> then=20 > >>>> contributed NOTHING to carrying away heat from the engine, = but do add=20 > >>>> to=20 > >>>> drag - that left only=20 > >>>> the air that past through the core (or over the cooling fins = of the=20 > >>>=20 > >>> cylinder=20 > >>>=20 > >>>> head) to provide for cooling. Since this air has now been = heated and=20 > >>>=20 > >>> expands=20 > >& gt;>=20 > >>>> to a larger volume, you traditionally need a larger exit area = to=20 > >>>=20 > >>> accommodate=20 > >>>=20 > >>>> this large volume of heated air. That air must leave the = engine=20 > >>>> compartment via the exit. So I just am unable to come up with = a=20 > >>>> scenario=20 > >>>> where having an inlet larger than the exit area would be = beneficial.=20 > >>>>=20 > >>>> Having said that, it did just trigger a thought about why = this might be=20 > >>>> tried and=20 > >>>> how it might be made to work.=20 > >>>> .=20 > >>>> We do know that for air exiting the cowl to provide minimum = drag it=20 > >>>=20 > >>> ideally=20 > >>>=20 > >>>> should be accelerated back to the airstream velocity before=20 > &g t;>>> intermixing.=20 > >>>=20 > >>> We=20 > >>>=20 > >>>> can theoretically do this by taking the larger volume of heat = air and=20 > >>>> designing an exit area=20 > >>>> which would accelerate the air molecules increasing the = velocity of=20 > >>>> the=20 > >>>> exiting air and reducing drag. However, to accelerate the = cowl air=20 > >>>=20 > >>> velocity=20 > >>>=20 > >>>> to anything really meaningful,=20 > >>>> would require added energy. This leads me to believe that = perhaps an=20 > >>>> exhaust augmentation system could be used to provide = increased velocity=20 > >>>> to=20 > >>>> the exiting air using the energy in=20 > >>>> the exhaust flow. If the exiting airflow velocity is = increased over=20 > >>>> t han=20 > >>>> normally associated with exiting air, then more air of course = could=20 > >>>> flow=20 > >>>> through a smaller opening, this would perhaps permit one to = have a=20 > >>>> smaller=20 > >>>> exit area than intake area and still=20 > >>>> get good cooling and low cooling drag.=20 > >>>>=20 > >>>> So with an exhaust augmentation system "helping" the air in = the cowl to=20 > >>>=20 > >>> exit=20 > >>>=20 > >>>> quicker and at a higher velocity, I can see where a smaller = exit area=20 > >>>=20 > >>> might=20 > >>>=20 > >>>> indeed be workable.=20 > >>>> But, without an exhaust augmentation system, I just don't see = how a=20 > >>>=20 > >>> smaller=20 > >>>=20 > >>>> exit area would be beneficial.=20 > >>>>=20 > >>>> Any mention of exhaust augmentation??=20 > >>>>=20 > >>>> Well that my $0.02 worth on the topic=20 > >>>>=20 > >>>> Ed=20 > >>>>=20 > >>>> Ed Anderson=20 > >>>> Rv-6A N494BW Rotary Powered=20 > >>>> Matthews, NC=20 > >>>> eanderson@carolina.rr.com> Hi Steve,=20 > >>>=20 > >=20 > >=20 > >=20 > >=20 > > --=20 > > Homepage: http://www.flyrotary.com/=20 > > Archive and UnSub: = http://mail.lancaironline.net/lists/flyrotary/=20 > >=20 >=20 >=20 >=20 > --=20 > Homepage: http://www.flyrotary.com/=20 > Archive and UnSub: http://mail.lancaironline.net/lists/flyrotary/ ------=_NextPart_000_0017_01C693E2.492855F0 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Dave, I have absolute no experience with any = prop other=20 than the fixed pitch wood Performance Propellers.  Several guys on = this=20 list, however do have in-flight adjustable IVO props, so they will = probably=20 respond.
 
Ed
----- Original Message -----
From:=20 hoursaway1@comcast.net =
Sent: Monday, June 19, 2006 = 6:58 PM
Subject: [FlyRotary] = Ivoprop

Ed;  This is Dave Cook, we met at several Sun-n-Fun flyin's=20 including this year. Do you (or anyone else reading) know anything = about the=20 Ivoprop magnum inflight adjustable,  am still shopping for a = prop, will=20 need to make a choice VERY soon. Application will be;  = RV6A =20 13B Turrentine build w/mods done, RWS EC2, EM2 & PSRU-B, 3.5"=20 throttlebody.  Thanks, David.
 
--------------=20 Original message --------------
From: "Ed Anderson"=20 <eanderson@carolina.rr.com>

> Thanks Charlie, I'll = read the=20 Low Flow Articles.
>
> Its no secret that you reduce = exit=20 airflow drag by accelerating it to the
> outside airstream = velocity.=20 We also know that if we make an area smaller
> that the air = velocity=20 will speed up. I will be very interested in how they
> do it = without=20 incurring drag. It would take a higher pressure area in front =
> of=20 the narrow exit in order to force the hot air through a smaller = area.=20
> Since mass flow will remain constant, you can increase the = velocity=20 and get
> the same amount of air through a smaller exit area = or=20 increase the area and
> get a larger volume of air through at = a=20 slower velocity.
>
> But when you decrease the exit = area you=20 generally will experie nce pressure
> increase in front of = the narrow=20 area (which in this case is inside the
> cowl). That pressure = increase in back of a core or fins would tend to
> oppose the = air=20 flow coming in to the determent of good cooling. If they had =
>=20 exhaust augmentation then I could see how that would work.
> =
>=20 But, I should stop speculating and read the articles and see if that =
> improves my understanding of how a smaller exit improves = cooling.=20
>
> Ed
>
>
> ----- Original = Message -----=20
> From: "Charlie England"
> = To:=20 "Rotary motors in aircraft"
> = Sent:=20 Saturday, June 17, 2006 9:00 PM
> Subject: [FlyRotary] Re: = Exit area=20 smaller than intake was External
> Diffusion
> =
>=20
> > I've read several articles that talk about making the = exit=20 smaller than
> > the inlet. The key was not exhaust = augmenta tion,=20 but exit ducting that's
> > effectively the reverse of the = 'pressure recovery' of the inlet. Think of
> > the P-51. = IIRC, the=20 CAFE Foundation articles talk about it.
> >
> >=20 http://cafefoundation.org/v1/research.htm
> >
> = > Try=20 the 'local flow' articles (BTW, look at the most efficient exit = shape;=20
> > it's not gills or a 'reverse NACA').
> > =
>=20 > I think that the old 130% of inlet ideas gained popularity = before=20
> > homebuilders really understood how to get air in & = out of=20 a cowling
> > efficiently. If you look at that Mustang II = in the=20 exit area you will
> > almost certainly see some = significant=20 changes from 'stock' below the
> > cylinders & around = the=20 bottom of the firewall. I talked to Tracy Saylor
> > = (sp?), owner=20 of the 180 hp, 230+ mph RV-6 about how he does it, & his mods =
>=20 > to guide the air after it cools the cylinders & oil are = pretty=20 impressive.
> >
> > Charlie
> > =
> >=20 Ed Anderson wrote:
> >
> >> Ok, thanks, = Thomas.=20
> >>
> >> I understood correctly 135% OF = the exit=20 - just conveyed my understanding
> >> improperly. Yes, = if you=20 have them already scanned I would like a copy.
> >> I = hope=20 there are a few photos as I am interested whether or not they may =
>=20 >> be using exhaust augmentation (whether they realize it or = not).=20
> >>
> >> Ed
> >>
> = >>=20 ----- Original Message ----- From: "Thomas y Reina Jakits"
> = >>=20
> >> To: "Rotary motors in = aircraft"=20
> >> Sent: Saturday, June = 17, 2006=20 4:30 PM
> >> Subject: [FlyRotary] Re: Exit area smaller = than=20 intake was External
> >> Diffusion
> >> =
&=20 gt; >>
> >>> Ed,
> >>> there = is a=20 mistake as the intake is not 135%bigger than, but 135% of the =
>=20 >>> exit.
> >>> It still makes it 1.35 = times bigger=20 than the exit.
> >>>
> >>> I posted = this=20 last in April 2005, the latest response to the subject was
>=20 >>> on
> >>> 14th of december by Monty = Roberts.=20
> >>> It always starts with a question to verify the = intake=20 bigger than exit
> >>> claim,but "no mistake" that's = what it=20 is!
> >>>
> >>> Please search the = archive or=20 let me know if you want me to repost the
> >>> post! =
> >>> It was about Brian Schmidtbauers Mustang II = being the=20 fastest around!
> >>> Also menetioned is Dave = Anders' RV-4,=20 details in the CAFE report.
> >>> I have the = essential pages=20 of the Kitplanes article scanned, let me know
> >>> = if=20
> >>> you want them emailed....
> = >>>=20
> >>> It just shows that rules of thumb are not = always the=20 best solution. Most
> >>> likely just the most = economic one=20 to build.....
> >>>
> >>> Thomas =
>=20 >>>
> >>> PS: Search "Kitplanes" and go for = the=20 14th Dec.,2005 posts!!
> >>>
> >>> =
>=20 >>> ----- Original Message ----- From: "Ed Anderson" =
>=20 >>>
> >>> To: = "Rotary=20 motors in aircraft"
> = >>> Sent:=20 Saturday, June 17, 2006 6:35 AM
> >>> Subject: = [FlyRotary]=20 Exit area smaller than intake was External
> >>> = Diffusion=20
> >>>
> >>>
> = >>>> That's=20 very interesting, Thomas. I too recall seeing in several places >=20 >>>> reference to
> >>>> exit area = being some=20 multiple of the inlet with the ratios varying from
> = >>>>=20 1.2 -1.7.
> >>>> There certainly could be some = kind of=20 phenomena I have not hear of or
> >>>> read = about, but=20 seems strange you would ever have your intake area more
>=20 >>>
> >>> than
> >>> =
>=20 >>>> the exit area. But assuming no error then it would = appear=20 to me that
> >>>> external diffusion is taking = place.=20
> >>>>
> >>>> What that = indicates to=20 me is that the exit area (what ever size
> >>>> = it was)=20 provides adequate airflow for cooling flow through the engine =
>=20 >>>> compartment.(assumption is the engine did not get = cooked).=20 Enough air
> >>>
> >>> mass
> = >>>
> >>>> ; HAD to leave the cowling = sufficient=20 to carry away the necessary BTUs of
> >>>> heat. = That=20 said, then if the inlets were 135% larger than the exit
>=20 >>>> area,
> >>>> then air HAD to be = spilling=20 around the inlet or area of external
> >>>
>=20 >>> diffusion.
> >>>
> = >>>> The=20 air molecules in this part of the airflow (external to the cowl) =
>=20 >>>> then
> >>>> contributed NOTHING = to=20 carrying away heat from the engine, but do add
> = >>>> to=20
> >>>> drag - that left only
> = >>>>=20 the air that past through the core (or over the cooling fins of the =
>=20 >>>
> >>> cylinder
> >>> =
>=20 >>>> head) to provide for cooling. Since this air has = now been=20 heated and
> >>>
> >>> expands =
>=20 >& gt;>
> >>>> to a larger volume, you=20 traditionally need a larger exit area to
> >>> =
>=20 >>> accommodate
> >>>
> = >>>>=20 this large volume of heated air. That air must leave the engine =
>=20 >>>> compartment via the exit. So I just am unable to = come up=20 with a
> >>>> scenario
> >>>> = where=20 having an inlet larger than the exit area would be beneficial. =
>=20 >>>>
> >>>> Having said that, it did = just=20 trigger a thought about why this might be
> >>>> = tried=20 and
> >>>> how it might be made to work.
> = >>>> .
> >>>> We do know that for air = exiting=20 the cowl to provide minimum drag it
> >>>
>=20 >>> ideally
> >>>
> >>>> = should=20 be accelerated back to the airstream velocity before
> &g = t;>>> intermixing.
> >>>
> = >>> We=20
> >>>
> >>>> can theoretically do = this by=20 taking the larger volume of heat air and
> >>>> = designing=20 an exit area
> >>>> which would accelerate the = air=20 molecules increasing the velocity of
> >>>> the =
>=20 >>>> exiting air and reducing drag. However, to = accelerate the=20 cowl air
> >>>
> >>> velocity =
>=20 >>>
> >>>> to anything really = meaningful,=20
> >>>> would require added energy. This leads me = to=20 believe that perhaps an
> >>>> exhaust = augmentation=20 system could be used to provide increased velocity
> = >>>>=20 to
> >>>> the exiting air using the energy in =
>=20 >>>> the exhaust flow. If the exiting airflow velocity = is=20 increased over
> >>>> t han
> = >>>>=20 normally associated with exiting air, then more air of course could =
>=20 >>>> flow
> >>>> through a smaller = opening,=20 this would perhaps permit one to have a
> >>>> = smaller=20
> >>>> exit area than intake area and still =
>=20 >>>> get good cooling and low cooling drag.
>=20 >>>>
> >>>> So with an exhaust = augmentation=20 system "helping" the air in the cowl to
> >>> =
>=20 >>> exit
> >>>
> >>>> = quicker=20 and at a higher velocity, I can see where a smaller exit area =
>=20 >>>
> >>> might
> >>> =
>=20 >>>> indeed be workable.
> >>>> But, = without=20 an exhaust augmentation system, I just don't see how a
> = >>>=20
> >>> smaller
> >>>
>=20 >>>> exit area would be beneficial.
> = >>>>=20
> >>>> Any mention of exhaust augmentation?? =
>=20 >>>>
> >>>> Well that my $0.02 worth = on the=20 topic
> >>>>
> >>>> Ed =
>=20 >>>>
> >>>> Ed Anderson
>=20 >>>> Rv-6A N494BW Rotary Powered
> = >>>>=20 Matthews, NC
> >>>> eanderson@carolina.rr.com> = Hi=20 Steve,
> >>>
> >
> >
> = >=20
> >
> > --
> > Homepage:=20 http://www.flyrotary.com/
> > Archive and UnSub:=20 http://mail.lancaironline.net/lists/flyrotary/
> > =
>=20
>
>
> --
> Homepage: = http://www.flyrotary.com/=20
> Archive and UnSub: = http://mail.lancaironline.net/lists/flyrotary/=20
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