REFLECTOR: Reflector Digest, Vol 33, Issue 61 Exhaust coating
bdtopp at comcast.net
bdtopp at comcast.net
Mon Feb 19 10:58:26 CST 2007
Are there any dis-advantages to getting exhaust ceramic coated? For example, does it make if more difficult to inspect for cracks in the exhaust.....or.....does it hide cracks?? Any other dis-advantages?
-------------- Original message --------------
From: Brian Michalk <michalk at awpi.com>
> Jet Hot did mine as well.
> They are used to doing hot rods, so they want to make it shiny and red,
> chrome or some other splashy color. I told the tech I did not care what
> it looked like. I wanted the absolute minimum of temperature transfer.
> He said ceramic, flat black inside and out. I had my intake manifolds
> and exhaust done. It wasn't very expensive as far as aviation goes.
>
> I had another engine start yesterday. After one run, I inspected the
> exhaust sometime between three and five minutes after shutdown and the
> exhaust was already cool enough to touch.
>
> Mark Riley wrote:
> > Try having your exhausts ceramic coated. They lowered my CHT's and as an
> > additional benefit, keep them from rusting. I had mine done by Jet Hot.
> >
> > -----Original Message-----
> > From: reflector-bounces at tvbf.org [mailto:reflector-bounces at tvbf.org] On
> > Behalf Of reflector-request at tvbf.org
> > Sent: Sunday, February 18, 2007 7:18 PM
> > To: reflector at tvbf.org
> > Subject: Reflector Digest, Vol 33, Issue 61
> >
> > Send Reflector mailing list submissions to
> > reflector at tvbf.org
> >
> > To subscribe or unsubscribe via the World Wide Web, visit
> > http://www.tvbf.org/mailman/listinfo/reflector
> > or, via email, send a message with subject or body 'help' to
> > reflector-request at tvbf.org
> >
> > You can reach the person managing the list at
> > reflector-owner at tvbf.org
> >
> > When replying, please edit your Subject line so it is more specific
> > than "Re: Contents of Reflector digest..."
> >
> >
> > Today's Topics:
> >
> > 1. Exhaust wrap. was updraft cooling (Scott Derrick)
> > 2. Exhaust wrap. was updraft cooling (Scott Derrick)
> > 3. Re: Updraft cooling (Unterreiner)
> >
> >
> > ----------------------------------------------------------------------
> >
> > Message: 1
> > Date: Sun, 18 Feb 2007 17:15:37 -0500 (EST)
> > From: "Scott Derrick"
> > Subject: REFLECTOR: Exhaust wrap. was updraft cooling
> > To: velocity at davebiz.com, "Velocity Aircraft Owners and Builders list"
> >
> > Message-ID: <49344.75.6.245.222.1171836937.squirrel at tnstaafl.net>
> > Content-Type: text/plain;charset=iso-8859-1
> >
> > I tried that when I had updraft cooling. I was having major cooling
> > issues so I wrapped the exhaust. Had no effect at all on my cooling. I've
> > been told it also can cause your pipes to corrode faster over time.
> >
> > The fix for my cooling woes was to get absolutely fanatical about tight
> > baffling, temps dropped 75 degrees.
> >
> > Scott
> >
> >
> >> Chuck, I think you're right. My A&P suggested that I wrap the exhaust
> >> pipes with insulating fabric (appears to be made from fiberglass) on my
> >> updraft system. This should keep the heat more contained in the pipes
> >> and exhausting outside of the plane. I have not flown yet since
> >> wrapping so I can't tell you how much it affects temps.
> >>
> >> Chuck Jensen wrote:
> >>
> >>> I've not seen the layout of an updraft cooling system, but does the
> >>> air get preheated from passing by the exhaust pipes before it every
> >>> gets to the cylinder heads? If it does, that would greatly increase
> >>> the volume of air required because of the reduced delta T across the
> >>> heads. By comparison the top NACAs provide clean, cool air directly
> >>> to the CHs. Too simple--I must be missing something?
> >>>
> >>> Chuck Jensen
> >>> * *
> >>> -----Original Message-----
> >>> *From:* reflector-bounces at tvbf.org [mailto:reflector-bounces at tvbf.org]
> >>> *On Behalf Of *John Dibble
> >>> *Sent:* Saturday, February 17, 2007 2:41 PM
> >>> *To:* Velocity Aircraft Owners and Builders list
> >>> *Subject:* Re: REFLECTOR: updraft cooling
> >>>
> >>> I think the amount of air going past the cylinders will determine the
> >>> degree of cooling, so it's a matter of making the NACA or armpit scoop
> >>> and ducts big enough for sufficient air.
> >>>
> >>> John
> >>>
> >>> Ron Brown wrote:
> >>>
> >>>
> >>>> And, the downdraft NACA cooling for some unexplainable reason, runs
> >>>> about 40 degrees cooler than the updraft cooling. Mark Machado
> >>>> converted what is now the factory trainer from updraft to downdraft
> >>>> and says the heads ran 30-40 degrees cooler. My 173 Elite RG runs
> >>>> 360-370 max on a long climb out and 320-340 degrees during a 2600
> >>>> rpm/155 kt cruise. I highly recommend the NACA cooling system.
> >>>>
> >>> ------------------------------------------------------------------------
> >>>
> >>> _______________________________________________
> >>> To change your email address, visit
> >>> http://www.tvbf.org/mailman/listinfo/reflector
> >>>
> >>> Visit the gallery! www.tvbf.org/gallery
> >>> user:pw = tvbf:jamaicangoose
> >>> Check new archives: www.tvbf.org/pipermail
> >>> Check old archives: http://www.tvbf.org/archives/velocity/maillist.html
> >>>
> >> --
> >> Dave Philipsen
> >> Velocity STD-FG
> >> N83DP
> >>
> >>
> >> _______________________________________________
> >> To change your email address, visit
> >> http://www.tvbf.org/mailman/listinfo/reflector
> >>
> >> Visit the gallery! www.tvbf.org/gallery
> >> user:pw = tvbf:jamaicangoose
> >> Check new archives: www.tvbf.org/pipermail
> >> Check old archives: http://www.tvbf.org/archives/velocity/maillist.html
> >>
> >>
> >
> >
> >
> > ------------------------------
> >
> > Message: 2
> > Date: Sun, 18 Feb 2007 17:15:42 -0500 (EST)
> > From: "Scott Derrick"
> > Subject: REFLECTOR: Exhaust wrap. was updraft cooling
> > To: velocity at davebiz.com, "Velocity Aircraft Owners and Builders list"
> >
> > Message-ID: <49346.75.6.245.222.1171836942.squirrel at tnstaafl.net>
> > Content-Type: text/plain;charset=iso-8859-1
> >
> > I tried that when I had updraft cooling. I was having major cooling
> > issues so I wrapped the exhaust. Had no effect at all on my cooling. I've
> > been told it also can cause your pipes to corrode faster over time.
> >
> > The fix for my cooling woes was to get absolutely fanatical about tight
> > baffling, temps dropped 75 degrees.
> >
> > Scott
> >
> >
> >> Chuck, I think you're right. My A&P suggested that I wrap the exhaust
> >> pipes with insulating fabric (appears to be made from fiberglass) on my
> >> updraft system. This should keep the heat more contained in the pipes
> >> and exhausting outside of the plane. I have not flown yet since
> >> wrapping so I can't tell you how much it affects temps.
> >>
> >> Chuck Jensen wrote:
> >>
> >>> I've not seen the layout of an updraft cooling system, but does the
> >>> air get preheated from passing by the exhaust pipes before it every
> >>> gets to the cylinder heads? If it does, that would greatly increase
> >>> the volume of air required because of the reduced delta T across the
> >>> heads. By comparison the top NACAs provide clean, cool air directly
> >>> to the CHs. Too simple--I must be missing something?
> >>>
> >>> Chuck Jensen
> >>> * *
> >>> -----Original Message-----
> >>> *From:* reflector-bounces at tvbf.org [mailto:reflector-bounces at tvbf.org]
> >>> *On Behalf Of *John Dibble
> >>> *Sent:* Saturday, February 17, 2007 2:41 PM
> >>> *To:* Velocity Aircraft Owners and Builders list
> >>> *Subject:* Re: REFLECTOR: updraft cooling
> >>>
> >>> I think the amount of air going past the cylinders will determine the
> >>> degree of cooling, so it's a matter of making the NACA or armpit scoop
> >>> and ducts big enough for sufficient air.
> >>>
> >>> John
> >>>
> >>> Ron Brown wrote:
> >>>
> >>>
> >>>> And, the downdraft NACA cooling for some unexplainable reason, runs
> >>>> about 40 degrees cooler than the updraft cooling. Mark Machado
> >>>> converted what is now the factory trainer from updraft to downdraft
> >>>> and says the heads ran 30-40 degrees cooler. My 173 Elite RG runs
> >>>> 360-370 max on a long climb out and 320-340 degrees during a 2600
> >>>> rpm/155 kt cruise. I highly recommend the NACA cooling system.
> >>>>
> >>> ------------------------------------------------------------------------
> >>>
> >>> _______________________________________________
> >>> To change your email address, visit
> >>> http://www.tvbf.org/mailman/listinfo/reflector
> >>>
> >>> Visit the gallery! www.tvbf.org/gallery
> >>> user:pw = tvbf:jamaicangoose
> >>> Check new archives: www.tvbf.org/pipermail
> >>> Check old archives: http://www.tvbf.org/archives/velocity/maillist.html
> >>>
> >> --
> >> Dave Philipsen
> >> Velocity STD-FG
> >> N83DP
> >>
> >>
> >> _______________________________________________
> >> To change your email address, visit
> >> http://www.tvbf.org/mailman/listinfo/reflector
> >>
> >> Visit the gallery! www.tvbf.org/gallery
> >> user:pw = tvbf:jamaicangoose
> >> Check new archives: www.tvbf.org/pipermail
> >> Check old archives: http://www.tvbf.org/archives/velocity/maillist.html
> >>
> >>
> >
> >
> >
> > ------------------------------
> >
> > Message: 3
> > Date: Sun, 18 Feb 2007 19:17:55 -0500
> > From: "Unterreiner"
> > Subject: Re: REFLECTOR: Updraft cooling
> > To:
> > Message-ID: <003a01c753bb$67b196f0$0a01a8c0 at DELL280IMAGE2>
> > Content-Type: text/plain; format=flowed; charset="iso-8859-1";
> > reply-type=original
> >
> > Dave,
> >
> > Let me know if you come up with any ingenious ideas on your engine
> > cooling. My email is naomi at yadtel.net.
> >
> > Goodluck,
> > Dean Unterreiner
> >
> > ----- Original Message -----
> > From:
> > To:
> > Sent: Sunday, February 18, 2007 11:30 AM
> > Subject: Reflector Digest, Vol 33, Issue 52
> >
> >
> >
> >> Send Reflector mailing list submissions to
> >> reflector at tvbf.org
> >>
> >> To subscribe or unsubscribe via the World Wide Web, visit
> >> http://www.tvbf.org/mailman/listinfo/reflector
> >> or, via email, send a message with subject or body 'help' to
> >> reflector-request at tvbf.org
> >>
> >> You can reach the person managing the list at
> >> reflector-owner at tvbf.org
> >>
> >> When replying, please edit your Subject line so it is more specific
> >> than "Re: Contents of Reflector digest..."
> >>
> >>
> >> Today's Topics:
> >>
> >> 1. Re: Updraft cooling (John Dibble)
> >> 2. Re: CBs and fuses (John Tvedte)
> >>
> >>
> >> ----------------------------------------------------------------------
> >>
> >> Message: 1
> >> Date: Sun, 18 Feb 2007 10:27:36 -0600
> >> From: John Dibble
> >> Subject: Re: REFLECTOR: Updraft cooling
> >> To: velocity at davebiz.com, Velocity Aircraft Owners and Builders list
> >>
> >> Message-ID: <45D87E78.9A701FF2 at bluefrog.com>
> >> Content-Type: text/plain; charset=us-ascii
> >>
> >> According to my Franklin engine manual, the measured CHT will be 50 C (90
> >> F) higher with a spark
> >> plug probe, located on the bottom plug, compared to a bayonet probe,
> >> located on the top of the
> >> cylinder. Maybe the temperature difference is due to the direction of air
> >>
> >
> >
> >> flow. I have downdraft
> >> cooling. The air should be much warmer after passing the cylinder.
> >> Therefore the temperature at
> >> the bottom of my cylinders should be higher than at the top. If the
> >> bayonet probe is used and
> >> cooling is switched from updraft to downdraft, a lower CHT may not
> >> necessarily mean the overall
> >> cylinder temp is lower. Just a thought.
> >>
> >> John
> >>
> >> Dave Philipsen wrote:
> >>
> >>
> >>> Dean,
> >>>
> >>> I'm in the same boat (plane) as you. I bought a Velocity that was built
> >>> by someone else and it has updraft cooling too. But, I think that's the
> >>> way they all were originally. The NACA scoops were introduced as
> >>> standard a little later. I'm in the midst of working on ways to cool it
> >>> more efficiently. At least this forum will help perhaps by providing us
> >>> with some ideas.
> >>>
> >>> Unterreiner wrote:
> >>>
> >>>> I have an IO-360 in my Velocity with updraft cooling. The guy who built
> >>>>
> >
> >
> >>>> the
> >>>> plane went to alot of trouble to get it to cool properly in cruise, and
> >>>>
> >
> >
> >>>> it
> >>>> still needs to be modified so it will cool better during takeoff. Also,
> >>>>
> >
> >
> >>>> the
> >>>> Lycoming engines are designed to be cooled from the top down. I wish
> >>>> the guy
> >>>> who built my plane would have used the NACA plenum system. It's alot
> >>>> simpler, cools the engine the way it's supposed to be cooled and is
> >>>> less
> >>>> prone to develop cooling problems.
> >>>>
> >>>> Dean Unterreiner
> >>>> ----- Original Message -----
> >>>> From:
> >>>> To:
> >>>> Sent: Saturday, February 17, 2007 5:52 PM
> >>>> Subject: Reflector Digest, Vol 33, Issue 47
> >>>>
> >>>>
> >>>>
> >>>>
> >>>>> Send Reflector mailing list submissions to
> >>>>> reflector at tvbf.org
> >>>>>
> >>>>> To subscribe or unsubscribe via the World Wide Web, visit
> >>>>> http://www.tvbf.org/mailman/listinfo/reflector
> >>>>> or, via email, send a message with subject or body 'help' to
> >>>>> reflector-request at tvbf.org
> >>>>>
> >>>>> You can reach the person managing the list at
> >>>>> reflector-owner at tvbf.org
> >>>>>
> >>>>> When replying, please edit your Subject line so it is more specific
> >>>>> than "Re: Contents of Reflector digest..."
> >>>>>
> >>>>>
> >>>>> Today's Topics:
> >>>>>
> >>>>> 1. Re: updraft cooling (Scott Derrick)
> >>>>> 2. Re: updraft cooling (John Dibble)
> >>>>> 3. Re: updraft cooling (Douglas Holub)
> >>>>> 4. Re: updraft vs sidedraft vs updraft cooling (gpoole)
> >>>>> 5. Re: updraft cooling (Al Gietzen)
> >>>>>
> >>>>>
> >>>>> ----------------------------------------------------------------------
> >>>>>
> >>>>> Message: 1
> >>>>> Date: Sat, 17 Feb 2007 15:57:56 -0500 (EST)
> >>>>> From: "Scott Derrick"
> >>>>> Subject: Re: REFLECTOR: updraft cooling
> >>>>> To: "Velocity Aircraft Owners and Builders list"
> >>>>> Message-ID: <43917.63.164.47.227.1171745876.squirrel at tnstaafl.net>
> >>>>> Content-Type: text/plain;charset=iso-8859-1
> >>>>>
> >>>>> Doug,
> >>>>>
> >>>>> I had updraft on my IO360 and it worked fine. I had to run LOP in the
> >>>>> summer(I did all the time anyway) to keep the engine cool enough.
> >>>>> There
> >>>>> were times when I stopped for gas and during the following departure
> >>>>> climbout I would have to level off at an intermediate altitude for
> >>>>> awhile
> >>>>> to get the oil temps back down below 230.
> >>>>>
> >>>>> Installing my 520 I conferred with Velocity(ScottB and Brendon) and
> >>>>> was
> >>>>> advised I would need to use downdraft as they had never successfully
> >>>>> seen
> >>>>> an updraft system work for the big six cylinder engines. So I did
> >>>>> the
> >>>>> conversion.
> >>>>>
> >>>>> I thought that using NACA intakes would "theoretically" be more drag
> >>>>> effecient ?
> >>>>>
> >>>>> Scott
> >>>>>
> >>>>>
> >>>>>
> >>>>>
> >>>>>> I can understand why Burt Rutan and Nat Puffer are proponents of
> >>>>>> updraft
> >>>>>> cooling. From an engineering point of view, it has a lot going for
> >>>>>> it.
> >>>>>> You
> >>>>>> need more cooling when the airplane is climbing. If the cooling
> >>>>>> intake is
> >>>>>> below the wing, the pressure is higher during a climb so you
> >>>>>> automatically
> >>>>>> get more cooling during a climb. Similarly, it would be nice if
> >>>>>> cooling
> >>>>>> was minimized during descent. The pressure is reduced under the wing
> >>>>>> during descent, and so there is less cooling to the engine. Also,
> >>>>>> you've
> >>>>>> got convection working with you instead of against you with an
> >>>>>> updraft
> >>>>>> system.
> >>>>>>
> >>>>>> That all adds up to more drag with down draft cooling, because the
> >>>>>> NACA
> >>>>>> scoops have to be large enough so that there is adequate cooling
> >>>>>> during
> >>>>>> climb out, when the pressure at the NACAs is at its minimum.
> >>>>>>
> >>>>>> But the down draft is a lot simpler to implement, and that's probably
> >>>>>> going to be the deciding factor for me.
> >>>>>>
> >>>>>> Doug Holub_______________________________________________
> >>>>>> To change your email address, visit
> >>>>>> http://www.tvbf.org/mailman/listinfo/reflector
> >>>>>>
> >>>>>> Visit the gallery! www.tvbf.org/gallery
> >>>>>> user:pw = tvbf:jamaicangoose
> >>>>>> Check new archives: www.tvbf.org/pipermail
> >>>>>> Check old archives:
> >>>>>> http://www.tvbf.org/archives/velocity/maillist.html
> >>>>>>
> >>>>>>
> >>>>> ------------------------------
> >>>>>
> >>>>> Message: 2
> >>>>> Date: Sat, 17 Feb 2007 15:04:56 -0600
> >>>>> From: John Dibble
> >>>>> Subject: Re: REFLECTOR: updraft cooling
> >>>>> To: Velocity Aircraft Owners and Builders list
> >>>>> Message-ID: <45D76DF8.5468770B at bluefrog.com>
> >>>>> Content-Type: text/plain; charset="us-ascii"
> >>>>>
> >>>>> I assume that updraft simply refers to the intake air coming from
> >>>>> below
> >>>>> as opposed to downdraft where the air comes from the NACAs above. I
> >>>>> think the way it passes the engine is the same. It would be
> >>>>> inefficient
> >>>>> to pass the air past the exhaust pipes first.
> >>>>>
> >>>>> John
> >>>>>
> >>>>> Chuck Jensen wrote:
> >>>>>
> >>>>>
> >>>>>
> >>>>>> I've not seen the layout of an updraft cooling system, but does the
> >>>>>> air get preheated from passing by the exhaust pipes before it every
> >>>>>> gets to the cylinder heads? If it does, that would greatly increase
> >>>>>> the volume of air required because of the reduced delta T across the
> >>>>>> heads. By comparison the top NACAs provide clean, cool air directly
> >>>>>> to the CHs. Too simple--I must be missing something?
> >>>>>> Chuck Jensen
> >>>>>>
> >>>>>> -----Original Message-----
> >>>>>> From: reflector-bounces at tvbf.org [mailto:reflector-bounces at tvbf.org]
> >>>>>> On Behalf Of John Dibble
> >>>>>> Sent: Saturday, February 17, 2007 2:41 PM
> >>>>>> To: Velocity Aircraft Owners and Builders list
> >>>>>> Subject: Re: REFLECTOR: updraft cooling
> >>>>>>
> >>>>>> I think the amount of air going past the cylinders will determine the
> >>>>>> degree of cooling, so it's a matter of making the NACA or armpit
> >>>>>> scoop
> >>>>>> and ducts big enough for sufficient air.
> >>>>>>
> >>>>>> John
> >>>>>>
> >>>>>> Ron Brown wrote:
> >>>>>>
> >>>>>>
> >>>>>>
> >>>>>>> And, the downdraft NACA cooling for some unexplainable reason, runs
> >>>>>>> about 40 degrees cooler than the updraft cooling. Mark Machado
> >>>>>>> converted what is now the factory trainer from updraft to downdraft
> >>>>>>> and says the heads ran 30-40 degrees cooler. My 173 Elite RG runs
> >>>>>>> 360-370 max on a long climb out and 320-340 degrees during a 2600
> >>>>>>> rpm/155 kt cruise. I highly recommend the NACA cooling system.
> >>>>>>>
> >>>>>>>
> >>>>>> ----------------------------------------------------------------
> >>>>>> _______________________________________________
> >>>>>> To change your email address, visit
> >>>>>> http://www.tvbf.org/mailman/listinfo/reflector
> >>>>>>
> >>>>>> Visit the gallery! www.tvbf.org/gallery
> >>>>>> user:pw = tvbf:jamaicangoose
> >>>>>> Check new archives: www.tvbf.org/pipermail
> >>>>>> Check old archives:
> >>>>>> http://www.tvbf.org/archives/velocity/maillist.html
> >>>>>>
> >>>>>>
> >>>>>>
> >>>>> -------------- next part --------------
> >>>>> An HTML attachment was scrubbed...
> >>>>> URL:
> >>>>>
> >>>>>
> > http://www.tvbf.org/mailman/private/reflector/attachments/20070217/daaba585/
> > attachment.htm
> >
> >>>>> ------------------------------
> >>>>>
> >>>>> Message: 3
> >>>>> Date: Sat, 17 Feb 2007 16:13:01 -0600
> >>>>> From: "Douglas Holub"
> >>>>> Subject: Re: REFLECTOR: updraft cooling
> >>>>> To: "Velocity Aircraft Owners and Builders list"
> >>>>> Message-ID: <007e01c752e0$ca67f130$6a01a8c0 at Workshop>
> >>>>> Content-Type: text/plain; format=flowed; charset="iso-8859-1";
> >>>>> reply-type=original
> >>>>>
> >>>>> "I thought that using NACA intakes would 'theoretically' be more drag
> >>>>> effecient ?"
> >>>>> -------------------------------------------------------------------
> >>>>> I was just comparing updraft to downdraft. It looks like I could put
> >>>>> one
> >>>>> big
> >>>>> NACA underneath the rear seat. I was thinking of using that spot for
> >>>>> ram
> >>>>> air, though.
> >>>>>
> >>>>> I'm a little confused about the benefits of a NACA scoop. I need to
> >>>>> read
> >>>>> up
> >>>>> on them some more. I think that if the cowl lip were extended up a
> >>>>> little
> >>>>> to
> >>>>> catch the air it might be more efficient than the NACA scoops. But
> >>>>> even
> >>>>> if
> >>>>> it were more efficient, you would be making it a little harder for air
> >>>>>
> >
> >
> >>>>> to
> >>>>> flow to the propeller because the cowl would be getting a little
> >>>>> taller.
> >>>>> But
> >>>>> then, you lose some head room in the back seats with the NACAs.
> >>>>> Decisions,
> >>>>> decisions.
> >>>>>
> >>>>> Doug Holub
> >>>>>
> >>>>> ----- Original Message -----
> >>>>> From: "Scott Derrick"
> >>>>> To: "Velocity Aircraft Owners and Builders list"
> >>>>> Sent: Saturday, February 17, 2007 2:57 PM
> >>>>> Subject: Re: REFLECTOR: updraft cooling
> >>>>>
> >>>>>
> >>>>>
> >>>>>
> >>>>>> Doug,
> >>>>>>
> >>>>>> I had updraft on my IO360 and it worked fine. I had to run LOP in the
> >>>>>> summer(I did all the time anyway) to keep the engine cool enough.
> >>>>>> There
> >>>>>> were times when I stopped for gas and during the following departure
> >>>>>> climbout I would have to level off at an intermediate altitude for
> >>>>>> awhile
> >>>>>> to get the oil temps back down below 230.
> >>>>>>
> >>>>>> Installing my 520 I conferred with Velocity(ScottB and Brendon) and
> >>>>>> was
> >>>>>> advised I would need to use downdraft as they had never successfully
> >>>>>> seen
> >>>>>> an updraft system work for the big six cylinder engines. So I did
> >>>>>> the
> >>>>>> conversion.
> >>>>>>
> >>>>>> I thought that using NACA intakes would "theoretically" be more drag
> >>>>>> effecient ?
> >>>>>>
> >>>>>> Scott
> >>>>>>
> >>>>>>
> >>>>>>
> >>>>>>
> >>>>>>> I can understand why Burt Rutan and Nat Puffer are proponents of
> >>>>>>> updraft
> >>>>>>> cooling. From an engineering point of view, it has a lot going for
> >>>>>>> it.
> >>>>>>> You
> >>>>>>> need more cooling when the airplane is climbing. If the cooling
> >>>>>>> intake
> >>>>>>> is
> >>>>>>> below the wing, the pressure is higher during a climb so you
> >>>>>>> automatically
> >>>>>>> get more cooling during a climb. Similarly, it would be nice if
> >>>>>>> cooling
> >>>>>>> was minimized during descent. The pressure is reduced under the wing
> >>>>>>> during descent, and so there is less cooling to the engine. Also,
> >>>>>>> you've
> >>>>>>> got convection working with you instead of against you with an
> >>>>>>> updraft
> >>>>>>> system.
> >>>>>>>
> >>>>>>> That all adds up to more drag with down draft cooling, because the
> >>>>>>> NACA
> >>>>>>> scoops have to be large enough so that there is adequate cooling
> >>>>>>> during
> >>>>>>> climb out, when the pressure at the NACAs is at its minimum.
> >>>>>>>
> >>>>>>> But the down draft is a lot simpler to implement, and that's
> >>>>>>> probably
> >>>>>>> going to be the deciding factor for me.
> >>>>>>>
> >>>>>>> Doug Holub_______________________________________________
> >>>>>>> To change your email address, visit
> >>>>>>> http://www.tvbf.org/mailman/listinfo/reflector
> >>>>>>>
> >>>>>>> Visit the gallery! www.tvbf.org/gallery
> >>>>>>> user:pw = tvbf:jamaicangoose
> >>>>>>> Check new archives: www.tvbf.org/pipermail
> >>>>>>> Check old archives:
> >>>>>>> http://www.tvbf.org/archives/velocity/maillist.html
> >>>>>>>
> >>>>>>>
> >>>>>> _______________________________________________
> >>>>>> To change your email address, visit
> >>>>>> http://www.tvbf.org/mailman/listinfo/reflector
> >>>>>>
> >>>>>> Visit the gallery! www.tvbf.org/gallery
> >>>>>> user:pw = tvbf:jamaicangoose
> >>>>>> Check new archives: www.tvbf.org/pipermail
> >>>>>> Check old archives:
> >>>>>> http://www.tvbf.org/archives/velocity/maillist.html
> >>>>>>
> >>>>>>
> >>>>>>
> >>>>> ------------------------------
> >>>>>
> >>>>> Message: 4
> >>>>> Date: Sun, 18 Feb 2007 09:29:29 +1100
> >>>>> From: "gpoole"
> >>>>> Subject: Re: REFLECTOR: updraft vs sidedraft vs updraft cooling
> >>>>> To: "'Velocity Aircraft Owners and Builders list'"
> >>>>>
> >>>>> Message-ID: <00b801c752e3$1725de40$4deb64cb at gregb97b7132b4>
> >>>>> Content-Type: text/plain; charset="windows-1250"
> >>>>>
> >>>>> I have been making the same deliberations as Doug for quite some time.
> >>>>> There are compromises with every option ..sigh! Scoops vs NACA
> >>>>> ducts...
> >>>>>
> >>>>> If pinching air before the prop with a scoop on the belly is
> >>>>> considered to
> >>>>> affect prop efficiency then perhaps (surely?) Al G's & several other's
> >>>>> approach of putting radiators in the wing is the way to go. I like
> >>>>> the
> >>>>> idea
> >>>>> of being able to tailor the amount of air to the radiators to balance
> >>>>> the
> >>>>> compromise between drag and amount of cooling required by having
> >>>>> variable
> >>>>> inlets. Only problem is that the air needs to do several sharp turns
> >>>>> to
> >>>>> get
> >>>>> to the cylinder heads....which would should slow it down
> >>>>> considerably....
> >>>>>
> >>>>> Would be interested in this thread continuing to see what others
> >>>>> think....
> >>>>>
> >>>>> Greg in Sydney.
> >>>>>
> >>>>> gregpoole at saaachapter11.com
> >>>>>
> >>>>>
> >>>>> -----Original Message-----
> >>>>> From: reflector-bounces at tvbf.org [mailto:reflector-bounces at tvbf.org]
> >>>>> On
> >>>>> Behalf Of Douglas Holub
> >>>>> Sent: Sunday, 18 February 2007 9:13 AM
> >>>>> To: Velocity Aircraft Owners and Builders list
> >>>>> Subject: Re: REFLECTOR: updraft cooling
> >>>>>
> >>>>> "I thought that using NACA intakes would 'theoretically' be more drag
> >>>>> effecient ?"
> >>>>> -------------------------------------------------------------------
> >>>>> I was just comparing updraft to downdraft. It looks like I could put
> >>>>> one
> >>>>> big
> >>>>>
> >>>>> NACA underneath the rear seat. I was thinking of using that spot for
> >>>>> ram
> >>>>> air, though.
> >>>>>
> >>>>> I'm a little confused about the benefits of a NACA scoop. I need to
> >>>>> read
> >>>>> up
> >>>>>
> >>>>> on them some more. I think that if the cowl lip were extended up a
> >>>>> little
> >>>>> to
> >>>>>
> >>>>> catch the air it might be more efficient than the NACA scoops. But
> >>>>> even
> >>>>> if
> >>>>> it were more efficient, you would be making it a little harder for air
> >>>>>
> >
> >
> >>>>> to
> >>>>> flow to the propeller because the cowl would be getting a little
> >>>>> taller.
> >>>>> But
> >>>>>
> >>>>> then, you lose some head room in the back seats with the NACAs.
> >>>>> Decisions,
> >>>>> decisions.
> >>>>>
> >>>>> Doug Holub
> >>>>>
> >>>>> ----- Original Message -----
> >>>>> From: "Scott Derrick"
> >>>>> To: "Velocity Aircraft Owners and Builders list"
> >>>>> Sent: Saturday, February 17, 2007 2:57 PM
> >>>>> Subject: Re: REFLECTOR: updraft cooling
> >>>>>
> >>>>>
> >>>>>
> >>>>>
> >>>>>> Doug,
> >>>>>>
> >>>>>> I had updraft on my IO360 and it worked fine. I had to run LOP in the
> >>>>>> summer(I did all the time anyway) to keep the engine cool enough.
> >>>>>> There
> >>>>>> were times when I stopped for gas and during the following departure
> >>>>>> climbout I would have to level off at an intermediate altitude for
> >>>>>> awhile
> >>>>>> to get the oil temps back down below 230.
> >>>>>>
> >>>>>> Installing my 520 I conferred with Velocity(ScottB and Brendon) and
> >>>>>> was
> >>>>>> advised I would need to use downdraft as they had never successfully
> >>>>>> seen
> >>>>>> an updraft system work for the big six cylinder engines. So I did
> >>>>>> the
> >>>>>> conversion.
> >>>>>>
> >>>>>> I thought that using NACA intakes would "theoretically" be more drag
> >>>>>> effecient ?
> >>>>>>
> >>>>>> Scott
> >>>>>>
> >>>>>>
> >>>>>>
> >>>>>>
> >>>>>>> I can understand why Burt Rutan and Nat Puffer are proponents of
> >>>>>>> updraft
> >>>>>>> cooling. From an engineering point of view, it has a lot going for
> >>>>>>> it.
> >>>>>>> You
> >>>>>>> need more cooling when the airplane is climbing. If the cooling
> >>>>>>> intake
> >>>>>>> is
> >>>>>>> below the wing, the pressure is higher during a climb so you
> >>>>>>> automatically
> >>>>>>> get more cooling during a climb. Similarly, it would be nice if
> >>>>>>> cooling
> >>>>>>> was minimized during descent. The pressure is reduced under the wing
> >>>>>>> during descent, and so there is less cooling to the engine. Also,
> >>>>>>> you've
> >>>>>>> got convection working with you instead of against you with an
> >>>>>>> updraft
> >>>>>>> system.
> >>>>>>>
> >>>>>>> That all adds up to more drag with down draft cooling, because the
> >>>>>>> NACA
> >>>>>>> scoops have to be large enough so that there is adequate cooling
> >>>>>>> during
> >>>>>>> climb out, when the pressure at the NACAs is at its minimum.
> >>>>>>>
> >>>>>>> But the down draft is a lot simpler to implement, and that's
> >>>>>>> probably
> >>>>>>> going to be the deciding factor for me.
> >>>>>>>
> >>>>>>> Doug Holub_______________________________________________
> >>>>>>> To change your email address, visit
> >>>>>>> http://www.tvbf.org/mailman/listinfo/reflector
> >>>>>>>
> >>>>>>> Visit the gallery! www.tvbf.org/gallery
> >>>>>>> user:pw = tvbf:jamaicangoose
> >>>>>>> Check new archives: www.tvbf.org/pipermail
> >>>>>>> Check old archives:
> >>>>>>> http://www.tvbf.org/archives/velocity/maillist.html
> >>>>>>>
> >>>>>>>
> >>>>>> _______________________________________________
> >>>>>> To change your email address, visit
> >>>>>> http://www.tvbf.org/mailman/listinfo/reflector
> >>>>>>
> >>>>>> Visit the gallery! www.tvbf.org/gallery
> >>>>>> user:pw = tvbf:jamaicangoose
> >>>>>> Check new archives: www.tvbf.org/pipermail
> >>>>>> Check old archives:
> >>>>>> http://www.tvbf.org/archives/velocity/maillist.html
> >>>>>>
> >>>>>>
> >>>>>>
> >>>>> _______________________________________________
> >>>>> To change your email address, visit
> >>>>> http://www.tvbf.org/mailman/listinfo/reflector
> >>>>>
> >>>>> Visit the gallery! www.tvbf.org/gallery
> >>>>> user:pw = tvbf:jamaicangoose
> >>>>> Check new archives: www.tvbf.org/pipermail
> >>>>> Check old archives:
> >>>>> http://www.tvbf.org/archives/velocity/maillist.html
> >>>>>
> >>>>> --
> >>>>> No virus found in this incoming message.
> >>>>> Checked by AVG Free Edition.
> >>>>> Version: 7.1.412 / Virus Database: 268.18.1/690 - Release Date:
> >>>>> 16/02/2007
> >>>>>
> >>>>>
> >>>>> --
> >>>>> No virus found in this outgoing message.
> >>>>> Checked by AVG Free Edition.
> >>>>> Version: 7.1.412 / Virus Database: 268.18.1/690 - Release Date:
> >>>>> 16/02/2007
> >>>>>
> >>>>>
> >>>>>
> >>>>>
> >>>>> ------------------------------
> >>>>>
> >>>>> Message: 5
> >>>>> Date: Sat, 17 Feb 2007 14:52:30 -0800
> >>>>> From: "Al Gietzen"
> >>>>> Subject: Re: REFLECTOR: updraft cooling
> >>>>> To: "'Velocity Aircraft Owners and Builders list'"
> >>>>>
> >>>>> Message-ID: <000001c752e6$4ecd94c0$6400a8c0 at BigAl>
> >>>>> Content-Type: text/plain; charset="us-ascii"
> >>>>>
> >>>>> Subject: REFLECTOR: updraft cooling
> >>>>>
> >>>>>
> >>>>>
> >>>>> I can understand why Burt Rutan and Nat Puffer are proponents of
> >>>>> updraft
> >>>>> cooling. From an engineering point of view, it has a lot going for it.
> >>>>>
> >
> >
> >>>>> You
> >>>>> need more cooling when the airplane is climbing. If the cooling intake
> >>>>>
> >
> >
> >>>>> is
> >>>>> below the wing, the pressure is higher during a climb so you
> >>>>> automatically
> >>>>> get more cooling during a climb. Similarly, it would be nice if
> >>>>> cooling
> >>>>> was
> >>>>> minimized during descent. The pressure is reduced under the wing
> >>>>> during
> >>>>> descent, and so there is less cooling to the engine. Also, you've got
> >>>>> convection working with you instead of against you with an updraft
> >>>>> system.
> >>>>>
> >>>>> Doug;
> >>>>>
> >>>>>
> >>>>>
> >>>>> I'd think that both climbing and descending are high AOA, and would
> >>>>> have
> >>>>> similar air pressure under the wing; and given the strake
> >>>>> configuration,
> >>>>> it
> >>>>> is not clear that there is increased pressure during climb. I also
> >>>>> think
> >>>>> that the main reason for difficulties with the stock armpit scoops and
> >>>>> updraft is they are poorly designed scoops. Need to have ever
> >>>>> increasing
> >>>>> x-section after the entrance, and possilby placing them a bit further
> >>>>> outboard from the strake/fuselage intersection would be helpful.
> >>>>>
> >>>>>
> >>>>>
> >>>>> I have an 'armpit' scoop for my radiator which is very effective.
> >>>>>
> >>>>>
> >>>>>
> >>>>> But the down draft is a lot simpler to implement, and that's probably
> >>>>> going
> >>>>> to be the deciding factor for me.
> >>>>>
> >>>>>
> >>>>>
> >>>>> And since it seems to work well, why not? The amount of natural
> >>>>> convection
> >>>>> driving force is likely overcome by a few knots of forward speed.
> >>>>>
> >>>>> Al
> >>>>>
> >>>>>
> >>>>>
> >>>>>
> >>>>>
> >>>>> Doug Holub
> >>>>>
> >>>>> -------------- next part --------------
> >>>>> An HTML attachment was scrubbed...
> >>>>> URL:
> >>>>>
> >>>>>
> > http://www.tvbf.org/mailman/private/reflector/attachments/20070217/bff4b314/
> > attachment.html
> >
> >>>>> ------------------------------
> >>>>>
> >>>>> _______________________________________________
> >>>>> Visit the gallery! tvbf:jamaicangoose
> >>>>>
> >>>>> End of Reflector Digest, Vol 33, Issue 47
> >>>>> *****************************************
> >>>>>
> >>>>>
> >>>> _______________________________________________
> >>>> To change your email address, visit
> >>>> http://www.tvbf.org/mailman/listinfo/reflector
> >>>>
> >>>> Visit the gallery! www.tvbf.org/gallery
> >>>> user:pw = tvbf:jamaicangoose
> >>>> Check new archives: www.tvbf.org/pipermail
> >>>> Check old archives: http://www.tvbf.org/archives/velocity/maillist.html
> >>>>
> >>>>
> >>>>
> >>>>
> >>> --
> >>> Dave Philipsen
> >>> Velocity STD-FG
> >>> N83DP
> >>>
> >>> _______________________________________________
> >>> To change your email address, visit
> >>> http://www.tvbf.org/mailman/listinfo/reflector
> >>>
> >>> Visit the gallery! www.tvbf.org/gallery
> >>> user:pw = tvbf:jamaicangoose
> >>> Check new archives: www.tvbf.org/pipermail
> >>> Check old archives: http://www.tvbf.org/archives/velocity/maillist.html
> >>>
> >>
> >> ------------------------------
> >>
> >> Message: 2
> >> Date: Sun, 18 Feb 2007 10:29:52 -0600
> >> From: "John Tvedte"
> >> Subject: Re: REFLECTOR: CBs and fuses
> >> To: "Velocity Aircraft Owners and Builders list"
> >> Message-ID:
> >> <182DCED417B03E45BDB40B10169D1D020A95EF at exchange-2003.comp-sol.com>
> >> Content-Type: text/plain; charset="iso-8859-1"
> >>
> >> Personally I think CB's are the proper choice - I think it makes more
> >> sense for the Pilot to choose to reset or NOT reset a circuit.
> >>
> >> John
> >>
> >> ________________________________
> >>
> >> From: reflector-bounces at tvbf.org on behalf of John Overman
> >> Sent: Sun 2/18/2007 10:16 AM
> >> To: bbradburry at allvantage.com; reflector at tvbf.org
> >> Subject: Re: REFLECTOR: CBs and fuses
> >>
> >>
> >>
> >> Hi Bill;
> >> I ordered them from Mouser Electronics, they are
> >> also available from Digi-Key and Allied Electronics
> >> Supply. They are called PTC resettable fuses and are
> >> manufactured by Bournes, Raychem Tyco, and Little
> >> Fuse. There is a good explaination about how the work
> >> on Raychem and most of the other's websites. Here's a
> >> rough explaination of how the work. They contain
> >> "tracks" of carbon which makes the connection. When
> >> they get hot the tracks "flow out" so they are no
> >> longer conductive thus breaking the circuit. If the
> >> device causing the overload is shut off, the fuse
> >> quickly cools and the tracks reform thus "resetting"
> >> the fuse. If the device is not turned off the circuit
> >> remains open. I will install them in "Proto-Board" and
> >> hard wire them to terminal blocks (Buchanan terminal
> >> blocks) also from Mouser 12 terminals 2.5"wide for
> >> $6.03, mounted along the edge of the board.
> >> I ordered the RayChem fuses because they have them
> >> rated up to 14 amps and they can be paralleled which
> >> would give you a 28 Amp fuse. 0.5 amp fuses are $0.54
> >> ea. and 14amp fuses are $1.34 ea.
> >> They are reported to trip faster, and more
> >> accurately, than a breaker and cool to reset faster.
> >> Greg Richter (Blue Mountain Avionics) uses them in his
> >> "Power Board".
> >> I hope this isn't more information than you wanted,
> >> and that it helps.
> >> John Overman
> >> Velocity RG N711VE (reserved)
> >>
> >>
> >> --- Bill Bradburry wrote:
> >>
> >>
> >>> Hi John.
> >>> Where will you get the resettable fuses? Several
> >>> folks on the list have
> >>> suggested that I install CBs in my flight critical
> >>> areas. I am thinking
> >>> that the resettable fuses might solve the problem...
> >>> What do you think?
> >>>
> >>> Bill Bradburry (Lancair Legacy FG / Renesis)
> >>>
> >>>
> >>> Subject:
> >>> Re: [FlyRotary] CBs and fuses
> >>> From:
> >>> John Overman
> >>> Date:
> >>> Sat, 17 Feb 2007 16:15:29 -0800 (PST)
> >>>
> >>> Al or anyone, speaking of fuses, I'm about to order
> >>> PTC resettable fuses in my Velocity, and haven't
> >>> been
> >>> able to find any load values for the stock mazda
> >>> coils, the fuel injectors, the EC2 or the EM2, Al as
> >>> I
> >>> recall you are using LS1 coils not Mazda but I
> >>> haven't
> >>> come up with anything. I even looked in the RX7
> >>> manual
> >>> to see what size fuse Mazda used. It just says the
> >>> fuses are listed under the cap.
> >>> John Overman
> >>> Velocity RG N711VE
> >>> (reserved)
> >>>
> >>>
> >> _______________________________________________
> >> To change your email address, visit
> >> http://www.tvbf.org/mailman/listinfo/reflector
> >>
> >> Visit the gallery! www.tvbf.org/gallery
> >> user:pw Check new archives: www.tvbf.org/pipermail
> >> Check old archives: http://www.tvbf.org/archives/velocity/maillist.html
> >>
> >>
> >> -------------- next part --------------
> >> A non-text attachment was scrubbed...
> >> Name: not available
> >> Type: application/ms-tnef
> >> Size: 6761 bytes
> >> Desc: not available
> >> Url :
> >>
> >>
> > http://www.tvbf.org/mailman/private/reflector/attachments/20070218/7fc5bc37/
> > attachment.bin
> >
> >> ------------------------------
> >>
> >> _______________________________________________
> >> Visit the gallery! tvbf:jamaicangoose
> >>
> >> End of Reflector Digest, Vol 33, Issue 52
> >> *****************************************
> >>
> >
> >
> >
> > ------------------------------
> >
> > _______________________________________________
> > Visit the gallery! tvbf:jamaicangoose
> >
> > End of Reflector Digest, Vol 33, Issue 61
> > *****************************************
> >
> >
> > _______________________________________________
> > To change your email address, visit
> http://www.tvbf.org/mailman/listinfo/reflector
> >
> > Visit the gallery! www.tvbf.org/gallery
> > user:pw = tvbf:jamaicangoose
> > Check new archives: www.tvbf.org/pipermail
> > Check old archives: http://www.tvbf.org/archives/velocity/maillist.html
> >
>
> _______________________________________________
> To change your email address, visit
> http://www.tvbf.org/mailman/listinfo/reflector
>
> Visit the gallery! www.tvbf.org/gallery
> user:pw = tvbf:jamaicangoose
> Check new archives: www.tvbf.org/pipermail
> Check old archives: http://www.tvbf.org/archives/velocity/maillist.html
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