REFLECTOR: Reflector Digest, Vol 33, Issue 61 Exhaust coating
Ron Brown
romott at roadrunner.com
Sun Feb 18 21:37:01 CST 2007
My hanger mate has this stuff (or something like it) installed on his
turbocharged Subaru (Crossflow), and I am amazed at how cool the pipes are -
even at the turbo - and the pipes are still shiny like they were new. No
burned or discolored pipes. (Unfortunately, his nice Lancair 320 still
doesn't fly - Crossflow sucks).
I found this web page - http://www.jet-hot.com/
It sounds like the Subaru has "JET-HOT EXTREME STERLINGT - Similar to
Sterling but will hold its shine up to 1,400°F and will protect parts up to
1,700°F. This coating insulates slightly better than sterling and is
semi-textured. (Made from our MC-15 formula.)"
Ron
----- Original Message -----
From: "Mark Riley" <anriley at comcast.net>
To: <reflector at tvbf.org>
Sent: Sunday, February 18, 2007 7:52 PM
Subject: Re: REFLECTOR: Reflector Digest, Vol 33, Issue 61 Exhaust coating
> 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
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>
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>
> 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" <scott at tnstaafl.net>
> Subject: REFLECTOR: Exhaust wrap. was updraft cooling
> To: velocity at davebiz.com, "Velocity Aircraft Owners and Builders list"
> <reflector at tvbf.org>
> 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" <scott at tnstaafl.net>
> Subject: REFLECTOR: Exhaust wrap. was updraft cooling
> To: velocity at davebiz.com, "Velocity Aircraft Owners and Builders list"
> <reflector at tvbf.org>
> 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" <naomi at yadtel.net>
> Subject: Re: REFLECTOR: Updraft cooling
> To: <reflector at tvbf.org>
> 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: <reflector-request at tvbf.org>
> To: <reflector at tvbf.org>
> 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 <aminetech at bluefrog.com>
>> Subject: Re: REFLECTOR: Updraft cooling
>> To: velocity at davebiz.com, Velocity Aircraft Owners and Builders list
>> <reflector at tvbf.org>
>> 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: <reflector-request at tvbf.org>
>>> > To: <reflector at tvbf.org>
>>> > 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" <scott at tnstaafl.net>
>>> >> Subject: Re: REFLECTOR: updraft cooling
>>> >> To: "Velocity Aircraft Owners and Builders list" <reflector at tvbf.org>
>>> >> 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 <aminetech at bluefrog.com>
>>> >> Subject: Re: REFLECTOR: updraft cooling
>>> >> To: Velocity Aircraft Owners and Builders list <reflector at tvbf.org>
>>> >> 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 --------------
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>>> >> 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" <doug.holub at tx.rr.com>
>>> >> Subject: Re: REFLECTOR: updraft cooling
>>> >> To: "Velocity Aircraft Owners and Builders list" <reflector at tvbf.org>
>>> >> 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" <scott at tnstaafl.net>
>>> >> To: "Velocity Aircraft Owners and Builders list" <reflector at tvbf.org>
>>> >> 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" <gpoole at zeta.org.au>
>>> >> Subject: Re: REFLECTOR: updraft vs sidedraft vs updraft cooling
>>> >> To: "'Velocity Aircraft Owners and Builders list'"
>>> >> <reflector at tvbf.org>
>>> >> 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" <scott at tnstaafl.net>
>>> >> To: "Velocity Aircraft Owners and Builders list" <reflector at tvbf.org>
>>> >> 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" <ALVentures at cox.net>
>>> >> Subject: Re: REFLECTOR: updraft cooling
>>> >> To: "'Velocity Aircraft Owners and Builders list'"
>>> >> <reflector at tvbf.org>
>>> >> 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" <johnt at comp-sol.com>
>> Subject: Re: REFLECTOR: CBs and fuses
>> To: "Velocity Aircraft Owners and Builders list" <reflector at tvbf.org>
>> 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 <bbradburry at allvantage.com> 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 <mooneydryver at yahoo.com>
>>> 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
>>
>>
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>> Url :
>>
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> 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
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>
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