REFLECTOR: Reflector Digest, Vol 33, Issue 61 Exhaust coating
Chuck Jensen
cjensen at dts9000.com
Mon Feb 19 11:53:27 CST 2007
The consensus seems to be that if you coat only one side, coat the
inside. Coating the outside and not the inside causes the exhaust pipes
to become very hot with no way to dissipate the heat. It's my
understanding that cracks will show up with the ceramic coating without
a problem. Wrapping the exhaust pipes is considered by many to be the
worst of all worlds--it keeps the pipes very hot and makes crack
detection difficult. However, mine are neither ceramic coated nor
wrapped, so I'm just passing along CW.
Chuck Jensen
-----Original Message-----
From: reflector-bounces at tvbf.org [mailto:reflector-bounces at tvbf.org] On
Behalf Of bdtopp at comcast.net
Sent: Monday, February 19, 2007 11:58 AM
To: Velocity Aircraft Owners and Builders list
Subject: Re: REFLECTOR: Reflector Digest, Vol 33, Issue 61 Exhaust
coating
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 be! nefit, 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: Con tents 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
> ! > is sues 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 pre! heated 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
! > &g t;>> 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.
> >>>>
> >>>
------------------------------------------------------------------------
> >>&g! t;
> >>> _______________________________________________
> >>> 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 arc hives: 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 ti! me.
> >
> > 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
> &! gt;> > 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.
&! gt; > ;>>
> >>> 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
> >>
> >! ;> < BR>> >
> >
> >
> > ------------------------------
> >
> > 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: Reflec! tor Dig est, 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 do! wndraft
> >> 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 o! n
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. I! t's alo t
> >>>> 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
>! >&g t;>>> 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 e! ngine c
ool 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 pre ssure 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.
> >&! gt;> >>>
> >>>>>> 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
&! gt; > ;>>>> 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:
> >>>>>
> >>>>>
&! gt; > ;>>>>
> >>>>>> 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
> >&g! t;>& gt;>>> 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/daaba
585/
> > attachment.htm
> >
> >>>>> ------------------------------
> >>>>>
> >>>>> Message: 3
> >>>>> Date: Sat, 17 Feb 2007 16:13:01 -0600
> >>>>> From: "Douglas Holub"
> >>>>> Subject: Re: REFLECTOR: up! draft c ooling
> >>>>> 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.
> >>>>>
&g! t; > >>>> 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,
> &! gt;> >>> 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 st! opped f or 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 ?
> >>>>>>
> >! ;>&g t;>>> 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
>! ; >& gt;>>>>> 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 implem! ent, an
d 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 updr!
aft coo ling
> >>>>> 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
> >&! gt;> >> 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
> >>>>>
> >>>>>
> >>&! gt;> > -----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
th! at 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
> >>>>> ta! ller. < BR>> >>>>> 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 h! ad
to r un 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.
> >&! gt;> >>>
> >>>>>> 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
&! gt; > ;>>>>>> 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 add! ress, v isit
> >>>>> 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 E! dition.
> >>>>> 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
&! gt; > ;>>>>
> >>>>>
> >>>>>
> >>>>> 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 wi! ng
> >>>>> 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
> >>>>> up! draft i s 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!
&g t; >>>>> 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/bff4b
314/
> > 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
> >>>! ;
& gt; >>> _______________________________________________
> >>> 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!
&g t; >> 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
> >> rat! ed up t o 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 t! hinking
> >>> 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
> >>&! gt; com e 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: app! licatio n/ms-tnef
> >> Size: 6761 bytes
> >> Desc: not available
> >> Url :
> >>
> >>
> >
http://www.tvbf.org/mailman/private/reflector/attachments/20070218/7fc5b
c37/
> > 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
> > *****************************************
> >
> >! ;
& gt; > _______________________________________________
> > 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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