Today's Message Index:
----------------------
1. 06:20 AM - Re: Used RV buying best practices? (Dave Reel)
2. 07:45 AM - Re: RV7A OVERHEATING (smoothweasel@juno.com)
3. 07:51 AM - Re: Used RV buying best practices? (Dean Pichon)
4. 08:26 AM - Re: RV7A OVERHEATING (Tim Bryan)
5. 08:34 AM - Re: RV7A OVERHEATING (Mike Robertson)
6. 09:30 AM - Re: RV7A OVERHEATING (Kevin Horton)
7. 09:36 AM - Re: RV7A OVERHEATING (J. Mcculley)
8. 09:36 AM - Re: Used RV buying best practices? (Bob)
9. 10:22 AM - Re: RV7A OVERHEATING (Walter Tondu)
10. 10:41 AM - Re: RV7A OVERHEATING (Ed Holyoke)
11. 12:37 PM - Crazy Horse (Bill VonDane)
12. 04:13 PM - Short Notice - Jefferson City, MO Fly-in - KJEF (David Schaefer)
Message 1
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| Subject: | Re: Used RV buying best practices? |
I think your approach is useful Andrew when you look to buy a used RV.
Though some may have been flown little, they may have been built with
used engines and components and made primarily to sell. In other cases,
such as my RV-8A, the aircraft was made from all new components, flown
only 50 hours, and not made to sell but being sold because my health has
deteriorated. So you're concerns are guaranteed to be satisfied & you
just need to look and take a flight. So, there's a big swing between
possibilities depending on how the plane got to the sale market. Good
luck.
Dave Reel
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| Subject: | RV7A OVERHEATING |
Just an update. we are continuing to work on the cooling issues.....
the numbers i gave previously are higher now (probably due to higher O.S
.A. temp).
On a flight yesterday at low alt level flight the numbers are as follows
.
TAS 162 (verified by GPS)
MP 23 in
rpm 2350 (Verified correct)
Oil Temp. 232 deg F
CHT 395 deg F
EGT 1350 (rich of peak)
this information was established in constant flight for approx. 45 min.
also we connected a magnahelic to the low pressure side of the cowl. (be
hind the baffle) at 150 knots we have 4.5" w.c.. we have not tested it o
n the entering side yet but 4.5" on the low press raised my eye brows. I
then measured the outlet cross sectional area and after taking into acc
ount for the ext. stacks it was much smaller than the rv-8 it shares a h
anger with and also has a lot more obstacles tripping the airflow and th
erefore causing turbulence. I then measured the outlet on my rv-4 and th
e -7a even has a smaller outlet than my -4. These are all stock cowls.
bottom line we still feel like we have to small of outlet on the cowl.
we are still testing.........we shall see.
Weasel
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| Subject: | Used RV buying best practices? |
This is an excellent endeavor and would likely be useful to many potential
buyers. I have a -4 and can speak better about this model than the others
so I will offer a few things. (There are obviously many things to look for
, but these are some of the common weak points/issues in -4's and probably
other models as well.)
Condition of the cowl attachment features (hinges with broken eyelets, fast
eners in elongated holes, etc.)
Are there wrinkles in the firewall? (Suggesting hard landing(s))
Are the weldments behind the firewall the later (thicker) versions (Photos
and dimensions of both versions would be useful)
Asymmeterical main gear suggesting one may have been bent
Cracks around rivets in elevators and rudder (Was the rudder constructed wi
th 0.016 or 0.20 skin?)
Does the aircraft have the long or short gear? Longer is newer
I'm sure others can add many more.
From: andrew@oc384.netTo: rv-list@matronics.comSubject: RV-List: Used RV bu
ying best practices?Date: Wed, 2 Apr 2008 10:17:18 -0500
I think a set of Best Practices for used RV pre-buy/purchasing would be hel
pful. Has anything like this been compiled before? I=92m thinking about:
Indicators of good construction (with photos)
Indicators of poor construction (with photos)
What to look for in the logs (good and bad)
What tests to do? (avionics, engine, etc)
Should an Oil Analysis be done?
What quirks to be aware of between models=85
I think something like this would be very helpful to any non-A&P shopping f
or a used RV.
-Andrew
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Message 4
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| Subject: | RV7A OVERHEATING |
Temperature comparisons are real hard to get but when I added louvers to
the
bottom of my cowl I gained about 10 degrees cooler CHT temps. I later
opened up the exit air and gained about another 5 or 6 degrees. My oil
temps run cool at about 165 degrees. My CHT=92s are still high. Very
few
things I have done made as much difference as the louvers and opening
the
bottom cowl up a little more.
In my case a -6 I just cut the center lower part of the cowl about 1 =BD
=93
back as it was actually a little past the metal skin on the fuse.
This is just a reference point for you.
Tim
_____
From: owner-rv-list-server@matronics.com
[mailto:owner-rv-list-server@matronics.com] On Behalf Of
smoothweasel@juno.com
Sent: Thursday, April 03, 2008 8:39 AM
Subject: RE: RV-List: RV7A OVERHEATING
Just an update. we are continuing to work on the cooling issues.....
the numbers i gave previously are higher now (probably due to higher
O.S.A.
temp).
On a flight yesterday at low alt level flight the numbers are as
follows.
TAS 162 (verified by GPS)
MP 23 in
rpm 2350 (Verified correct)
Oil Temp. 232 deg F
CHT 395 deg F
EGT 1350 (rich of peak)
this information was established in constant flight for approx. 45 min.
also we connected a magnahelic to the low pressure side of the cowl.
(behind
the baffle) at 150 knots we have 4.5" w.c.. we have not tested it on the
entering side yet but 4.5" on the low press raised my eye brows. I then
measured the outlet cross sectional area and after taking into account
for
the ext. stacks it was much smaller than the rv-8 it shares a hanger
with
and also has a lot more obstacles tripping the airflow and therefore
causing
turbulence. I then measured the outlet on my rv-4 and the -7a even has a
smaller outlet than my -4. These are all stock cowls.
bottom line we still feel like we have to small of outlet on the cowl.
we are still testing.........we shall see.
Weasel
_____________________________________________________________
Earn up to $300 hour. Click here to get information on starting
<http://thirdpartyoffers.juno.com/TGL2112/fc/REAK6ZpPCf5s36c9PRQtFyClaNN5
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Message 5
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| Subject: | RV7A OVERHEATING |
With any 'a' model you have tons of obstacles in the outlet area that coaus
e all kinds of turbulence. Several people have installed louvers to the le
ft and right of the outlet with great results. Your CHT's seem just a tad
bit high for the power, rpm, and cruise time you gave. Granted, with a new
engine a bit high can be normal but I think they level you gave indicates
one of a couple of things. first, check your baffles to make sure they are
tight around the engine and upper cowling. Second, make sure the ramp are
as of the inlets are smooth and don't have any excess holes. Tthe third th
ing is the outlet flow area. Go ahead and get the pressure reading in the
top inlet area. Once you compare the top and bottom you will have a much b
etter idea.
A friend, with an RV-9A, decided to install louvers and had great results.
Even though he did not have any temps out of limits, he wanted to see what
effect it had. Both the oil temps and the CHTs went down significantly.
And with the louvers painted the same color as his cowling they do not look
out of place. One quick reminder though. If you do install the louvers,
when you cut through the honecomb part of the cowling, make sure to apply s
ome eposy glue or resin to the cut areas to stop oil, grease, and water fro
m getting into the honeycomb area of the cowling and causing delamination.
Mike Robertson
Das Fed
Repeat offender
From: smoothweasel@juno.comDate: Thu, 3 Apr 2008 14:38:51 +0000To: rv-list@
matronics.comSubject: RE: RV-List: RV7A OVERHEATING
Just an update. we are continuing to work on the cooling issues.....
the numbers i gave previously are higher now (probably due to higher O.S.A.
temp).
On a flight yesterday at low alt level flight the numbers are as follows.
TAS 162 (verified by GPS)
MP 23 in
rpm 2350 (Verified correct)
Oil Temp. 232 deg F
CHT 395 deg F
EGT 1350 (rich of peak)
this information was established in constant flight for approx. 45 min.
also we connected a magnahelic to the low pressure side of the cowl. (behin
d the baffle) at 150 knots we have 4.5" w.c.. we have not tested it on the
entering side yet but 4.5" on the low press raised my eye brows. I then mea
sured the outlet cross sectional area and after taking into account for the
ext. stacks it was much smaller than the rv-8 it shares a hanger with and
also has a lot more obstacles tripping the airflow and therefore causing tu
rbulence. I then measured the outlet on my rv-4 and the -7a even has a smal
ler outlet than my -4. These are all stock cowls.
bottom line we still feel like we have to small of outlet on the cowl.
we are still testing.........we shall see.
Weasel
_____________________________________________________________Earn up to $3
00 hour. Click here to get information on starting a medical career.
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Message 6
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| Subject: | Re: RV7A OVERHEATING |
Speaking of baffling - have a look at the two duct ramp pieces that
were fibreglassed to the inlets on the upper cowl. I understand that
depending on how you set up your baffles, that it is possible for high
pressure air on the top side of the engine to go through the tunnels
between those duct ramps and the cowl. The high pressure air may be
able to go through those tunnels and end up on the low pressure side
of the baffles. It this can happen, it would greatly reduce the
amount of air that is available to go through the cylinder fins and
the oil cooler. You may need to block off one end of that tunnel with
fibreglas.
Kevin Horton
On 3-Apr-08, at 11:27 , Mike Robertson wrote:
> With any 'a' model you have tons of obstacles in the outlet area
> that coause all kinds of turbulence. Several people have installed
> louvers to the left and right of the outlet with great results.
> Your CHT's seem just a tad bit high for the power, rpm, and cruise
> time you gave. Granted, with a new engine a bit high can be normal
> but I think they level you gave indicates one of a couple of
> things. first, check your baffles to make sure they are tight
> around the engine and upper cowling. Second, make sure the ramp
> areas of the inlets are smooth and don't have any excess holes.
> Tthe third thing is the outlet flow area. Go ahead and get the
> pressure reading in the top inlet area. Once you compare the top
> and bottom you will have a much better idea.
>
> A friend, with an RV-9A, decided to install louvers and had great
> results. Even though he did not have any temps out of limits, he
> wanted to see what effect it had. Both the oil temps and the CHTs
> went down significantly. And with the louvers painted the same
> color as his cowling they do not look out of place. One quick
> reminder though. If you do install the louvers, when you cut
> through the honecomb part of the cowling, make sure to apply some
> eposy glue or resin to the cut areas to stop oil, grease, and water
> from getting into the honeycomb area of the cowling and causing
> delamination.
>
> Mike Robertson
> Das Fed
> Repeat offender
>
>
> From: smoothweasel@juno.com
> Date: Thu, 3 Apr 2008 14:38:51 +0000
> To: rv-list@matronics.com
> Subject: RE: RV-List: RV7A OVERHEATING
>
> Just an update. we are continuing to work on the cooling issues.....
> the numbers i gave previously are higher now (probably due to higher
> O.S.A. temp).
> On a flight yesterday at low alt level flight the numbers are as
> follows.
> TAS 162 (verified by GPS)
> MP 23 in
> rpm 2350 (Verified correct)
> Oil Temp. 232 deg F
> CHT 395 deg F
> EGT 1350 (rich of peak)
> this information was established in constant flight for approx. 45
> min.
> also we connected a magnahelic to the low pressure side of the cowl.
> (behind the baffle) at 150 knots we have 4.5" w.c.. we have not
> tested it on the entering side yet but 4.5" on the low press raised
> my eye brows. I then measured the outlet cross sectional area and
> after taking into account for the ext. stacks it was much smaller
> than the rv-8 it shares a hanger with and also has a lot more
> obstacles tripping the airflow and therefore causing turbulence. I
> then measured the outlet on my rv-4 and the -7a even has a smaller
> outlet than my -4. These are all stock cowls.
> bottom line we still feel like we have to small of outlet on the cowl.
> we are still testing.........we shall see.
> Weasel
>
>
--
Kevin Horton
Ottawa, Canada
Message 7
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| Subject: | Re: RV7A OVERHEATING |
Can you provide the following additional data that could be helpful:
1. Ambient temperature at the flight altitude.
2. Indicated (calibrated) airspeed.
3. Actual measurements, or best estimate of square inches of clear area
of cooling air outlet.
4. Same as 3 above for inlet cooling area.
5. Make/model and face area of oil cooler; Is this a new or used cooler?
Also the cross section area of any scat tube feeding the cooler and
where that air is sourced; Are all the air leakage cracks at the cooler
face thoroughly sealed with the equivalent of red 600 fahrenheit silicon
sealant? Does the exit air from the cooler flow out through the same
cooling air exit as in item 3 above?
6. What is the sensor pickup location of your oil temperature indication?
Are your CHT temperature probes in the cylinder head wells or under the
spark plugs?
Jim
--------------------------------------------------------------------------------------
smoothweasel@juno.com wrote:
> Just an update. we are continuing to work on the cooling issues.....
>
> the numbers i gave previously are higher now (probably due to higher
> O.S.A. temp).
>
> On a flight yesterday at low alt level flight the numbers are as follows.
>
> TAS 162 (verified by GPS)
>
> MP 23 in
>
> rpm 2350 (Verified correct)
>
> Oil Temp. 232 deg F
>
> CHT 395 deg F
>
> EGT 1350 (rich of peak)
>
> this information was established in constant flight for approx. 45 min.
>
> also we connected a magnahelic to the low pressure side of the cowl.
> (behind the baffle) at 150 knots we have 4.5" w.c.. we have not tested
> it on the entering side yet but 4.5" on the low press raised my eye
> brows. I then measured the outlet cross sectional area and after taking
> into account for the ext. stacks it was much smaller than the rv-8 it
> shares a hanger with and also has a lot more obstacles tripping the
> airflow and therefore causing turbulence. I then measured the outlet on
> my rv-4 and the -7a even has a smaller outlet than my -4. These are all
> stock cowls.
>
> bottom line we still feel like we have to small of outlet on the cowl.
>
> we are still testing.........we shall see.
>
> Weasel
>
>
>
>
>
> _____________________________________________________________
> Earn up to $300 hour. Click here to get information on starting a
> medical career.
> <http://thirdpartyoffers.juno.com/TGL2112/fc/REAK6ZpPCf5s36c9PRQtFyClaNN5axaGezer7vCfQ07T4GItaLqiML/>
>
> *
>
>
> *
Message 8
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| Subject: | Re: Used RV buying best practices? |
At 09:17 AM 4/2/08, you wrote:
>I think a set of Best Practices for used RV pre-buy/purchasing would
>be helpful. Has anything like this been compiled before? I'm thinking about:
It would seem to me that the RV world is in a transisition where a
lot of RV owners are now or will be non builders. As we see more non
builders as RV owners, this issue of how well is an RV built will
increasingly become more and more important.
In my opinion the best way(s) to learn how to inspect an RV:
1. Build an RV or metal airplane, or
2. Build a non metal airplane, or
3. Read the archives, or
4. Read the Bible that I used to build my RV, "AC
43.13-1B Acceptable Methods, Techniques, and Practices, Aircraft
Inspection and Repair."
The AC covers all aspects of building, inspection and aircraft
repair. It even has pictures, drawings, diagrams, tables etc.
There is nothing special about how an RV is built. It uses standard
techniques and practices that would be the same for a Mustang II or
any of the RV series aircraft.
Bob
RV6 "Wicked Witch of the West"
Message 9
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| Subject: | Re: RV7A OVERHEATING |
On 04/03 12:18, Kevin Horton wrote:
>
> Speaking of baffling - have a look at the two duct ramp pieces that
> were fibreglassed to the inlets on the upper cowl. I understand that
> depending on how you set up your baffles, that it is possible for high
> pressure air on the top side of the engine to go through the tunnels
> between those duct ramps and the cowl. The high pressure air may be
> able to go through those tunnels and end up on the low pressure side
> of the baffles. It this can happen, it would greatly reduce the
> amount of air that is available to go through the cylinder fins and
> the oil cooler. You may need to block off one end of that tunnel with
> fibreglas.
Follow this thread for more information dissemination and pretty pics
about what Kevin is writing about: Also, check out the poll results.
http://www.vansairforce.com/community/showthread.php?t=8209
--
Walter Tondu
http://www.rv7-a.com - Painting
http://www.evorocket.com - Empennage
Message 10
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| Subject: | Re: RV7A OVERHEATING |
Weasel,
Just as a data point, on our 6A with O-320, we used to see oil temps in
the 200 to 220 degree range on not very hot days until we moved the oil
cooler from the firewall to behind the baffle at #4 cyl. Do the math of
cross sectional area in the scat tube to surface area of the oil cooler
then think about length of tube, bends etc. In our case, with 3" scat,
it was 1.5" squared x pi, or about 7 sq" with 18" of scat and 1 bend vs.
4 x 5 or about 20 sq" directly in the airflow. Now we see 180 to 190
degrees on warm days. This is the Niagara cooler. I'm not sure which one
Van's supplies now, but I don't think that it is the Stewart Warner
which is the one you really want.
Others have made good suggestions about cowl airflow. I think that you
probably need to address the airflow through the cooler as a separate
issue. One approach might be to combine 2 or more scats into a plenum
above the oil cooler. What out that you don't create a bunch of
turbulence, though. Stuff in the exit airflow path from the cooler can
have a negative impact on cooling performance, too.
Pax,
Ed Holyoke
smoothweasel@juno.com wrote:
>
> Hello all, It's been a long time since i have found time to read "the
> list". I have been helping a friend finish a rv-7a and test fly it.
> It has a new superior 360 parallel valve engine, Hartzell blended
> airfoil prop, the oil cooler is the one that comes with the finishing
> kit and is mounted on the firewall with a 3.5 in scat duct going to it
> (with no sharp bends in the duct). the cowl air exit is the standard
> size. ie. no extra openings.
>
> His problem is over heating oil. With 52 deg. F. Outside air crusing
> at 24 in map. and 2350rpm on the prop the oil will run about
> 220-225deg F. The CHT runs about 360-370 deg. F. The engine now has
> 30hr or more on it.
>
> Will the Oil temp drop any more with "break in"? Should it have more
> exit air leaving the cowl....some have suggested installing "luvers"
> on the botom of the cowl to help with that...?
>
> Also the airplane cruises at the above power setting at 8000ft at
> 164kn TAS he thinks this is a little slow...... Is this what most of
> you are seeing with the same engine/prop combo???
>
> btw i tried to search the archives on this but didnt find the specific
> info..........probably dont know how to look it up right...
>
>
>
> Thanks for any thoughts
>
> Weasel RV-4 400hr
>
>
> _____________________________________________________________
> Click here to become a professional counselor in less time than you
> think.
> <http://thirdpartyoffers.juno.com/TGL2112/fc/Ioyw6iigjRkllMv4ZGFXw1J0mnPH95dNcFS3uxBE5YnuT7oNq7kzGL/>
> *
>
>
> *
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You say you want to fly Crazy Horse?
http://www.airshowbuzz.com/videos/view.php?v=baccdea1
do not archive
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| Subject: | Short Notice - Jefferson City, MO Fly-in - KJEF |
I received this email earlier in the day:
*As I promised late last year, here is you notice of a last minute fly in.
Weather is scheduled to be 'SUNNY' !!*
*Once again, the owner of 'NICKS' restaurant has agreed to open his doors
on Saturday just for this fly in and he will be serving 11 A.M. -- 2 P.M.
on April 5th.*
*A partial menu follows:*
*Country Fried Ham Plates or Sandwiches*
*Country Fried Chicken Plates or Sandwiches*
*Pork Tenderloin Plates or Sandwiches*
*Fish Plates or Sandwiches*
*There is no 'formal program'.....just a short notice plain ol' fly in and
maybe some hangar/war stories.*
*Additionally, L.C. Flight Shop located in the terminal building next to the
Nick's Restaurant will be open between 10 A. M. and 3 P.M. for your
convenience. Also Jefferson City Flying Service will have a couple of
additional linemen on duty to assist with the parking. *
*The Jefferson City Tower Frequency is: 125.6 and we now have a new
parallel taxi way for runway 12/30.*
*I will appreciate it very much if you would be so kind as to respond to the
undersigned with the type aircraft and number in your party along with an
approximate time of arrival. Email or telephonic response either will work!
*
*Looking forward to meeting you,*
*Bob Morgan*
*Cell: 573-680-5211
Bob Morgan [N1142G@mchsi.com]
*
**
Since the weather is supposed to be nice. I wanted to pass it on to the
rest of the RV Community.
--
David W. Schaefer
RV-6A N142DS formerly "Geek One' reborn "Nerdgasm"
TMX-IO360 Dual-LightSpeed Plasma IIIs, Hartzell Blended Airfoil, GRT EFIS
www.n142ds.com
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