Today's Message Index:
----------------------
1. 01:03 AM - JPI vs EI (TeamGrumman@AOL.COM)
2. 05:57 AM - Aileron Trim (Dave)
3. 06:07 AM - Re: Aileron Trim (flyv35b)
4. 06:19 AM - Re: JPI vs EI (flyv35b)
5. 07:53 AM - Extra seat available to AYA Convention (923te)
6. 09:13 AM - Re: JPI vs EI (Gil Alexander)
7. 10:25 AM - Re: Aileron Trim (TeamGrumman@AOL.COM)
8. 10:36 AM - Re: JPI vs EI (TeamGrumman@AOL.COM)
9. 11:03 AM - Re: JPI vs EI (Gil Alexander)
10. 01:17 PM - Re: JPI vs EI (flyv35b)
11. 10:44 PM - Re: JPI vs EI (TeamGrumman@AOL.COM)
Message 1
| INDEX | Back to Main INDEX |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
--> TeamGrumman-List message posted by: TeamGrumman@aol.com
There is a saying, "If a man has a watch, he'll always know what time it is.
If he has two watches, he'll never be quite sure."
For a long time now, it's been my contention that the JPI reads 50 degrees
higher than the EI. We're talking CHT.
Question is, which one is reading right? The EI uses a probe that sits in
the CHT well and measures the temp inside the well. The JPI places the
thermal couple against the top of the well and measures by direct contact.
For just as long, I've been waiting until I have an EI to use back-to-back
with the JPI. As luck would have it, one of my customers replaced the US-8A EI
with a JPI 700. The #3 CHT generally runs about the same as #2.
I replaced the #3 JPI probe with a CHT probe from an EI. I stole some power
from the main bus and a ground from the avionics rack and put the EI on the
glare shield. I ran the wire to the probe along the outside of the fuselage,
taped in place. The JPI probe was nylon wire tied under the #3 cylinder to
measure the temp of the air leaving the #3 cylinder. It was about 1 inch from
the fins.
Here are the results.
Condition, Altitude, IAS, OAT, RPM, CHT #1, CHT #2, EI-CHT #3, CHT #4, (JPI
#3 under cyl)
Before starting, 1550, 0, 83, 0, 84, 84, 76, 84,
(84)
IDLE, 1550, 0, 81, 1000, 268, 256, 244,
265, (177)
Runup, 1550, 0, 82, 1800, 356, 331, 321,
343, (209)
Straight-Level, 3500, 132, 71, 2700, 423, 424, 350, 410,
(186)
Straight-Level, 6000, 130, 65, 2750, 430, 430, 357, 415,
(186)
Climb ..............., 7000, 110, 61, 2590, 426, 430, 367,
416, (200)
Climb ..............., 9000, 102, 54, 2560, 445, 447, 382,
430, (207)
Climb ............, 10500, 102, 48, 2570, 438, 447, 378,
433, (205)
Climb ............, 11500, 102, 43, 2580, 430, 436, 370,
430, (200)
Climb ............, 12800, 100, 39, 2550, 420, 428, 363,
418, (196)
Climb ............, 13700, 100, 35, 2600, 414, 418, 356,
408, (191)
Strght-Level, 14100, 114, 36, 2680, 400, 408. 344, 400,
(179)
Strght-Level, 13500, 120, 38, 2700, 387, 397. 334, 394,
(170)
Strght-Level, 12500, 122, 41, --------, 387, 400. 335, 395,
(170)
Strght-Level, 10500, 127, 46, --------, 397, 405. 340, 398,
(170)
Strght-Level, 7500, 133, 60, --------, 417, 425. 355,
412, (179)
Roll-out . . . , 1550, 0, 80, 1000, 291, 286, 274,
294, (205)
As you can see, EI-CHT #3 is up to 74 degrees cooler than JPI-CHT #2. Even
before start-up, the EI probe was 8 degrees cooler. On roll-out, the EI was
still about 10 derees cooler. Apparently the EI probe is not as linear as
the JPI probe. As for the temp under the #3 cylinder, the temp under climb and
cruise conditions was consistently 230-240 degrees cooler than #2 JPI-CHT.
And, 60-70 degrees less with the EI.
So, when you are using a JPI and the CHT is 450, is it really 450? Or is it
380? I think what it comes down to is, what type of probe was used for the
original certification and how did they determine that 450 (or 500) is the max
recommended temperature.
Gary
Message 2
| INDEX | Back to Main INDEX |
| PREVIOUS | Skip to PREVIOUS Message |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
--> TeamGrumman-List message posted by: "Dave" <ddmcknight@alltel.net>
I was at a fly-in yesterday and saw a Cheetah with an in-flight adjustable trim
tab on the LH aileron. I never found the owner of the airplane to find out more
about it. Does anyone know of an STC for this mod??
Dave McKnight
Tiger N880DM
Message 3
| INDEX | Back to Main INDEX |
| PREVIOUS | Skip to PREVIOUS Message |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
| Subject: | Re: Aileron Trim |
--> TeamGrumman-List message posted by: "flyv35b" <flyv35b@ashcreekwireless.com>
A company in FL called Aero-Trim (a one man operation) sells the STC and
parts. The price is pretty high for a rather cheap set of components.
Cliff A&P/IA
----- Original Message -----
From: "Dave" <ddmcknight@alltel.net>
Subject: TeamGrumman-List: Aileron Trim
> --> TeamGrumman-List message posted by: "Dave" <ddmcknight@alltel.net>
>
> I was at a fly-in yesterday and saw a Cheetah with an in-flight adjustable
> trim tab on the LH aileron. I never found the owner of the airplane to
> find out more about it. Does anyone know of an STC for this mod??
>
> Dave McKnight
> Tiger N880DM
>
>
>
Message 4
| INDEX | Back to Main INDEX |
| PREVIOUS | Skip to PREVIOUS Message |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
--> TeamGrumman-List message posted by: "flyv35b" <flyv35b@ashcreekwireless.com>
> As you can see, EI-CHT #3 is up to 74 degrees cooler than JPI-CHT #2.
> Even
> before start-up, the EI probe was 8 degrees cooler. On roll-out, the EI
> was
> still about 10 derees cooler. Apparently the EI probe is not as linear
> as
> the JPI probe. As for the temp under the #3 cylinder, the temp under
> climb and
> cruise conditions was consistently 230-240 degrees cooler than #2 JPI-CHT.
> And, 60-70 degrees less with the EI.
The EI may be linear, just a lower slope "curve" or straight line. But
compared to what as you mention below?
> So, when you are using a JPI and the CHT is 450, is it really 450? Or is
> it
> 380? I think what it comes down to is, what type of probe was used for
> the
> original certification and how did they determine that 450 (or 500) is the
> max
> recommended temperature.
The type of probe and instrumentation used during certification testing
would be interesting to know and how it might compare to either the JPI or
EI probes. I'm sure that neither one of these 2 systems was used as neither
company was in existence when the engine was certified. Another point, the
FAA has allowed use of one or both of these systems for STC certification
testing with calibrated instrumentation (how that is done I'm not sure) and
both companies had instrumentation that is approved for replacement of the
original primary EGT and CHT instrumentation (all analog instruments to my
knowledge).
Cliff
Message 5
| INDEX | Back to Main INDEX |
| PREVIOUS | Skip to PREVIOUS Message |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
| Subject: | Extra seat available to AYA Convention |
--> TeamGrumman-List message posted by: "923te" <923te@cox.net>
If anyone needs a ride to the AYA convention between Oklahoma and Sacramento
I have seats available in my Tiger. I could swing up to Kansas or Texas.
Regards,
Ned
Message 6
| INDEX | Back to Main INDEX |
| PREVIOUS | Skip to PREVIOUS Message |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
--> TeamGrumman-List message posted by: Gil Alexander <gilalex@earthlink.net>
Gary... It seems like EI is the only manufacturer that does not use a CHT
probe with a spring to maintain contact with the bottom of the cylinder well.
The pictures at JPI web site
http://www.jpitech.com/probes/images/200/probe_25.jpg
and the Chief aircraft picture of the EI probe - shows no spring.
http://www.chiefaircraft.com/Aircraft/EngineInstruments/Images/EI_P100.jpg
HOWEVER, EI makes this CHT probe - and calls it military style...
http://www.chiefaircraft.com/Aircraft/EngineInstruments/Images/EI_P101.jpg
and needs this adapter...
http://www.chiefaircraft.com/Aircraft/EngineInstruments/Images/EI_A101.jpg
Perhaps you need to do the test with $16 extra per CHT probe and use the
Military style CHT probe (apparently AN5541-1 specification)?
Alcor shows the spring on this drawing....
http://www.alcorinc.com/db/images/drawing/86251.pdf
I presume the standard EI configuration shipped is the cheaper version
without the spring.
Since a MIL Spec. measurement method exists, I would bet Lycoming used the
spring loaded probes for their testing...
This seems to be shown in the Lycoming Flyer when they talk about BAYONET
CHT probes
http://www.prime-mover.org/Engines/Lycoming/Flyer/Operation.html
...It would seem to me that it can't be a bayonet without the spring....
....gil in Tucson
Just getting ready to install Insight (GEM) probes... that do come with
springs...:
)
At 06:18 AM 6/26/2005, you wrote:
>--> TeamGrumman-List message posted by: "flyv35b"
><flyv35b@ashcreekwireless.com>
>
> > As you can see, EI-CHT #3 is up to 74 degrees cooler than JPI-CHT #2.
> > Even
> > before start-up, the EI probe was 8 degrees cooler. On roll-out, the EI
> > was
> > still about 10 derees cooler. Apparently the EI probe is not as linear
> > as
> > the JPI probe. As for the temp under the #3 cylinder, the temp under
> > climb and
> > cruise conditions was consistently 230-240 degrees cooler than #2 JPI-CHT.
> > And, 60-70 degrees less with the EI.
>
>The EI may be linear, just a lower slope "curve" or straight line. But
>compared to what as you mention below?
>
> > So, when you are using a JPI and the CHT is 450, is it really 450? Or is
> > it
> > 380? I think what it comes down to is, what type of probe was used for
> > the
> > original certification and how did they determine that 450 (or 500) is the
> > max
> > recommended temperature.
>
>The type of probe and instrumentation used during certification testing
>would be interesting to know and how it might compare to either the JPI or
>EI probes. I'm sure that neither one of these 2 systems was used as neither
>company was in existence when the engine was certified. Another point, the
>FAA has allowed use of one or both of these systems for STC certification
>testing with calibrated instrumentation (how that is done I'm not sure) and
>both companies had instrumentation that is approved for replacement of the
>original primary EGT and CHT instrumentation (all analog instruments to my
>knowledge).
>
>Cliff
Message 7
| INDEX | Back to Main INDEX |
| PREVIOUS | Skip to PREVIOUS Message |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
| Subject: | Re: Aileron Trim |
--> TeamGrumman-List message posted by: TeamGrumman@aol.com
In a message dated 6/26/05 5:58:21 AM, ddmcknight@alltel.net writes:
> I was at a fly-in yesterday and saw a Cheetah with an in-flight adjustable
> trim tab on the LH aileron.=A0 I never found the owner of the airplane to=20find
> out more about it.=A0 Does anyone know of an STC for this mod??
>
Although this seems like a good idea, I've never found one that didn't affect
the yaw on the plane. Yes, I said yaw. For some reason, having the trim
hangin out from under the aileron affects the trim and aerodynamics on that
aileron. I tried everything to get one particular plane straight and couldn't.
To install the electric trim, you have to cut a hole in your aileron and run
wires. That's right, cut a hole in a perfectly good aileron. I have had
two planes with no provision to remove the aileron for the aileron AD. On
one, I had to remove the aileron trim mechanism and that required drilling out
the rivets in the aileron. As you can imagine, it stretched the hell out of
the aluminum on the aileron.
Like the avionics master, there is no justification for it other than
compicating a very simple system. Save you money and buy a panel mounted GPS
or
panel mounted intercom.
Message 8
| INDEX | Back to Main INDEX |
| PREVIOUS | Skip to PREVIOUS Message |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
--> TeamGrumman-List message posted by: TeamGrumman@aol.com
In a message dated 6/26/05 9:14:38 AM, gilalex@earthlink.net writes:
> Since a MIL Spec. measurement method exists, I would bet Lycoming used the
> spring loaded probes for their testing...
>
First of all, I take what Lycoming recommends with a grain of salt. There
is much too much evidence that some of their recommendations (i.e., shock
cooling) don't really exist. And, their blanket recommendations on leaning do
not
coincide the recent testing (i.e., GAMI).
That said, I serious doubt that spring loaded thermal couples were ever used
by the military. Any probe inserted into the CHT well is a bayonet. The
other probe fits under the spark plug.
Message 9
| INDEX | Back to Main INDEX |
| PREVIOUS | Skip to PREVIOUS Message |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
--> TeamGrumman-List message posted by: Gil Alexander <gilalex@earthlink.net>
Gary,
The probes have an official, govt. published AN spec. (AN5541-1) that would
have been created in the 40's(?) - Army-Navy=AN -- before there was a US
Airforce??
The AN specs. went obsolete for govt. use when they got replaced by MSxxxxx
specs., a long time ago.....
These spring loaded thingies, and the threaded holes in cylinder heads for
them, have been around a longggg.... time.
Physical contact, vs. hanging around in a hot well, seems to make much more
sense for repeatable temperature readings, since IR temperature sensors
didn't exist pre-war (the WWII war...)
I'll see if we still have a copy of the AN-5541 spec. on file at
work..... gil A
At 10:36 AM 6/26/2005, you wrote:
>--> TeamGrumman-List message posted by: TeamGrumman@aol.com
>
>
>In a message dated 6/26/05 9:14:38 AM, gilalex@earthlink.net writes:
>
>
> > Since a MIL Spec. measurement method exists, I would bet Lycoming used the
> > spring loaded probes for their testing...
> >
>
>First of all, I take what Lycoming recommends with a grain of salt. There
>is much too much evidence that some of their recommendations (i.e., shock
>cooling) don't really exist. And, their blanket recommendations on
>leaning do not
>coincide the recent testing (i.e., GAMI).
>
>That said, I serious doubt that spring loaded thermal couples were ever used
>by the military. Any probe inserted into the CHT well is a bayonet. The
>other probe fits under the spark plug.
>
>
Message 10
| INDEX | Back to Main INDEX |
| PREVIOUS | Skip to PREVIOUS Message |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
--> TeamGrumman-List message posted by: "flyv35b" <flyv35b@ashcreekwireless.com>
> Gary... It seems like EI is the only manufacturer that does not use a CHT
> probe with a spring to maintain contact with the bottom of the cylinder
> well.
EI also sells the military style bayonet probe. It's their P-101. The most
common one is their P-100. As I recall they said there wasn't much
difference in the readout between them, but I have never tried to verify
that.
Cliff
Message 11
| INDEX | Back to Main INDEX |
| PREVIOUS | Skip to PREVIOUS Message |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
--> TeamGrumman-List message posted by: TeamGrumman@aol.com
I think the question should be,
if the FAA sets their temperature limits based on the some arbitrary guidline
that was established with the probes that read 70 degrees lower, then it
would be impossible to pass the climb/cooling tests with the probes that read 70
degrees higher.
Why do I care? If I use the JPI probes in comparison to guideline using the
lower reading probes, my cowling will never pass the climb cooling test.
Right now, I climb out at 110 knots, full rich, and even with 80 OAT, I can
over temp on the JPI quite easily. The EI probe, on the other hand, barely
gets to 400 degrees.
Gary
Other Matronics Email List Services
These Email List Services are sponsored solely by Matronics and through the generous Contributions of its members.
-- Please support this service by making your Contribution today! --
|