Today's Message Index:
----------------------
1. 02:17 AM - Re: JPI vs EI (FLYaDIVE@AOL.COM)
2. 07:37 AM - Re: 28747 with a Powerflow (bhauskne@san.rr.com)
3. 08:23 AM - Re: Need someone to do drawings of the cowling (Phil)
4. 11:03 AM - Re: 28747 with a Powerflow (TeamGrumman@AOL.COM)
5. 11:11 AM - Re: Need someone to do drawings of the cowling (TeamGrumman@AOL.COM)
Message 1
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--> TeamGrumman-List message posted by: FLYaDIVE@aol.com
> > 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.
================================
Hey Team:
If you will recall; it was only recently that Lycoming CHANGED the Max CHT
from 525 Deg F down to 500 Deg F. And way back when the engine was being
certified Neither JPI or EI were in existence. And I'm not even sure if there
were
thermocouples back in the 40's? Yes, there were temperature gages but they
were liquid filled Boron Tubes.
The thermocouple is a product of two materials joined together and when
hooked to a milliamp-meter (completed circuit) produces a small current flow, which
changes with temperature. There are three types of thermocouples that will
work in our temperature range J, K and JK. The range of these thermocouples do
over lap each other. But, it is the JUNCTION that plays the major part. How
the junction was made and the size of the junction.
How it was made ... It could be as simple as two of the wires (Constantine
and Copper, or Iron) being twisted together ... Or they could have been brazed
... Or they could have been twisted and then silver soldered. All these
methods I have used and there is no difference that could be detected. Well,
twisted ... That does require a bit more contact area then the braze type.
What does effect the reading is the quality of the circuit they are hooked
to. They are usually connected and BALANCED via a Whetstone Bridge. This
compensates for the length of wire and the current drop along the way.
Now, if there is a difference between readings it is NOT the probe it is the
circuit.
The only time (in our use) that there is a probe problem is if there is a
difference between probes going to the same gage (circuit). Then I would look
at
ALL connections and junctions, whoops, can't do that in our sealed probes.
But! Hey did you read the install notes? They request:
Short runs
Straight runs, and
Keep away from other electric generating devices (Mags & Alternators).
As for calibration, that is fairly simple. There are two standards that can
be reproduced quite easily, Heat and Cold. Boiling and Freezing. Now, I know
here I'm repeating what you already know. Waters Boils at 212 Deg F (100 Deg
C) at sea level on a SAD (Standard Atmospheric Day). And water freezes at 32
Deg F (0 Deg C). The freezing part is just a bit tricky, you will need a pan
to hold two ice trays of ice and enough water to cover the ice.
Start by putting in one tray of ice. Add water to cover the ice. Stir, for
1 minute, then add the second tray of ice and cove with water and stir again
for 1 minute. Now, put your laboratory mercury thermometer in the mixture ...
32 Deg F! What! Not 32 Deg F? Add a teaspoon of salt and stir.
Now, here is another trick, I tried it and the ONLY thing I could see was the
time to react. Before installing the probes in the cylinders, squirt is some
Heat Sink Compound (available at any good electronic store). This increase
the RATE of heat transfer ... NOT the amount of heat. That is because the
probe is in a seal area and the dead space in that area will transfer the heat,
just slower than if it was encapsulated in heat sink compound. I did my test on
the stove top and in the freezer, using an aluminum cigar tube.
Barry
"Chop'd Liver"
Message 2
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| Subject: | 28747 with a Powerflow |
--> TeamGrumman-List message posted by: "bhauskne@san.rr.com" <bhauskne@san.rr.com>
Gary,
Great report, thanks. Looking forward to seeing the new installation at
AYA Convention.
Any particular challenges with the installation of the new Powerflow
configuration (how's the fit?). I realize you have the Au-cowl installed,
so how many hours do you think an installation would require for a 70s
Tiger?
What prop were you running with the performance numbers below?
Cheers!
--Brian
Tiger N28289
=======================
Gary speaks.......
I decided to go with the Powerflow. The
new shorter powerflow.
First flight today. I got about an additional 100 rpm at 12,500 feet.
Some is due to reduced drag.
1) climb at 7000 feet at 110 knots and 2590 rpm was 800 fpm
2) climb at 9000 feet at 102 knots and 2560 rpm was 600 fpm
3) climb at 10000 through 11500 feet at 102 knots and 2570 rpm was 5500 fpm
4) climb at 12500 feet at 100 knots and 2550 rpm was 350-400 fpm
5) climb at 13500 feet at 100 knots and 2600 rpm was 350 fpm
6) at 14,500 ft and flat out at 2680 rpm I was indicating 114 knots. OAT
was 36F
7) at 13,500 ft and flat out at 2730 rpm I was indicating 120 knots. OAT
was 41F
8) at 7500 ft and flat out at classified rpm I was indicating 133 knots.
OAT was 60F
Overall, I was pleased with the Powerflow.
Gary
Message 3
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| Subject: | Need someone to do drawings of the cowling |
--> TeamGrumman-List message posted by: "Phil" <Phil@ReliantAir.com>
Gary, did you find someone to do your cowling drawings? If not I might be
willing to take a stab at it. I have Turbo Cad and some previous experience
as a draftsman a long time ago.
Let me know
Phil Kelsey
Reliant Air
1979 Grumman Tiger
-----Original Message-----
From: owner-teamgrumman-list-server@matronics.com
[mailto:owner-teamgrumman-list-server@matronics.com] On Behalf Of
TeamGrumman@aol.com
Subject: TeamGrumman-List: Need someone to do drawings of the cowling
--> TeamGrumman-List message posted by: TeamGrumman@aol.com
One of the requirements of the STC process, is drawings of the cowling.
Some professional drafting like prints would be great.
Any ideas?
Gary
Message 4
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| Subject: | Re: 28747 with a Powerflow |
--> TeamGrumman-List message posted by: TeamGrumman@aol.com
In a message dated 6/27/05 7:38:20 AM, bhauskne@san.rr.com writes:
> Any particular challenges with the installation of the new Powerflow
> configuration (how's the fit?). I realize you have the Au-cowl installed,
> so how many hours do you think an installation would require for a 70s
> Tiger?
> -------- Well, for the most part, as in the original installation, the
Powerflow fits very well. Very well. If only everything fit as well.
However, the support rod is still attached to the lower right engine mount. From
this location to the muffler, the angle is very shallow. The sin of that angle,
as a result, is very small. So, there isn't much of a support, if at all.
Particularly so for the weight of the muffler. I could bend the support rod
with little effort. The muffler needs to be supported from the rear, near
the firewall/engine mount location. I changed mine somewhat from the
instructions to provide a better support because I didn't want the muffler to ever
hit
my fiberglass cowling.
>
> What prop were you running with the performance numbers below?
> Cheers!
> --Brian
> ------- It is a Sensenich prop that was overhauled a couple of months ago.
I had them blend out all of the tiny ripples in the blades. 65 inch pitch.
Message 5
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| Subject: | Re: Need someone to do drawings of the cowling |
--> TeamGrumman-List message posted by: TeamGrumman@aol.com
In a message dated 6/27/05 8:24:42 AM, Phil@ReliantAir.com writes:
>
> Gary, did you find someone to do your cowling drawings?=A0 If not I might=20be
> willing to take a stab at it.=A0 I have Turbo Cad and some previous experience
> as a draftsman a long time ago.
> Let me know
>
> Phil Kelsey
> Reliant Air
> 1979 Grumman Tiger
>
Well, maybe. I'm waiting to hear from a possible source. If it doesn't
work out, I'll try again. Thanks for the offer.
Can you make engineering drawings that the FAA will accept?
Gary
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