Today's Message Index:
----------------------
1. 06:49 AM - Re: Re: Instrument panel (flyv35b)
2. 07:34 AM - Re: Pannel (Richard Mutzman)
3. 11:49 AM - Re: Re: Instrument panel (teamgrumman@aol.com)
4. 11:58 AM - Re: Re: Pannel (teamgrumman@AOL.COM)
5. 07:46 PM - Re: Re: Instrument panel (teamgrumman@AOL.COM) (Lawrence Massaro)
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 |
|
| Subject: | Re: Instrument panel |
I think that Bill suggested putting the nav CDI next to the flight
instruments is probably because when using it for an ILS approach you want
to keep your scan confined to as small and area as possible. You are
constantly looking at the CDI and comparing that with the DG and AI and VSI,
so closer is better.
As far as the MP gauge is concerned it is hard to explain the value of it
unless you have flown a plane with a CS prop for awhile, which most Grumman
owners have not. It is a more precise way to set power and it reacts
instantly and is beneficial even with a fixed pitch prop. Granted, it is
not mandatory, just useful. For instance, what is your power setting and
how much did it change when you drop the nose significantly and start a
decent from altitude when you were near redline at cruise? A manifold
pressure gauge will tell you that whereas your tachometer will stay right at
2700 rpm for a maximum speed descent. It's pretty much accepted practice
that you want to maintain at least 15" MP at least so as to no unduly cool
the cylinders and not backdrive the engine. Also during climb if you choose
to make a power reduction, how far back to you pull the throttle as the rpm
doesn't react immediately or change much. Manifold pressure tells you
exactly how far to pull the throttle back - 2" hg, 3" or whatever.
And finally, if you have a modified plane such as a 2 place with a bigger
engine then the POH is of little help in determining what the power setting
is. With a MP gauge you can go to Lycoming's curves for a specific engine
and determine that, but you must know MP. Make up a little chart of MP vs.
RPM vs. fuel flow and % power. I have a Lynx with an O-320 engine and a MP
gauge and I use it all the time to adjust power. The tachometer just
follows along and ends up wherever and is mainly used to prevent excessive
RPM.
Cliff
----- Original Message -----
From: "cwleach" <corl@aya.org>
Sent: Saturday, February 20, 2010 6:26 PM
Subject: TeamGrumman-List: Re: Instrument panel
>
> [quote="flyv35b(at)minetfiber.com"]Nice looking panel! The only thing I
> would add would be a manifold pressure gauge to the right of the tach,
> and swap the JPI and nav head as Bill suggested.
>
>
> I put the Nav head next to the ... NAV RADIO! What a concept, huh! :-)
>
> "In the clouds" I have GPS 1 showing the CDI and numerical ground track
> and desired track information while GPS 2 shows the moving map display. In
> this way I can simply match the #1 displayed Actual Track with Desired
> Track numbers, check the deviation from Course on the adjacent CDI, then
> adjust heading 1 or 2 degrees to change the actual track to correct any
> error. I've found the "digital approach procedure" to be far more accurate
> than chasing needles anyway. YMMV.
>
> I only purchased 1 Nav head because eventually an HSI (Aspen?) will
> replace the DG leaving the CDI for Nav 2. Why buy two when you'll be
> replacing one soon-ish? My airplane seems to be getting heavy despite
> leaving stuff out!
>
> ... just curious what true benefit a manifold pressure gauge would serve
> other than to give Gary a little more $$ for installation costs?
>
>
> Read this topic online here:
>
> http://forums.matronics.com/viewtopic.php?p=287430#287430
>
>
>
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 |
|
Gary=2C
Nice pannel in the Cheetah. I had your overlay powder coated in almost the
same color and texture. Looks good with the new glareshield I also instal
led.
How much do you charge for the drilled yokes?
Richard Mutzman
N399RM
Dayton=2C OH (Home of AYA 2010)
_________________________________________________________________
Hotmail: Trusted email with powerful SPAM protection.
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: Instrument panel |
A couple of things.
I think that Bill suggested putting the nav CDI next to the flight instrum
ents is probably because when using it for an ILS approach you (he, SIC)
want to keep your (his) scan confined to as small and area as possible.
You (he) are (is) constantly looking at the CDI and comparing that with
the DG and AI and VSI, so closer is better.
CDI Location: The factory put the VOR indicators next to the avionics sta
ck. I wonder if they new about scan techniques. But, then, I asked that
same question when I bought my first plane 26 years ago. The first thing
I did was to exchange the ADF/tach and VOR indicators. I liked it closer
to my center-of-interest. Personally, I'd like to have a GMX 200 in the
middle of my scan. The Horizon gyro and the DG (or HSI) side-by-side abo
ve it.
It's pretty much accepted practice that you want to maintain at least 15"
MP at least so as to no unduly cool the cylinders and not backdrive the
engine.
15" MAP: This is interesting. I've been flying for 30 years. I've never
heard that the manifold pressure should be above 15 inches for a fixed pi
tch prop.
To unduly cool: This assumes that there is such a thing as shock cooling.
I don't buy the myth of shock cooling. Shock heating maybe, but not sho
ck cooling. There is just too much empirical evidence against the myth.
As far as the MP gauge is concerned it is hard to explain the value of it
unless you have flown a plane with a CS prop for awhile, which most Grumm
an owners have not. It is a more precise way to set power and it reacts in
stantly and is beneficial even with a fixed pitch prop.
More precise way to set power (using MAP): I don't buy this either. This
may be true in a plane with a constant speed prop, but not for a fixed pi
tch. If you use MAP to set power, it's only because the EI tach has 10 rp
m resolution. Then, of course a small change in MAP will show up faster
than rpm. A digital Horizon tach is a lot more useful than just being th
ere to tell me if I go over redline. I can fine tune less than 5 rpm with
out a vernier. All of my power charts, in the Grumman handbook, are based
on altitude and rpm. There is no mention of manifold pressure.
Interesting side note: During the Climb-Cooling and carb-heat-rise flight
tests for the Jaguar cowling, the FAA kept asking what the manifold press
ure was for a given flight test. It took six months for them to read, abs
orb and accept the fact that the POH only had altitude and rpm. When I ex
trapolated between altitudes and rpms I had to explain to them just what
the process was that allowed me to find a point not in the chart. Seriou
sly, they did not understand extrapolation.
For instance, what is your power setting and how much did it change when
you drop the nose significantly and start a decent from altitude when you
were near redline at cruise? A manifold pressure gauge will tell you that
whereas your tachometer will stay right at 2700 rpm for a maximum speed
descent.
Power setting: Question: why do I care what power setting I use during a
descent? If I were at 80% in cruise do I care if I'm at 78% (or even 60%
) during a descent? Some pilots might. I don't. Again, with a constant
speed prop, I might. I don't know.
I have a JPI 800 in my Tiger. It displays percent power all the time with
out the need to look up anything. Do I use the percent power feature? No
t really. I do look at it and think about it while leaning above 75% powe
r. I watch CHTs the most. And, that means, keeping the CHTs under 470 de
grees. I know there are those of you who will think that is insane. The
EI I used for a year told me that 470 on my JPI was about 390 to 400 on
the EI. We'll see when I pull the cylinders.
The only real use of percent power, aside from leaning, is for computing
fuel burn. In the old days, it was really important to know fuel burn be
cause fuel gauges were so inaccurate (imagine inaccurate fuel gauges being
accepted procedure in automobiles). With fuel flow displaying current fu
el burn, fuel used, and fuel remaining, there is seldom doubt what is in
the tanks.
The dozen or so times I flew N254 (after I installed the first MT constant
speed prop on a Grumman in the United States; sorry, had to throw that in
) I still flew it at redline during a descent. I still climbed at WOT and
as near to 2700 rpm as I could. Perhaps over a long time of flying it,
I might rely on MAP.
And finally, if you have a modified plane such as a 2 place with a bigger
engine then the POH is of little help in determining what the power setti
ng is. With a MP gauge you can go to Lycoming's curves for a specific engi
ne and determine that, but you must know MP. Make up a little chart of MP
vs. RPM vs. fuel flow and % power. I have a Lynx with an O-320 engine and
a MP gauge and I use it all the time to adjust power. The tachometer just
follows along and ends up wherever and is mainly used to prevent excessiv
e RPM.
No POH for an O320 in an AA1x: OK Bill, tell us, what do you do for perce
nt power in your O320 powered 2-seater? If you had a JPI 800, it would di
splay percent power for you. In fact, if you let my put in a JPI 830, you
will have, at all times, in one unit:
RPM, Manifold Pressure, EGT/CHT, Oil Temp, Oil Pressure, OAT, Volts, Carb
Temp, % power, EGT delta, Fuel Flow, Gallons used, Gallons remaining, AND
miles per gallon. And it takes up a lot less space than you are currentl
y occupying.
The tachometer just follows along and ends up wherever and is mainly used
to prevent excessive RPM.
Question: What is excessive rpm? What is excessive CHT?
At my current rate of flying my plane, I will have 1000 hrs on my LyCon ma
ssaged cylinders in about 3 years. At that time, 7 years since installati
on, the engine will have about 2100 hours and 35 years on it. It's never
been off the plane. I plan on having LyCon do a complete tear down and
thorough inspection at that time. Why? Because most of that 1000 hours
will be at CHTs in the neighborhood of 420 to 430 degrees (on a JPI) and
at rpms in the neighborhood of 2800. My engine/prop combination has a sw
eet spot at about 2825 rpm.
Questions? Comments? Let's hear them . . . . .
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 |
|
To drill your yokes: about $30 to $50. It's all in the setup time. I hav
e a jig and for the most part, it works first time out. Drilling a long
hole sometimes causes the drill bit to wander off.
Prepping the yoke: Stripping and sand blasting the yokes takes about an
hour, $90.
Powder coating: This can be a little as $65 for both or as much as $125.
It depends on how much of a hurry you want them and whether the powder
coater has to stop and clean the gun for your special color.
Wiring: The switches run about $10 each ($20 total) and the installation
takes about an hour ($90) including the wiring and drilling the shafts an
d the back of the yoke.
So, all together, with your yokes, about $295 to $375. Generally, the yok
es are in the $300 to $375 range. I have some yokes that need to be strip
ped and sand blasted if you don't want to wait. I would need yours in exc
hange.
You can save me a lot of time and you a lot of money if you strip and bead
blast the yokes.
I know that sounds like a lot of money, and it is. It's just very time co
nsuming to get it right.
-----Original Message-----
From: Richard Mutzman <rcmutz@msn.com>
Sent: Sun, Feb 21, 2010 7:10 am
Subject: TeamGrumman-List: Re: Pannel
Gary,
Nice pannel in the Cheetah. I had your overlay powder coated in almost th
e same color and texture. Looks good with the new glareshield I also inst
alled.
How much do you charge for the drilled yokes?
Richard Mutzman
N399RM
Dayton, OH (Home of AYA 2010)
Hotmail: Trustedo/201469227/direct/01/' target='_new'>Sign up now.
========================
===========
========================
===========
========================
===========
========================
===========
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 |
|
Nice panel...
Speaking of the Aspen...
I installed an Aspen and one side benefit is that it allowed me to
move my GNS530/NAV/COMM stack to dead
center of the panel. The Aspen DG/HSI is used as the primary for
ILS/GPS/WAAS approaches. I put the other head
and the tach on the other side of the GPS and use that for COMM 2 as
a secondary in the event the Aspen goes TU.
The VSI was sent to the great VSI graveyard in the sky and I moved
the steam AI to that spot.
The Aspen took a while to get used to but now I cant say enough good
about it. Of course YMMV.
Lawrence Massaro
'92 AG-5B KRNM
>Subject: TeamGrumman-List: Re: Instrument panel
>From: "cwleach" <corl@aya.org>
>
>
>Nice looking panel! The only thing I would
>add would be a manifold pressure gauge to the right of the tach,
and swap the
>JPI and nav head as Bill suggested.
>
>
>I put the Nav head next to the ... NAV RADIO! What a concept, huh! :-)
>
>"In the clouds" I have GPS 1 showing the CDI and numerical ground
track and desired
>track information while GPS 2 shows the moving map display. In this way I
>can simply match the #1 displayed Actual Track with Desired Track
numbers, check
>the deviation from Course on the adjacent CDI, then adjust heading 1 or 2
>degrees to change the actual track to correct any error. I've found
the "digital
>approach procedure" to be far more accurate than chasing needles
anyway. YMMV.
>
>I only purchased 1 Nav head because eventually an HSI (Aspen?) will
replace the
>DG leaving the CDI for Nav 2. Why buy two when you'll be replacing
one soon-ish?
>My airplane seems to be getting heavy despite leaving stuff out!
>
>... just curious what true benefit a manifold pressure gauge would
serve other
>than to give Gary a little more $$ for installation costs?
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! --
|