---------------------------------------------------------- TeamGrumman-List Digest Archive --- Total Messages Posted Sun 02/21/10: 5 ---------------------------------------------------------- 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 _____________________________________ Time: 06:49:17 AM PST US From: "flyv35b" Subject: Re: TeamGrumman-List: 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" 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 _____________________________________ Time: 07:34:57 AM PST US From: Richard Mutzman Subject: TeamGrumman-List: Re: Pannel 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 _____________________________________ Time: 11:49:53 AM PST US Subject: Re: TeamGrumman-List: Re: Instrument panel From: teamgrumman@aol.com 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 _____________________________________ Time: 11:58:16 AM PST US Subject: Re: TeamGrumman-List: Re: Pannel From: teamgrumman@AOL.COM 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 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 _____________________________________ Time: 07:46:54 PM PST US From: Lawrence Massaro Subject: TeamGrumman-List: Re: Re: Instrument panel (teamgrumman@AOL.COM) 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" > > >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 ------------------------------------------------------------------------------------- Post A New Message teamgrumman-list@matronics.com UN/SUBSCRIBE http://www.matronics.com/subscription List FAQ http://www.matronics.com/FAQ/TeamGrumman-List.htm Web Forum Interface To Lists http://forums.matronics.com Matronics List Wiki http://wiki.matronics.com Full Archive Search Engine http://www.matronics.com/search 7-Day List Browse http://www.matronics.com/browse/teamgrumman-list Browse Digests http://www.matronics.com/digest/teamgrumman-list Browse Other Lists http://www.matronics.com/browse Live Online Chat! http://www.matronics.com/chat Archive Downloading http://www.matronics.com/archives Photo Share http://www.matronics.com/photoshare Other Email Lists http://www.matronics.com/emaillists Contributions http://www.matronics.com/contribution ------------------------------------------------------------------------------------- These Email List Services are sponsored solely by Matronics and through the generous Contributions of its members.