GRT Wiring Diagram

Wiring diagram - GRT Horizon 1, dual DU, GNC 300XL, GTX 327, SL 30, and DigiFlight

(click on the picture to enlarge)


Electrical System Wiring Diagram

My electrical circuit design is a mix of Bob's (AeroElectric Connection) and Van's wiring. I purchased Van's wiring kit and modified it using Bob's Z-13 and Z-30 diagrams. I downloaded the wiring diagram by Vern Little and used it as the base. The wiring diagram is in ExpressSch, a free circuit layout program. My complete electrical wiring diagram in ExpressSch is here: electrical.sch. Following are individual pages in the pdf format.

Engine Wiring (Engine.pdf)

Battery Bus (BatteryBus.pdf)

Main (main.pdf)

Lights (Lights.pdf)

Post (Posts.pdf)

GPS2 Shared with APRS tracker(GPS2.pdf)

Fuselage Wiring Route (Fuselagewiringdiagram.pdf)

Switch Layout (Switcheslayout.pdf)

Engine Performance Tables from GRT - 6/29/2007

Here are engine performance tables from GRT. Sandy sent me tables for O320, O360 and Rotax 912S. Click the title to download. I believe that the O320 table is taken from Lycoming Curve 13275 published in 1977. For new engines, Curve 13381 is better. The GRT data do not work for my O-320-D2A engine.

Note: enter engine performance table under the "Engine Limits" setup menu.




Carl Morgan's collection of different engine performance tables

GRT Engine Performance Table-, O320-D2A (EnginePerformanceTable.doc)

If you have the same setup as mine, you may download this file and load it to your GRT EFIS. It is used for EFIS to estimate the % engine horse power.

Today (3/27/2007) I came across an article on Kitplanes magazine by Dennis Douglas. He described a different engine charts from Lycoming supplementary publication, No. 2283-H dated February 28, 2000. The power chart in the newer publication is labeled "Curve 13381". The old chart I have is from the engine Operator's Manual, revised in January 1977. The curve is labeled 11260-A. According to Lycoming, Curve 13381 represents the engines manufactured today. So far I have not changed the data in my performance table. Following are old and new charts.

Sea Level and altitude Performance chart (Figure3-6, Curve 11260-A, Operator's Manual, January 1977).

Sea Level and altitude Performance chart from 4/2006 Kitplanes article (Lycoming Curve 13381, 2/28/2000)

Also in Lycoming Operator's Manual on page 3-27.

I entered the new performance data to my EFIS and there is slight difference between the new and the old reading.

Here is the procedure I used to extract data from the charts:

"Sea level data is interpreted from the left hand side lower curves (the ones with percent rated power label). First, the 75% curve stops at 2200 rpm. I interpolated it and the 2300 and 2000 rpm curve in order to get the manifold pressures for 75% and 2000, 2100, 2200 rpm. In real life operations, we don't really need them. There is also no 55% curve but has 53% curve. So I interpolated from 53% curve a 55% curve. Nothing is precise here. If you have your engine manual with you, let us find the manifold pressure at 75% power and 2200 rpm. Simply find the intersection of the 75% curve with the 2200 rpm curve, draw a vertical line down and you will find 25.8 in HG on the bottom scale. You may do the same for the rest of the table entries. Again, these are approximations.
Now let us see how to find delta HP. Since delta HP is different for different rpm setting, we have to select one rpm. I chose 2400 rpm for my delta HP calculation. First, we will use the curves on the right hand side. Let's begin with 2000 ft and 2400 rpm. Plot a dot on the 2400 rpm curve at 2000 ft. Draw a horizontal line from the dot to the HP scale at the center of the page. I have 141 hp. Notice the 26" manifold pressure curve intersect 2400 rpm on the right of the dot. So the dot is between 26" and 28". I interpret the manifold pressure to be 26.4" (roughly). Now go to the left hand side the upper curves. Draw a vertical line from 26.4" and intersect with the upper 2400 rpm curve. The, draw a horizontal line from this intersection to the Horse Power scale . I have 135 hp. Therefore, the delta HP at 2000' = 141 hp - 135 hp = 6 hp."
After reviewing the procedure again, I realized that it is easier to use the left upper set of curves (in Curve No 11260-A, there is lower curves in Curve No. 13381) to find 55% and 75% power manifold pressures. Draw a 55% power line (88 hp) and a 75% power line (120 hp) on the left curve. At intersections of percent power lines and rpm curves find corresponding manifold pressures on the bottom scale.

Leaning Using SFC on GRT EFIS - 7/12/2007

I had a few email exchanges with Greg Toman of GRT on engine performance table. In one of the emails, he shared the following information with me. It is quite interesting. I will have to try it during my next flight. I will report back of my experience with this information.
"Interestingly, I do have some confirmation that the power setting table we published for the O-320 may be quite accurate. If you select the "STATS" version of the engine page, you will note a field that is called "SFC". This is specific fuel consumption. It reports the number of pounds of fuel required by the engine to produce 1 hp for an hour. It is a measure of engine efficiency. This calculation is based on both the % power, and the fuel flow calc. Interestingly, I can carefully lean to about 0.39 SFC. This is exactly what is to be expected for the Lycoming engine operated as efficiently as it can be, with magneto ignition.
I will be writing up more about SFC, but I found it very useful for verifying I had leaned to max economy. I carefully lean my engine until right at peak EGT (for the first cylinder to peak), which is just rich of the point where roughness occurs. I usually note a SFC of 0.39-0.40...very good. (I usually cruise at 8500-10,500 feet, at 50-65% power.) I monitor the SFC, and sometimes (usually due to a change in altitude or OAT), I see it increase to 0.41-0.42. This means I need to lean again, an sure enough, I can almost always bring it back to 0.39. Its also interesting that I get roughness at about 0.41-0.42 SFC at 75% power. " Greg T.
After posting the summary of what Greg suggested on GRT EFIS forum, I got a few warnings. People warn that SFC is not accurately calculated and peak EGT is bad for engine. One mentioned that using the traditional lean to rough then enrich until smooth obtain about 0.39-0.41 SFC. Today (7/13/2007) when I flew back from KLOU at 9,500 ft I tried two leaning methods and observed the SFC number. Using the lean to rough then smooth method, I saw 0.40-0.42 SFC. When 50 degree LOP the SFC was 0.38-0.39. Indeed SFC is sensitive.

N103LF Pilot Handbook (N103LFPOHfinal.doc,N103LF POH in pdf)

Here is my Pilot Operations Handbook. It is for your reference only.

Panel labels (Panellabel.doc)

For panel labels I purchased Avery Ink Jet clear label (#8665) and print it on my inkjet printer. Then, I carefully cut the label only through the transparency and not the backing. The transparency between labels are removed and a clear coat paint is sprayed over the label. For switch labels that are to be placed in a row, I used Scotch tape to hold them together. Right before pressing them on the panel, the backing is peeled off. The end result can be seen on my homepage (panel views). It worked pretty well, except the color fading problem. So, this is not exactly the best solution. Well, at least the label font size is just about right.

RV-9A Takeoff and Landing Procedures (RV9alandingprocedure)

The procedures are what Mike Seager taught during transistion training.


I have the following antennas on my airplane:

  • COM1: Homemade belly bent, use TED transponder antenna base. 21.75" SS hing pin (crimped on using cable ferrule), for Garmin GNC300XL GPS/COM.

    (click on the picture to enlarge)

  • COM2: Belly bent antenna, for Garmin SL30 NAV/COM under the pilot seat.
  • Nav: Van's copper strip wing tip antenna (left wing).

    (click on the picture to enlarge)

  • Marker Beacon: Van's copper strip wing tip antenna (right wing).

    (click on the picture to enlarge)

  • Transponder: rod antenna (TED) under right gear mount.
  • ELT: whip antenna in the tail cone.
  • APRS: homemade bell bent. Using broken transponder antenna base and piano hing pin. Next to left main gear mount. (19")
  • APRS GPS: Under left front access panel.

  • (in the photo from left to right: transponder antenna, COM1 antenna, COM2 antenna, and APRS antenna)

Today I compared the belly bent and the copper strip antenna by tuning into KPMH AWOS (125.175) at 5,500 ft. At 47 nm COM2 received the AWOS continuously and clearly. At 43 nm COM1 did so. The $6 windshield antenna did not do that badly. After two years of survice I finally replaced the windshield antenna. My wife complained too many times about the ugly copper strip on the windshield. So far I have no problem with my Nav and Marker beacon receptions.

Update (2012): After ground controller at IND and RDU could not hear my transmission I decided to add the windshield antenna back. I simply use a copper foil strip and glue it to the windshield. It works fine.

Weight and Balance

Here is a weight and balance spread sheet. You can enter wheel weights (put the airplane on the scales and read the weight under each wheel) and find CG in Section 1. After you have the wheel weights you can find CG under different loading in Section 2. Under Section 3 you can find nose wheel loading under the load. Section 4 is a nose wheel loading table under different CG and total weight.

Click here to download the spread sheet.