GRT Mini

[flightlogic]

Erik. Good coincidence. It is a really nicely engineered, bright screen EFIS.
I remember half way through production run of G396, they got way brighter. Display technology has advanced so much. You are never going to miss the old pump!!!

[lrgabriel]

Rev A para 2.3 (p14) says it's desirable to have the Mini powered off during engine start in order to increase the life of the backlight.

Does including a backup battery help at all with this?

Edit: along the installation lines, what is the footprint of the external GPS antenna?

Thanks for your time!

[Canadian_JOY]

Irgabriel - a few words of explanation... In that paragraph you cited you'll see a reference to the backlight being a CCFL, or a Cold Cathode Flourescent backlight. These backlights have a lifespan which is dependent on the number of start-up cycles they receive. As such it is advisable to not subject them to multiple turn-on cycles associated with starting the engine (imagine you don't get the engine started the first time, so you crank again... and maybe a third or fourth time... that really adds start-up cycles on the backlight).

Installing a backup battery which provides power during an engine start "brown out" condition is a good idea so you can keep your EFIS and engine monitor alive during engine start.

With respect to the Mini, I'm not sure that it is still using a CCFL backlight and may have migrated to LED backlighting (the wording in the installation manual may be a direct cut and paste from the HS/HX manual). If the Mini is using LED backlighting then you are less likely to see a reduction in backlight lifespan as a result of power cycling during engine starts. Irrespective of this consideration, having the EFIS and engine monitor powered by a backup battery will allow you to monitor the engine more closely and will allow your EFIS to align more quickly.

In our installation the Horizon HS EFIS has one of its power inputs tied to the main buss and one tied to the essential buss - whichever bus has the higher voltage is the one which powers the HS. The Mini is powered directly from the essential buss. The essential buss is powered by its own battery and that battery is charged from the main buss through an isolation diode. This architecture provides a simple means of achieving brown-out protection and redundant power sources for the EFIS devices.

The footprint of the GPS antenna is quite small, about 1.5" x 1.5". It's surprisingly heavy for its size!

[lrgabriel]

I'm predominantly wondering if the caution against having the Mini powered during engine start is related to 1. Overall low voltage on the bus, or 2. Unstable voltage on the bus.

CCFL backlights use intricate inverter/voltage regulation schemes, and I didn't know if the caution was related to low voltage--easily cured by using GRT's backup battery--or if it was related to noise, which isn't so easy to isolate.

I have two completely independent electrical systems. The only time they're anywhere near each other is when the starter contacts close and connect both batteries to the starter. As a result, I'm hoping the Mini's backup battery will solve its sensitivity to engine starts--I don't have a bus that's isolated from them, and I don't want to add a switch for a single device.

Thanks for the note about the GPS antenna--I have exactly a 2" square I was hoping it would fit in.

[n38139]

I just installed my Mini X. I have the autopilot function as well. It was purchased as a back up for my Sport SX in the event of an inflight failure. It has a great screen, is easy to read and works the autopilot servos as described. It is actually brighter than my Sport SX. I had an issue with the autopilot function but it was my on fault with my source selector switch.

I am very pleased and everyone that has seen it loves it. I do have a back up battery that I wired thru a Diode that provides 12v at all times during a start or emergency operation.

Thanks to Ben at GRT for all the technical support, I've called him enough he knows my number

[KatieB]

Originally Posted by Vag277

Katie

Does the Mini B come with a nav (GPS) data base that covers Australia?

Kim

For airports, navaids, and man-made obstacles: The only free nav database we are able to provide is the U.S. database. All other locations will need a Jeppesen subscription database, downloadable here. Note that the Jepp page says HX/SX but the Mini uses the same data package.

If you already have a GRT EFIS screen with a Jepp subscription, you can load the single subscription database into each GRT EFIS in the plane. So if you add a Mini to your GRT system, it won't cost you more subscription fees.

For Synthetic Vision (Mini-X, Mini-AP): If you specify at the time of purchase that it's going to fly in a different part of the world than North America, we'll load the SV terrain data for your continent here at GRT before it ships. That does not cost anything extra, but it is too much data to host on our website, so we need to load it here.

About the backlight-- Great questions. I'll ask the engineers for some more detailed info.

[Vag277]

Katie

Thanks

Kim

[KatieB]

Hi All,

We've just published the first revision to the Mini software. Minis recently shipped will likely have all 3 updated, but check yours to make sure.
Check your software versions by observing the boot-up screen (before pressing ACCEPT on startup.) All 3 software versions and the navigation database date will be displayed on that screen.

The Mini is unique to other GRT EFIS systems in that one software package applies to all Mini models. Your unit will automatically detect and load the portion of the software package that it requires.

AHRS software is loaded differently than the regular GRT EFIS in that it is a single-step process. (Set Menu > AHRS Maintenance > Load AHRS Software).

Air Data (Pitot Block) software is probably going to be a rare update, but you might see some changes to this early on as Minis gain more fleet hours. Ensure you have Version 3.

Complete instructions for updating your Mini (all models) can be found in the Appendix of the Mini-B Installation, Setup and User Manual.

Also, there's a new Navigation database update available as well. Make it an update party!

[KatieB]

Originally Posted by lrgabriel

I have two completely independent electrical systems. The only time they're anywhere near each other is when the starter contacts close and connect both batteries to the starter. As a result, I'm hoping the Mini's backup battery will solve its sensitivity to engine starts--I don't have a bus that's isolated from them, and I don't want to add a switch for a single device.

The CCFL backlight does not apply to the Mini-- it's all LED. So, that sentence of the manual will be revised. Todd said the Mini is built to take voltage spikes related to engine start, but it's best practice to keep it separated from the starter circuit. (Why stress it if you don't have to, is the thinking here.) A backup battery will protect it against voltage drops which can cause it to reboot during engine start.

[KatieB]

Originally Posted by n38139

I just installed my Mini X. I have the autopilot function as well. It was purchased as a back up for my Sport SX in the event of an inflight failure. It has a great screen, is easy to read and works the autopilot servos as described. It is actually brighter than my Sport SX. I had an issue with the autopilot function but it was my on fault with my source selector switch.

I am very pleased and everyone that has seen it loves it. I do have a back up battery that I wired thru a Diode that provides 12v at all times during a start or emergency operation.

Thanks to Ben at GRT for all the technical support, I've called him enough he knows my number

Steve-- thanks for the review. Glad you like it!!