Garmin GNC 355 replacing SL-40 and connecting to Skyview classic in a ULS

[cgc]

Hi everyone!

First time post. Just recently got my new to me 2013 RV12 ULS (so excited!).

I've been search through the treads to see if anyone has first hand experience installing a Garmin GNC 355 in an RV12 with a Skyview classic and SL-40 radio (radio to be replace by the 355) but haven't really found any. I'm wondering if anyone would be willing to share their experience with connecting the Arinc 429 and Flightcom 403 to the GNC 355 and if there were other issues encountered like power, heat or space in the tray?

Any help or input would be very much appreciated. Thanks JT

 

[penguin]

The SL-40 interface is a serial interface using an RS232 format, receive, transmit and ground. The data transmitted is frequency info. The GNC 355 will provide much more data so limiting yourself to the SL40 interface will mean you don't use a chunk of functionality.

To just use the same interface as the SL-40 (see page C8 of install manual and page A3) connect to one of the RS232 ports and configure it (on the GNC 355) as Aviation output1, for example J3551 pin 9 (RS232 out 1), pin 31 (RS232 in 1) and pin 52 (RS232 gnd 1). There are 3 RS232 streams, doesn't matter which you use as long as it is configured correctly in the setup menu. The relevant SL40 pins are pin 3 transmit (ie out), pin 10 receive, pin 11 serial ground.

To use the other functionality available - such as the GPS route info - will need more understanding of the Skyview interfaces than I have.

Flight com - just read the install manual for audio in and out & PTT.
ARINC, connect out from 355 to in on the receiver, there are 2 ARINC 429 streams, same caution as 232.

Just get out from one box going to in on the other box and vice-versa.

 

[Jetguy]

Do you have a pic of your panel you could upload so all can see your panel for better evaluation?
The GNC 355 seems over kill for the RV12.

 

[cgc]

Thank you both for the reply! I've attached the images I've got in my phone. Sorry I don't have one image of the whole set up.

I guess my logic for going with the 355 instead of maybe adding a 175 was simplicity. I figured having just the single unit would draw less power, reuse the power feed from the SL40 and leave more space in the panel for me to add the Dynon autopilot and baro control knobs above. I also have noticed the SL40 glitch a few times and was thinking it might be on it's way to a repair soon. My goal in the expansion is to have a basic IFR trainer with RNAV capability. Also, thank you for the clarity on the pin alignments.

Appreciate the help! JT

 

[Jetguy]

The first problem that I see is the depth of the 355, which is 11.23 inches or 285 MM. I'm not near my 12 so I can't measure it. Just measure yours from the front of the panel to the seam of the cowl for a rough estimate. But I bet its to deep. What you need is an IFR rated navigator that will interface with the Skyview. The 175 depth is 6.58 inches. Just keep the sl40 and when it dies replace it with a GTR 200 which is compatible with the 175 for freq exchange. Width and height is the same as the SL40. And width of the 175 is also the same as the SL40. Height of both would be approx 2.02 + 1.35 = 3.37 inches. You may have enough room above for the horizontal AP Panel.

 

[Jetguy]

Oh one other thing, the GTR200 has a great intercom built into it which is far superior to the 403. For a little more money you can get bluetooth capability for the 200 for connecting you phone for music. You can remove the 403 and toss it.

 

[cgc]

Excellent point on the depth. Didn’t check that one. You’re probably right about the 175. Seems like it’s the more common approach.

Where do you tap in for power using a 175? Seems like a lot of the RV12 system components are self contained and don’t offer much flexibility.

Really appreciate the help. JT

 

[12vaitor]

Hi everyone!

First time post. Just recently got my new to me 2013 RV12 ULS (so excited!).

I've been search through the treads to see if anyone has first hand experience installing a Garmin GNC 355 in an RV12 with a Skyview classic and SL-40 radio (radio to be replace by the 355) but haven't really found any. I'm wondering if anyone would be willing to share their experience with connecting the Arinc 429 and Flightcom 403 to the GNC 355 and if there were other issues encountered like power, heat or space in the tray?

Any help or input would be very much appreciated. Thanks JT

You should better define the capabilities you are looking for in a "basic" IFR trainer. Do you want a NAV capability (ILS &VOR) in addition to GPS? Something like an Avidyne IFD440 might be a better approach for a certified navigator with Comm, Nav, and GPS capability. I managed to install an Avidyne IFD540 in my RV-12 panel, its a tight fit at 11" long with about 1/2" of firewall clearance. I have a Dynon ARINC-429 interface that connects the 540 to the SV network along with a GPS serial interface to get full performance for coupled AP approaches. Most of the power demand is the radio transmitting, so you should see mostly a wash vs the SL40 power demand on transmit.

If you go with a NAV capability that also means adding a VOR/LOC antenna (Van's RV-12 kit assembly instructions show how to add one). Also plan on adding another GPS antenna for whatever unit you select.

John Salak
RV-12 N896HS

 

[bbaggerman]

The first problem that I see is the depth of the 355, which is 11.23 inches or 285 MM. I'm not near my 12 so I can't measure it. Just measure yours from the front of the panel to the seam of the cowl for a rough estimate. But I bet its to deep. What you need is an IFR rated navigator that will interface with the Skyview. The 175 depth is 6.58 inches. Just keep the sl40 and when it dies replace it with a GTR 200 which is compatible with the 175 for freq exchange. Width and height is the same as the SL40. And width of the 175 is also the same as the SL40. Height of both would be approx 2.02 + 1.35 = 3.37 inches. You may have enough room above for the horizontal AP Panel.

I ran into the same depth issue when I looked at replacing my Garmin (Apollo) SL40 with a Garmin 355. I would be sweet if it would go but I think the 355 is a little bit longer than the SL40. And the SL40 is already up against the firewall. So it will be a GPS 175 for me.

My other complicating issue is that I already had the Dynon panels for autopilot and knobs. I have no room to go up for the taller GPS 175. So I went with the remote mounted Dynon radio. I made a new upper panel that now holds all three Dynon panels and gets rid of the SL40. My next step will be to replace the fuses and switches with the VP-X Sport electronics circuit breakers, thus liberating more panel space. It integrates nicely with the Dynon. Lastly in will go the GPS 175.

 

[cgc]

Hey there,

Thanks for the additional information. I'd love to add VOR/ILS but I don't think the Avidyne is in my budget.

I spoke with someone at Steinair today and they're able to make up all of the necessary wiring harnesses needed. The only thing they were unable to help with is the power source. There's a few options but It's not really clear to me what is the easiest/safest/correct choice. It seems like there might be enough spare capacity tapping into the same power source as the SL40 or he suggested going directly back to the battery and adding a breaker and switch. The other thing I thought of was pulling out the cigarette lighter between the seats and maybe rewiring that feed to the 175 plus a new usb power in the panel.

@bbaggerman Did you have any ideas about where you were going to pull power from?

Thanks for the help!
JT