Second SkyView Display in RV-12

All,

As you can imagine, we often get asked about the SkyView installation in the RV-12. One question concerns a second display. Here is the complete answer; you can do it but you must be aware of all the factors involved.

Van's Aircraft has determined after extensive testing that a high load demand on the Rotax electrical system relative to its limited output will, over time, lead to failures of electrical system components.

An RV-12, when equipped with the optional lighting kit, will be nearly at the full capacity of the electrical system. The addition of a second SkyView display will put the electrical system over it's electrical load limit. Van's has taken the approach to optional electrical equipment that, to avoid confusion and long term service issues (particularly with aircraft that are not owned by the original builder), all optional equipment must be altogether compatible with all other options and all the standard equipment.

The limited load capacity of the Rotax electrical system coupled with the fact that there are numerous options associated with the addition of a second display (display size, possible second ADAHRS, possible second GPS) are key reasons that Van's is not developing a second display option for a SkyView equipped RV-12.

If the aircraft does not have the optional lighting kit installed, addition of a second display will not overtax the electrical system however subsequent owners of the aircraft will likely either ignore or not be aware of this fact. The experience of Van's Aircraft is that it is better to require all optional equipment be altogether compatible with all other options and all the standard equipment.

Adding a second SkyView Display can be accomplished by purchasing a second display, either an SV-D700 or SV-D1000, from Dynon or one of their authorized Dynon dealers. As with any such change, the responsibility for ensuring the proper mechanical and electrical installation lies with the builder. Dynon publishes electrical and mechanical specifications for the SkyView displays on its Website; you will need to perform work to determine how to fit the display and how it connects to your electrical system, including performing your own power budget calculations as well as making revisions to the aircraft operating and maintenance documentation.

Note, the SV-MAP-270 GPS Navigation License you receive with your Avionics Kit from Vans allows the SkyView navigation features to function on BOTH displays installed in one airplane; an additional license is not required.

-Robert
Dynon Marketing

Thanks very much Robert. Can you tell us if the dual 10" Skyview display as offered in the Flight Design CTLS (along with AP, Garmin, etc) involves also having the optional external Rotax alternator also installed in that plane? Their website is not clear on that.

I just looked at the Flight Design site, www.flightdesignusa.com and it shows they offer dual 10" Skyviews, night lighting package including landing light, a Garmin 696 and an autopilot. I don't see anywhere where they talk about doing this with an add on alternator.

I'm not bringing this up to be argumentive and I have no reason to doubt what Vans and Dynon have to say about this but I would like to know what is different between these two. Is Flight Design including the aux alternator as part of the upgrade and just not talking about it? Or, is it just a difference in philosophy?

Just curious. Either way, for my needs, I would only put in one.

John,
The photo of the 912S on their website shows the second alternator, although that doesn't necessarily mean it's standard equipment for their installations. Anyway, one nice big screen is fine for me too. I just want to know how much it will cost, and when it will be available.

sandpiper said:

I just looked at the Flight Design site, www.flightdesignusa.com and it shows they offer dual 10" Skyviews, night lighting package including landing light, a Garmin 696 and an autopilot. I don't see anywhere where they talk about doing this with an add on alternator.

I'm not bringing this up to be argumentive and I have no reason to doubt what Vans and Dynon have to say about this but I would like to know what is different between these two. Is Flight Design including the aux alternator as part of the upgrade and just not talking about it? Or, is it just a difference in philosophy?

Just curious. Either way, for my needs, I would only put in one.

Click to expand...

Robert,

Thank you. I didn't catch that. I was looking for it being listed on an option list. Now I can sleep peacefully knowing the CTLS has an aux alternator option to carry the load of that expensive panel. It also explains why the cost of the dual Skyview is that much over the cost of the standard D100/D120 panel.

Not so fast! Here is an email from Flight Design on this issue. NO second alternator!
From: Bill Hollifield [mailto:[email protected]]
Sent: Friday, December 16, 2011 4:38 PM
To: [email protected]
Subject: CTLS Rotax Alternator
Does the CTLS with dual Dynon Skyview, and fully equipped (i.e. including autopilot, Garmin, etc), have only the standard Rotax electrical system or does it include the optional 40+amp alternator?
Thanks,
Bill Hollifield

REPLY received today:
Bill:
The LS with the SkyView does not need the optional alternator. It is well within the 80% usage or allowable capability of the standard alternator. Tom Peghiny
Tom Peghiny
President, Flight Design USA
860-963-7272
++++++
++++++
I am reconfirming that this is for the dual screen since he did not specifically say "dual."
<<<REVISION>>> Flight Design has confirmed that this is the dual-screen Skyview, which is the only option that they sell.
The package is dual SkyView, radio, mode S transponder, Garmin 696, autopilot, intercom, ELT, position lights, landing light, interior light. Shoot, the CTLS even has electric flaps.
<<<END REVISION>>>

ALSO - in these pictures, which seem to all be of the dual-screen, fully equipped CTLS, there is no optional alternator. http://flightdesignusa.com/aircraft/ctls/photos/

Opinion: Van's decisions reflect a variety of business reasons and their particular opinion regarding design limits and factors. Nothing wrong with that. This is just additional information for post-certification mods.

I intend to fly with the single screen for awhile before deciding to add the double, or a Garmin 796, or whatever - and continuing to do research on the issue.

Keep in mind Vans never said it would not work, they simply thought that tasking the alternator that heavily would be better if it were not tasked so heavily. I can certainly agree with them. Although I have penty of alternator to run two, I am still trying to decide if I even want two. Others have said that the display is easy to read from the passenger side, so maybe the space is better used for a backup ASI and maybe an altimeter.

I've said before on various threads that in my limited experience of our dual SkyView equipped RV-12, the standard alternator copes with the electrical load just fine. If it ever does become an issue, and I can't see why it should then I'll let you all know

For what it's worth, I can't see how the optional external 45A alternator is going to fit inside the CT cowling - we've got a number of Tecnams with it fitted (and I've posted the pics on another thread).

Since Jerry is having great success, I can see how it would make some RV-12 customers question the decision not to offer the option of the second screen.

My only response is... Would it be proper for Van's to offer it if they had found that there were instances where component failure in the system could occur because of the alternator output capability being exceeded?

Even if it happened to only a few of the dual screen customers, it would still not be a good thing. Who would be responsible for paying for the repairs?

If you were one of those customers, would you be satisfied with the explanation that there are other dual screen RV-12's flying without any problems, so you will have to pay for repairs (you must have done something wrong)?

It has been proven with flight testing that failures can (I am not saying they will) occur. If an RV-12 builder chooses to install the second screen after certification, there is no question who is responsible for repairs if they have component failures in their electrical system.

I didn't actually claim 'great success', I'm merely trying to provide a bit of balance and info on what we have seen - and as I have said we only have a small number of hours on the aircraft so far. No p*ss*ng contest from this side of the Pond!

I fully appreciate why Van's are being over cautious and I don't have a problem with that. Also, we are lucky in the UK not having to abide by the US rules on following the Van's build book totally when it comes to things like panel design.

Our electrical system on and behind the panel is purely ours and not using any plug and play equipment as per Van's standard design. Perhaps that is where there is a difference between the Van's setup and that seen on the CT?

If the Van's SkyView option was available at the time we wanted the avionics etc then we would have gone with it and saved a ruck of time building a bespoke system. As it wasn't (last December) we went our own way.

Jerry- your experienced-based info is REALLY appreciated. And please keep us up-to-date. And to also see the CTLS - a CERTIFIED design - with dual SV, lights, and all that other equipment (including a separate autopilot, which seems to me to likely be a higher power-consumer than the built-in functionality of the Skyview) - well, that is also very important info for those of us not flying yet that were planning on a dual Skyview! I imagine if the CTLS has electrical load problems in the field we will hear about them. A look at that panel (from the link above) is a good idea if readers have not already done so.

Hi Jerry,

Can you give us an update on how your second skyview screen is going thanks?

I had been hoping there would be a solution for this problem by now. I have the engine installed and Vans are in the process of shipping the Avionics kit.

I am not bound by the same rules that the US RV 12 builders are, however I don't to do a change that will cause a problem.

I have wondered if the second screen can run on its own power or another battery until the main battery is up to speed in the cruse?

In case some people are wondering why I want a second screen. Well there are three or four reasons, but the most important is for the backup situation. I have a new I phone and it froze while I was using it the other day. It was a few minutes before I could get it to operate again.

Cheers

Julian RV 120316

I recommend downloading the Skyview installation guide from the Dynon Website. The single screen setup includes a single backup battery good for about an hour. That dynon battery supplies the Dynon screen, the ADAHRS, the Engine module. It does NOT power the AP servos or the transponder. Also, that single battery cannot back up more than one screen - just the one it is connected to. That battery charges ONLY when the engine is running and ships power is being produced.

You can't "force" the single screen to run off of an attached dynon battery if it is receiving 12V ships power, which is the case whenever the master switch is on. . You CAN run it off the dynon battery by turning it on with the ships master switch off.

To add a 2nd screen and run it off of a second, attached dynon backup battery while the other screen is running on ships power, you would have to install a physical switch to the power lead going to the second screen. This is because the SV turns on whenever it detects 12V (like when you turn on the master.)

But then if you did that, then switched the 2nd screen over to ships power later, that 2nd dynon battery would begin charging - probably at a higher amp draw than having the 2nd screen on the entire time would have involved. I have heard that charging 2 backup dynon batteries was one of the load issues Vans was concerned about with the dual screen setup. Also that backup battery is a heavy handful. You do NOT have to have a backup battery at all.

I intend to ask something in another thread about displaying the total load on the alternator. My ammeter is only displaying the amps associated with charge or discharge to the ships battery. That is usually very low - because the ships battery only works a second or two to start the Rotax! Even less on a restart the same day. The total load is what we need to know.

Presumably you *could* wire up a throwover switch to have one Dynon backup battery and direct it to either of 2 screens. But that is NOT called out for in the Dynon materials and a consultation with them would be advised!

Okay Bill lets say why run a second backup battery for the second skyview. If we lose the planes power for some reason we still have the backup battery to the left screen. My next silly idea is why let the planes battery charge the first battery. I bet this system degrades the backup battery over time, in the same way a laptops battery does not last very long, when the laptop is run on mains power all the time. My idea is that you charge the backup battery before you fly and then have a switch to supply the backup power should it be required.

Cheers

Julian 120316

You need to read the Dynon installation and operation manuals warnings about charging issues with their backup battery. Your scenario is at odds with that. They want their system to have control of the charging.
The laptop battery issue analogy sounds like the behavior of older nicads we all started with back in the day, but isn't nearly as applicable with new battery technology.

Think about this: You are saying to have a second screen (B) for the purpose of an inflight failure of screen (A). For just that failure, you do not need a backup battery for (B). It runs off ships power as long as you want.

So lets say when you land you investigate and find that screen A is "dead" - needs to go back to the factory. OK, take off the top cover and move over screen B to the A position (15 minute job if you have the special screwdriver with you), or just hook up the backup battery to screen B and close the cover. Then you are like every other single screen RV-12.

Adding a second backup battery is apparently to address the SIMULTANEOUS failure of screen A AND ships power! Is this likely enough to worry about? Even so, you should be VFR anyway and able to land and figure out what happened even with no screen at all. You have to fix the ships power issue before you proceed anyway.

Bill

Hi Julian

With the British weather (even in summertime...), work and the RV being painted we have only got just under 20 hours on her so far.

As has been said, the Rotax starts quicker than most cars so the drain on the main battery for start is negligible.

We start the engine with only the P1 screen fired up. In fact the last bit of the pre-flight is the lights check, then climb aboard leaving the P1 screen booting up so it isn't being switched on and off all the time.

By the time you're airborne, the first few minutes show a load of 12-14 amps or so. Then by the time you're in the cruise (don't forget that in the UK 2-3000ft is normal cruise altitude) and the fuel pump and landing light are off, the load drops to 9 or 10 amps and remains there for the flight.

As far as we are concerned, the alternator load is well within its capabilites. I've said before, perhaps we'll find a problem later but then again perhaps not!

And two SV1000s really are the dogs...!