Figuring out the Panel

It seems that most of the frustration that aircraft designers have stems from the difficulty of pursuing what sometimes turn out to be mutually exclusive goals. At the very least, any design is a flying pile of trade-offs. Those of us that are building RVs (and kitplanes in general, it seems) don't have much to do with the actual design of the aircraft, which is probably fortuitous for everyone involved. However, one of the few things that the typical builder actually gets to design (as opposed to fabricate) is the panel of the aircraft.

Because of this, it seems like it's probably a good idea to figure out what you want out of the panel before you start putting instruments into it. The ideas behind the design of any aircraft panel will vary depending on the mission profile of the airplane (this is one of the great parts of going experimental, after all), Let's figure out what conflicting ideals we're going to try to balance:

  1. A day or night VFR panel, but one with enough empty space to eventually upgrade to an IFR panel. Obviously this would be a big project if I decide to do it, but perhaps we can make it easier if we plan the panel with empty space in the right places.
  2. Some amount of "traditional" panel design. (The reasons for this will be detailed later.) Hopefully, this will have less to do with the selection of the instruments and more to do with how they are being arranged. We're going to try to come up with something that looks fairly normal (as far as traditional panels are concerned) while still using some of the whiz-bang nifty new stuff that's out there.
  3. Somehow, we've got to attempt to balance light weight and low cost with (among other things) some amount of redundancy.


As mentioned above, the main way that the panel is going to be traditional is the layout of the instruments, not the selection of the instruments. I think it's a good idea to have something that's at least somewhat close to the traditional way of laying out the standard 6 flight instruments. Here's an example of the standard layout of flight instruments in an IFR-capable RV-8. This airplane belongs to Doug Preston:

Here's the same sort of standard layout of flight instruments in Mike Seager's factory-built RV-7:

In this airplane, I particularly like the idea of a row of switches along the bottom (as opposed to on the top or on one side of the panel), and I like the darker background color.

Here's an example of a RV-9A panel that's still under construction. This airplane belongs to David Edgemon. Here's David's panel:

There are a few things David's done to this panel that I really like. Let's go ahead and list 'em and make a few observations:

  • The centerpiece is a Dynon, which is cool. This also is the first flush-mounted Dynon that I've seen in an RV. It looks much better than the ones that are not flush-mounted.
  • Because of the aforementioned Dynon, there's less of a motivation to have the traditional flight instruments where they are normally - David's still got an airspeed and altimeter in the same general vicinity, though. I think this is a real good idea (even with an EFIS), so I'll probably try to strike a balance between the traditional arrangement and leaving a few instruments out - probably the directional gyro and the turn and bank, as (a) they're both in the Dynon, and (b) we're starting with a VFR airplane. "No directional gyro" seems a bit weird, but I think if I use a vertical compass card compass instead of the traditional kind, it would be possible to use the compass as a directional gyro. Besides, you've probably got a handheld GPS with you not to mention the compass that's in the Dynon.
  • David's not using the stock Van's panel - this one is from Affordable Panels. This is great because (as you can see in the picture) it's modular. This makes it easier to work on if you want to yank just half of it out to work on. The combination of the modular panel and the tipper canopy makes the panel extremely accessible, which helps us get to our goal of being able to upgrade the panel with a minimum of fuss.
  • The fuel gauge (on the far left) that David's using is from Electronics International. These are cool because you are able to get readings for both your gas tanks on the same gauge, so you'll save a bit of space. I like this because it helps on the aforementioned goal of saving panel space. They're expensive, though, and for some reason they are cheaper in Van's Accessories Catalogue than on the EI website.
  • There's no starter key. The starter keys in aircraft don't really offer much protection against theft, so this is not quite as crazy as it sounds. The virtues of putting a starter button and switches in the aircraft instead was debated at the Aeroelectric Workshop that I went to, and it's nice to see someone else actually do it.
  • I like the extra panel area David's added to the bottom, but I'm hoping to be able to really only have to put the prop/throttle/mixture controls on it so it doesn't have to go all the way across. Although David's way looks more finished, I'm worried I'd bump my knees on the lower panel getting in and out of his airplane.


That's all for now (20 May 04) - check back soon!


New (as of August 2004) thoughts: here's actually what this is going to look like out of the gate - it's a first draft, so be nice:

Here's the key:

  1. Airspeed
  2. Dynon EFIS
  3. Altimeter
  4. Dynon Engine Monitor (isn't out yet, but it should be by the end of the year, which is earlier than we're going to need it.)
  5. Blank (for now - autopilot later?)
  6. Blank (clock, maybe?)
  7. Vertical Speed
  8. VOR/Glideslope
The two smaller spaces on the far left are going to be a compass, probably, and a something else. Probably a gas gauge, but not quite sure yet. I haven't even thought about the switches at the bottom, but I'm sure they'll be mags, lights, flaps, and all that. Obviously the transponder, radio, and (eventually) a panel-mounted GPS and extra radio aren't even in the picture - they'll be off to the right, exactly where you think they should be, probably.

Other thoughts: we've got a potentially blank spot, so it might not be a bad idea to add another VOR. It would make the most sense from a design perspective to put this close to the radio whose information it represents, but if we put it in spot (4) then we have to move the Dynon Engine monitor into the realm of where the standard 6-pack, is, which I don't really want to do. I'm probably not going to do this, but adding another VOR and then moving the engine monitor to right below the other Dynon would certainly make for a unique panel . . . maybe in a unique bad way, I have no idea.


That's all for now (1 Aug 04) . . . hopefully this will start to get interesting in the next few months when panel parts start showing up. Hopefully there will be a bit more planning before that happens, though.


Thoughts as of October: I'm having second thoughts about going with Dynon. One of the main cool things was going to be the ability to have a duplicate display with the engine monitor, but the engine monitor doesn't look like it's going to be coming out really very soon, and I sure don't want to be one of the first people to debug this. How much would this change if we used the EFIS Lite from Blue Mountain? Well, that wouldn't be the only change if we're not going with the Dynon Engine monitor. What about the ACS 2002? Expensive, but it's cool.

Anyway, here are the new ideas, illustrated:

And these aren't anywhere close to scale. Using these instead of the Dynons will have an impact on the layout, I'm sure. Also on my checkbook. We'll keep thinking about this, and maybe try to fly with someone with a Blue Mountain. (If you want to know more about their stuff, you can order a DVD from their website, which I've just done. It's free!)


New thoughts as of late November: a few interesting things to note. Dynon has announced a date that they are planning on releasing the engine monitor - May 2005, so that will probably be just after Sun-n-Fun. If they're able to stick to that date, that's sort of back in the list of viable options, as that'll be before we need it. Sure would be nice to see a few other people flying with them before plunking down money, though.

Also, I talked to Sam Buchanan at the last TVRVBG meeting about Dynon and Blue Mountain - Sam used to be a beta tester for Blue Mountain, and currently flies with a Dynon. He's of the opinion that the Dynon is a little farther along in the development cycle - i.e., lots of people that are flying with a BMA system are still on the development team whether they want to be or not. That's probably more true with the BMA EFIS One, though. This isn't the first time I've heard this.

I think the moral of the story is that waiting until the last possible minute to make an EFIS decision. There's a high probability that something else interesting will come out before then, anyway.


New thoughts as of December: well, yup. Looks like something else interesting is going to come out before then - Trutrak has just announced that they'll be officially introducing a new primary flight instrument at Sun-n-Fun of 2005. Here's a picture:


Looks really neat - having a backup for the Dynon would really be good to make this safe for IFR. Let's sit tight and see what the pricing ends up being on these things. Probably I'll go for the smaller one.


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