Garmin IFR Navigators

There's no doubt that pilots love Garmin's IFR navigators. Most of the airplanes in my flying club's fleet have Garmin GNS 430s or GTN 650s. They're easy to use and bullet proof.

I've seen many of the newly completed E-ABs include a GTN 650 to fulfill the IFR navigation role. On occasion, some homebuilts sport the larger GTN 750 or an Avidyne IFR navigator of competing sizes and functionality. Even some of the more cost conscience panel are using available GNS 430/530 configurations.

I've given some thought to the role an IFR navigator would play in my Sling TSi panel. From an initial configuration perspective, an IFR navigator is not needed when the plane rolls off the production floor (that is, out of my garage). Certification and flight testing would involve no IFR use, and in fact, I wouldn't fly the plane IFR until it has at least 100 hours on it, maybe more.

So, what's my problem this time?

I find it interesting that the dimensions of the GTN 650, 635, & 625 cases are identical. Their weights are published as 7.0, 6.2, and 5.4 pounds respectively, so it appears the insides are different, as would be expected. I also find it interesting that each model is 8 tenths of a pound different from the next model regardless of the additional radio technology.

I bring this up because Sling builders have written about the need to modify the subpanel in order to fit the GTN 6xx and I wonder why Garmin made them all the same size. Perhaps Garmin's intention is to allow for slide-in upgrades between the 6 series and future offerings? Perhaps it is easier from a production/cost perspective to use the exact same form factor?

Whatever the reason, the large depth dimension of nearly 12 inches can be an inconvenience for some builders whose airplane designs typically accommodate smaller, modern avionics. We don't need a GPS navigator to fly IFR, but this where approach, departure, and en route systems are trending.

Cost Estimates

A couple of weeks ago, Barry Jay from TAF USA sent me the Sling TSi kit price list. Since then, I've been working out cost estimates, build schedules, and cash flow timing to coincide with the build schedule. I think I have it all worked out now, but I'm not getting into those details here.

The estimated price with factory options and without paint, avionics, or tools is $119,227. Since I'm lucky enough to reside in the great state of California, add to the base cost another $8,942 in sales tax for a grand total of $128,169. This does not include shipping, but I live only 90 minutes away from Torrance and I have a big truck.

My truck being used as a Halloween prop

The factory options I selected include dual toe brakes (because my feetsies need two more things to do and my hand need one less), factory interior (nicest in the market), the firewall forward package, and the electricals kit. The price also includes strobe/nav/positions lights, but it doesn't include the ELT. I am not, nor will I ever, select the BRS option. I'll post more on that another time.

I figured the tools I'll need will come in under $2,000 and the paint (or wrap) that I do myself about $2,500. With avionics (and more CA sales tax), add another $10,000 to $35,000 to the overall price.

My objective is to cap avionics at $21,000. This likely eliminates an IFR navigator on the first pass, which actually puts the project in a position to lose a chunk of money at some point. For example, the Sling will require ADS-B out and that will require a compliant GPS source. In the Garmin universe, this is a GPS 20A ($845) and a GA 35 antenna ($309) and miscellaneous install components ($60). That's about $1,100 in equipment that would go away when an IFR navigator is introduced. An upfront option to consider is to buy a used one and then re-sale it.

Finally, factoring in a few miscellaneous items, an all-in cost under $160,000 would be desirable. Boy, it adds up quickly.

A New Beginning

Hello all and welcome to my experimental airplane builder's log. My name is Matt Tyler and I am a Software Engineer, private pilot, ground school instructor, and general enthusiast on just about anything. I've decided to build an airplane and this is my obligatory blog to journalize the effort.

Before getting too far into the introduction, I want to mention my lovely and extremely supportive wife, Dawn. Dawn is my rock, my muse, my encouragement, my best friend, and my biggest supporter. Together, we can do anything.

Well known Plus One Flyer fleet member

I belong to Plus One Flyers in San Diego. It's the largest flying club in the world with over 90 airplanes on four airports and more than 1,600 members. It's a great club with about 50 airplanes that I'm endorsed to fly and there's always something available when I need it. However, they are the typical Pipers and Cessnas with all the limitations we've come to expect from these platforms. Although renting periodically for short durations is far less expensive than ownership, really stretching the travel further and more often is not financially practical.

We want our own airplane, but the selection in our price range is limited. In particular, owning a type certified plane has the following drawbacks:

1. For our price range, airplanes are 30+ years old
2. Lack of modern avionics
3. Expensive to maintain
4. Slow - PA28s and C172 are typically below 130 KTAS and faster planes with retractable gear are more expensive and come with increased risk
5. Not very comfortable - Cabin width and visibility were really sacrificed in these designs

There are advantages to type certified airplanes that I may get into later. For me, it is fair to say that the disadvantages outweigh the advantages.

Why do I want to build an airplane? Building an airplane offers the opportunity to mitigate all the reasons why buying a type certified airplane are unappealing. For the price of an old, slow, outdated, costly, and uncomfortable platform, I can build a modern, fast, comfortable, and cost effective airplane entirely suited to our needs. And when the time comes it's not suited to our needs, I can modify it until it is.

I spent the past year researching kit plane manufactures in order to understand the market. I really understand the market. I was originally convinced that we only needed a Light Sport Aircraft (LSA) for what we wanted to do. That is, an airplane that carried two people and cruised at least 150 mph at altitude. They seamed relatively inexpensive (<$70k all-in) and easy to build. However, after looking at the resale value of various options, the LSA route didn't make much sense as it appeared their resale value was less than the cost to build. Further, the desired speed characteristics weren't really meeting our requirements.

Next, I turned to the standard in experimental airplanes: Van's. Still convinced that two seats were all that we needed, the RV-7, -9, and -14 were good choices. Not only did they offer neck-breaking speed and excellent fuel economy, they resold for more than the cost to build and there are massive networks of support available. I settled on the RV-14A for it's large cabin width and build ease.

Then, a few months ago, I realized that we needed an airplane either capable of carrying more than two people or capable of carrying larger items. Given our flying habits, a two seat airplane was not practical. I first turned to the RV-10, which by all rights is the most successful and capable four-seat experimental build airplane in the world. With almost 900 completed and flying builds, this is the standard. But the cost, time, and effort to build was beyond what I wanted to commit to. Choosing to build an airplane requires a dedication to all three of these components and any doubt guarantees failure. I needed an alternative.

By happenstance, I was watching a video of an interview with MGL Avionics representative Matt Liknaitzky. In the background of the video was an airplane I had never seen before called the "Sling 4". Some quick research revealed this was an EAB and the kit is manufactured out of South Africa by The Airplane Factory. Consequently, the U.S. distributor was located in Torrance, CA, just a two-hour drive, or 45-minute flight, from my house. So, I called them up.

Me at Catalina with Sling 4 N981RW

After a weather delay and a Presidential TFR, I finally got the opportunity to fly the Sling 4. I flew a Cessna 172N with a 180 hp engine up to Torrance and met with Barry Jay and Jean. We toured the factory, then Jean and I took the Sling 4 for a spin. We flew to the local practice area for maneuvers followed by lunch in Catalina. Over lunch, Jean gave me the inside scoop on the Sling 4's design concepts. A lot of engineering went into this platform in order to get the unusual performance it exhibits with just a 115 hp engine. I was impressed.

When we returned to Torrance, I was convinced this was the airplane for me. Then I learned there was a new version of the Sling 4 called the Sling TSi that used the Rotax 915 engine. The same airplane with 25 more horsepower. Where do I sign up?

Last week I received the finalized price list for the Sling TSi. It will cost about $13,000 more than the Sling 4, but it's worth the price difference. This is the plane we're going to build for reasons I may get into during a later post.

Prototype Sling TSi

I plan to begin the build in January 2019. Between now and then, I have house projects that I have promised to complete and money I need to save up. My hopes are to be completed by November of 2020 so that I may test fly the airplane on or about my 50th birthday.

Thank you for stopping by and I hope this blog will be of some help to you.