Dad Putz dropped by over Thanksgiving and volunteered (heh heh) to help with the elevator skins. Once we got those done and the first couple of ribs in each pilot-drilled, however, I decided to go ahead and and put together the horizontal stabilizer before completing the elevator assembly so that we could float the elevators in there more accurately. Chris Jolin came over on a Sunday afternoon to help do some finishing work on the horizontal stabilizer spars (thanks, Chris!), and Brennan and Coryn both pitched in with drilling, clecoing, and deburring as usual.
These are various photos of the flaps coming together in the fall of 2012 – the first work done on the plane. The kids’ cousin Jarrod was at our house either on the way to or coming from camp with Brennan (I can’t remember – that’s what I get for posting these so late!), and it was great to have him helping out.
In Chapter 3, the Cozy plans have you do three little “practice” projects that gradually help you dial in the various techniques you’ll need to successfully complete the airframe.
The first layup is just six layers of BID (bi-directional fiberglass) laid up flat on the bench, with some sort of release agent underneath – I used wax paper. You make the thing oversize, and then cut it to a more precise size (about 10″ by 16″ if I remember – I don’t have the plans in front of me). Then you let it cure, and weigh it, aiming for no dry fibers and between 10.5 and 12.5 oz’s. The plans say 11 is perfect, and 10.5 is the lightest you can safely go. Mine ended up at about 10.75, so I’m feeling fine and dandy about that. And my epoxy passed the “scratch test,” so all’s well there.
The second layup is meant to give you confidence that these foam/fiberglass sandwich pieces are really as strong as they need to be to stand up to the loads that they’ll be subjected to while flying. To do this one, you take a piece of foam and shape it into, essentially, a thick ruler, with tapered sizes and ends. (The plans aren’t clear, but I went ahead and used urethane foam, which I don’t think is typically used for anything structural in the Cozy, but what the hey. It’s practice.) Then you lay up four layers of fiberglass, alternating UND (unidirectional fiberglass) and BID on the table, then slurry the foam and press it into the middle, then four more layers, and let it cure. Once that’s done, you try to destroy it but putting a wood dowel underneath and putting all of your weight on the ends. Yep, my 200 pounds couldn’t break it. I was eventually able to get it to start to de-laminate by working it on both sides, but that took some doing and a LOT of weight. There were several places where I had a hard time getting out air bubbles, and those spots proved to be the weakest spots. Go figure. There will be no air bubbles on this plane if I can help it – period.
By the way, I’m not knife-trimming any glass on this project if I can help it. I used the Fein Multimaster on all three of these to cut the fully-cured glass, and it worked like a charm. Very little follow-up sanding to do, and that was only for aesthetic purposes. The edges were always nice and smooth.
The third layup (really it’s the third, fourth, and fifth layup) ends up becoming a bookend, by the most circuitous route possible, in order to allow you to practice all of the major techniques you’ll need to build your airframe: UND layup, BID layup, dry micro inside corner, flox corner, etc. AND you get to mount your favorite photo. So mine isn’t beautiful, mostly because I didn’t obsess over getting everything perfect but I was able to get the various steps done satisfactorily. The only air bubbles in this thing are around the photo. I should have just made it smaller so that the glass could have adhered to itself in the corners – I don’t think micro would have helped. And the flox corner is HUGE. I love flox. Future corners will be smaller And yes, that is a photo of our family in front of FIFI, the only remaining flying B-29 in the world, at OSH this past summer. I remember us being pretty wet and tired when that was taken…
What is a Cozy Mk IV?
I’ve learned that just telling my friends that I’m building a Cozy is kind of a waste of time, since almost nobody outside the experimental aviation community has any idea what these things are. I might as well be telling them that I’m building an Illudium Q-36 Explosive Space Modulator, because they’ll still ask, “What’s that?” :-) The short answer is that it’s a 4-seat composite (foam and fiberglass) aircraft with a canard/pusher-prop configuration, and it looks like this…
At this point, the best stepping-off point for more information about the Cozy is at Marc Zeitlin’s Cozy Builders site. He’s got a good weblog of his own building progress from back when he was still building, links to tons of other good information (including many builders’ sites), and maintains a very helpful builder’s Google Group.
Why build anything?
Why not just go out and buy an airplane? That can be done. I have a private pilot’s license, and I love to fly. And, believe it or not, certified aircraft are somewhat affordable, especially if you go in with a couple of buddies. (You can regularly find C150/2′s in the 20-30k range, and they tend to maintain their value if you maintain them.) Some people could make the case for renting as well, which I won’t try to do here. However, I have several problems that simply purchasing an airplane wouldn’t solve. First, our families live all over the place. We live in the Twin Cities (MN) area, and we have family we try to see with some regularity who live in Oregon, Alberta, and North Dakota. If I were to try to purchase an aircraft that could get my wife and I to those places in less time than I could drive there, I’d be looking for something in the 150K + range, which is not going to happen. Second, being required to have an A&P do all of the work on your airplane means big bucks. Seriously big bucks. And it’s not because A&P’s are gouging people. (Well, some of them might be, but that’s not my experience.) The trouble is that when you start down the road of flying a certified aircraft, your choices regarding who can work on your plane and what parts they can use become much more limited, which means they also become much more expensive. Third (and probably most importantly), I love to learn. The whole point of experimental aircraft is the education of the builder, and the opportunity to not only own your aircraft, but to become intimately acquainted with it through the building process, enough to feel confident to maintain it properly. That’s incredibly attractive to me.
I’m not naive enough to assume that a project like this will always be easy, or even fun. I have a feeling, though, that it will be somewhat similar to my doctoral work, just without all of the arbitrary deadlines and stuffy advisers! (I know there are some stuffy people in aviation. Trust me – nothing close to the folks who were watching my dissertation.) Ultimately, I’ll have gained an education along with an aircraft, which just going out and making a purchase could never accomplish.
Why build a Cozy (and not something else)?
But which aircraft? There are a lot of options out there. I spent about fifteen years mulling this one over, because, well, I figured that as long as I wasn’t in a position to start building, I may as well plan for the day in case it came. One resource that was helpful to me was the book pictured here. It’s not exhaustive, but it helped me to feel my way through some relevant issues. I started out with a list of values I thought were important:
- Speed/Range: Since I’m building this airplane to travel distances, it needs to be fairly fast (at least 175 mph cruise) and possess good range (at least 600 miles).
- IFR Capable: I don’t have my IFR rating yet, but I plan to try to get it in this aircraft, and I plan to use it. If you can’t fly IFR and you live in southern Minnesota, you don’t fly much from November until April.
- Cost: I want the option of building this aircraft for a price somewhere in the range of a brand-new decked-out minivan. That means somewhere between 40K and 50K. I realize I could spend more (depending on engine, prop, avionics, IFR/night capability, etc.), but I don’t want to HAVE to spend more just to get it to its first flight.
- Two Side-By-Side Seats + Baggage: We have three children, and I knew pretty early on that trying to purchase or build an aircraft that would carry all of us plus baggage would be out of range financially. (The old adage goes, “Add a seat, double the price.”) So the mission is for my wife and I to be able to travel comfortably with our luggage. And she’s not going to want to sit in the “back.” Additional seats are a bonus.
- Possible To Finish In My Lifetime: I’d like to be able to start using this aircraft within the next decade for sure with an average of ten hours per week work-time invested.
- Good First-Time-Builder Project: I need a project that has many successful first-time buildersand since I may only ever build one of these, it needs to be a good first-time project.
- Helpful Builder Community: I’m going to need a lot of advice along the way.
- Good Safety Record: Enough said.
- Cool Factor: Not the most important thing, but if you’re going to build an airplane, you might as well think it looks awesome just sitting there.
So I started comparing those values to some of the major designs that are out there:
Velocity: Everything there but the price. The lowest-end kit you can buy from Velocity is about 33K, and that doesn’t include engine, avionics, carpet, or even an air freshener.
Sonex: It seems close at first glance, but the speed/range/IFR capability just aren’t quite there. It’s really a short-range sport plane, not a long-distance cruiser.
GP-4: I fell in love with this airplane when I first saw George Pereira’s prototype in his hanger at Rio Linda, CA when I was flying out there with a buddy of mine. (It’s for sale – 70k is a steal, I would say.) It’s a performer, and the price is right, but it’s not a good first-time-builder project, and would likely take me about 80 years to finish, based on the 4000+ hours it’s taking most builders. It’s also a bit tricky to fly. There also aren’t a lot of these things that have been completed, so the builder community is pretty limited. Someday.
Lancair Legacy: Like the GP-4, this one has the performance, and I could finish this in a much shorter amount of time, but the the cost is way too high, and the need to invest in a kit means significant outlay up front. I’ve got five years (at least) to work on this, so I don’t need all that investment sitting around my garage for years before I get it put together.
Vans RV-7: I almost went for this one. It’s got everything on my list. In the end, it was a decision between this one and the Cozy. I finally steered away from the RV’s because of the slightly higher completion price, and the need to invest up-front in the kit.
So I decided to go with the Cozy. It’s got all of the characteristics above, plus it’s a plans-built aircraft, which means that I can order materials as I can afford them. It’s built tough (no in-flight breakups to this point), it won’t stall/spin because of the canard configuration, and it’s got four seats if you need them. It’s not a true four-seater in the sense that you can’t put four people and baggage in it, but the “baggage compartment” is more versatile than it would be in an RV-7, for example. The only qualms I had about building it were because of the need to control shop temps, which isn’t important for metal aircraft. I’m now confident I can handle that. So, decision made. Alison blessed the project and bought me the plans as a gift when I finished my doctorate. Time to get going!
I’ve gotten a few questions about my shop setup, so here it is.
I’m doing this project in a space that’s about 18 feet by 26 feet – sortof. I don’t really have that much space available to me, because there are all sorts of things other than growing airplanes vying for it, such as the family van, a car, our elliptical machine, a file cabinet, bikes, etc. That little space at the end (about a third of my total space) is what I’m starting with. We’ll see how long I can stay in that area without disturbing everything else. I’ve worked hard to keep my footprint to a minimum, so it might work for a few years…
It’s cold in Minnesota for a good five months a year, and VERY cold for a couple of months (January/February), so the garage is fully insulated (walls/doors/ceiling), and I’ve got a hung electric heater in the corner that keeps things toasty. I had the same heater in my garage in North Dakota, and my dad has the same one in his way-bigger garage in North Dakota. The thing just works. Funny thing is, you can’t find these units in the big box stores. You have to go shopping at places like Farm and Home or Fleet Farm to find them. Don’t know why Home Depot or Menards don’t stock them. They’re either selling the big propane heaters (I am NOT interested in plumbing for one of those) or little electric space heaters. Anyway…
I saw that a number of builders had constructed cloth cabinets to keep their fiberglass clean and organized, so I decided to do the same thing. You can see it closed up in the photo up top, and then you can see it open in this photo. Both this cabinet and the hotbox (below) hang on pair of opposite-notched 2×4′s – one is screwed into the wall (runs the length of the wall – you can’t see it in the photo), and one is screwed into the back of the closet. So it’s easy to just take the thing down if I need to, or move it down the wall. I used leftover siding from my kids’ playhouse that went up last summer, along with some 2×2 stiffeners I made out of 2x-something I had lying around. It’s 4 feet by 4 feet by 12 inches deep, has a hinged front cover held closed with cheapo hooks, and the cover folds down onto the front part of my workbench (I haven’t had time to put legs on it yet – might not ever – we’ll see) forming a cutting table that I surfaced with some reject shower siding I managed to pay the folks at Menards very little for. You really need that, because the glass will get all messed up on the plywood, unless you have perfectly surfaced stuff, which I’m too cheap to buy, obviously Some of the folks who are building Cozies spent a ton of time and treasure creating fantastic workshops, and my hat’s off to them, but I figure I’ll be more picky about spending money on my workshop so I can spend more money on the plane. Yep. Anyway, this thing works great. I originally thought I’d need one of those self-healing mats so I could use a rotary tool to cut my glass, but now that I’m using the Dritz scissors (or whatever they’re called now), I just need something smooth that the glass won’t catch on. Swinging the front down on the table requires me to keep things clean. I may get frustrated with that eventually, but for now, all’s well.
One of the things that got drilled into my head after reading the first few chapters of the plans and watching the Rutan composite video about twenty times (I swear if I hear Burt Rutan or Mike Melvill say, “Now, this is PURE E-PO-XY” one more time I’ll throw something at the screen. Info excellent and necessary. Producer BAD. I still can’t believe that the people who made the video actually put their intro sequence on it. If you haven’t watched it, it’s just part of hazing required to do these projects correctly.) is that this whole deal is about temperature control. If your room is at the right temp, your materials are at the right temp, and your epoxy is at the right temp, it’s hard to mess up the layup. I’ve done a ton of reading on other people’s sites, and from what I can tell, you just can’t get away from temperature control. You’re either going to have to redundantly control temp for two things (space and epoxy), or you’re going to have to spin the wheel every time you get to your shop and figure out what new temperature variable got plopped into your process and make up for it with space heaters, strategically-placed plastic, hair dryers, fans, etc. I’m going at this with the theory that if my shop is right, and my epoxy is right, the layup will be in the ballpark. So I built an epoxy hotbox much the same way I built my cloth cabinet, with a baseboard thermostat hooked up to a 65-watt light bulb inside, and foam insulation all around. The thermostat is factory-set to only go to 85 degrees, but I just snipped off the guard with my handy-dandy Fein Multimaster tool (yet another indispensable find), and now we’re keeping that hotbox consistently between 92 and 98 degrees. Perfect.
My bench is a little small. (No snide comments please.) It’s about 3 feet by 6.5 feet, and it’s topped with a solid-core door that I bought from Bauer Brothers Salvage for about $20. I actually bought two, since I’ll likely need ‘em both before I’m done. (That place is amazing, in the “I should really be wearing a fireproof suit when I go inside” sense. If you know what you’re looking for, it’s like a big treasure hunt. Otherwise, it’s just, well, amazing, like I said…) I figure I’ll need more length as the project progresses, but for right now this is perfect. It’s got a shelf underneath, so I don’t really have dust protection under there, but I do have plenty of space for hardware/tools/etc. I used 4×4′s that used to hold up a fence that went around our property when we moved in a few years back, so my el-cheapo North Dakota roots are showing through there as well. I wired it for electricity, which has turned out to be seriously handy. I would do that again, for sure. No more extension cords – power is always right where you need it. I just wired a male plug into the near end of the circuit, and I plug that into the wall outlet with an extension cord. Done. I can leave my stuff plugged into the table, and just unplug from the wall one time when I’m done for the day. I also took one builder’s advice (can’t remember who anymore – I’m sure it wasn’t unique) and put threaded “feet” on the bottom of the legs so I could level the table when I needed to without having to shim.