There are a number of questions regarding the how and why of this project that seem to be of obvious general interest. I'm guessing I'll update this as I get into the build process and have more discussions with folks.
DISCLAIMER: Everything you see here, and throughout this blog is my own opinion. I'm not an aerospace engineer (though in fact I am a physicist so I've got a vague idea of what's going on here ;-) ) and have no professional qualifications to urge folks in any particular path. There may be errors in what I say here, so DO NOT accept what I say as the gospel truth. I am NOT giving advice here - just chronicling my experience so that I can reflect on how stupid I was as a younger man when I get old. And hopefully provide you, the reader, with an interesting read along the way.
1.) Why fly?
This is always a personal question, and for many folks the pure enjoyment factor is sufficient justification. For me, the justification is much more pragmatic - I live far from my family with no commercial airport nearby. In particular, the options to see various family members are:
Parents: 17 hrs by car, 8 hrs by commercial airline
In-laws: 7 hrs by car, 5.3 hrs by commercial airline
Sibling / other extended family: 14 hrs by car, 7.5 hrs by commercial airline
The direction of travel for these is different for the most part. Fold in the fact that I've got kids and the travel situation isn't really conducive to making these trips particularly often.
On the other hand, I have a small airport for GA use that's about 15 minutes away, and there are airports on the other end of all these trips that are within 25 minutes of the destination. The result is that I can meet or beat the commercial flight trip time, can travel whenever I want (even on short notice!) and have the option of stopping wherever I want to take a break / let kids run around. Finally, there's lots of beautiful country to see between me and all of these destinations. Oh yeah, and I get to travel while feeling like a human (no TSA).
So even if I'm not saving much total time over a commercial flight on average, the whole travel experience is going to be better / less stressful which increases the chances that I'll actually make these trips. And if the weather is decent (no headwinds, everything goes efficiently) with the plane I want to build, my total trip time for each of these trips beats the airline by almost 2 hours! This completely ignores other incidental trips that will most likely start happening as a direct result of being able to fly. The world becomes much smaller when you have your very own plane.
2.) Why build?
Because I want to. Seriously, that's the most relevant factor - and I think that a successful build is largely dependent on that attitude. It takes far too much time and effort to build a plane to simply do it for the shiny toy or cost-effectiveness.
Those are contributing aspects though. For example, there's the fact that the plane I want isn't available as a certified plane. The closest certed plane to what I want is probably a C177RG or a Mooney - both of which are old and/or very expensive. Also, my weighting of cross country efficiency vs room in the cabin is more weighted toward the cross country performance than even these planes are on average. With the build, I'll probably dump the same money into getting a brand-new plane that it would cost to buy a 30+ year old certed plane.
I also get to do all the work. At the end of the build process I know the history of
every part on this plane. I get to maintain the thing, which means I get to track the history of every component as carefully as I desire (nice for a control freak like me). I get to perform all the inspections, which I claim will be so much more effective because of how invested I am in the project. In short, by building the plane I have the opportunity to know as much as is possible about the craft that I trust to not kill me and my family when we fly it, and I have the opportunity to use this knowledge to maintain the craft as well as can be done.
Finally, it gives me a large project to do with my kids when they're old enough to care. I'm not in a hurry to get this done (I'm giving myself 10-12 years), and I think that my family can have a lot of fun with the project as a result.
3.) Why the Cozy?
Simply put: because it does long range VFR cross country better than any other aircraft in its class, and that is my main requirement. Plus, it's
sexy and
unique - just how many canards are there in the GA fleet?
The class of planes I'm considering is 2+2/4 place planes meant for long distance flight with a decent useful load. I'll list off a few planes below for comparison.
RV-10: really cool plane, but very expensive to build. Can get similar cruise speed, but the engine (and fuel burn) is larger since it's a draggier plane. It hauls 4 people and their stuff better, but in my mind that isn't enough to make up for the expense and efficiency loss.
BD-4: good numbers, but there doesn't seem to be as much of a support community as the Cozy. It was a tempting project, but in the end I fell in love with the Cozy community and that settled that.
Bearhawk: awesome payload, but slow and comparatively short-legged.
Zodiac Ch640: short legged.
Sportsman 2+2: cost/benefit ratio just isn't there for the long-distance cross country.
These all are great planes, but the freedom of the plans-built Cozy combined with its ridiculous efficiency just win in my book. I'll be able to build the plane for cash at my own pace, and when I'm done I'll have one of the most efficient 2+2 planes out there.
4.) Why mod?
Remember! Everything I say is MY OWN OPINION, NOTHING MORE! It is entirely possible that there are factual errors in what I've written below, though I really hope I'm not all that far wrong!
This is a fun question - certainly it is common knowledge that any deviation from the plans will lengthen the build time and almost certainly increase the final weight of the plane, so you'd better have a good reason to be messing around with stuff. So, at this point my philosophy is going to be to only perform mods that I feel very strongly about. Any question of need / utility means the mod won't happen. The list of changes I'm likely to make are:
-Raise the canopy/turtleback by 1.5" to increase headroom. This is particularly relevant for the back seats, whose biggest comfort issue is headroom IMO. Plenty of other folks have done this in some way or other, and it seems reasonably straightforward.
-
Cozy Girrrl strakes - a very popular mod which makes some more room in the cabin and doesn't appear to effect the plane's flight characteristics.
-Under-wing hardpoints to mount removable
baggage pods. If I do any flying with 4 people (and considering I've got 2 kids I'll certainly do some), I'll run out of baggage room very quickly. This helps - a little (enough).
-
Turbo rotary engine w/ IVO prop. This is the big one, and is justified as a safety issue. I live at 7200' with a 6000' runway, and the stock Cozy takeoff performance would present an unacceptable level of risk in all but the most optimal conditions. The Cozy will never be considered a short-field plane, a condition which is exacerbated in the stock configuration by a cruise-optimized fixed pitch prop combined with a naturally aspirated engine. So, when the DA is 9000' I'm using an effectively underpowered engine to push a completely suboptimal prop.
The obvious solution is a CS prop, and it's possible that I'll end up going that route alone (e.g. mated to a Lycoming). The downside of that route is that you're limited to the more expensive and heavy MT prop. As far as I can tell, the IVO is simpler, cheaper, and lighter, and simply can't take the torque-reversal that happens in a 4-cylinder Lyc.
So having a CS prop will make sure that the engine is delivering the most power it can under a given set of circumstances. However, one can question whether the power being generated really is enough when at high DA. As far as I can tell, it is not unreasonable to expect the stock 180 HP Lycoming to be making only 135-140 HP under circumstances I can easily see myself taking off in - perhaps worse. I would prefer it if I could expect more power than that.
The obvious answer is to slap a turbo on the Lyc. Considering the whole safety issue part of this, the cost of doing so really isn't the problem in my mind. The real problem with the CS, Turbo Lyc is the apparent weight and balance issues. As far as I can tell, from a W&B perspective the Lyc is very expensive and I don't want to trade a possible power safety issue for a CG one.
And that's where the turbo rotary comes in. From what I can tell off the Great Internets, rotary engines such as the Mazda 13b have very good power/weight ratios. It is proving challenging for me to get truly quantitative comparisons, but from what I can tell the engines are light enough that a 13B + IVO prop + turbo would come out to roughly the same weight as a Lyc + MT prop. People have estimated getting (theoretically) 230 HP or so out of this engine, but I really doubt I would ever want to run it that hard. If I could get 180-200HP for takeoff at my altitude, I would be happy as a clam. Getting a third more power than the stock engine config plus using the power as efficiently as possible should give me plenty of safety margin.
All that says nothing about the cool factor of these engines. With fewer moving parts and a comparatively modern design, rotary engines appeal to my sense of elegance. And, I can run the silly thing on auto gas if I need to. Really there are a lot of different reasons I like the idea of a rotary, but the above-mentioned high DA performance is really what turned it from "oh, that would be interesting" to "I should really consider this."
Given all that, you might argue that I really ought to be building another plane. It's possible that you're right, but I don't want to build another plane :) . In my mind, the above mods are a very straightforward (albeit time consuming) method of dealing with my major issues with the plane. Really, it is a demonstration of the beauty of plans-built planes that you can do these perturbations so relatively easily and still end up with a safe aircraft.
5.) Where will you build?
I'm going to build in a 2-car garage at my home for as long as possible. The geometry of this space is slightly odd (e.g. not quite the standard space you'd expect from a garage), and it actually helps me a little. Pictures will start coming once I start making progress on the setup process. We keep the wife's car in the garage currently, and that will stay true as long as possible. I have what I think are clever ideas on how to make that a tractable issue, but inevitably the other car will get kicked out for at least a little while in the later stages.
Since I'm a long ways out, I don't particularly know what the end game is going to look like. I certainly expect that the final assembly will require movement to a hangar. I imagine that I'll try to get the engine mounted and tested to the extent that I can at home, but won't be able to complete the wing attachment until I'm at the airport. Fortunately I have a while to figure out a hangar situation before this becomes relevant.
