Hi, I'm ready to learn!

[Len Evansic]

Hi Everyone,

 

My name is Len, and I'm contemplating building a Cozy or similar canard airplane. To be honest, I'm probably a bit too green to think about doing this, but I've had dreams of building a Rutan canard airplane since I first saw one in my youth. I'm a mechanical engineer working at Cornell University (and working on my Masters) in their Mechanical and Aerospace Engineering department. I build soccer-playing robots in my spare time.

 

Of all things that triggered and renewed my interest of late was the approval of the LSA licensing this summer. It got me thinking about making time to get a pilot's license, and revisiting my dreams. As I looked into the LSA though, I realized that it was too limited for what I need, and that the private license would be better suited to me. I also found the wonderful diversity of Rutan-based and inspired canards that now exists.

 

I've been lurking around the forum and I've visited many vendor and builder sites. Now I find myself with more questions than answers, and more drive than I ever had to build my own plane.

 

I guess first of all, since I am not a pilot yet, and most likely the planes that are available to train on are not canard designs, am I crazy to want to build one of these? How in the world could I insure it? What if I deviate from Nat's plans (I'm a big guy and want a little room)?

 

I'm not worried about working with composites, as I've worked on fiberglass boats for years, but what about using stronger and lighter layups with carbon fiber instead of fiberglass? Can the plans be scaled slightly (e.g. a 5-10% scale-up in linear dimensions)?

 

I'm ready to learn, and welcome whatever advice I can get.

 

-- Len

[Jon Matcho]

Len, welcome! It takes a while, but the whole world will end up building a canard sooner or later...

 

...am I crazy to want to build one of these?

Not at all, even without a license. However, you need to be certain you like being up in the air, so having a pilot's certificate does not hurt at all.

 

How in the world could I insure it?

You'll need a pilots license and a few hours in someone else's canard. Keep lurking around these groups and you'll find out more about that.

 

What if I deviate from Nat's plans (I'm a big guy and want a little room)?

You have to balance these considerations with whether you'll put your life at risk.

 

what about using stronger and lighter layups with carbon fiber instead of fiberglass?

Some have done this, but not really worth it IMO. For some parts, sure/maybe, but for other places, particularly the wings -- no way.

 

Can the plans be scaled slightly (e.g. a 5-10% scale-up in linear dimensions)?

Things can be scaled here and there, such as the fuselage width (but keeping the wings the same). Don't touch the wings and consider only the smallest adjustments to give yourself a bit more room. There are a handful of tricks, even with keeping the plans as-is. A plans-wide linear scale-up is NOT possible, as the wings don't scale, as well as aerodynamics in general.

[Len Evansic]

Jon,

 

I saw the Aerocanard "adjustments" mentioned all over the place, and had wondered about the insurability status because of Nat's legal issues with Aerocad. I realize that any of the other modifications I was considering would make my plane "Not a Cozy" by Nat's definition, and was wondering if the same would hold for insurance companies. To be honest, Phil Johnson's Kinda Kozy is just about what I'm looking to build, without the canopy changes.

 

I also came to the conclusion that I definitely do not know enough to mess with any dimensions on the wings, so they will stay as plans. I still have to get the plans, but I was considering bowing the sides of the fuselage to give more room and a more sleek appearance.

 

Why wouldn't you want to use carbon fiber in the wings?

 

-- Len

[Spodman]

Erm, if you don't know enuf to mess with the wings you probably shouldn't mess with anything else either. The design really shouldn't be played with just by eye or imagination, but by actual knowledge of what any changes will do. If you build as per the plans you will get an aircraft with reasonably well known flight characteristics that will be (with the required test program) be safe to fly your family in. If you change things then you are the test pilot trying out a new design. On the other hand, I'm just a newbie like you but kinda old and cautious.

 

There are modifications approved by Nat for the larger frame. 25mm wider at the seatback and mount the canopy 25mm higher. For those with piano legs the center console goes and you can slosh over a bench seat. Nat's standard answer to those who want to bloat his design are to sit in one first, you may be fine. I'm 195cm & 110kg, and am intending the first two mods.

 

I've read on this and other forums that every change you make will take MUCH longer than if you build as per the plans, and you will regret the change later.

 

Substituting CF into any of the airframe is a divisive issue you can read about if you search the archive. In short it will increase the cost for no real weight benefit and extra problems may arise, unless you know your materials. If you just slap on extra layers of FG, or CF over the plans-required FG you will add weight and not neccessarily add strength to the whole structure.

[Jon Matcho]

I saw the Aerocanard "adjustments" mentioned all over the place, and had wondered about the insurability status because of Nat's legal issues with Aerocad.

I am going to present my plane as a slightly evolved Cozy Mark IV, which is a slightly evolved Long-EZ, which is a canard, which I built from plans. I believe, although I'm not certain, that the modifications to the plane are not critical. I also know you can name it anything you like and can certainly register the serial number as #1 (first one out of your "factory"). In any event, I'm not too concerned about my adjustments and will cross this bridge when I get to it.

 

To be honest, Phil Johnson's Kinda Kozy is just about what I'm looking to build, without the canopy changes.

The hardest part is NOT having plans for these ideas out there. Phil has some great ideas, and the best made case for retracts, but as far as I know is not selling or supporting his designs as plans. This may be an obstacle for you.

 

...I was considering bowing the sides of the fuselage to give more room and a more sleek appearance.

That's a major change, and one I haven't seen completed. I believe I've heard about it before, but you'll have some work to do with designing the structure. Remember what someone said, "Don't build and fly that plane, or you will die." Think twice about major mods, for a number of reasons.

 

Why wouldn't you want to use carbon fiber in the wings?

Fiberglass flexes in flight, like an in-air suspension system. Carbon, if used for what I assume your are suggesting to be the entire wing, will make for a harder ride. Also, you have to worry about new forces from a carbon wing transferring energy to the fuselage, which may not be designed to support these new forces. I wouldn't touch the wing.

 

I've thought about using carbon myself, first with skinning the fuselage, then with the bulkheads. The bulkheads make more sense to me, as they can be infinitely stiff. However, it was also pointed out to me that carbon explodes into a million tiny darts upon impact. As a result, you're best covering it with fiberglass anyway. After thinking it through myself, the most I'll use carbon is possibly as an aesthetic covering on my instrument panel.

 

What you might want to consider are 'composite sandwhiches', such as glass+kevlar+foam+kevlar+glass, which has interesting qualities over a glass+glass+foam+glass+glass structure.

 

I may use kevlar within the underbelly of my fuselage somewhere, to protect me from that crash landing I worry about now and again. Just be careful, and get all the feedback you can. You're line of study sounds like a great start, but remember that if you change nothing, you'll be in the air much faster and with a much more predictable schedule.

[Carl P. Lindon]

To be honest, Phil Johnson's Kinda Kozy is just about what I'm looking to build, without the canopy changes.

 

 

You might want to re-think not following Phillip's canopy modifications. Phillip has generously hosted a couple of visits from me, including one which included sitting in the cockpit with him and closing the canopy . At 6ft 3in and Phillip being slightly taller than me there was ample headroom for both of us and no problem with headsets etc . Both height and width modifications came into play and were immediately apparent. I would consider widening of the canopy essential to any tall/large builders looking for a less cozy Cozy MkIV. As you refine your change list and get closer to final decisions you might want to contact Phillip and get information on what needs to be done to alter the canopy and fuselage longerons. And one more thing, the front opening arrangement gives much better access/egress for the co-pilot and provides a good level of "failsafe" operation in that the canopy cannot completely open in flight no matter what latches might fail.

[Daniel Dillon]

I sat in a Cozy MK IV today for the first time. I am about ready to buy the plans and get started. (Technically, I have gotten started if you consider workshop preparation, cleanout, etc.)

 

Sitting in a Cozy.. I found that I simply could not fly it because of legroom. My knees came square up against the bottom of the panel, and there is no way I could work the pedals. But the Cozy looks like the perfect airplane for me to build.

 

I would need the pedals several inches deeper and/or an inch or two further back on the backrest.

 

I found the width to be very cozy.. but that is ok by me.

 

Comments are highly welcome.

 

 

Erm, if you don't know enuf to mess with the wings you probably shouldn't mess with anything else either. The design really shouldn't be played with just by eye or imagination, but by actual knowledge of what any changes will do. If you build as per the plans you will get an aircraft with reasonably well known flight characteristics that will be (with the required test program) be safe to fly your family in. If you change things then you are the test pilot trying out a new design. On the other hand, I'm just a newbie like you but kinda old and cautious.

 

There are modifications approved by Nat for the larger frame. 25mm wider at the seatback and mount the canopy 25mm higher. For those with piano legs the center console goes and you can slosh over a bench seat. Nat's standard answer to those who want to bloat his design are to sit in one first, you may be fine. I'm 195cm & 110kg, and am intending the first two mods.

 

I've read on this and other forums that every change you make will take MUCH longer than if you build as per the plans, and you will regret the change later.

 

Substituting CF into any of the airframe is a divisive issue you can read about if you search the archive. In short it will increase the cost for no real weight benefit and extra problems may arise, unless you know your materials. If you just slap on extra layers of FG, or CF over the plans-required FG you will add weight and not neccessarily add strength to the whole structure.