Len Evansic

I had the same thought too, but the problem with radiant heaters is that they are radiant. You don't actually heat up the shop, just surfaces that are exposed to the radiant heat. From my understanding, everything used in the layups has to be ~75° F. Foam, glass, epoxy, and ambient. The epoxy is no problem with a hot box, but the foam, glass and air are a different matter. The foam is a good insulator, and will take a long time to heat up thoroughly. Likewise, the air will not be adequately heated by a radiant heater. You'd be better off with a forced air convection type heater, heating the air in the shop. Unfortunately, this takes a good bit more energy, and you would have to insulate your shop to make it more worthwhile. At least, that's what I'm planning on going with, once I get my garage a bit more insulated. Since winters are so long, dark and cold here, I'll probably build one of those PVC & poly tents as well, so that I won't have to heat up so much space. Edit Checking on the same site you listed, I found this 30k BTU garage heater that would be perfect with the optional blower installed: Propane Garage Heater Depending on insulation or not using a tent, you may need two of these. -- Len

I think carbon fiber is a good idea, but nanotubes are a very, very bad idea. I read an article about two months ago about the horrible sickness and sometimes death that some of the early nanotube researchers had experienced. Apparently, unlike coal dust or asbestos that just sits in your lungs, nanotubes just start there and move anywhere they can in your body. They are not able to be digested or destroyed, and they are too sharp to be held captive by any cellular tissue. Making a plane of this material would necessarily cause lots of dust, most of which could touch unprotected skin or mucous membranes, and from there wreck havoc. Nanotubes are too new, and for now, too dangerous to use for anything. This technology is still in the stage of cavemen playing with fire, or Ben Franklin flying kites in thunderstorms. Unfortunately, it may take far longer for this stuff to ever become safe for mere mortals (not that lightning is). The engine sounds good though. -- Len

I'm completely talking out of my butt here, but from what I've read in a few places, there are two things that limit the Vne to 220 mph. First, as a manufacturer, you can set the Vne to anything you want, as long as the plane still holds together and is controllable in flight when you slightly exceed this speed, while fully loaded. It's probable that this is a speed that Nat felt comfortable with in his Lycoming-powered Cozy. He certainly pushed the envelope while testing, and probably reigned this in for safety's sake. The second reason I've seen listed for this Vne is fear of catastrophic failure due to flutter. I've read a few accounts that state that above this speed, flutter tends to occur, with the canard flapping like hummingbird wings. Likewise, there are a few arguments about approaching Mcrit for the Roncz airfoil at higher altitudes, if you go much above this speed. I'm sure that flutter can and does occur at a speed higher than 220 mph, but where does it start? Are there other factors like build quality or material used that can move this speed point? I've asked about using carbon fiber and kevlar in certain areas to improve strength with similar or less weight, but have been discouraged by others. At the same time, the Berkut people use these materials in a very similar design, and don't experience flutter up to their Vne, which is in excess of 300 mph. I fail to see why carbon fiber or kevlar could be used judiciously in a Cozy design to raise Vne while reducing the specter of flutter. By the way, since you mentioned jet power, Greg Richter retrofitted a jet engine in his Cozy III. His webpages (address escapes me right now, but he is the CEO of Blue Mountain Avionics) state that he is really worried about the Mcrit issue, as the jet pushes him through an aerodynamic region that is not understood. He's mostly worried not about hitting high speeds, but how the plane handles slowing down from them. -- Len

Um, Strider, Hmmm. OK, so I thought the Cozy and Long-EZ used a modified Eppler 1230 for the main wing airfoil, and a Roncz 1145 (or is it 1045) for the canard. When I look into your model's airfoil folder, I see Eppler 804 and Roncz 904 foils. Are these mis-named or approximates for the real ones? I have an older XPlane Cozy model by someone else (with retracts) that uses an Eppler 1230 and a modified GU 25, similar to the original Long-EZ. Just wondering what the difference is. -- Len

Last-a-foam is made by General Plastics. General Platics They even show the grid-cut version on one of their product pages (for curved surfaces). -- Len

I know it would require redundant computer controls, and that there are other failure modes that this doesn't address, but I was just throwing this out as an idea to see what others think. I guess what I was looking at here is something similar to what SpaceShip 1 and other planes do when they go trans-sonic. At this point control surfaces are entire surfaces, not just the trailing edges. Since I've seen a lot of posts that ponder the actual speed of Mcrit at different altitudes with respect to the Roncz foil, and given its relatively high fixed AOA, that varying that may help out at the high end. Following this, I thought about other places where this may be helpful. I disagree that this will not have effect in flutter conditions. Vibrations are one of my specialties. Changing the AOA of the canard will change the aerodynamic forces imparted on it. This can damp or drive resonance to a different frequency, which will help out with flutter. I do agree that adding this type of control will add one more thing to worry about breaking. I like many others who are also new to this type of plane, worry about deep stall, because it is talked about so much in forums like this one. Bad things can happen, would it be that bad to have alternative safety measures? What if your ballast was off because you never touch it, but removed it to cary another passenger last week. Yes, I know you should catch it in pre-flight, but what if you don't because you had other things on your mind? People still have gear-up landings, because they get distracted. -- Len

Ah, but jet fighters are jets, and modern ones are designed to specifically be unstable in flight for better maneuvering ability. In fact, most of the fighters designed in the last fifteen years are totally uncontrollable by humans, relying instead on a bunch of embedded computers, making split second decisions to adjust the flying parameters to match the pilot's input. Forget about the CG envelope in relation to the wing surfaces, the important location is relative to the thrust. What we need is a Cozy with thrust vectoring and a super-powerful jet engine. Forget the piddly one that Greg Richter put in his, we need one with afterburners! Oh, and a bunch of computers to control fully moveable canards and other control surfaces by wire. I'm sure Nat would have an opinion on this. OK, now back to reality. What if someone were to work out a system that would vary the AOA of just the canard when unsafe conditions were detected? Not full fly by wire, but a wired in failsafe for something like deep stall? I just think of this because I would prefer to fly the plane down, rather than rip it apart with a parachute. It wouldn't fix some major structural problem like loosing a winglet, but it may help with a deep stall, at least in varying the AOA until it catches flight again. And it may help with obtaining a higher Vne, by decreasing the canard AOA at high speeds. I know that the plane isn't designed to do bad things with a properly positioned CG, but just in case. -- Len

Wow, you're a much better virtual pilot than I am. The model that Curt provided the other day worked better for me, but I kept over-correcting when trying to land. I think I need a bit more practice. Still, I noticed some behavior that didn't match what is claimed on some web pages. John Slade claims that his Cozy lifts off of the ground at 70 mph, while both Cozy models I tried in X-plane needed at least 100 Kts. before lifting off. I'm still trying to hit max speed in either model, without going into a dive to do it. Also, the air-brake doesn't seem to provide enough drag or slope increase for hitting a normal aproach. I think the models are nice, but not accurate enough yet. I guess what the sim lacks most is real seat-of-the-pants feel. Like almost everybody else, I can't afford a snazzy hydraulic simulator platform, so I'll just have to do the next best thing and build one of these for real. -- Len

Thanks Curt! I'll try it out tonight! -- Len

I'm using a Saitek Cyborg Evo joystick. It's nice, but I think it isn't stable enough in the neutral position for X-Plane. When I do the calibration thing, the neutral position appears to be biased towards the left end of the bar (non-linear or non-centered) for pitch, yaw and rudder. As I mentioned before, I tried to trim these biases out, but it doesn't seem to work. A fresh install and a new download of my existing model (O-320 powered with Infinity retracts) is waiting for me at home to distract me from the election coverage. -- Len

I can't contain myself. I'm so anxious to build and fly a canard I bought XPlane to simulate the actual physics of flying. So I've searched for and found XPlane models for Long EZ, Vari-EZ, and Cozy Mk. IV's on the web, but I think there are either serious bugs in them, the program itself, or my ability to fly this type of plane. First I tried out the Cozy model. It was made for the 6.x version of XPlane, and I'm running version 7.61. I thought XPlane was throwing some serious weather and turbulence at me because the plane would jump up and down all over the place in flight. When I made the panel transparent, I saw that the elevators were fluttering chaotically. I botched a landing, and tried again, but the plane was jumping around while parked on the runway! Something's not right... Next-up the Long-EZ. This seemed to handle much better, but it also seemed to be almost untrimmable for level flight. No matter how straight and level I had the plane, it would constantly turn or pitch and not maintain a heading. Aleron, rudder, and elevator trim could not remove either of these tendencies. Frustrated, I thought that maybe my installation of XPlane was suspect, so I loaded up a Cesna 172. This model was rock solid. Very trimmable, and nothing erratic. Extremely easy to fly and control. So, after this, I got to thinking. Since XPlane uses an aerodynamic model of the plane to govern the simulation, is the canard type of plane an inherently difficult to control beast? Am I just lacking the proper finesse, or are these models I downloaded just screwed up? I'm new to flying and have never had the privilege of flying in a canard plane, so any insight would be greatly appreciated. -- Len

Chris, Dave, and Mike, Thank you all. Rotary is definitely starting to look more attractive to me now. I wish there were some sort of long-term reliability registry for auto engines and their reduction units, but I guess that's why these planes are experimental. Now if I can get someone to answer my questions in the Subaru forum... I guess I'll go to check on the crickets. -- Len

Thank you very much for the explanation! This is definitely helping me to wrap my brain around Wankel engines. Now more questions. So how much does this improve the life of the engine? How much oil needs to be added to the gas, and is it available at most airports? Does this mean that there is no oil in the crankcase, or whatever you call where the crank passes through? I've seen quite a few articles talking about oil consumption on Lycoming engines. Does the rotary use more oil than a Lycoming typically does? I know this last one may look like a troll for an apples to oranges comparison, but I am curious about this as gas and oil are necessary consumables. -- Len

That's why I'm here, to banish my own ignorance. Let me throw out some of my ignorant beliefs here to be smashed. Disabuse me at will (but don't spin through overly rose-colored glasses). First, It is my understanding that many rotary engines tend to have sealing problems that get worse with wear and turbocharging. This is why Mercedes dropped the Wankel and went to a turbodiesel in their C111/C112 cars back in the 70's. I understand that Mazda has done a lot of work to reduce these problems, but I am still worried about them. What is the typical automotive life of one of these engines? 80,000 miles, 100k? 200k? I have no idea, but knowing this would help me evaluate if I want to trust one in an airplane. My mother has had several 250k+ mile Subaru's that never needed an overhaul. I myself had a twenty-year-old diesel Benz that has 190k miles, and when I pulled the head that had a hairline crack, it still had cylinders that look like glass. The anecdotal evidence I've seen does not indicate that rotaries can come close to touching these for reliability. Because of the power to weight ratio, I would like to use a rotary, but I am not convinced of the ease of maintenance or reliability. I am heavily leaning towards an auto conversion, not primarily because of initial cost, but because of the recurring problems that others note with cert. engines. These design-rooted problems tend to cost a lot, which is unattractive to me. -- Len

So in an effort to research engines, I couldn't fail to notice the Subaru conversions. Eggenfellner and Crossflow offer engines that they have 'modified', but both are cryptic in describing what they've done, besides the PSRU's. Does anyone out there know what is required? I am having trouble discerning what they do to span the difference between their prices (~$22-28,000 US) and the ~$850 that a JDM Subaru engine costs on ebay. I know the ECU and the related auto-specific stuff (O2 sensors) have to be worked around, but what modifications to a Subaru block or heads is necessary? As an aside, how much does a four cylinder 2.0 - 2.5 L weigh? The other posts I saw here focused on a bigger cowl on a Velocity. I've seen many Subaru engines, and know that they are certainly no bigger than a Lycoming. I've seen Al Wick's page, as well as Phil Johnson's. Is anyone else building or flying with a Subaru engine? -- Len

I'm hoping for the Honda too, but came to realize that the pent-up market demand will make this engine not too affordable in the near future. When you look out there at the turnkey (converted or new) engines, it appears that the price range is from $20,000 - $75,000. I'd be willing to wager that the Honda will fall into a $35,000 or higher price after a year on the market. Rotary is my next-best bet for the reasons you cited, since I don't want the vibration and noise of a typical Lycoming. engine. I guess my worry about the rotary is with general reliability and hassle. It can't come close to the cooling efficiency of a conventional engine, because it doesn't have the necessary surface area for the coolant to extract heat from. A good external cooling system could cause problems by dropping the coolant temperature too much, inducing thermal shock. I also don't want to be mixing fuel and oil like I would for a chainsaw or weedwacker. -- Len

OK, so I'm new and confused. Is there something wrong with the Continental engines, or are they a particularly good value? Why is there such a discrepancy in prices between the Continental and Lycoming engines? I'm still looking between cert. engines and auto-conversions, and just don't have enough context when it comes to certified engines. I've gathered that an O-360 is a 360 cid. 180 hp. engine, and that an IO has injection, a TIO has a turbo and fuel injection, and both are more expensive than the "O" engine. All of the suffix (A1B2...) codes go right over my head. -- Len

OK, so I'm new here, and still feeling out the various engine choices that others on the forum have used, before I commit to anything. I understand the reason that many auto-conversions are used and some of the issues encountered. When it comes to the rotary though, I find myself constantly scratching my head. In almost every detailed page I've found so far, it seems as though everyone disables some oil injectors in their engines, and instead use a pre-mixed 2-cycle type fuel. Why? Why disable the lubrication system, and why bother with the hassle of having to mix oil with the gas, as if it were a 1960's Saab? What other changes have to be made to the engines, and why do so many people choose the rotary over other more conventional auto-conversions, like the Subaru or the converted Benz diesels? Is it just to be different? I am genuinely curious to find the answers to these questions. -- Len

Did he put up anything on any websites, or does this predate the web? The log of that project would be a very interesting read. I saw other threads were a 3" widening was discussed (and argued), and this after-the-build widening should bode well for them. I'm still in the info gathering stage, but so far I've been advised to leave the wings alone, and at most widen an inch and elevate the turtledeck by an inch. Wow, a bisection and 6" insertion of materials just boggles my mind. I'm pretty sure that everybody he discussed this with, must have told him that he was crazy. This is something that couldn't (more appropriately shouldn't) be done, but the assertion that it it flew like a Cozy does inspire me. -- Len

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

I'm still in my gathering information stage on this project, and I don't aim to be as ambitious as a 15% scale-up. Nonetheless, I am interested in a less cozy interior. What I'm curious about is how the general enlargement will affect the flying of the plane. I mean, from what I understand, the Cozy III and IV have the same wings as the Long-EZ. Both of them have widened the fuselage, but neither has changed the wing planform and airfoils, save the shortening of the canard and the update to the Roncz airfoil on the canard. If the wing dimensions are scaled up, how are the aerodynamics affected? Nat didn't change dimensions with the fuselage enlargement, and the plane flies just fine. Would it make more sense to enlarge all of the fuselage measurements by 10%, and only increase the wing dimensions by 5%, only in the lengthwise direction, taking the difference of the fuselage up in the strakes. I suggest this by imagining a Cozy scaled up to the size of the Beech Starship, or a 727. A scaled up Cozy would look like a Fisher-Price plane with extremely thick wings. Also, the fuselage houses mostly air, which isn't that dense, but the wings house fuel, which is. I know that you could just use less of the wing volume for fuel storage, but it seems that enlarging the fuselage has less of a detriment to wing loading. -- Len

Was the guy with the 15% scale-up successful? I mean, has he completed his plane and flown it yet, and if so did he have any adverse problems? By any chance does he have a web site? -- Len

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