ekisbey

Try doing a seach on this forum for words such as "carbon" or "spar." Although you've not mentioned the spar yourself, you'll find that it's usually one of the first things folks come up with for carbon-reinforcement, or modification. This often leads to lengthy discussions on hypothetical modifications of other parts, such as bulkheads or firewalls. Not to discourage you, but you'll find this topic is nearly beaten to death, with two main opinion camps; the "build it to plans" camp and the "I'm not afraid to try something new" camp. I tend to favor the former, since the thread often dies after someone posts a good reason to stick to the plans methods and materials. I think the general consensus is that for the most part, any advantages (which tend to negligible) of redesigning or modifying major components or structural items is outweighed by the risk of introducing unacceptable behaviors or failure modes to other (perhaps unrelated) components on the aircraft. Build it to plans and you can rest assured that it will do everything it's supposed to. Try something different, and you're sailing (or perhaps flying) without charts. You'll see what I mean when you find the relevant threads. Good luck.

There's a comment in the latest newsletter that several builders were considering/using Jabirus, but no specifics. None flying. I've not heard anyone own up to buying one yet.

Several of my in-laws work for Bombardier. I'll have to find out more...

I'm in Killeen, but military commitments have been preventing me from making any real progress. Every time I start thinking I'll get to make some real progress, we get a new set of deployment orders. Most recently it was to Montana to fight forest fires. Got back Saturday. There's a canard builder in the Waco area I hear, but it's not a Cozy. It might be a Velocity, but I can't recall for certain. Do some web searches, there's bound to be more.

Non-engineer speaking here, again. ;] It seems to me that carbon fiber has different properties than glass. I know this seems like a ridiculously obvious statement, but the caveat here is that there's more to the difference between the two than just the overall strength-to-weight ratio. I'm not trying to rain on anyone's parade, certainly, but I wonder just how much solid unbiased research has been put into the idea of carbon fiber parts? Just how DOES carbon fiber affect the aircraft as a whole? I see a lot of folks who seem to be deciding, almost arbitrarily in some cases, to install or redesign parts with carbon. My question is, if you build a part out of glass, and then build a similar part out of carbon using the same "recipe" (for lack of a better term), does the carbon part weigh the same but have greater strength? Or does it weigh less but have equal strength? These questions be come relevant below. Second issue, drawing from the first, and referring to comments by TES111 and Mr. Slade; Let's say you make a part out of carbon and alter the recipe, ending up with simlar strength but less weight compared to a similar fiberglass part. By the very nature of what you've done, you've changed the overall properties of the aircraft and the manner in which vibration or stress are transmitted to other parts of the structure. Most significantly, two components that share similar physicals but different mass will vibrate in a different manner, and transmit those vibrations with different levels of efficiency. I tend to mentally compare it to the impedance mismatch beteween two conductors, or perhaps a bell made of glass as compared to one made of a polycarbonate. They're going to sound different; one will ring longer and louder, and the other will absorb the energy fairly quickly. One might be felt ringing through the handle, the other might transmit nothing. Basically, what I'm getting at is that if you build a part with a different material that what's reccommended, just because the other material is physically stronger doesn't mean it's not weakening, or at least changing, something else equally critical. I hear similar arguments against carbon or other "alien" (again, for lack of a better term) materials on a pretty regular basis. I obviously agree with them. However, since I don't have a lot of experience on the subject, I'm interested in finding out more. Where does one find data detailing the strength of carbon fiber parts in all the aspects that are relevant here? Torsional rigidity, compression, tension, etc?

Jim, I'm not really qualified to interject here, but something is nagging at me that I hoped you could clarify. You speak of thrust generated by an idling engine. It would appear to me that there is a kind of threshold speed above which the drag generated by an idling prop is equal to or greater than drag generated by a stopped or windmilling prop, especially if it's been installed to stop in the dead zone behind the strakes. In other words, above that airspeed, the prop is not providing thrust, but is instead contributing to drag. I don't know whether this is true or not, but if it is true, it points to my question. At what speed does this occur and is this speed significantly different from the normal landing speed of the MkIV?

I'm interested in the doc as well.

Demise? So this is no longer available, I take it? You'd think someone would have taken this concept and run with it... Unless his demise was somehow related to this system?

Is there a Mark IV flying with retracts? Unless there is, I'd say the data was suspect.

I don't think the question is about whether or not the spar is strong enough to handle the loads with retracts. Personally, I'm pretty sure it is. Unfortunately, that's not the question, or perhaps it's improperly phrased. The correct question would be "Is the spar designed to accomodate retractible landing gear?" The answer for that, I believe, is "No," unless I'm way off base with regard to what Nat's been saying for years. It simply wasn't designed for retracts, and it wasn't tested for retracts. So while it may be strong enough to handle the forces that retracts will add to the equation, you're tapping into the safety margin of a structure that's supposed to be doing something else. Remote as the possibility may seem, I wouldn't want to find out the hard way about a problem nobody ever thought of or tested for. On the other hand, they sure are tempting. I mean, it just looks so cool, it's almost worth considering in spite of what I just said! I'd like to see a system where the retracts attach to the same bulkheads as the fixed gear strut. No idea how you'd make that work, but I guess there's a reason why I'm not an engineer. That looks like about two cents, doesn't it? Good, I can shut up now.

Butt spice crimper, eh? I'm trying very hard not to ponder that...

Check out these entries out of the mail-list archives. Thanks to Mr. Slade's search engine it only took me moments to find it. http://kgarden.com/cozy/arch/auto_gas.htm#msg95

It's a valid concern, one that I share. Especailly now that the feds are toying around with the idea of 10% ethanol/additives by volume to "drop prices."

He does sit on quite a bit of foam. He has it set up in such a way that he can remove it in sections to fit people of various height, and they stay in place with velcro (the cushions-- not the people! ), if I remember correctly. He had pulled out everything before I stepped in, leaving me a lttle dubious about the comfort level. Somewhat to my surprise I found that even without any cushioning, it was still very comfortable. I can't vouch for how I'd feel about it four hours into a flight, but for the short time I sat in the plane, it was fine. I've heard rumors of several of us taller folks riding on nothing but glass and paint. I'll certainly end up moving my rudder pedals forward, as well as moving the front seatback towards the rear a bit. The latter is not so much for the legroom as it is for the distance betwwen the seat and the stick. I found that my arm was a little too long to hold the stick comfortably and still have a full range of motion. Either I'll have to change the angle on the stick or move the seat back some, or both. I'd prefer not to move the seat, but I'm not certain how much change I'll be able to make to the stick, so in grand procrastinatory fashion I'll make that decision when it's time to assemble the tub. I don't know anything about a hieght "cutoff" for raising the canopy. I suppose it's a matter of preference. I considered it, but I have a sneaky suspicion that there's more to it than meets the eye, and if you check out the web pages of some of the builders, they're full of stries about this or that surface not lining up, things not mating together properly, fairing difficulties... and that's with the per-plans dimensions. Made me somewhat leery of the idea.

I'm a litte taller than that and still had no problem fitting in Nat's Cozy. I took the opportunity when passing through Pheonix to stop in and see his plane first-hand last year. Unles you're VERY long in the torso, your biggest problem won't be headroom. The front seatback slants rearward at a deceptive angle, and your position is more like you'd be in a sportscar; somewhat reclined. I ended up with little more than my head and shoulders poking up over the fuselage sides and into the canopy bubble, with no sensation that my head was too close to the top or sides. THere was lots of room left. What you're more likely to find troublesome is the location and size of the rudder pedals. The plans location put them in my shins, and even with the adjustable pedals, I'll be forced to move them forward some. Point is, build it. You'll fit. People told me that for six months before I finally went to see one close up. Turns out they were right all along and I could have been six months closer to finishing this project.

Good to know he's watching over us...

Referring to the thread " Canard Community Forum > Tech Shop > Electrical > Affordable moving map? " This reminds me of a question and puzzling response during a conversation with Nat last year. We were discussing the layout of the interior, the center console and panel especially. I'd noticed that Nat's panel had a very straight forward no-frills appearance, yet he managed to use up most of his available panel space. I remember asking if he knew whether a BMA EFIS/One would fit in a Cozy panel, and he seemed to think it would. I knew the EFIS was pretty good sized, and having looked at the dimensions and specs of both the panel and the EFIS, concluded that it would fit, but only just. I then asked if having such a large hole cut out of the panel would weaken it appreciably. He replied that it might, a little, but didn't seem to concerned. Well, I figured that if he wasn't concerned, then I didn't need to be, so I was going to leave it at that. So, in my ignorance, I made a comment that got me a strange response. I said something like "well, I guess it's not structural anyway so, yeah, sure." Nat immediately gave me a funny look and corrected me, saying that the panel was, indeed, structural. Now, what I meant by "structural" may or may not have been what he meant. What I meant was that to my understanding, the panel wasn't critical to the integrity or strength of the fuselage. I was puzzled, but he seemed a little miffed that I might say such a thing and I promptly changed the subject. He was being kind enough to show me his aircraft on very short notice (he'd been doing something and I'd interrupted him), and I was worried I might say or doing something that might offend him or alter his disposition. Anyhow, that coversation keeps bubbling up in my mind each time I think about putting holes in the panel. Obviously, it's been designed for that very purpose, and something the size of the EFIS/One isn't large enough to violate whatever limits are designed into it. However, if I cut a hole that size, and later move it, fill it with something else, patch it over, etc., and cut another, similar sized hole elsewhere else, or two... You get the idea, I'm sure. At what point are there too many holes? IS the panel critical to the strength of the fuselage? How much is too much when removing material from the panel? Would anyone need, at some point, to cut the whole thing out and replace it? Another reason for asking this is I'm considering opening up the the underneath for a bit more leg room. The angle of the seats makes it difficult to get more than one of my long legs in and out at a time. This is really a non-issue normally, someting I rarely notice, since I've been getting in and out of things that way since high school. I noticed this the first time I climbed into Nat's plane, but thought little of it. However, a recent embarrassing experience in a military vehicle caused me to realize that if the vehicle is on it's side and I don't have the leverage to lift my weight with my arms, it's next to impossible to get out. It made me think of the Cozy. If the plane (God forbid) were in an orientation other than upright, especially on it's side, I'm not certain I could free myself. Since I don't have a completed aircraft handy, I just can't go check this out and see if my fears are justified (No, I don't want to turn a plane on it's side, I just want to see exactly how much leverage I need to have to get myself out). At this stage of contruction, it would be pretty simple to make these kinds of adjustments. A mere inch of diameter could make all the difference. That inch adds a lot of strength. How should I resolve this?

Is this meant literally, as in it won't fit no matter how you try it, or do you mean it's too large to be practical? From what I've gathered it will fit, but only just. It won't leave much room for anything else. I keep looking and drooling, but the steadily lengthening price tag on the EFIS/One forces me to place it in the category of wish-ware. I'll keep on wishing, though...

In December I got the opportunity to visit Falcon Field and spoke with Mr. Puffer in person. I also used the opportunity to sit in his aircraft and "try it on for size." While I'll admit there was not a lot of extra room, I didn't feel at all cramped or squeezed in. There was clearance for my head, twisting rapidly from side to side put me nowhere near the canpoy, and everything was within arms reach. The only two complaints I had were that the rudder pedals were located in my shins and I couldn't reach the stick unless I jammed my elbow back towards the strake. Width was not an issue, and I have a fairly large frame. After discussing my fit with Nat we both agreed that no modifications were absilutely necessary, other than to move the rudder pedals and maybe move the seat backwards a little, to give me a better angle on the stick. Even that was not really necessary because it'd be simpler to change the angle on the stick. While I liked the thought of the higher canopy, it was not at all necessary. I'll wait as long as I can to make that decision. I tend to agree with Rui's comment that you'll get used to the dimensions after you've spent some time in the aircraft. It could be that I'm one of the uncommon ones, but I felt used to it the first time I got in. My wife and I were both struck with how well it fit. My car is nowhere near that comfortable.

Jake, you might want to consider going after the OH-58 Kiowa. After the Chinook, which is rare outside the logging industry, it's the closest helicopter we have to what you'll find in the civilian market, which translates, of course, into job skills. But more importantly (yeah, my priorities aren't skewed!), most of the Kiowa pilots I knew on Campbell were under the impression that they'd be tapped first when the Comanche gets fielded, since it's destined for a similar role. They also tend to fly more hours in the Kiowa compared to the CH-47's and AH 64's. I suspect the Comanche would be similar. I've considered several times going the W/O rotorjock route, but I'm pusing the age bracket and I'm just a hair too tall. If I could do it though, I'd certainly go for the Kiowa.

You know, that's a heck of an idea for a site. A webcam showing live progress in the workshop, even if it only updates every minute or so... Hmm...

Just remind her of the unpleasantness of driving long distances. and she'll come around. I figured that we make the round trip from Texas to the west coast several times annually. 36 hours one way on average, about a hundred dollars on gas, and another 50 or so on food, plus hotel fare at least once, more if I don't push it too hard or get a late start one morning. Don't forget the screaming kid, traffic annoyances, and arriving tired and dirty. Once I pointed it out to her she started coming up with reasons of her own, and before long she was pushing me to get started. I know not everyone can be as fortunate to have their significant other as excited about the project as mine, but if you can get yours behind you on the project, it makes a world of difference, believe me. All those backrubs are well worth it. Take a massage class if necessary. You'll not regret it.

If I had 43 million dollars to spend on my aircraft (what we pay General Atomics of southern California to build each RQ-1 Predator UAV system), I wouldn't use a rotary either. I damn sure wouldn't use a Rotax. Especially not on a Cozy. Assuming I end up using a rotary, I have no intention of re-inventing the wheel. I'm building the plane 'cause I'm sick of wheels. I want an aircraft so I can get there quickly, comforably, and safely. The rotary looks like it could be the answer, even considering the engineering problems that confront it. Piston engines have a full century of refinement behind of them, but they had their own problems at the start. They still have problems. The rotary is still in it's infancy in comparison. If there are still problems that exist in engineering a rotary into an aircraft application, then I'll join these guys in hammering them out when the time comes, but nobody's re-inventing anything. If there wasn't serious potential in the rotary engine, it wouldn't be recieving a fraction of the attention it's getting now in the experimental arena. And if the homebuilders and experimenters are playing with them, then you can count on the GA manufaturers to be watching very closely, letting us work out all the bugs and proof-of-concept footwork. How long will it be before a company such as Lyc or TCM has it's name stamped on a rotary? Maybe never, but the folks in this topic don't seem to be waiting. I wonder if maybe they know something you don't?

Seems like a good month in Texas for airshows. Galveston last weekend, Temple this weekend, fly-in mid-month... loving it.

Make sure you place the emphasis on "experiment" in experimental. How the heck do you get away with something like that for five years without anyone noticing??