Marc Zeitlin

Does anyone who keeps bandying about the claim that rotary's have only 3 moving parts have any statistics on how much less engine maintenance the Mazda rotary engine cars need in comparison to say, flat four opposed engine Subaru's? Or any other 4 cylinder car? Did Mazda EVER make any claims of their engines being more reliable than any other engines? I didn't think so.

In order to be able to ensure a reasonable level of O2 in the bloodstream (generally, saturated O2 levels of 90% or better for the brain to work properly, and over 70% or so for it to work at all and for you not to die), you need to have a "partial pressure" of O2 that's above a certain level. Since at all altitudes the O2 is about 20% of the air, as the air pressure goes down with altitude, so does the O2 partial pressure (this is why you get less O2 as the altitude climbs). Pressurized aircraft deal with this issue by ensuring that the pressure inside the cabin is always high enough so that the partial pressure of O2 is always within safe levels (commercial airliners pressurize to an equivalent of 5K to 8K feet, usually). Now, in an UN-pressurized aircraft, unless you're wearing a pressure mask or astronaut space suit, you'll be wearing a cannula or regular mask (like airliners have), so as soon as whatever gas is in the bottle comes out, it'll be at the ambient pressure. If it's just AIR in the bottle, then you haven't raised the "partial pressure" of the O2 going into your nose any, and it won't help your saturated O2 levels in your blood. If the bottle holds O2, then the gas entering your nose will be mostly O2 (along with some ambient air diluting it), so the "partial pressure" of O2 in your nose will be a lot higher than the O2 PP further away. This is good for your SpO2 (saturated O2) levels in your blood. SCUBA has the opposite problem - as you descend, the pressure rises, and if you use pure O2, you'll have TOO MUCH O2 in your blood, and it'll poison you. On the other hand, if you use plain air, then you have to be very careful about going too deeply, or the nitrogen can come out of solution as you ascend, and you'll get the bends. Gas for breathing in SCUBA gear has to be tailored carefully depending upon how deep you're going, and your ascent rate has to be slow enough to let the dissolved gasses come out slowly, if necessary. a) correctb) correct c) nope - hand layups COULD be designed to withstand the pressure - they just weren't in this case Hope this helps.

For what? Breathing? Pressurizing a cabin? Are you talking in general, or about COZY's in particular? COZY's are NOT pressurized (and cannot be). If you're talking about breathing in an unpressurized aircraft, then above 12.5K ft., you need oxygen, not pressurized air. It sounds like you're talking about breathing at high altitudes, so since you need O2 for that, pulling compressed air off the engine (either from a turbocharger or some other compressor) will be useless - you need pure O2. I know of no GA aircraft that have O2 generators on board - everyone (myself included) uses O2 tanks, which need to be refilled on occasion. The standard COZY fuel selector is L-R-Off. No Both. Same as in low wing GA aircraft, like a Piper Warrior. There's no magic about COZY fuel system. "Both" only works if you can guarantee equal fuel flow (and fuel return, if there's a return line). This is more difficult in low-mid wing planes. Hence the L-R-Off. Some folks (Steve Wright in particular) have put in LARGE cross flow tubes so that he CAN guarantee equal flow, and he also has a single point refueling port, with only an "on-off" valve to the engine. This is the simplest solution (but of course, means that there's only one fuel tank, in practice, so contamination or leakage leaves you with no backup. This is not a common problem, however, so the increased risk is small IMO). The COZY fuel system is no more complex than any other low wing GA aircraft.

Maybe discussions on how to break the laws of your individual countries are best left to private emails?

My W&B allows me up to 450 lb. in the front seat with no ballast to get to the forward CG limit. Nat's 400 lb limit is artificial - he was not able to support it in a discussion last year on the mailing list, if you remember. He was using it as a "safety factor" on forward CG limits, but there already IS a forward CG limit, and I've tested my plane at it at all weight ranges.

Huh? All they have to do is go to an FBO, rent a 201 HP aircraft for a couple of hours with an instructor, and get the "High Performance" endorsement. What's the big deal? Just because you can't get it in YOUR plane, how does that change anything?

Yes. There is not exemption for experimentals from this requirement - see: http://eaa.org/communications/eaanews/050509_rating.html UNLESS you don't carry passengers in your experimental. Kind of limits the usability of anything other than single seaters, however. I'm sure that there are many aircraft out there that are listed as having 200 HP engines, when, in fact, they may actually have more than that. Without dynoing the engine, who would know......

You're not the first, apparently - many others have reported the same thing. I doubt that even Al (or Jeff) know the #'s. My best guess, from the mailing list stats and the FAA registry, is 3 to 7 flying Aerocanards (or things that are mostly aerocanards, but are called something else) and another 20 or so in progress. Just an educated guess.

They are the same SIZE, but structurally different (to deal with the almost 50% increase in gross weight. They CANNOT be interchanged.

See: http://canardaviationforum.dmt.net/showpost.php?p=24834&postcount=14 and http://www.centennialofflight.gov/essay/Theories_of_Flight/Stability_II/TH27G8.htm

No. They're really "dihedral effect" adjustments after the fact. At least that's what I've been told.

Jon, don't start this argument again. In the chapter you reference, part three states: (3) the amount and substantiality of the portion used in relation to the copyrighted work as a whole; and This obviously means that the more of the copyrighted work you copy, the less likely the courts are to consider it "fair use", no matter what the purpose. Copying the whole this is extremely unlikely to be considered fair use. Please. You're going to need a far better argument than this to claim that it's OK to copy and distribute other folks copyrighted plans sets.

Where to start....... Not so much. As we've discussed before, The biggest problem with Rutan derivative canard aircraft operating from soft fields is the geometry/deflection of the nose gear due to drag on the small nose wheel. You allude to this somewhat below, but you miss the point that this is the single largest issue. Landing on grass/soft fields is not much of a problem, as long as they're smooth, but takeoffs are a big problem due to nose-down deflection of the nose gear. This is a very minor issue WRT operating from soft fields. Short fields are a different issue, but that's not what you're addressing. As an Aeronautical Engineer, I tried real hard to figure out what you're attempting to say here, but I failed. It makes no sense to me whatsoever. Hmmm, same issue as above - no clue what you're on about. Now THAT'S true, especially on the nose wheel, since it's so small, and it's the single largest reason for problems with soft fields, as I mentioned previously. Actually, it has little to do with where the propeller is, and more to do with the ground incidence angles and nose wheel geometry. It would be easy to design a canard aircraft that sat with a 10 degree nose up incidence angle, and had nose gear that didn't REDUCE the incidence angle as drag was applied to the nose wheel. But there would be other problems, such as a VERY long nose strut, and poor prop clearance (or very tall main gear, as well). But IF the canard aircraft were built that way, it would perform about as well as the tractor/taildragger aircraft.

Right from the beginning. the first thing you do is build bulkheads, and the only way you can do that is with the templates. Almost none that will get you anything that looks like an airplane.

There is no proof in the pudding. Maybe some raisins, but no proof. The saying is: "The proof of the pudding is in the eating". Where the word "proof" uses the meaning "test" (which IS one of "proof"'s real meanings). The saying actually means that "you test the pudding by eating it". What, when you think of it, would "The proof is in the pudding" mean? Anyway, the "Infinity I" doesn't exist, and neither does the "steerable nosegear". If I were a betting man (which I am), I'd bet $100/yr for the next ten years that it won't exist, either. Infinity has been threatening to develop/fly this plane since at LEAST 1996, and it hasn't moved an inch since then. Nice stickgrips (if way overpriced), but that's about it.

If only it existed. Oh, right. This is just a wish list for non-existent aircraft.

I don't remember you asking about them. The aerodynamic analysis of the Long-Ez (and a couple of other planes, IIRC) were printed in a Sport Aviation article from April, 1997. The article was written by David Lednicer, who's an aerodynamicist in Washington who has worked with/for John Roncz. In multiple conversations with David, he threatened to do a COZY MKIV analysis as well, but never did (AFAIK). He ran those analyses in VSAERO, which is a panel code, NOT a full blown Navier-Stokes analysis. It is much simplified, and isn't useful for looking at flight regimes near stall, I'm led to believe. From the standpoint of figuring out where to modify a L.E. to reduce drag, you'll get a lot more bang for your buck by reading back issues of the CSA newsletter, and looking for all the articles on drag reduction.

The aluminum is far stronger (and heavier, hence the use of small bits).

Why do you say that? (I had to write more than just "Why?" - the forum apparently had a minimum post length of 10 characters).

I'm not really sure what advice you're looking for - since it's a certificated aircraft, you need an A&P to work on it (as you stated) and there's a relatively limited # of things you can do yourself. Maybe if you were more explicit in what you're looking for..... Also, given what these things cost (unless you stole it at the auction), why would you buy this thing? You can get a primo COZY MKIV for the same $$$, and do all the work on it yourself (as well as be faster, carry more, etc.)? Just curious.....

There are (AFAICT) 8 or so flying COZY's of one flavor or another in the greater L.A. area. One in Tehachapi, one in Rosamond, one up near Barstow, a couple in the Compton area, and a few out on the southern side of the San Gabriels (Cable, Chino, etc.). We're planning on having a COZY get together up at the Big Bear airport (L35) on Saturday, Oct. 22nd, for breakfast - if we're lucky, there will be 4 - 8 COZY's there. You're certainly welcome to come and check them out - I can't guarantee a ride, especially at 250 lb. and 6800 ft. elevation, but you can try them on for size, and talk about simple mods for larger folks (6' 1" is no problem, but 250 lbs is getting on the large side [although my CFII was 240 lbs and 5' 9", and we were able to squeeze into my plane, which is set up for smaller folks]). If you're seriously thinking about buying an already flying COZY, you'd be well served to be on the COZY mailing list - most of the 8 flyers in the LA area are on the list (as are ~70 other COZY flyers and ~250 builders). You should also join the canard-aviators mailing list, as well as the Central States Association (paper quarterly newsletter). There is one COZY that's for sale in the Phoenix area at this point, and possibly one on Long Island, NY. Generally, about two to five COZY's change hands every year. Contacting me via email at the address listed below is the most likely way to elicit a response.

You are correct that "unloading" the rudder can cause a flutter susceptibility, but that will only happen if the rudder is shimmed INWARD, not OUTWARD. Deflecting the rudder outward ADDS a load to it, so unless the shim (rudder stop, whatever you want to call it) has compliance (as mine had), it won't be a flutter contributor. There have been numerous instances of rudder flutter caused by folks adjusting their rudders inward (for trim reasons). This unloads the rudder. Shimming the opposite rudder outward would have achieved the same trim condition, without the flutter issue (if the shim/stop was stiff).

No. I put in an adjustable stop, so that I could tailor the T.E. position if need be for initial rigging. Turns out there was compliance in the system, and at 202 mph IAS the rudder(s) would flutter. Once I took out the adjustable stop and put in hard stops (blobs of flox, sanded flat to give the right rudder position), the flutter disappeared. The full description of the problem and solution is in the COZY archives from late 2002, I believe.

Since I am one of the folks that has had rudder flutter, the answer is "easily", if you modify it as I did (don't have a HARD stop for the inward direction). With respect to the "Full Length" rudder, the only reason not to do it from top to bottom is for the protection in a tip-back. This is not insignificant, but it's not an overwhelming reason not to do it. Velocities don't have to worry about that, since they always sit on all three wheels - no grazing.

Folks: I was asked by Bob Tilley to be a member of an accident evaluation team for Rotor-EZ N2992 which crashed in May, fatally injuring the pilot. I have posted the accident evaluation at: http://www.cozybuilders.org/N2992_Accident_Eval/ The evaluation team consisted of Bob Tilley, Steve Wright, myself, and one other well respected member of the canard community who prefers to remain anonymous. This analysis is based on some first hand visual inspection, visual inspection of photographs of the crash site and wreckage, verbal reports of eyewitnesses, and a small amount of testing of crash aircraft hardware and equivalent hardware. Although this report was written by Marc J. Zeitlin, it is the forensic engineering judgement of the whole team, and this analysis and the resulting conclusion is the consensus opinion of all four people on the investigation team. I believe that this analysis is far more detailed and accurate than anything the NTSB is likely to produce, given the lack of familiarity with the airplane type and canard concerns, and the small amount of time devoted to the investigation. This is clearly a generic "canard aircraft" issue, and the canard-aviator's mailing list is the venue which presents itself to the widest canardian audience. Although I have posted the announcement of the publication of this report to the COZY mailing list, the Canardzone Forum, and the Canard Aviation Forum as well, I do not want to carry on four conversations about the same thing. If other members of the investigation team would like to reply in other venues, that is certainly their choice - in the interest of time and energy (mine), I will only follow discussions on the C-A list.