Marc Zeitlin

But it also has a T-tail, which can become blanked by the wake of the main wing in a stall attitude.

Just build it to... wait... nevermind. An aircraft gets into a deep stall when the CG is not far enough ahead of the Aerodynamic Center to ensure that the front wing will stall first. With T-tail aircraft, especially business jets that tend to have the main wing pretty far back on the fuselage, a normal stall can cause the horizontal stabilizer to be in the turbulent wake of the stalled wing. Since the stab is no longer acting like a wing, the AC of the aircraft effectively moves forward and the CG is not far enough ahead of the NEW AC to be able to get out of the stall. What the ventral fins do is create lifting surfaces far enough aft so that the AC of the aircraft will remain far enough aft of the CG, even when the horizontal stab is blanked, so that the aircraft won't deep stall. So, in this case, you need the "new" lifting surfaces to be aft of the normal AC of the aircraft so that they'll have an effect during a stall. Canard are no different - the front wing must stall first, and not allow the rear wing to stall. IF the rear wing stalled, because the CG was not far enough ahead of the AC, then you'd want to move the AC rearward (as stated above), and whatever lifting surfaces you were putting on the aircraft would have to be to the rear of the normal aircraft AC, and the more rearward the better. If you can ensure that the AC of the aircraft will always be far enough behind the CG, then you either won't be able to deep stall, or you'll be able to recover if you get into an incipient deep stall. As to the question of whether ventral strakes on the lower cowl would work for this purpose, my GUESS would be not unless they were huge, as the airflow there is pretty messed up (that's the technical term), the boundary layer is thick and they wouldn't be very far behind the normal aircraft AC, which is somewhere around the FS-104 - FS-106" point on a COZY MKIV.

The CG of the aircraft is slightly below the longerons - actually probably about 9" to a foot below the longerons. Since the winglets are above this, if they were perpendicular to the wings (which have no geometric dihedral) then when the rudders were deflected, they would create a non-balanced (by the opposite winglet) force towards the fuselage, but above the CG by about 1/2 the height of the winglet. This force times the moment arm would create a moment around the CG of the aircraft, attempting to raise the wing with the deflected rudder. With the winglet canted inward, the force vector from the rudder is pointed more closely at the CG of the aircraft, so the moment arm is smaller and the rolling moment is smaller, meaning that there's less yaw/roll coupling. Think about the extremes - if the winglets were canted inward 90 degrees, then a rudder deflection would ONLY force the wing down - it would be like an upward aileron deflection. If the winglets were canted outward 90 degrees, essentially becoming wing extensions, then a rudder deflection woudl ONLY force the wing upward, like a downward aileron deflection. While absurd conditions, analyzing these pathological cases indicates the sign of the effect, if not the magnitude. It's not. With a one degree cant inward: sin(1 degree) = .017 so the component of inward winglet lift that is directed downward is 1.7% of the total. If the inward lift is even a couple hundred pounds (I think that's way overestimated), then the downward force might be 3 - 5 lb. at an absolute maximum. This is hardly significant in the context of a 2000 lb. aircraft.

The point of increasing the effective aspect ratio is to lower the induced drag. Since, when operating at low CL's, the induced drag is a very small part of the overall aircraft drag, lowering the induced drag by a few percentage points when the induced drag is only ~20% of the overall drag will change the overall drag by well under 1%. Now, change the effectiveness of this induced drag reduction due to the cant of the winglets by a few percentage points, and the overall drag change due to the winglet cant will be so far deep into the noise (in the 0.01% - 0.1% range) that whether you had a large breakfast will have more effect on the speed of the aircraft than the winglet cant will. Whitcomb winglets make a difference when at high CL cruise. Other operating regimes don't benefit much from them, or from higher aspect ratios. I said pretty clearly: "They're vertical (or slightly inward canted) to minimize the yaw/roll coupling that would otherwise occur with rudder deflection with an outboard cant." Since the winglets are above the CG, when the rudders are deflected they will not only create a yawing torque but will also create a rolling torque, and the rolling torque will be OPPOSITE to the desired coordinated flight roll with yaw - i.e., as the right rudder is deflected, causing the nose to yaw to the right, a coordinated turn would have the right wing lowering. However, with a vertical winglet and a deflected rudder, the force vector from the deflected right rudder will cause a roll to the left to begin. Canting the winglet inward points the rudder force vector more closely at the CG so that this opposite roll torque is minimized. It has nothing to do with creating downforce (reducing lift) and thereby reducing canard lift requirements. This would make no sense whatsoever, especially given your belief that the winglets are substantially contributing to increased L/D as Whitcomb winglets - this would be in direct opposition to that effect.

Actually, they're not exactly 90 degrees (at least on the COZY MKIV, and the LE is, I believe the same as the COZY MKIV). There is a slight inward cant to the winglets in the nominal case. The tolerance on the dimension to the tip of the winglet is +/- 1 inch, so you will see some measurable and visible differences in the apparent angle of different aircraft's winglets. It makes no difference to performance, which is why the tolerance is so large. I believe that you're thinking of Whitcomb winglets, which are used to maximize L/D when aircraft are cruising at or near the max. L/D point, which would be at a much higher Lift Coefficient than EZ's normally fly at (because we're flying lower and faster than would be optimal for efficiency). In that case, the winglets ARE more efficient when they're canted slightly outboard. However, in the EZ family, that's not what the winglets are for - they're there as vertical stabilizers and rudders, not as effective aspect ratio enhancers. Whatever small effect they have at reducing spanwise flow isn't affected by tiny changes in cant angle. They're vertical (or slightly inward canted) to minimize the yaw/roll coupling that would otherwise occur with rudder deflection with an outboard cant. Since airliner winglet don't have rudders on them, they don't need to worry about this issue. I think that he was referring to the toe-in/out angle of the winglets, not the main gear, yes? If so, the dimensions on the plans explicitly determine the toe-in/out angle of the winglet, and in those cases, are toleranced to +/- 0.05". You don't get to pick your own aerodynamics for the winglets, and following the example of a 737 wouldn't be appropriate - it's an entirely different airplane, with an entirely different aerodynamic design, with an entirely different operating regime.

Agreed 100%. I think that a lot of the Rotax powered homebuilt aircraft tend to be Kitfox type low and slow planes - if something goes wrong, they just land in the closest 200 ft. long field. If you look at Rotax powered certificated aircraft (Katana's, etc.), you'll see real aircraft stuff under the hood - not car parts and crappy rubber. There's nothing intrinsically wrong with the 4-stroke rotaxes - as you say, you just need to treat anything in an aircraft like an aircraft.

Glenn did not have "engine trouble", he had an engine compartment fire most probably caused by having sub-standard fuel line components, which have nothing to do with what type of engine he had. See: http://www.cozybuilders.org/Glenn_Saunders/index.html for info on his accident.

A larger engine with a larger, higher pitched prop will produce more idle thrust. However, there's no reason (if the weight and CG of the aircraft are the same) that more thrust should cause you to have to land faster. All that's required to keep the approach path the same is more drag to balance the higher idle thrust. Remember: L=W and D=T in unaccelerated flight. So, use your landing brake, use both rudders, and/or slip. Voila - same glide path, same approach speeds as with a smaller engine/prop combination. You may need to use more brake on the ground, but that says nothing about the glide path. If folks are landing faster with larger engines, they don't need to.

What is it, after all the discussions we've had here and on other mailing lists regarding this issue, that you think the non-existant 51% rule (in actuality, the "major portion rule") means? If you study the FAA's interpretation of that question, you'll have your answer.

See NASA Technical Memorandum 85760 for an analysis of a front-engined canard aircraft, and the stability differences between it and the more common rear engine version. Especially see pages 42 onward.

Doubt it very much. First of all, from the EZjet website: http://www.ezjetinc.com/services.php "Our main business is performing engine conversions (from propeller driven to jet) on Longeze's, Berkuts, Cozy's and Velocity's. We do these upgrades on FLYABLE planes only." This is most obviously NOT a flying aircraft. Plus, nobody in their right mind would put two T-58's on a Long-EZ. Given the idle thrust, you'd have to run out of fuel before you could land.

It's Mike Bowden's Long-EZ, which had twin Jabiru 2200's (80HP) engines. His exact words, on December 15th, 2000 were: "More drag, less performance" All the photo websites referenced in his posts on the canard-aviators mailing list hare no longer active. There are three pics at: http://www.roughriver.org/2001_photos.html

This airplane has since been modified back into a single engine aircraft, since the performance was not any better than the single, with all the issues of two engines. And it most certainly wasn't a turbo prop, since no reasonable turbine engines of an appropriate size exist.

Folks: After watching years of discussions regarding the "Open-EZ" project, copyright infringement questions, plans copying questions, and the latest round of claims by various people about public domain issues, etc. (and finding myself stuck in Mojave before going home from work due to the roads being closed by the CHP since they had all of 2.3" of snow on them), I decided to ask Burt what the deal is. Here's what Burt says regarding the Long-EZ copyright ownership, public domain issues, and TERF. I cannot vouch for the legal accuracy of what he said to me, but this is what he stated. He/RAF currently still own the copyright for the Long-EZ plans and templates. They have NEVER been put in the public domain (whatever some others may claim). RAF never "authorized" TERF to sell copies of the plans, although he/RAF DID authorize them to distribute the CP's (which claim all over them that everyone is free to redistribute them). Burt's recollection is that TERF started distributing the plans without permission, although Burt told them to at least tell people not to build airplanes from them, and they do that. He was not aware that TERF was still distributing them. He did state that he has never pursued legal efforts against anyone who copied the plans and/or sold them - he just stated that he would tell anyone that asked him whether they could sell their plans, either before or after completing an airplane from them, that THEY would become the support mechanism for the next owner - RAF would not support anyone that hadn't purchased plans from RAF. He stated that while he/RAF still owns the copyrights, he would not attempt to protect that ownership by legal means. So, straight from the horse's mouth. Assuming it's accuracy, do with it what you will from a moral standpoint, knowing that you will not be pursued legally - obviously TERF hasn't been, whatever their claims of "authorization".

I do not disagree with anything you said here. The notion of bringing the plans into the 20th century, if not the 21st, with the incorporation of everything you've mentioned is an excellent idea - one that I toyed with for the COZY plans numerous times (and gave up on, given the amount of work involved - having OCR'd and digitized the COZY newsletters without ANY updating or rewriting, with Nat's permission, I've got a pretty good idea of what would be involved with doing that for the COZY plans). And I certainly do/did not question your intentions - it's fairly obvious that anyone contemplating doing a crapload of work and then giving it away has relatively pure intentions. The issue was always with the way the intentions were being expressed - i.e. copying someone else's work, and in this case redistributing something that's being sold by a licensed distributor (TERF). If TERF bought the work from you, or licensed you, or said "go for it - we're good with what you're doing", then bingo - you're done, and more power to you. Or if you rewrote the plans in your own words - same thing. But the cart was before the horse. That was my only objection. Get the ducks lined up first - then shoot them.

It's more than just "not a good idea" - it's a violation of copyright laws. Actually, I said almost exactly that in the first sentence of the second to last paragraph of my first response. I said: "If you rewrote the plans in your own words and redrew the drawings, then the infringement would be arguable." You are incorrect with respect to copyright laws. All that needs to happen for all this to be OK is for someone to get permission in writing from TERF/Rutan to do it. It sounds like someone is attempting that, and if it happens, that's a good thing. But working within the legal structure is an important aspect of the project. Stealing intellectual property is not. It's been 30 years since the LE plans were published - no one has re-written them. If it's so trivial, just do it and the canard community (or at least the 15-20 people who are interested in building brand new 2-seat canard aircraft) will thank you. It's been clearly stated that this will NOT violate any copyright laws, so there's no-one that can/would complain about the effort in any way.

Since they ARE copyrighted, as are zillions of other "plans" for doing something, and since the rights to reproduce them have been transferred to TERF, it's unclear how you could entertain this notion. Since only a lawsuit against TERF could ever resolve the question (if there is one) in court, it seems reasonable to assume that there IS a copyright (since there is) and that it's valid. They are copyrightable, and copyrighted. That's why this effort went to the trouble to reproduce them independently, rather than just copying them. "In their own words", in effect. Exactly. If someone wanted to take the 1000's of hours it would take to rewrite the LE plans in their own words, without copying or plagiarizing, but which would result in exactly the same aircraft, that would be perfectly legal and acceptable, and no-one could say boo about it.

is not a prohibition from doing so. The ONLY thing a license from RAF EVER got anyone was official support from the factory. So this isn't a license - BFD. So? 2000 aircraft have been built from those plans. You don't think a few more could be? Have people become substantially stupider, so they can't understand them anymore unless they're provided on a computer in PDF format?

Maybe your memory isn't quite as "above average" as you remember it being. So? Burt's email is readily available, as is the TERF contact information. Prior to putting in substantial effort in copying/redistributing copyrighted information, a prudent course of action would have been to contact one or both of these entities and see if they would be interested in using your efforts in a legal fashion. High Five! You smacked me down hard, and I'm feeling the pain. Like I said, anyone who's not interested in reading what I write is welcome to just ignore it or put me on the Ignore list so they never see it. No skin off my teeth. ...Long response to a useless discussion of caching elided...

The website says: "These documents are for educational & entertainment purposes." It does not say that by purchasing the CD you are enjoined from building an aircraft. Since one of the purposes of building an experimental amateur built aircraft is education, and since you purchased the CD legally, it's hard to see what rule/law/contract you'd be violating by building an airplane while referencing the documentation. Don't think so. Use the TERF CD or a set of plans bought secondhand (available from other builders, EBAY, or elsewhere). With respect to unreadable CP's, all the CP's are available in highly readable PDF format on my website. The CP's are NOT covered by any copyright, since they say on them that everyone is ENCOURAGED to redistribute them. The plans say no such thing.

Hereby acknowledged.

Fascinating that you do not choose to support your claims in your first response. Heh. Mightly low soapbox - are you sure that you aren't stepping up? Condescending - at times. Illiterate? Hardly. As*hole? Yeah, sometimes. Deserve? I don't use that word. I've earned what I've got (along with being lucky) - neither I, nor anyone else, "deserves" anything. I think you're thinking of Elliot Spitzer. Maybe you need to grow a thicker skin - you post to the forum, make a claim that you're mugging someone, and then call the person that says that they're going to get the police if you don't stop rude. Then you give them a hard time because they didn't pat you on the back and say "good boy" when you threw the purse down on the ground and ran away. Respect is earned - it is not a right. I start out respecting people, but when they do something disrespectful, well... Actually, having met you at a fly-in and given your friend a ride in my plane, I actually do have a pretty good idea of who you are. Unless you're batman, I also have a pretty good idea of what you're capable of, too. Pretty much the same as everyone else on the planet. What's that supposed to mean? I have been threatened by far more capable people than you. If you don't like to read what I write, it's pretty simple to put me on your "Ignore list". Just go to the "User CP", up at the top left of the forum control panel menu, click on "Buddy/Ignore List", and then put my name in the "Ignore" column. Voila - you'll never see my postings again, and your adrenaline and stress levels will be far lower. Get a grip. Maybe those gentle readers would be interested in having you respond to the questions I asked in my second posting, regarding my supposed support for your activities and which files I might have downloaded from a website that I can't find?

Maybe you could point me to a post with my support for your position - I couldn't find it. What other people support is of no concern to me. Interestingly enough, you stated yourself, on 2/6/2008, with respect to this issue: "Hopefully I wasn't misunderstood. I in no way want the plans or other documents from the terf cd included, all the things I listed were freely available on the web for download." Apparently you changed your mind. I don't find it surprising that I don't see what was rude about what I said, but just how much rudeness would not be excessive when pointing out extra-legal behavior? I don't have a clue what/where your website is (the link from your personal information doesn't point to anything useful), or what files you think I've downloaded from it.

Let me make this as clear as I possibly can, as someone who has access to Burt Rutan on an as-needed basis. This is a clear instance of copyright infringment. It is one thing to take hand-drawn drawing templates and re-draw them using CAD - the shapes cannot be copyrighted, and there's a reasonable argument to be made that there's no copyright infringement going on with the template distribution under the "Open-EZ" effort. However, merely taking existing written words and entering them into a computer, whether through manual typing or through OCR, and replacing the words "Long-EZ" with "Open-EZ" (while claiming, amazingly enough, that the "Open-EZ" was originally Burt Rutan's design, and keeping all of the existing plans drawings intact) does not get around copyright laws. TERF currently has the only rights from RAF to distribute Long-EZ plans, and you are CLEARLY violating these copyrights and distribution rights by doing what you are. I am in no position to issue a "cease and desist" request, but have no doubt that if this effort continues in this vein that I will ensure that the people who have an interest in this matter (Burt/RAF and TERF) will be notified of the infringement occurring. If you rewrote the plans in your own words and redrew the drawings, then the infringement would be arguable. This is most certainly not. And Jon, don't even think of bringing up "Fair Use" in the context of direct copying of a complete book and redistributing it without cost, taking revenue away from TERF who sells the plans under license. I'm disgusted. You want the plans? Buy them from TERF.

And as you well know, Rich, making people pay grievously for their errors is what I live for :-). God knows I make myself pay for mine... Not the quote I would have used, but I get the point. I was assuming a revolver - the standard tool of RR players. It's very difficult to spin the chambers on a Kalashnikov. Pretty much like engineers, or other human beings. I agree with just about everything you've said in this particular message. Been there, done that. Any search of the forum and COZY mailing list archives will turn up voluminous entries on the subject. Do unto others, and all that. Thanks for noticing. Having good typing skills (thanks, summer school in 1973) helps a lot.