Marc Zeitlin

Because aerobatics causes higher stresses in aircraft than non-aerobatic flights do. And per 91.307, parachutes are only required when doing aerobatics with non-crew passengers - otherwise, they're not required. Why do you ask questions that you already know the answers to? What percentage of GA flights are aerobatic? Where were we talking about aerobatics in aircraft that were neither designed or approved for aerobatics? Based on going down at 100-200 mph at a 45 degree angle after the canard comes off. Even at 100 mph, the downward velocity would be 100 fps, so impact would occur about 4 seconds after canard departure. If you believe that you can (without an ejection seat) open the canopy, unbelt, climb out, and jump out of the aircraft all within 4 seconds, more power to you. Nope. But the issue (at least in Steve Drybread's case) wasn't how close the chute would be to the ground when it opens - it's whether he could have gotten out of the plane and pulled the cord, and the answer is clearly no. I can't get out of my plane in 4 seconds sitting still on the ground, much less in the air. Those are the only situations in these canards where parachutes might have been useful that I can think of. There may be others - I just can't think of them at the moment. True. The only in-flight fire I can think of was at relatively low altitude, and the plane (a VE) was flying fine. The fatality occurred on the ground - not because the pilot couldn't get to the ground in time. I certainly wouldn't have bailed out of a flying canard airplane because there was a fire in the engine compartment. I'm not claiming that there aren't times at which a parachute might be useful - there are. I'm just claiming that modifying the aircraft to facilitate parachute usage, when the mods increase risk in other areas, may not be the optimal solution.

Of course. But how many folks flying GA aircraft wear a chute all the time? I can guarantee you it's close to zero. There's a reason for that. If you take a look at the distribution of accident types, the count of fatal ones that could have been non-fatal if a parachute was worn and used is a very small percentage of the total. Yeah, so? The list of things that would cause someone to need to jump out of an aircraft are exceedingly small - structural failure is about the only thing I can think of. There have been a total of three or four structural failures of Rutan derivative canard aircraft that I can think of, and ALL were caused by builder error or the functional equivalent - none by the design. Given all the folks that have been injured and killed by OTHER, more likely and more easily fixable problems, using something that never happens in a correctly built aircraft as a justification for mods that ADD risk in other areas seems, as I've said, counterproductive. Anyone contemplating modifications to aircraft, purportedly for safety reasons, should read Al Wick's website explanation of risk management. Actually, we should ALL read it, since most people don't have the faintest clue how to evaluate or manage risk. Nope. His canard came off at low altitude - somewhere in the neighborhood of 400 ft, IIRC - wouldn't have been enough time to do anything. Same with Paul Conner - deep stall at low altitude - 200 ft. or so - no chance for exit. Maybe Gus Sabo could have used one, but since we really don't know what happened to his plane, it's hard to say. Came apart while dodging T-Storms over Mexico at high altitude (18K ft or more) without O2. Hypoxia, loss of control - who knows.

The number is zero. Hasn't happened, or at least if it has, it hasn't been reported. So, with all the things that DO happen to these planes (canopies opening on takeoff, landing gear up, etc.), planning for things that never happen seems counterproductive.

Whether the air is moving and the wing is stationary or the air is stationary and the wing is moving is immaterial - the aerodynamics are exactly identical, since we're nowhere near relativistic speeds. Velocity doesn't matter - acceleration does - that's where forces come from. F=ma, right? At any rate, the air particles do exactly the same thing whether in a wind tunnel or over a moving aircraft wing - they don't know the difference.

You're hardly the only one in that category :-). Sounds like a plan!

Do you have a problem with it because you can't understand it, or is there some mathematical or test basis for your problem? Things are considered proven when the theory matches the data. In fact, the streamlines and downstream conditions shown in the figures on that web page match exactly with what the mathematics of inviscid flow around and airfoil predict, match CFD analyses (which needs no theory, just an understanding of the underlying physics of fluids), and also match exactly what's found in smoke tests of airfoils in wind tunnels, as well as the pressure distributions. Here's an on-line simulator: http://www.grc.nasa.gov/WWW/K-12/airplane/foil2.html Some actual flow visualization: http://www.aoe.vt.edu/~devenpor/aoe3054/manual/expt1/text.html And again: http://amasci.com/wing/airgif2.html In what way does it appear flawed, given that it matches theory, numerical analysis, and the facts? If you don't state what you think is incorrect and how, it's difficult to address the issue/question.

See: http://www.av8n.com/how/htm/airfoils.html for a pretty good explanation of how wings work. That whole site is very good, with few errors. None of that "equal transit time" crap.

I'm not arguing with you - I tried the tape, found no change in characteristics, and took it off. I've never had an issue with the ailerons on my plane, but I do know of other folks with canard aircraft that would like more effectiveness at low speeds, and there are some folks that swear that the tape gives them that. I was just pointing out the claim, not that I necessarily agree with it. What would the tape have to do with flutter resistance? Flutter is an aeroelastic phenomenon... I'm not following.

Some folks believe that it improves aileron effectiveness at low speeds (besides the small drag reduction).

With respect to pods, this was answered in post #82. The hell hole/rear seat area sump will add 3-5 gallons. Chris Esselstyn's 260 HP O-540. Not if you want to fly across the Pacific. Otherwise, as stated in post #82, how long do you want to be able to fly without getting out of the plane to stretch your legs and pee? The COZY's Vne is 220 mph IAS. Doesn't matter what engine is in it - that's the limit for a stock COZY airframe. If, for some reason, you were going to fly particularly high, so that the TAS would be very much higher than the IAS, it might be lower, but no-one knows. On a separate note, you ask a lot of questions, and that's a good thing, because it shows that you're trying to learn and understand. But it takes other folk's time to answer them, and given that you've explicitly stated that you don't want to take your time to research these questions, what you're doing is trading other folk's time for your convenience. All of these questions have been asked and answered many times before, in many places, all of which are easily searchable, either via the on-line CP's, the on-line COZY newsletters, the on-line COZY mailing list FAQ, the on-line COZY mailing list archive, the on-line canard-aviators archive, ez.org, this and other canard web fora, et. al. If you're not willing to put in the time yourself to do some research, why should other folks be willing to put in the time to answer your questions? Please - help us help you. This is for ALL folks - not just Guy.

Deltahawk is certainly an attractive option, if they ever really start selling them. They're another one that was at OSH back in 1996, claiming that they'd be shipping in a year. That's not correct. They have not certified ANY engines as of yet - they're website claims that they're HOPING to certify them in the near future. See: http://www.deltahawkengines.com/aboutdeltahawk.shtml and http://www.deltahawkengines.com/status00.shtml They're hoping for TC by the end of 2008 (which, given their history, could mean any time between 2009 and 2015). They haven't, as stated above, and if certification implied durability, Lycomings and Continentals wouldn't fail :-). Look, I'm rooting for these guys (and for Theilert to start selling in the experimental market). They've obviously got deep pockets, are making slow but steady progress, and have what will probably be a very good product. But they have NOT achieved what you claimed (yet), and it'll be sometime before they do. They've had engines in beta test for 4 years now, and still are not shipping in volume to the experimental market, much less the certificated market.

In theory? Sure. But you've got two problems - first, you'll be burning 30-50 gph, so you'll have all of a 1 hour flight duration with VFR reserves. Second, they spin the prop at 1800 RPM. Good luck handling 400 HP efficiently with a 70" propeller spinning 1800 RPM on the back of a COZY, CS or not. You'll need a LOT of large, paddle blades, and the efficiency will not be great.

I need a laugh every once in a while - thanks for bringing up zoche. They were ready for production, and would be shipping next year, back when I went to OSH in 1995. Scam. That's Gary and Char Spencer's LE, and Chrissi is correct - it's got a direct drive V-8 in it.

A L.E. with the same O-360 will be about 20 mph faster in cruise.

Huh? That's what a stock COZY MKIV will do with an O-360. On a standard day, at 8K ft., I'll generally get about 200 mph TAS on 9.4 gph. Build a COZY MKIV, and that's what you'll get.

Yup. I seem to remember a discussion about it somewhere, but can't find it. Interesting experiment. She's kind of confused about the theory behind a number of things, but her confusion doesn't affect the results much. Her concept of the lift being a combination of Bernoulli, Newton, and the "Coanda Effect" is a common misconception, and the effect of the canard on the main wing lift is not from turbulence, but from downwash (which also has nothing to do with the Coanda Effect). Not really minor nits, from a theoretical standpoint, but hey, she's an undergrad. I cringe when I read my Master's Thesis, 27 years later... She recognizes that the results may not be scalable because of the reynolds # effect, and it's clear that the canard position doesn't affect the wing lift as much as the reynolds # increases, and even less so at higher AOA's. Interesting undergrad experiment, though.

That was my interpretation as well. You, obviously, have more than enough experience to know what you're looking at/for during surface prep. For Jason, Mr. Mann continually sighs either because there's a lack of O2 in his location, or else because he's subtly expressing his displeasure with my know-it-all attitude, albeit an attitude that he shares. See: http://www.answers.com/topic/sighing?cat=health

For folks thinking of sandblasting, you may want to take a look at the "Composite Bonding Forum" presentation from 2005 at: http://www.cozybuilders.org/Oshkosh_Presentations/index.htm Abaris claims that this is a "high risk method" of increasing the surface energy of the substrate, and dependent on operator skill. (Page 23 of 51). Scaled never sandblasts composite surfaces to be bonded (or finished in any way) - we alway peelply/sand. Personally, spraying dirt at high pressure at my layups is not something I'm interested in doing. Aluminum, steel, other metals, sparkplugs - sure. Not composites - at least not for me.

What does this accident have to do with variable incidence canards? You can claim what you like, but without evidence, it means nothing. When one refers to an archive that others should search through to find information to support your claims, pointing to the stacks of magazines that you have in YOUR house hardly qualifies, whatever the definition of an archive might be. If you believe that people should pay attention to what you claim, you should be willing to back it up with facts. The aliens told me so when I was abducted - don't believe me? Look in the archive.

While there's some interesting (and somewhat accurate) discussion in the thread you quote, this says nothing about why you'd want to get rid of the Roncz airfoil (and replace it with?), which was the claim that I was asking about. Having read all of the CP's and all of the COZY newsletters, dating back to the early 1980's, we're in the same boat on exposure to canard information. There is no mention of variable incidence canards in any of the CP's or COZY newsletters (both of which are on-line and searchable), either. Remember, you referred to an "archive", not to "some boxes of stuff in my basement". Basically, in other words, you think you remember seeing something somewhere about someone who had a problem with trying a variable incidence canard on some sort of aircraft, but you can't tell us who, where, how or when, nor even point us to reference material where we might find it for ourselves. Not a data point. Claims need evidence. Again, I'm not in favor of this idea on Rutan derivative canard aircraft in any way, shape or form, but if there are going to be arguments against it, they should be accurate.

And still no reference.

Huh? How so? And why would you want to? To which archives do you refer? I have a pretty good memory, and have no recollection (in 12 years of following canard developments closely) of seeing any reference to adjustable angle of incidence canard airfoils being attempted. There was ONE anecdotal reference in the canard-aviators archive in 1999 to a memory of two engineers attempting a full-flying canard (like a stabilator), but that's not at all the same thing. Slightly more information would be useful for finding the references you claim.

Pointers to who, when, where? While I believe that this is NOT a good idea, for many reasons, I've never heard that anyone tried it. The reason for the takeoff roll/landing roll distance in canards is due to wing loading - very little of it is due to the canard configuration. This has been discussed on the mailing lists and fora many times previously. Look at any aircraft with similar wing/power loading - the takeoff/landing distances will be similar. OWT's die hard.

Depends on how much more you want. I used the AeroCad prefab strakes, and ended up with about 58 gallons if I fill it to the tippy-top. Don't let it warm up, though - I'll lose 3 gallons out the vent. You can move the inner ribs inboard and gain probably 5-10 gallons that way, but you lose luggage space in the strakes. You also move your CG forward a bit - may or may not be a large issue - probably not much. You can use baggage pods as fuel tanks - Mike Melvill did that for his round the world flight with his L.E. You can probably add 10-20 gallons that way for a COZY MKIV. All this presupposes that the 1000 NM range of the COZY with stock tanks is somehow not enough - that's 6-7 hours in the air. Many folks have installed windows in the bottom surface of the strakes so that rear seat folks can see downward. No problem. Klaus Savier has windows in the lower sides of his VE for downward vision. You could do that in a COZY in the front, but it would take some judicious thinking about what to do with the armrests, torque tube, and controls. Personally, I don't think it would help with visibility much - it's pretty simple to bank 20 degrees, look straight down, and then level out.

The company is "Ballistic Recovery Systems". It's "BRS", not "BSR". BSR, in the context of parachutes, stands for "Basic Safety Requirements". Since the Cirrus uses the chute at it's primary spin recovery methodology, and canards don't spin (nor have structural failures not caused by the pilot doing something exceptionally stupid, either in the build or during flight) Adding 60 lb. of weight to every flight to mitigate a contingency that occurs 10E-6 of the time seems counterproductive to me.