Marc Zeitlin

As has been discussed previously, the reason for the 205/206 NOT being approved for VE/LE/COZY's had nothing to do with structural properties, and all to do with cure times and exotherming. Since the Berkut KIT comes with all major parts fabricated (spars, wings, etc), and the only thing that the builder does is ASSEMBLE parts with tapes, etc., the dangers of exotherming from large, deep, heavy layups is very much reduced. There's NO WAY you could lay up a spar cap using 105/205/206 without having an exotherm, but 2 BID tapes are no problem. Since you're building from scratch, not a kit, I'd stay away from the 205/206 for any of the large layups, and just use them for tapes/filling, if I were you (and anyone else not building from a kit).

Way. 7890

Sherman, set the wayback machine to 1995, or 1996. Wow - look at Oshkosh - I haven't been here for 10 years. Cool stuff - look at this - here's a 4-cylinder 2-stroke diesel - company name, Deltahawk or somesuch - just perfect for the COZY I just started building. When will they have them ready? What - next year? That's terrific - I won't quite be ready for an engine then, so by the time I am a couple years later, they'll have a bunch of them in the field with lots of time on them. Fast forward to 2007. Still in beta testing... Look how blue I've gotten in the intervening 11 years, holding my breath for so long. Not healthy. What people SAY they're going to do, what they PLAN to do, and what they actually DO are three very different things. Only what they DO matters.

Dr. Pepper out the nostrils again - dang!

Elimination of the centerline heat duct will also substantially weaken the structure of the fuselage, too. The heat duct is an integral part of the stiffening of the fuselage floor. I would NOT recommend removing it, no matter what you use for heating. Maybe, if you can afford the headroom loss.

There's Steve Drybread's Berkut canard coming off due to the canard attach bolts not being installed. There's Gus Sabo's plane coming apart at high altitude, probably due to hypoxia and flight through T-Storms in Mexico. There's one report in the CP's of a VE/LE winglet departing the aircraft due to peel ply being left in the structural layups. There's a French COZY that had a fatal crash, and post crash inspection showed multiple build errors in layups in multiple areas of the aircraft - IIRC the COZY newsletters have that one reported. There may very well be more that I can't think of. Read the CP's from start to finish. Read the COZY newsletters from start to finish. Read the accident reports on the NTSB web site (and the two reports that I've got on my web site).

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.