Marc Zeitlin

O.K. thanks. I used "hard shell" for the search. Looks like it is not a good process.

You might want to search the COZY mailing list archives before making that judgement. There have been many discussions over the years on this technique, and it has it's place. When done correctly, the strength is more than adequate.

But... what about those that don't think it looks better? I, for one, am not smitten with the look.

I'm with you - I think it looks like crap, but that's what makes the world go round.

The theory is that by doing this the ailerons will have more undisturbed air crossing them, which will increase the roll rate/authority. However, the theory is not yet a proof and most are keeping their canards straight.

That may have been the original theory, but the folks that have the dihedral canards say that they can't tell any difference whatsoever from the straight one. Mostly, it's for looks.

decoupling in the sense that non-existing push-rods can't actuate the control surfaces when a wing is flexing.

Thanks. I can see how the hydraulics could ameliorate that issue (if it was one).

IHydraulic lines would de-couple the potential differing flexing modes of a wing and its control surfaces, which could potentially reduce flutter risk.

My gut feeling is, that this advantage will be largest for high aspect-ratio wings.

 

Does this make sense to anyone?

Not yet. What would be the mechanism for this "de-coupling", in relation to mechanical actuation?

The bandying that is usually thrown about is generally directed toward LYCOMING, not other four cylinder water cooled CAR engines. Although, the fact still remains: 3 MOVING PARTS. I don't care how you slice it- 3 will be more reliable than 40+ .....

And you determine this how - by induction? Other than handwaving, is there ANY evidence anywhere that rotary engines (wankels) are more reliable, once built up into something usable, than piston engines of ANY type? If so, I'd be glad to see it, and glad to consider using a more reliable engine, with a longer TBO, believe me. But if all you've got is "well, it's obvious, isn't it", then that doesn't cut it in the world of science, evidence, and proof. Now, you're perfectly welcome to your religion, but admit that that's what it is.

 

and if you can't see that look at the rotary's big brother: it's called a turbine. Maybe you've heard of those. I don't see 40+ moving parts on them either, do you?

Other than having parts that move in a vaguely circular motion, there is no familial connection between gas turbine engines, which run on the Brayton thermodynamic cycle, and wankels, which run on the Otto thermodynamic cycle. One is continuous combustion, and one is intermittent. No comparison.

 

And we would all like to have the level of reliability of a turbine, right?

Absolutely. But without the fuel burn or expense. But this has nothing to do with Wankel engines, because they're not gas turbines.

 

Alot of guys that are crying about the rotary are just pissed because they just realized they could've purchased a more reliable power source with less money and a longer TBO.

I've flown 338 hours in the past 3.5 years. There are a couple of auto engine conversions in canards that have flown that much, and reliably, but it's certainly not the norm. I would have liked a Subaru in my plane, but I wasn't willing to be the first to do it, and given the lack of evidence of reliable operations of either Subarus or Mazdas in canard pushers, I'm still glad I went the direction I did. When you've flown 100 hours/year for 3 to 5 years running, without having to perform any major surgery, I'll be happy to consider copying your engine installation.

 

Stick with your Lycoming, or Subaru, or whatever you have. That's your choice.

Why, thank you for the permission.

 

This thread was reanimated by someone asking about resale value. The answers that he got were accurate with respect to that - the resale value will probably be lower, but the cost of the build will be lower too. What was forgotten is that aircraft engines, over the past 5-15 years, have been APPRECIATING in value - you can sell a runout O-360 for what you would have purchased a 500 hour engine for 15 years ago. I don't think that has happened, or will happen, with auto engine conversions. Calculating the cost of ownership of a homebuilt aircraft is not simple - it is extremely dependent upon what assumptions you make regarding the cost of money, the appreciation rate of the engine and/or airframe, and many other factors. Maybe auto engines are more cost effective in the long run, and maybe not. I could cobble #'s together to prove it either way.

 

Use an auto conversion if you like - there's nothing wrong with doing so, and you'll have a good time trying to figure out how to make it work (just as I did with my Lycoming engine). But don't do it on the false premise that there's some intrinsic advantage, either in reliability, cost, or fuel economy. All of those claims have yet to be substantiated by evidence.

 

In the end, I rebuild my motor with a 15$ set of sockets and a torque wrench. Try doing that with a piston engine.

I have - a couple of times. One four cylinder motorcycle, and one car. No big deal.

..... Who needs an A&P mechanic when you only have 3 moving parts? Gets rid of alot of guess work.

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.

....I really don't understand the reason it's OK to breathe pressurized air on a comercial jet, on a Lancair or in a scuba tank, but not out of an aviation bottle. Can you elaborate?

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.

 

Also, on the Cozy, is the reason it can't be pressurized because (a) too many holes, it's impossible to seal, (b) the structure isn't built to withstand that type of outward force, © the materials (foam vs. molded Lancair), (d) some combination of the above, (d) none of the above, something else?

a) correct

b) correct

c) nope - hand layups COULD be designed to withstand the pressure - they just weren't in this case

 

Hope this helps.

.... For long distance high altitude flying, whats the most common way to supply pressurized air?

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.

 

Do most people just use bottles or is there a way to run a compressor off the engine (or electrically) to a small tank? I ask this because I see people talking about long duration (say NY to GA) flights.

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.

 

 

... Im curious as to why there cant be a fuel selector like in general aviation... left, right, both, or off.

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.

 

Whether its fuel injected with return lines or carberated, wouldnt this be the simplest in terms of pilot workload?

"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).

 

Is the complexity of the cozy/canard fuel system due to the low wing layout?

The COZY fuel system is no more complex than any other low wing GA aircraft.

'Gift' usually works too. Make sure that no bills, invoices etc are included with your parcel. Have them mailed seperate.

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

.... If you need more than 400 lbs in the front seat, you can build a wider canard and test with that.

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.

Considering that the cutoff date was last year, it would seem a pilot of a new EXP is in a catch-22 situation.

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?

Quick question... I know that some of the Subaru and Rotary installs put out 200+hp, do experimental flyers using them need to get a high performance endorsement?

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.

 

Or is the first rule of autoconversion fight club that we don't talk about autoconversion fight club?

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......

I sent Al an email about a month ago but didn't hear back from him.

You're not the first, apparently - many others have reported the same thing.

 

I asked how many Aerocanards are flying and being built as I don't 'hear' or see anything about them in any of the forums.

 

Does anyone know the #s?

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.

Is there a difference between the wing of the Long EZ as opposed to the Cozy Mark IV? Or is the only real difference in the wider fuselage? Can the wings from one be used on the other? Thanks

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

I'm a newbie with a noobe Q?... what is the dihedral effect?

See:

 

http://canardaviationforum.dmt.net/showpost.php?p=24834&postcount=14

 

and

 

http://www.centennialofflight.gov/essay/Theories_of_Flight/Stability_II/TH27G8.htm

are the canted up ends of the wings on the white (or is that whight) knight considered winglets?.... do the white knight's whinglettes do either?

No. They're really "dihedral effect" adjustments after the fact.

 

At least that's what I've been told.

Jon Matcho said:

Per the Fair Use clause of US Copyright Law, copying for research and education (the basis of the FAA definition of 'experimental aircraft') is NOT illegal. Reference Chapter 1 Section 107 of the Copyright Law of the United States.

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.......

 

The main drawback IMHO to grass field / soft field operations with a canard design such as the Rutan derived ones, is more of a wing shape issue.

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.

 

The wings are designed for high speed operation .....

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.

 

Tractor aircraft has better leverage from the lifting standpoint......

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.

 

An elevator in conventional aircraft works with gravity ......

Hmmm, same issue as above - no clue what you're on about.

 

The wheel drag on a grass strip is much greater than a solid surface strip.

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.

 

Although the drag on both aircraft lessens as it approaches VR, the tractor type, especially tail-draggers, will lessen the drag of the wheels more efficiently and more quickly than it's canardian cousin.

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.

Can someone explain at what point in the build process of a Long-EZ you need the templates?....

Right from the beginning. the first thing you do is build bulkheads, and the only way you can do that is with the templates.

 

.... Can I actually do any contruction without the templates?

Almost none that will get you anything that looks like an airplane.

You knowing the three sayings:

(3) "The proof is in the pudding."......

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.

I'd be very happy with an INFINITY 1, with Subaru SVX 3.3 L turbo and intercooler at about 350 hp. This tandem 2-seater aircraft's Vne of 400kts (460 mph or 740 km/h) surely makes it something out of the ordinary - and economical at the same time.

With a kit price of less than $33,000 and a range in excess of 1600 miles, it's the closest we'll come to a personal fighter aircraft at a reasonable price.

gupri

If only it existed.

 

Oh, right. This is just a wish list for non-existent aircraft.

dpaton said:

I'd love to know who did them originally, but no one seems to want to share if they know.

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.

..... Is it fair to say that the Aluminim hardpoints, which the engine mount connects to, is stronger or equally strong as the fiberglass layups which surroud it.?......

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

Surprises me that Marc Zeitlin isn't among them.

Why do you say that?

 

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