[RCSE] Canards-- what a canard!!!
Well, why are there no glider canards (Ducks in French) around, in other words, why are so very few aircraft designed with the stabilisator first, Donald asked. There are several reasons for that, some of them simple, some less so. First, the forward wing (of any plane) must always stall first. This leads to using more cambered airfoils on the front wing, or smaller chord, or higher aspect ratio, or high wingloading, and/or the use of extreme rigging angles. The Lockspeiser 3/4 scale prototype utility aircraft used three identical wing surfaces, the nose wing being set at an usual rigging angle, to lower its stalling speed, while the right and left wing panel had a pronounced dihedral, complemented with very big winglets. Its flying characteristics were described as interesting Not the most efficient of planes, but very cheap to manufacture, as all ribs were identical, the fuselage had constant cross section and so on. On a pure glider canard, when you are approaching stall, say in a thermal, you lose your elevator first, as it is situated on the front wing surface - which has to stall first unless you want to crash into the ground tail first - not a nice situation. So many practical canards, like the Saab Viggen just has trimming flaps on the forward wing, and have elevons/elevators on the main wing. Let's say we use a fairly high aspect ratio canard wing, of small chord, in front of the main wing. This will stall as predicted before the main wing and is possible to build without excessive costs. We now have to deal with the canard wing's tip vortices, that will hit the main wing midspan, and the difference in downwash angle for the main wing's innner sections and outer sections, a sure drag-producing way of designing an aircraft's wing arrangement. And fitting elevators to the main wing of a conventional canard means that they will be very inefficient, being so close to the CG, unless very big, so that is not a great alternative either. So let's say we have a high aspect nose wing, of greater span than the rear wing, with higher wing loading than the rear wing. Nice, good, simple. Sadly, this is just like how we design conventional, tail-equipped planes, so we already know that this works. So such a canard (following conventional design rules) probably works quite well, but we probably end up with a heavy plane (the high aspect ratio forward wing has still to be torsionally stiff, and as it is of smaller chord than the main wing it might easily weigh more than the main wing)! A bonus is that the extreme ends of the canard (beyond the span of the main wing) can be equipped with ailerons, to boost rolling power, but that is the nowm of conventional airplanes anyway, that the front wing carries the ailerons and the rear carries the elevators! Adding ailerons to the front wing of a normal canard, with a front wing of the same, or shorter span, than the main wing is a no-no, as the effects of the upwash/downwash from the moving ailerons will upset the flow over the rear wing, and might even result in control reversal! The aileron-equipped version of Lazy Bee suffers from this, to some extent, as the tail has such a big span compared to the wing, so it rolls not much better than the original version, which has no control surfaces on the wing itself. Tailerons, on the other hand, might work very well! As anyone tried it? Back to canards: So, while a canard can use flaps on both canard and main wing (the latter's doubling as elevators - flappevators?), things are much easier if we add a tail to this equation. Say we build a conventional plane with a conventional tail, but add a pair of auxilliary wing surfaces under the main wing, which we can rotate at will we are close to the ideal arrangement, as it doesn't really matter if it is the wing or theses auxilliary surfaces that stall first, as they are so very close together. This arrangement of wing surfaces is called Junkers' flaps (as used on Ju-52s and other aircraft) and is very efficient on models, too, as long as the gap is kept to a minimum. One student of Martin Hepperle did make some wind tunnel test the other year that proved that it worked well on models (have not seen the paper but had a letter from Martin about this). You can then use a main wing with almost nil camber with fullspan flaps, also of nil camber, mounted slightly below, and slightly forward, of the main wing's extreme TE. The control surfaces could as usual be subdivided into three sections, the outer acting as droopable/crowable ailerons, the middle as flaperons and the inner as pure flaps, or 80% flaps and 20% flaperons. Even Burt Rutan, who was initially inspired by the Saab Viggen, has stated that unless your aircraft is designed for very extreme use a conventional layout is always better. For deltas adding a delta, or swept, nose wing is sensible, as it improves the lift at high angles of attack, as it increases the wingtip vorticies. Once saw a guy with a
RE: [RCSE] Canards-- what a canard!!!
QWERTY is the term applied to a specific keyboard layout,(preceded by the teletype or telegrapgh keyboard). It is also a concept in education refering to an outdated technology or method of thinking adhered to for no other reason than convention, convenience, or habit, not a literal example limited to those specific keys. Actually thec purpose of the QWERTY keyboard was to intentionally slow down typists, not make it easier for them. I only picked alphabetical as one alternative. other more ergonomic setups have been tried and largely rejected as well. I would beg to differ on the euro keyboard, most folks can't just adapt easily as you intimate. I have German friends who tried to use our keyboard system, it was difficult for them, and they were skilled users, but I asume you would argue it is easier to go the other way. Lighten up it was a for fun analogy, and a good one. My point stands. We still use QWERTY keyboards over other similar if improved examples for the reasons I stated. Canards, well, that's another story, here comes the debate... Happy new year, JD -Original Message- From: Monkey King [mailto:[EMAIL PROTECTED]] Sent: Saturday, December 29, 2001 1:00 PM To: John Derstine Cc: glidergeek; [EMAIL PROTECTED] Subject: RE: [RCSE] Canards-- what a canard!!! On Sat, 29 Dec 2001, John Derstine wrote: There are not more canards for the same reason we keep QWERTY next to each other on a computer keyboard. Typwriter keyboards were designed so that a fast typist could not jamb the arms when typing quickly. It was discovered early that putting the above letters in that order would solve that problem. Actually, the design is to put frequently-used combinations in slightly awkward positions so they don't get hit at the same time. That applies to the entire keyboard, not just the qwerty combo. Today there is no need to do that, but we still hang on to the convention of QWERTY, there is no reason to do so today, it is a habit, a convention mindlessly branded into our culture. It would probably be easier to teach children to type in alphabetical order, but we cannot divorce ourself of our mindset. sigh... That mistake is made *all the time*. Alphabetical keyboards are, for all intents and purposes, random. As a random layout, they are difficuly to use. The Dvorak keyboard, for instance, supposedly solves the qwerty problem. It makes a bit more theoretical sense than qwerty, but it beats the pants off of any random (including alphabetical) layout. Maybe it is too much trouble to retool our minds and preconceptions. Perhaps it would be too expensive to shift production and impossible to retrain everyone. It's actually not that hard. It's like typing on a European keyboard if you're American. You pick it up pretty easily. Conventional tailed aircraft are not better, but it is culturally ingrained as the way to do it. Which is weird since the Wrights used canards. Rutan likes them because they offer maneuverability without sacrificing stability. I like them because they're sexy. RCSE-List facilities provided by Model Airplane News. Send subscribe and unsubscribe requests to [EMAIL PROTECTED] RCSE-List facilities provided by Model Airplane News. Send subscribe and unsubscribe requests to [EMAIL PROTECTED]
[RCSE] Canards-- what a canard!!!
Okay, all you aero junkies: When I was a kid, Burt Rutan was everybody's hero, and the canard planform was the answer to everyone's quest for maximum efficiency. You know the argument, the canard up front has a lifting force in the upward direction, and the wing also has a lifting force in the upward direction, where a conventional stabilizer back at the tail must endure an efficiency-consuming download to counter the lift/weight couple. Canards resist the stall because the forward 'wing' stalls before the main wing can stall, the downwash from the forward 'wing' induces just the right downward flow for the upward swing into the leading edge of the main wing, etc., etc. So, WHERE ARE ALL THE CANARDS Why do all the World Class sailplanes with a glide ratio of close to 60 to 1 have conventional tails? Why do all the pylon racers at Reno have a conventional tail? Why do all the corporate jets and fighter planes and RPVs and bush planes and flying boats and puddlejumpers and just-about- everything-else all have conventional tails? The Rutan Vari-Eze was supposed to be the shape of things to come. In the years since, the Beech Starship has fallen into ignonimity and the Solitaire is a relic of the fanciful notions of the past. WHERE ARE ALL THE CANARDS??? Don't even get me started on flying wings! Don Bailey Snohomish WA RCSE-List facilities provided by Model Airplane News. Send subscribe and unsubscribe requests to [EMAIL PROTECTED]
Re: [RCSE] Canards-- what a canard!!!
In a message dated 12/29/01 5:57:46 AM Pacific Standard Time, [EMAIL PROTECTED] writes: Why do all the pylon racers at Reno have a conventional tail? If I remember correctly, the Berkut, a re-designed long-eze built in Santa Monica, CA has been in the Reno air races the last couple of years. I'm not sure how it did though. BTW, my understanding is that Rutan thinks that the Berkut is a nice re--design of his plane. Kevin Andersen (closet canard lover)
RE: [RCSE] Canards-- what a canard!!!
There are not more canards for the same reason we keep QWERTY next to each other on a computer keyboard. Typwriter keyboards were designed so that a fast typist could not jamb the arms when typing quickly. It was discovered early that putting the above letters in that order would solve that problem. Today there is no need to do that, but we still hang on to the convention of QWERTY, there is no reason to do so today, it is a habit, a convention mindlessly branded into our culture. It would probably be easier to teach children to type in alphabetical order, but we cannot divorce ourself of our mindset. Maybe it is too much trouble to retool our minds and preconceptions. Perhaps it would be too expensive to shift production and impossible to retrain everyone. Conventional tailed aircraft are not better, but it is culturally ingrained as the way to do it. John Derstine Endless Mountain Models [EMAIL PROTECTED] http://www.scalesoaring.net/EMM/rand.htm -Original Message- From: glidergeek [mailto:[EMAIL PROTECTED]] Sent: Friday, December 28, 2001 11:55 PM To: [EMAIL PROTECTED] Subject: [RCSE] Canards-- what a canard!!! . So, WHERE ARE ALL THE CANARDS Why do all the World Class sailplanes with a glide ratio of close to 60 to 1 have conventional tails? Why do all the pylon racers at Reno have a conventional tail? Why do all the corporate jets and fighter planes and RPVs and bush planes and flying boats and puddlejumpers and just-about- everything-else all have conventional tails? RCSE-List facilities provided by Model Airplane News. Send subscribe and unsubscribe requests to [EMAIL PROTECTED]
RE: [RCSE] Canards-- what a canard!!!
Just as with any quest for a design that answers certain parameters, you shake out the ones that do not quite make it. From airliners to sailplanes to fighters, in any class of service, as designs refine they all seem to converge. Airliners all look alike now, 2 engines etc; sailplanes all have swept leading edges, t-tails, etc. The canard is a feasable concept, but for a certain goals does not result in the most effecient ship, maybe safer under certain conditions, but even then they are not a total fix (they may not stall in the typical sense, but they can sure fall from the sky under the right circumstance). The Starship was a great concept, and one cool looking airplane, but the Kingaire for the money was a much more feasable answer for most. Technical evolution, the market, and consumer tastes are tough task masters and the canard just did not quite make the grade in the game. Marc -Original Message- From: glidergeek [mailto:[EMAIL PROTECTED]] Sent: Friday, December 28, 2001 11:55 PM To: [EMAIL PROTECTED] Subject: [RCSE] Canards-- what a canard!!! Okay, all you aero junkies: When I was a kid, Burt Rutan was everybody's hero, and the canard planform was the answer to everyone's quest for maximum efficiency. You know the argument, the canard up front has a lifting force in the upward direction, and the wing also has a lifting force in the upward direction, where a conventional stabilizer back at the tail must endure an efficiency-consuming download to counter the lift/weight couple. Canards resist the stall because the forward 'wing' stalls before the main wing can stall, the downwash from the forward 'wing' induces just the right downward flow for the upward swing into the leading edge of the main wing, etc., etc. So, WHERE ARE ALL THE CANARDS Why do all the World Class sailplanes with a glide ratio of close to 60 to 1 have conventional tails? Why do all the pylon racers at Reno have a conventional tail? Why do all the corporate jets and fighter planes and RPVs and bush planes and flying boats and puddlejumpers and just-about- everything-else all have conventional tails? The Rutan Vari-Eze was supposed to be the shape of things to come. In the years since, the Beech Starship has fallen into ignonimity and the Solitaire is a relic of the fanciful notions of the past. WHERE ARE ALL THE CANARDS??? Don't even get me started on flying wings! Don Bailey Snohomish WA RCSE-List facilities provided by Model Airplane News. Send subscribe and unsubscribe requests to [EMAIL PROTECTED] RCSE-List facilities provided by Model Airplane News. Send subscribe and unsubscribe requests to [EMAIL PROTECTED]
RE: [RCSE] Canards-- what a canard!!!
On Sat, 29 Dec 2001, John Derstine wrote: There are not more canards for the same reason we keep QWERTY next to each other on a computer keyboard. Typwriter keyboards were designed so that a fast typist could not jamb the arms when typing quickly. It was discovered early that putting the above letters in that order would solve that problem. Actually, the design is to put frequently-used combinations in slightly awkward positions so they don't get hit at the same time. That applies to the entire keyboard, not just the qwerty combo. Today there is no need to do that, but we still hang on to the convention of QWERTY, there is no reason to do so today, it is a habit, a convention mindlessly branded into our culture. It would probably be easier to teach children to type in alphabetical order, but we cannot divorce ourself of our mindset. sigh... That mistake is made *all the time*. Alphabetical keyboards are, for all intents and purposes, random. As a random layout, they are difficuly to use. The Dvorak keyboard, for instance, supposedly solves the qwerty problem. It makes a bit more theoretical sense than qwerty, but it beats the pants off of any random (including alphabetical) layout. Maybe it is too much trouble to retool our minds and preconceptions. Perhaps it would be too expensive to shift production and impossible to retrain everyone. It's actually not that hard. It's like typing on a European keyboard if you're American. You pick it up pretty easily. Conventional tailed aircraft are not better, but it is culturally ingrained as the way to do it. Which is weird since the Wrights used canards. Rutan likes them because they offer maneuverability without sacrificing stability. I like them because they're sexy. -J John Derstine Endless Mountain Models [EMAIL PROTECTED] http://www.scalesoaring.net/EMM/rand.htm -Original Message- From: glidergeek [mailto:[EMAIL PROTECTED]] Sent: Friday, December 28, 2001 11:55 PM To: [EMAIL PROTECTED] Subject: [RCSE] Canards-- what a canard!!! . So, WHERE ARE ALL THE CANARDS Why do all the World Class sailplanes with a glide ratio of close to 60 to 1 have conventional tails? Why do all the pylon racers at Reno have a conventional tail? Why do all the corporate jets and fighter planes and RPVs and bush planes and flying boats and puddlejumpers and just-about- everything-else all have conventional tails? RCSE-List facilities provided by Model Airplane News. Send subscribe and unsubscribe requests to [EMAIL PROTECTED] RCSE-List facilities provided by Model Airplane News. Send subscribe and unsubscribe requests to [EMAIL PROTECTED]
RE: [RCSE] Canards-- what a canard!!!
On Sat, 29 Dec 2001, Marc Gellart wrote: converge. Airliners all look alike now, 2 engines etc; Except for those with 4 engines. And winglets. And engines on the tail/inboard/combo. sailplanes all have swept leading edges, t-tails, etc. Except for those with V tails or cross tails. The canard is a feasable concept, but for a certain goals does not result in the most effecient ship, maybe safer under certain conditions, but even then they are not a total fix (they may not stall in the typical sense, but they can sure fall from the sky under the right circumstance). The Starship was a great concept, and one cool looking airplane, but the Kingaire for the money was a much more feasable answer for most. Technical evolution, the market, and consumer tastes are tough task masters and the canard just did not quite make the grade in the game. So you're saying that the Viggen and Eurofighter are no good and behind the times? No, no, this nut ain't yet cracked. And when it is, I'll have to find a new art. -J Marc -Original Message- From: glidergeek [mailto:[EMAIL PROTECTED]] Sent: Friday, December 28, 2001 11:55 PM To: [EMAIL PROTECTED] Subject: [RCSE] Canards-- what a canard!!! Okay, all you aero junkies: When I was a kid, Burt Rutan was everybody's hero, and the canard planform was the answer to everyone's quest for maximum efficiency. You know the argument, the canard up front has a lifting force in the upward direction, and the wing also has a lifting force in the upward direction, where a conventional stabilizer back at the tail must endure an efficiency-consuming download to counter the lift/weight couple. Canards resist the stall because the forward 'wing' stalls before the main wing can stall, the downwash from the forward 'wing' induces just the right downward flow for the upward swing into the leading edge of the main wing, etc., etc. So, WHERE ARE ALL THE CANARDS Why do all the World Class sailplanes with a glide ratio of close to 60 to 1 have conventional tails? Why do all the pylon racers at Reno have a conventional tail? Why do all the corporate jets and fighter planes and RPVs and bush planes and flying boats and puddlejumpers and just-about- everything-else all have conventional tails? The Rutan Vari-Eze was supposed to be the shape of things to come. In the years since, the Beech Starship has fallen into ignonimity and the Solitaire is a relic of the fanciful notions of the past. WHERE ARE ALL THE CANARDS??? Don't even get me started on flying wings! Don Bailey Snohomish WA RCSE-List facilities provided by Model Airplane News. Send subscribe and unsubscribe requests to [EMAIL PROTECTED] RCSE-List facilities provided by Model Airplane News. Send subscribe and unsubscribe requests to [EMAIL PROTECTED] RCSE-List facilities provided by Model Airplane News. Send subscribe and unsubscribe requests to [EMAIL PROTECTED]
RE: [RCSE] Canards-- what a canard!!!
QWERTY is the term applied to a specific keyboard layout,(preceded by the teletype or telegrapgh keyboard). It is also a concept in education refering to an outdated technology or method of thinking adhered to for no other reason than convention, convenience, or habit, not a literal example limited to those specific keys. Actually thec purpose of the QWERTY keyboard was to intentionally slow down typists, not make it easier for them. I only picked alphabetical as one alternative. other more ergonomic setups have been tried and largely rejected as well. I would beg to differ on the euro keyboard, most folks can't just adapt easily as you intimate. I have German friends who tried to use our keyboard system, it was difficult for them, and they were skilled users, but I asume you would argue it is easier to go the other way. Lighten up it was a for fun analogy, and a good one. My point stands. We still use QWERTY keyboards over other similar if improved examples for the reasons I stated. Canards, well, that's another story, here comes the debate... Happy new year, JD -Original Message- From: Monkey King [mailto:[EMAIL PROTECTED]] Sent: Saturday, December 29, 2001 1:00 PM To: John Derstine Cc: glidergeek; [EMAIL PROTECTED] Subject: RE: [RCSE] Canards-- what a canard!!! On Sat, 29 Dec 2001, John Derstine wrote: There are not more canards for the same reason we keep QWERTY next to each other on a computer keyboard. Typwriter keyboards were designed so that a fast typist could not jamb the arms when typing quickly. It was discovered early that putting the above letters in that order would solve that problem. Actually, the design is to put frequently-used combinations in slightly awkward positions so they don't get hit at the same time. That applies to the entire keyboard, not just the qwerty combo. Today there is no need to do that, but we still hang on to the convention of QWERTY, there is no reason to do so today, it is a habit, a convention mindlessly branded into our culture. It would probably be easier to teach children to type in alphabetical order, but we cannot divorce ourself of our mindset. sigh... That mistake is made *all the time*. Alphabetical keyboards are, for all intents and purposes, random. As a random layout, they are difficuly to use. The Dvorak keyboard, for instance, supposedly solves the qwerty problem. It makes a bit more theoretical sense than qwerty, but it beats the pants off of any random (including alphabetical) layout. Maybe it is too much trouble to retool our minds and preconceptions. Perhaps it would be too expensive to shift production and impossible to retrain everyone. It's actually not that hard. It's like typing on a European keyboard if you're American. You pick it up pretty easily. Conventional tailed aircraft are not better, but it is culturally ingrained as the way to do it. Which is weird since the Wrights used canards. Rutan likes them because they offer maneuverability without sacrificing stability. I like them because they're sexy. RCSE-List facilities provided by Model Airplane News. Send subscribe and unsubscribe requests to [EMAIL PROTECTED]
