karel wrote:

> has the canard concept ever been applied to a flying boat?
> with pusher propellers?
> if not, any good reasons?
>
> KA
> (just wondering)

(1911 Voisin)
http://www.fiddlersgreen.net/AC/aircraft/Voisin-canard/info/info.htm

karel wrote:
> has the canard concept ever been applied to a flying boat?
> with pusher propellers?
> if not, any good reasons?
>

I know someone who made a VW powered canard equipped amphibian.
Dunno if it was a pusher or a puller, I'll ask next EAA meeting.

IIUC, the plane flew well in the air but would not break free of
the water at less than 70 mph. Considering that until then, the
air rudder was ineffective and the water rudder became ineffective
around 40 - 45 mph that make takeoffs a bit hairy.

He said landing speed on the water was also around 70 mph, not
sure of the reason for that, surely his stall speed was lower.

That plane has been dismantled and the engine used for his current
non-canard amphibian project (tractor), now undergoing taxi tests.

AFAIK, no website.

--

FF

yep ...

XTC amphibian
Also the Merganser (spelling ??) Circa late 70's. Not sure if it ever flew.
This is the VW design refered to by another post.


"karel" > wrote in message
...
> has the canard concept ever been applied to a flying boat?
> with pusher propellers?
> if not, any good reasons?
>
> KA
> (just wondering)
>
>

.......... :-)) wrote:
> yep ...
>
> XTC amphibian
> Also the Merganser (spelling ??) Circa late 70's. Not sure if it ever flew.
> This is the VW design refered to by another post.
>

A couple of weeks ago I was talking with Mr Merganser (also unsure of
the spelling) at a fly-in. He said the earlier attempt flew
beautifully
in the air but landing it was too dangerous. I previously heard about
the problems taking off from the water second hand.

This rather clearly implies that it did in fact, fly. His present
amphibian project is not a canard design.

Don't canard designs have a reputation for requiring a smooth
landing strip (paved, dry lakebed, etc) in order to take off
in a reasonable distance? Supposedly this is because a bumpy field
interferes with the establishment of laminar flow over the canard.

Seems like you'd have the same problem taking off from water.

--

FF

On 19 Jul 2005 06:06:37 -0700, wrote:


>
>Don't canard designs have a reputation for requiring a smooth
>landing strip (paved, dry lakebed, etc) in order to take off
>in a reasonable distance? Supposedly this is because a bumpy field
>interferes with the establishment of laminar flow over the canard.
>
>Seems like you'd have the same problem taking off from water.

I knew a clown once who had an amazing snake oil style. claimed to
undertake design projects on commission "...by the way here is my
latest experimental design." it was basically a longeze with a
hovercraft skirt for amphibious use. slick brochures and all.
ignoring the absurdity of his snake oil, what became evident is that
the resistance of hitting any wave during takeoff would have caused a
pitch down of the aircraft which would have stalled the canard
immediately causing a nosedive beneath the next wave.

thank heavens no one ever bought one.
Stealth Pilot

Stealth Pilot wrote:
> On 19 Jul 2005 06:06:37 -0700, wrote:
>
>
> >
> >Don't canard designs have a reputation for requiring a smooth
> >landing strip (paved, dry lakebed, etc) in order to take off
> >in a reasonable distance? Supposedly this is because a bumpy field
> >interferes with the establishment of laminar flow over the canard.
> >
> >Seems like you'd have the same problem taking off from water.
>
> I... it was basically a longeze with a
> hovercraft skirt for amphibious use. slick brochures and all.
> ignoring the absurdity of his snake oil, what became evident is that
> the resistance of hitting any wave during takeoff would have caused a
> pitch down of the aircraft which would have stalled the canard
> immediately causing a nosedive beneath the next wave.

Hmm. ISTM that a canard does not stall when the aircraft pitches
down, it stalls when the aircraft pitches up. Thus each time the
aircraft hits a bump or wave the nose pitches up stalling the canard
so that the nose of the aircraft comes down hard into the next
wave or onto the next bump and then nosedives under the wave or
bounces higher and stalls again.

Thanks, now I have a much better understanding of the rough field
take-off problem with a canard.

--

FF


>
> thank heavens no one ever bought one.
> Stealth Pilot

My distant relatives built several canard biplane pusher seaplanes
between 1911 and 1917. The used engines that they built themselves.
The planes were turned with their patented "Jib Sheet Rudder" which was
a surface the was mounted on the outside interplane struts between each
wing and pivoted to the outside to turn the plane. It was supposed to
have worked very well.

If you can find a copy of Jane's Planes from back then look for the
Boland Aeroplane and Motor Company. There is also a book called "Wings
of the Weird and Wonderful" that has a picture of the landplane
version.

Michele


karel wrote:
> has the canard concept ever been applied to a flying boat?
> with pusher propellers?
> if not, any good reasons?
>
> KA
> (just wondering)

The Rutan style smaller wings canards you see today are designed for
aerodynamic efficiency and speed and not for load carrying capacity.
Some of the canard efficiency (and turbulence advantage) is that both
the canard and main wing is lifting, whereas in conventional aircraft
the tail is actually pushing down. The canard flies just like other
wings - obeys the same law of physics - but current canard wing designs
are for higher stall speeds to stall before the main wing, a flight
safety feature. That means the landing/takeoff speed is limited by the
relatively high stall speed of the small canard wing. Canard aircraft
are generally more CG sensitive and the canard stall speed is dependent
on the CG position - means longer takeoff for front CG and shorter for
aft CG. By contrast the conventional design has the CG near lift center
of main wing which carries most of the load and essentially dictates
the stall speed - considerably lower for the large wing. It is possible
to design a canard with large wings and lower stall speeds suitable for
water landing. It would probably look something like the Wright
brothers design with the canard way out up front to minimize the canard
wing CG position dependency. But why bother.
--------------------------------------------------------------
SQ2000 canard: http://www.abri.com/sq2000

fredfighter wrote:

> Hmm. ISTM that a canard does not stall when the aircraft pitches
> down, it stalls when the aircraft pitches up.

Correct.

> .... Thus each time the
> aircraft hits a bump or wave the nose pitches up stalling the canard
> so that the nose of the aircraft comes down hard into the next
> wave or onto the next bump and then nosedives under the wave or
> bounces higher and stalls again.

Possible.

> Thanks, now I have a much better understanding of the rough field
> take-off problem with a canard.

Well, you would if that was the reason for the rough field issues, but
it isn't.

I fly a COZY MKIV, and what happens on a rough field, due to the
geometry of the nosegear (and NOT dependent solely on the fact that it's
a canard aircraft) is that as high grass or bumps cause the nose gear to
flex somewhat, the nose of the plane drops a couple of inches, causing
the AOA of the canard to decrease, and decreasing lift. If the drag
from the grass/dirt, etc. is high enough, the canard cannot reach a
speed or AOA where it can rotate the aircraft.

So the problem is one of inability to rotate due to drag on the nosegear
and resulting geometry changes that lower the AOA, NOT on canard
stalling.

I have taken off from a few paved runways that are very bumpy (AFN in NH
comes to mind), and if anything, the bumps can help to get the nose of
the plane in the air at speed, and never come close to raising the nose
far enough to stall the canard.

--
Marc J. Zeitlin
http://marc.zeitlin.home.comcast.net/
http://www.cozybuilders.org/
Copyright (c) 2005

The biggest issue with a canard is that the CLmax of the configuration is
low compared to a conventional configuration. This is for several reasons:

1. The smaller canard must stall first and that means that the wing will
never stall and hence never develop it maximum lift. Of course the opposite
is true for a conventional airplane. The larger wing stalls and developes
its maximum lift whilst the smaller tailplane remains unstalled.

2. Unless you do some tricky stuff you cannot really put a flap on a canard
because it is difficult to trim out the nose down pitching moments.

Low CLmax means that the configuration will not develop as much lift at a
given speed and hence the airplane will not be as suitable for short fields
as will a conventiona configuration.

For those without an engineering background, CLmax is simply a measure of
how much lift a given wing will produce per unit area at a given speed.
CLmax is the maximum lift coefficient.



"Marc J. Zeitlin" > wrote in message
...
> fredfighter wrote:
>
> > Hmm. ISTM that a canard does not stall when the aircraft pitches
> > down, it stalls when the aircraft pitches up.
>
> Correct.
>
> > .... Thus each time the
> > aircraft hits a bump or wave the nose pitches up stalling the canard
> > so that the nose of the aircraft comes down hard into the next
> > wave or onto the next bump and then nosedives under the wave or
> > bounces higher and stalls again.
>
> Possible.
>
> > Thanks, now I have a much better understanding of the rough field
> > take-off problem with a canard.
>
> Well, you would if that was the reason for the rough field issues, but
> it isn't.
>
> I fly a COZY MKIV, and what happens on a rough field, due to the
> geometry of the nosegear (and NOT dependent solely on the fact that it's
> a canard aircraft) is that as high grass or bumps cause the nose gear to
> flex somewhat, the nose of the plane drops a couple of inches, causing
> the AOA of the canard to decrease, and decreasing lift. If the drag
> from the grass/dirt, etc. is high enough, the canard cannot reach a
> speed or AOA where it can rotate the aircraft.
>
> So the problem is one of inability to rotate due to drag on the nosegear
> and resulting geometry changes that lower the AOA, NOT on canard
> stalling.
>
> I have taken off from a few paved runways that are very bumpy (AFN in NH
> comes to mind), and if anything, the bumps can help to get the nose of
> the plane in the air at speed, and never come close to raising the nose
> far enough to stall the canard.
>
> --
> Marc J. Zeitlin
> http://marc.zeitlin.home.comcast.net/
> http://www.cozybuilders.org/
> Copyright (c) 2005
>
>

On Wed, 20 Jul 2005 20:05:23 +1000, "......... :-\)\)"
> wrote:

>The biggest issue with a canard is that the CLmax of the configuration is
>low compared to a conventional configuration. This is for several reasons:
>
>1. The smaller canard must stall first and that means that the wing will
>never stall and hence never develop it maximum lift. Of course the opposite
>is true for a conventional airplane. The larger wing stalls and developes
>its maximum lift whilst the smaller tailplane remains unstalled.
>
>2. Unless you do some tricky stuff you cannot really put a flap on a canard
>because it is difficult to trim out the nose down pitching moments.
>
>Low CLmax means that the configuration will not develop as much lift at a
>given speed and hence the airplane will not be as suitable for short fields
>as will a conventiona configuration.
>
>For those without an engineering background, CLmax is simply a measure of
>how much lift a given wing will produce per unit area at a given speed.
>CLmax is the maximum lift coefficient.
>
>
>
>"Marc J. Zeitlin" > wrote in message
...
>> fredfighter wrote:
>>
>> > Hmm. ISTM that a canard does not stall when the aircraft pitches
>> > down, it stalls when the aircraft pitches up.
>>
>> Correct.

picture an aircraft flying along which has a sudden brutal increase in
the resistance of the wheels (note that is hypothetical, thankfully
the snake oil plane wasnt built)
say for instance your canard clips the main wheels on the top wire of
a fence.
in that scenario, which is similar to what I predicted with the
hovercraft skirt, the sudden rotation forward and down would be
catastrophic in that the sudden downward movement of the canard would
probably increase its angle of attack beyond the stall (due to a
change in realtive wind direction).
that is what I was referring to.
other than that I have agreed with all that has been posted.
Stealth Pilot

Stealth Pilot wrote:
> ...
> >> fredfighter wrote:
> >>
> >> > Hmm. ISTM that a canard does not stall when the aircraft pitches
> >> > down, it stalls when the aircraft pitches up.
> >>
> >> Correct.
>
> picture an aircraft flying along which has a sudden brutal increase in
> the resistance of the wheels (note that is hypothetical, thankfully
> the snake oil plane wasnt built)
> say for instance your canard clips the main wheels on the top wire of
> a fence.

Or a less drastic scenario, the nosewhell plows thorugh a clump
of grass...

> in that scenario, which is similar to what I predicted with the
> hovercraft skirt, the sudden rotation forward and down would be
> catastrophic in that the sudden downward movement of the canard would
> probably increase its angle of attack beyond the stall (due to a
> change in realtive wind direction).

Well, I thought that increasing the pitch (nose up) increased
the angle of attack and decreasing the pitch decreased the angle
of attack. Aren't both angles conventionally measured so that
an upward rotation of the nose of the plane is a positive change
in the respective angle?

E.g. lift increases with increasing angles until teh wing stalls.
If the canard is not stalled and then the nose of the aircraft
pitches downward the lift of the canard decreases pitching the
nose even more downward. In the air the aircraft would accelerate,
trading altitude for speed, thus increasing lift to compensate
for the reduced angle of attack. However on the ground there
is no altitude to trade for speed so the nose bounces.

Have I got it right yet?

--

FF

On 20 Jul 2005 10:27:47 -0700, wrote:

>
>
>Stealth Pilot wrote:
>> ...
>> >> fredfighter wrote:
>> >>
>> >> > Hmm. ISTM that a canard does not stall when the aircraft pitches
>> >> > down, it stalls when the aircraft pitches up.
>> >>
>> >> Correct.
>>
>> picture an aircraft flying along which has a sudden brutal increase in
>> the resistance of the wheels (note that is hypothetical, thankfully
>> the snake oil plane wasnt built)
>> say for instance your canard clips the main wheels on the top wire of
>> a fence.
>
>Or a less drastic scenario, the nosewhell plows thorugh a clump
>of grass...
>
>> in that scenario, which is similar to what I predicted with the
>> hovercraft skirt, the sudden rotation forward and down would be
>> catastrophic in that the sudden downward movement of the canard would
>> probably increase its angle of attack beyond the stall (due to a
>> change in realtive wind direction).
>
>Well, I thought that increasing the pitch (nose up) increased
>the angle of attack and decreasing the pitch decreased the angle
>of attack. Aren't both angles conventionally measured so that
>an upward rotation of the nose of the plane is a positive change
>in the respective angle?
>
>E.g. lift increases with increasing angles until teh wing stalls.
>If the canard is not stalled and then the nose of the aircraft
>pitches downward the lift of the canard decreases pitching the
>nose even more downward. In the air the aircraft would accelerate,
>trading altitude for speed, thus increasing lift to compensate
>for the reduced angle of attack. However on the ground there
>is no altitude to trade for speed so the nose bounces.
>
>Have I got it right yet?

your mental picture is a practical one but you are looking at an
aircraft with a gently changing angle of attack and your assumptions
are correct I think.

but picture if you will a *very sudden* pitchdown. the canard would
see the direction of the incident airflow change from directly ahead
to somewhere down in front of it. ...like a gust.

dont lose too much sleep over this, the scenario was hypothetical.
besides I have some more of my Turbulent's fuselage beckoning to me
for attention :-) ...and that vw engine I picked up yesterday for
converting.
Stealth Pilot

Stealth Pilot wrote:
> On 20 Jul 2005 10:27:47 -0700, wrote:
>
> ...
> >
> >Have I got it right yet?
>
> your mental picture is a practical one but you are looking at an
> aircraft with a gently changing angle of attack and your assumptions
> are correct I think.

The only part I questioned was the algebraic sense of the direction
or rotation. E.g. which direction was an increase and which a
decrease.

>
> but picture if you will a *very sudden* pitchdown. the canard would
> see the direction of the incident airflow change from directly ahead
> to somewhere down in front of it. ...like a gust.

Thinking about it, a *very sudden* pitchdown _during takeoff_ will
also re-orient the thrust line downward. Given the proximinty of
the ground during takeoff that may prove to be the dominant
consideration.

--

FF

Michele, hello from Venezuela. As your relative Frank Edward Boland was the first person to fly in Venezuela, I has been researching his life and work for several years now. Here are the results (in Spanish, not the latest version). I will like to have access to any files or records your family keep on that venture, in order to prepare an english version:

https://www.scribd.com/doc/201685272/101-Anos-Aviacion-en-Venezuela-Alejandro-Irausquin-Ing-Aeronautico-Ene2014

Thanks in advance

Alejandro Irausquin
Aeronautical Engineer/Latino-american aviation historian
LAAHS

El martes, 19 de julio de 2005, 17:54:19 (UTC-4), escribió:
> My distant relatives built several canard biplane pusher seaplanes
> between 1911 and 1917. The used engines that they built themselves.
> The planes were turned with their patented "Jib Sheet Rudder" which was
> a surface the was mounted on the outside interplane struts between each
> wing and pivoted to the outside to turn the plane. It was supposed to
> have worked very well.
>
> If you can find a copy of Jane's Planes from back then look for the
> Boland Aeroplane and Motor Company. There is also a book called "Wings
> of the Weird and Wonderful" that has a picture of the landplane
> version.
>
> Michele