Fast glass biplanes

[Jay]

Apart from the Quickie group of planes why aren't there more fast
biplanes? The quickies aren't exactly biplanes I know. It would
appear that 2 short wings can be built lighter than one long one since
the moment arm is half as long for the shorter wing pair. No struts
used because of drag, just short cantilever wings. You'd have a more
compact airplane that way with less weight that had the same drag as
an equal wing area monoplane.

[Dave Hyde]

Jay wrote:

> It would appear that 2 short wings can be built lighter
> than one long one since the moment arm is half as long
> for the shorter wing pair.

There are a lot of benefits to higher aspect ratio
wings that far outweigh the structural advantage of low AR
wings. Reduced drag is but one. Ever wonder why you
don't see any biplane sailplanes?

> You'd have a more compact airplane that way with less
> weight that had the same drag as an equal wing area monoplane.

'Fast' and 'biplane' just don't go together. Fast "biplanes"(*)
like the Quickie, Mong, etc. do not get their speed and low
drag from the fact that they have two wings, but rather in
spite of it. Induced drag decreases as aspect ratio increases,
so a longer span wing of equivalent area and wing section will
have less induced drag than two wings with a lower AR. Two wings
will also have at least double the interference drag of one,
regardless of whether or not they use interplane struts.

Dave 'dragster' Hyde


(*) Jay has already stated that he knows the
Quickie is not a true biplane. The same principles apply, however.

[Stealth Pilot]

On 15 Nov 2003 09:17:59 -0800, (Jay) wrote:

>Apart from the Quickie group of planes why aren't there more fast
>biplanes? The quickies aren't exactly biplanes I know. It would
>appear that 2 short wings can be built lighter than one long one since
>the moment arm is half as long for the shorter wing pair. No struts
>used because of drag, just short cantilever wings. You'd have a more
>compact airplane that way with less weight that had the same drag as
>an equal wing area monoplane.


I read once that a computer program exploring optimum biplane and
canard setups popped out the optimum setup as one where the forward
canard was 5 times the span of the rear one with the cg at 25% of the
chord of the forward canard.
I accept that that maybe an urban legend but put with the success that
mike arnold experienced with his AR5 you might just have an answer.

as well have a look at formula 1 aircraft designs. they are about as
competitive as you can get and on basically the same engine they are
now 100mph faster than 50 years ago.
havent seen a canard or biplane last very long among them.

Stealth Pilot

[Fred in Florida]

You're missing the point of the modern canard. They were developed to be a
stall/spin-proof alternitave to the conventional wing-tail layout. An
example: two friends built glass airplanes, one a Glasair with a 150 hp Lyc
and the other a Long-EZ with a 150 hp Lyc, both with fixed-pitch wood
props.. Flat out, the Glasair was faster, but only slightly -- 215 vs. 210
mph. Seems to me to be a small price to pay for an aircraft that won't
stall or spin. And if the engine quits, you want to be in the Long-EZ, not
the Glasair -- it glides much better.

Fred in Florida

"Stealth Pilot" > wrote in message
...
> On 15 Nov 2003 09:17:59 -0800, (Jay) wrote:
>
> >Apart from the Quickie group of planes why aren't there more fast
> >biplanes? The quickies aren't exactly biplanes I know. It would
> >appear that 2 short wings can be built lighter than one long one since
> >the moment arm is half as long for the shorter wing pair. No struts
> >used because of drag, just short cantilever wings. You'd have a more
> >compact airplane that way with less weight that had the same drag as
> >an equal wing area monoplane.
>
>
> I read once that a computer program exploring optimum biplane and
> canard setups popped out the optimum setup as one where the forward
> canard was 5 times the span of the rear one with the cg at 25% of the
> chord of the forward canard.
> I accept that that maybe an urban legend but put with the success that
> mike arnold experienced with his AR5 you might just have an answer.
>
> as well have a look at formula 1 aircraft designs. they are about as
> competitive as you can get and on basically the same engine they are
> now 100mph faster than 50 years ago.
> havent seen a canard or biplane last very long among them.
>
> Stealth Pilot
>

[Kevin Horton]

On Sun, 16 Nov 2003 13:07:23 +0000, karel adams wrote:


> "Fred in Florida" > schreef in bericht
> om...
>> You're missing the point of the modern canard. They were developed to
> be a
>> stall/spin-proof alternitave to the conventional wing-tail layout. An
>> example: two friends built glass airplanes, one a Glasair with a 150
> hp Lyc
>> and the other a Long-EZ with a 150 hp Lyc, both with fixed-pitch wood
>> props.. Flat out, the Glasair was faster, but only slightly -- 215
> vs. 210
>> mph.
>
> Even this surprises me, I had been led to understand that the canard
> design is inherently more efficient because the canard wing, besides its
> basic function as a stabiliser, also helps to generate lift; wheras the
> stabiliser in a conventional design must push down. So that for every
> 100 lbs of weight, the main wing in a conventional design carries 110
> lbs, in a canard only 90.
>
> Have I misunderstood?
> Or have the Glasir designers found a very clever trick?
>
> Thanks for explaining!
> KA
>
> (rest snipped)

With a canard, you need to have the design details and CG such that the
main wing can never, ever stall. If you screw up and have a design such
that the main wing can stall, the aircraft will pitch up at the stall, and
will almost certainly come down in an unrecoverable deep stall. The
original Velocity design had this problem, but they made some design
changes to fix it. But there was a fatal Velocity deep stall accident
recently, and the working theory seems to be that the builder did not
incorporate the design updates.

If you need to be sure the main wing never, ever gets close to the stall,
that means that you cannot use all the lift that the wing is capable of
producing. So, if you have two aircraft that weigh the same - a
"conventional aircraft" and a canard aircraft, and you want the same stall
speed, the canard aircraft will need a much larger wing. That larger wing
has more drag, so you need a very clean design in all other respects in
order to get the desired performance.

--
Kevin Horton RV-8 (finishing kit)
Ottawa, Canada
http://go.phpwebhosting.com/~khorton/rv8/
e-mail: khorton02(_at_)rogers(_dot_)com

[Ed Wischmeyer]

> And if the engine quits, you want to be in the Long-EZ, not
> the Glasair -- it glides much better.

That's a questionable statement!!

Compare the following for survivability in an accident:
* slower touchdown speed
* deformation of the structure to absorb energy
* lack of intrusions into the crew area (survivable space)

Looks to me like the Glasair would be much more survivable... not that
I'm personally interested in running the experiments

Ed "I'm supposed to teach a class on this stuff next term" Wischmeyer

[John Oliveira]

The only one I know of is the Lionheart - Semi Replica of Beech Stagger
Wing.

Fast, caries high load, round engine.


"Jay" > wrote in message
om...
> Apart from the Quickie group of planes why aren't there more fast
> biplanes? The quickies aren't exactly biplanes I know. It would
> appear that 2 short wings can be built lighter than one long one since
> the moment arm is half as long for the shorter wing pair. No struts
> used because of drag, just short cantilever wings. You'd have a more
> compact airplane that way with less weight that had the same drag as
> an equal wing area monoplane.

[Lpmcatee356]

My take on this is that while it is true that both surfaces on a canard or
tandem wing design are lifitng surfaces, the canard cannot use all of the
available lift from the main wing - if you want the stall protection - and thus
the main wing needs to be made much larger than needed for cruising flight if
one is to expect a reasonable landing speed.

In the case of my Quickie the Eppler main wing stalls at a fairly high angle of
attack but it's peak Cl is not that good. The result is that during landing
the canard is doing more than it's share of the work. Some Quickies (all
Quickies are single seat - the 2 seaters are Q-2/200's) land as fast as the
much maligned BD-5.

Another factor to consider is just because the little wing is in the back it
must not necessarily be providing down force. It can also lift and still be
part of a pitch stable plane.


>> props.. Flat out, the Glasair was faster, but only slightly -- 215
>vs. 210
>> mph.
>
>Even this surprises me, I had been led to understand
>that the canard design is inherently more efficient
>because the canard wing, besides its basic function
>as a stabiliser, also helps to generate lift; wheras
>the stabiliser in a conventional design must push down.
>So that for every 100 lbs of weight, the main wing in
>a conventional design carries 110 lbs, in a canard only 90.

[Ron Wanttaja]

On Sun, 16 Nov 2003 15:57:45 +0800, Stealth Pilot >
wrote:

>I read once that a computer program exploring optimum biplane and
>canard setups popped out the optimum setup as one where the forward
>canard was 5 times the span of the rear one with the cg at 25% of the
>chord of the forward canard.

Actually, that was contained in an article called "Canard Canard" in
AEROSPACE AMERICA magazine, back in the early '90s. I've posted about it
here in RAH several times, that's probably where you remember it from.
Used to have the article rattling around the office, somewhere.

Canard designs are just a different approach to the compromises necessary
for aircraft development. What they gain in eliminating the horizontal
stabilizer downforce, they lose in other areas.

Wanttaja Ron

[Lpmcatee356]

I'm not enough of an aviation know it all/historian so the only example I can
site off the top of my head is the Quickie, Q-2/200, Dragonfly, Flying Flea
family.

While the "little wing in the rear" isn't so little the physics are the same.
As long as the moment of the 2 "wings" move aft with an increasing angle of
attack, and forward with decreasing pitch the plane will be pitch stable at one
particular speed. This can be done simply by having the tail provide a down
force, but by properly selecting the airfoils so that the lift of the rear wing
increases faster than the front with increasing angle of attack you get the
same result.

I'm not a professional aerodynamisist, maybe even a poor amateur, and not a
very good teacher - so if your just learning about all of this in your PPL
ground school it might be a bit simpler to forget all about anything but
"conventional" airplanes for a while...........or find someone that can explain
it better than me.......which shouldn't be hard.

If you really want some interesting pitch stability mental exercise think about
a flying wing with negative sweep..........


>Well well I am learning again.
>My PPL ground school certainly disagrees with you!
>Do you have any example of such a design?
>
>TIA,
>Karel
>

[Fred in Florida]

"Ed Wischmeyer" > wrote in message
...
> > And if the engine quits, you want to be in the Long-EZ, not
> > the Glasair -- it glides much better.
>
> That's a questionable statement!!
>
> Compare the following for survivability in an accident:
> * slower touchdown speed
> * deformation of the structure to absorb energy
> * lack of intrusions into the crew area (survivable space)
>
> Looks to me like the Glasair would be much more survivable... not that
> I'm personally interested in running the experiments

Okay Ed, I'll take the bait. I assume you're taking issue with which
airplane you'd rather be in, not which one glides better. With engine off
and prop stopped and 80kn, a Long will glide losing 5-700 fpm. Tough to
match that in a Glasair. This would give the Long alarger raidus in which
to find a suitable landing place.

Slower touchdown speed? Unless at a very low gross weight, a Long would be
hard-pressed to get under 60 kn. It's part of the design, I assume, to
assure that the main wong won't stall. The Glasair could probably do
better.

Deformation of the structure? They're both glass -- don't know how you
could say one was better than the other.

Lack of intrusions? The Long's got the nosegear crank, but the Glasair's
got the sticks ... uh ... down *there*. Which is worse? I don't know.

As I said before, the whole reason for a canard airplane is for it's stall-
and spin-limiting abilities, not because it is "more efficient."

[Dave Hyde]

karel adams wrote:

> My PPL ground school certainly disagrees with you!
> Do you have any example of such a design?

Most conventional airplanes when flown in their
approved CG range will have a down force at the tail.
If the CG is moved aft of the aerodynamic center of
the wing alone but remains ahead of the neutral
point of the airplane, the tail will (generally)
have an upward force. Pitch stability will still
be positive, but in most GA cases far less than
most of us are used to.

If it's as you've related, your 'PPL ground school'
may be correct in a statistical sense, but not in a
technical one. Big surprise, that.

Dave 'phugoid phollies' Hyde

[Kevin Horton]

On Sun, 16 Nov 2003 20:25:33 +0000, Fred in Florida wrote:

>
> "Ed Wischmeyer" > wrote in message
> ...
>> > And if the engine quits, you want to be in the Long-EZ, not the
>> > Glasair -- it glides much better.
>>
>> That's a questionable statement!!
>>
>> Compare the following for survivability in an accident: * slower
>> touchdown speed
>> * deformation of the structure to absorb energy * lack of intrusions
>> into the crew area (survivable space)
>>
> Okay Ed, I'll take the bait. I assume you're taking issue with which
> airplane you'd rather be in, not which one glides better. With engine off
> and prop stopped and 80kn, a Long will glide losing 5-700 fpm. Tough to
> match that in a Glasair. This would give the Long alarger raidus in which
> to find a suitable landing place.
>
> Lack of intrusions? The Long's got the nosegear crank, but the Glasair's
> got the sticks ... uh ... down *there*. Which is worse? I don't know.
>

If I'm going to be in a crash, and it isn't on flat ground, I would rather
have the engine ahead of me than behind me. I figure it has a bit less
chance of ending up in the cockpit that way.

--
Kevin Horton RV-8 (finishing kit)
Ottawa, Canada
http://go.phpwebhosting.com/~khorton/rv8/
e-mail: khorton02(_at_)rogers(_dot_)com

[Stealth Pilot]

On Sun, 16 Nov 2003 18:08:58 GMT, Ron Wanttaja >
wrote:

>On Sun, 16 Nov 2003 15:57:45 +0800, Stealth Pilot >
>wrote:
>
>>I read once that a computer program exploring optimum biplane and
>>canard setups popped out the optimum setup as one where the forward
>>canard was 5 times the span of the rear one with the cg at 25% of the
>>chord of the forward canard.
>
>Actually, that was contained in an article called "Canard Canard" in
>AEROSPACE AMERICA magazine, back in the early '90s. I've posted about it
>here in RAH several times, that's probably where you remember it from.
>Used to have the article rattling around the office, somewhere.
>
>Canard designs are just a different approach to the compromises necessary
>for aircraft development. What they gain in eliminating the horizontal
>stabilizer downforce, they lose in other areas.
>
>Wanttaja Ron

see we remember what you write ron. :-)

back to the guys original question, I take it that the "lose in other
areas" is why you dont see them as racers mixing it with the less
compromised.

Stealth Pilot

[Ron Wanttaja]

On Mon, 17 Nov 2003 16:28:10 +0800, Stealth Pilot >
wrote:

>On Sun, 16 Nov 2003 18:08:58 GMT, Ron Wanttaja >
>wrote:
>
>>Canard designs are just a different approach to the compromises necessary
>>for aircraft development. What they gain in eliminating the horizontal
>>stabilizer downforce, they lose in other areas.
>
>back to the guys original question, I take it that the "lose in other
>areas" is why you dont see them as racers mixing it with the less
>compromised.

Nor do you see many canard sailplanes, which place the highest demands on
aerodynamics.

I wonder what one could do with a canard if you eliminated the need to have
the main wing stall before the canard? Seems like a fly-by-wire sort of
system could sense when the wing was about to stall and limit canard
up-travel to prevent it happening. Or the plane could incorporate a system
to provide sudden downforce if the plane started to pitch up
(compressed-air jets in the nose, etc.). Seems a pity that you have to
avoid operations at the wing's highest efficiency points in an otherwise
efficient design.

[C J Campbell]

"John Oliveira" > wrote in message
...
| The only one I know of is the Lionheart - Semi Replica of Beech Stagger
| Wing.
|
| Fast, caries high load, round engine.

Looking at Griffon's web site lately, they seem to talk about the Lionheart
in only a historical context and customer support. It does not appear that
they are producing kits any more.

[Bob Kuykendall]

Earlier, Ron Wanttaja > wrote:

> ...Nor do you see many canard sailplanes,
> which place the highest demands on aerodynamics.

The way it's been explained to me, the wake of the canard surface
interacts with the wing flow field so as to make it difficult to
arrive at reasonable compromises for both low- and high-speed flight.
Also, the tip vortex from the canard does things to the wing flow
fields that are hard to compensate for at any speed.

The only canard sailplane I know of, the Rutan Solitaire, had
performance that was whelming at best. Although it won the SHA
sailplane design contest that year, only two or three were ever built.
I believe that none are regularly operated.

Getting near the bounds of this topic, (but I suspect that Jay is
gonna like this one), NASA has done analysis that suggests that there
are substantial gains to be found in joined wing designs. Basically,
the main wing sweeps back and then turns up at a winglet. The
horizontal stabilizer sweeps forward, and joins smoothly to the top of
the winglet. This type of design has potential for low drag and good
strength-to-weight ratios. However, there is relatively little in the
way of real-world validation of these theories. For more information,
see the several technical papers on the topic by Ilan Kroo.

Thanks, and best regards

Bob K.
http://www.hpaircraft.com/hp-24

[Jay]

Dave Hyde > wrote in message
> There are a lot of benefits to higher aspect ratio
> wings that far outweigh the structural advantage of low AR
> wings. Reduced drag is but one. Ever wonder why you
> don't see any biplane sailplanes?

You bring up a good point about sailplane wings having the best L/D
ratios. But why not take each of those sailplane wings and put one
over the top of the other? You mentioned the interference drag, so
how far do wings need to be vertically separated for a given airfoil
and stagger for this effect to be negligable?

The fact that you don't see something commonly done says more about
the methods of development starting with what currently works, and
trying to make incremental improvement on it than anything else.
Sometimes the rat maze requires the rats (RAH) to back up and choose
another path, which in the short term means he is actually retreating
from the cheese (speed).

[slomo]

It's generally accepted to draw circle with a diameter of the wingspan,
centered at the middle of the wing. Do this once for every wing. Where
the circles intersect, they are interacting. I know of none that interact
positively. Some less negatively than others.

Another way to look at this is the aspect ratio. Aspect ratio is span
squared divided by the total area. More aspect ratio is better than less.

Anything less than 6 is not very efficient. Decent gliders are above 20.
I've flown one powered plane that was 10. It did very well. Flew like it
had a lot more area than it really had.



In article >,
(Jay) wrote:
>Dave Hyde > wrote in message
>> There are a lot of benefits to higher aspect ratio
>> wings that far outweigh the structural advantage of low AR
>> wings. Reduced drag is but one. Ever wonder why you
>> don't see any biplane sailplanes?
>
>You bring up a good point about sailplane wings having the best L/D
>ratios. But why not take each of those sailplane wings and put one
>over the top of the other? You mentioned the interference drag, so
>how far do wings need to be vertically separated for a given airfoil
>and stagger for this effect to be negligable?
>
>The fact that you don't see something commonly done says more about
>the methods of development starting with what currently works, and
>trying to make incremental improvement on it than anything else.
>Sometimes the rat maze requires the rats (RAH) to back up and choose
>another path, which in the short term means he is actually retreating
>from the cheese (speed).

[Dave Hyde]

Ron Wanttaja wrote:

> I wonder what one could do with a canard if you eliminated the need to have
> the main wing stall before the canard?

Canards with AOA limiters (or without) were at least for a while
the 'flavor of the month' in fighters. See Eurofighter, Gripen,
Rafale, Lavi, X-31, X-29, and A buncha MiG types. You don't
necessarily need to keep the wing from stalling, you just have
to have the control power to break the stall. Look at the size of
the canard and the range of motion on these airplanes sometime.

Dave 'kcud' Hyde

[Dave Hyde]

Jay wrote:

> You bring up a good point about sailplane wings having the best L/D
> ratios. But why not take each of those sailplane wings and put one
> over the top of the other?

Because a single wing of equivalent area but longer span will
be more efficient in terms of drag. Biplanes are a simple,
but inefficient, way of getting more lift from wing area
when an increase in span is not feasible. The are not, nor
in general are they intended to be, "low drag."

> You mentioned the interference drag, so how far do wings
> need to be vertically separated for a given airfoil
> and stagger for this effect to be negligable?

*negligible?* Some *large* fraction of the span. At a minimum.
Some airplanes are able to use the interaction for benefit,
but it's usually for things like lift improvement at high
AOA. Drag reduction requires doing things at the tips to
make the wings 'think' they are longer and thus have a higher AR.
Just slapping another wing on there ain't gonna do it.

> Sometimes the rat maze requires the rats (RAH) to back up and choose
> another path, which in the short term means he is actually retreating
> from the cheese (speed).

And knowing where to depart from the maze requires either a
foundation in basic principles or blind luck. Given the well-
known relationship between drag and aspect ratio, these principles
lead most people *away from*, not *to* biplanes for drag reduction.
How 'bout a challenge: I can show you mathematically and using physical
relationships why (without aerodynamic treatments like winglets or
conjoined
wings) two wings will produce more drag than a single wing of equivalent
area but higher aspect ratio. Your challenge: Prove the physics wrong.
Show how a second wing will result in less drag. Show me the math.

Dave 'usenet wind tunnel' Hyde

[ChuckSlusarczyk]

In article >, Ron Wanttaja says...


Maybe with todays technology that could be achievable.But for right now
all I can do is repeat what one of my Aero teachers said " the Indians knew
which end of the arrow to put the feathers" and "when did you ever see birds
with their tails where their beaks oughta be?" Although flying wings are
achieving with computers flight efficiency that here to fore was impossible with
pilot only control systems. Northrop was farther advanced with airframes then
the electronics industry was with computers.

See ya

Chuck

>
>I wonder what one could do with a canard if you eliminated the need to have
>the main wing stall before the canard? Seems like a fly-by-wire sort of
>system could sense when the wing was about to stall and limit canard
>up-travel to prevent it happening. Or the plane could incorporate a system
>to provide sudden downforce if the plane started to pitch up
>(compressed-air jets in the nose, etc.). Seems a pity that you have to
>avoid operations at the wing's highest efficiency points in an otherwise
>efficient design.
>
>

[ChuckSlusarczyk]

In article >, Dave Hyde says...

Don't bet any big money cause Dave (usenet wind tunnel) Hyde is right.
Just think, if he was wrong we'd be seeing Biplane Boeing 777's,these guys spend
millions to get a couple percent increased efficiency on their transports.
Better believe if a biplane was more efficient they'd be doing it.
No if's, ands, or buts. :-)

Chuck(Lewis 10X10 wind tunnel) S




>How 'bout a challenge: I can show you mathematically and using physical
>relationships why (without aerodynamic treatments like winglets or
>conjoined
>wings) two wings will produce more drag than a single wing of equivalent
>area but higher aspect ratio. Your challenge: Prove the physics wrong.
>Show how a second wing will result in less drag. Show me the math.
>
>Dave 'usenet wind tunnel' Hyde

[Dave Hyde]

ChuckSlusarczyk wrote:

> "when did you ever see birds with their tails where
> their beaks oughta be?"

When I drove through a turkey at 65 mph.

Dave 'last thing on his mind' Hyde

[Stealth Pilot]

On 17 Nov 2003 10:50:07 -0800, (Jay) wrote:

> But why not take each of those sailplane wings and put one
>over the top of the other? You mentioned the interference drag, so
>how far do wings need to be vertically separated for a given airfoil
>and stagger for this effect to be negligable?
>


jay
I seem to recall something that tried this.
the dynamics of the thing bought it undone.
as the forward wind flexes it alters the flow over the rear wing and
induces flexing. the thing can self destruct if you get the thing
wrong.

Stealth (everything is aeroelastic to some degree) Pilot

[ChuckSlusarczyk]

In article >, Dave Hyde says...

Yup that sure would have changed that Turkeys perspective.He no longer was
seeing where he was going but where he was.

Chuck (I turkey hunt with a shot gun) S


>ChuckSlusarczyk wrote:
>
>> "when did you ever see birds with their tails where
>> their beaks oughta be?"
>
>When I drove through a turkey at 65 mph.
>
>Dave 'last thing on his mind' Hyde

[Ben Sego]

Dave Hyde wrote:

> ChuckSlusarczyk wrote:
>
>
>>"when did you ever see birds with their tails where
>>their beaks oughta be?"
>
>
> When I drove through a turkey at 65 mph.
>
> Dave 'last thing on his mind' Hyde
>

I got a chicken at 80 once. The weirdest part was cleaning the egg off
the hood.

B.S.

[John Pelchat]

"C J Campbell" > wrote in message >...
> "John Oliveira" > wrote in message
> ...
> | The only one I know of is the Lionheart - Semi Replica of Beech Stagger
> | Wing.
> |
> | Fast, caries high load, round engine.
>
> Looking at Griffon's web site lately, they seem to talk about the Lionheart
> in only a historical context and customer support. It does not appear that
> they are producing kits any more.

The Lionheart is (was) an exceptionally pretty airplane. It seemed
that the cabin load and volume were comparable to a Cherokee Six.

IIRC (and I don't always) Kitplane wrote a pilot report and had some
adverse comments regarding stability or handling but I sensed they
were hopeful those things could be resolved; some of the problem
perhaps being related to mis-rigging after the plane was painted.

There were built two aircraft built by folks other than the company
that were lost in accidents on the runway although (again relying on
memory) one occurred on takeoff and one on landing. Sadly, one was on
its maiden flight. I don't recall any common root or contributory
causes.

I tried to go by and see the prototype once when I was in Huntsville,
AL but I had no luck.

Take care . . .

John

[John Pelchat]

"C J Campbell" > wrote in message >...
> "John Oliveira" > wrote in message
> ...
> | The only one I know of is the Lionheart - Semi Replica of Beech Stagger
> | Wing.
> |
> | Fast, caries high load, round engine.
>
> Looking at Griffon's web site lately, they seem to talk about the Lionheart
> in only a historical context and customer support. It does not appear that
> they are producing kits any more.

Follow-Up Message.

I looked at the NTSB site and gear design was mentioned in the
findings for both Lionheart accidents. I'm not an engineer, so I
leave it up to the rest of you to consider the information.

Sad though because I still think it was a drop-dead beautiful
airplane.

John

[Jay]

Dave Hyde > wrote in message >...

Thanks for taking the time to make insightful comments on the
discussion.

> Because a single wing of equivalent area but longer span will
> be more efficient in terms of drag. Biplanes are a simple,
> but inefficient, way of getting more lift from wing area
> when an increase in span is not feasible. The are not, nor
> in general are they intended to be, "low drag."

You must understand that when I say "biplane" I'm not talking about a
Jenny or Spad, I just mean an airplane that meets the requirement of
having 2 lifting surfaces. I understand those early designs were
optimized for the heavy powerplants and weak construction materials of
the era, and had high drag wings that developed a lot of lift at low
speeds.

> *negligible?* Some *large* fraction of the span. At a minimum.
> Some airplanes are able to use the interaction for benefit,
> but it's usually for things like lift improvement at high
> AOA. Drag reduction requires doing things at the tips to
> make the wings 'think' they are longer and thus have a higher AR.
> Just slapping another wing on there ain't gonna do it.

Okay, I think you nailed the departure of my logic from yours. I
don't believe that span is in the formula (at least not in high
order). I think its a function of the airfoil dimensions (chord,
thinkness, shape) and stagger. I do realize that near the
fusalage/tip there is disturbance but this diminishes as you move away
on the span. Imagine that you're an air molecule; how do you know if
you're 5' or 10' along the wing? You don't, when the wing comes
along, you just move along the bottom or zip across the top.

I know that the rule of thumb is higher aspect, higher efficiency
(L/D), but this is only part of the story. That rule makes an
assumption of a single wing. That is to say, assuming you only have a
single wing, and you need to decide how you can distribute your square
feet of area, you'd pick a long skinny wing.

> And knowing where to depart from the maze requires either a
> foundation in basic principles or blind luck. Given the well-
> known relationship between drag and aspect ratio, these principles
> lead most people *away from*, not *to* biplanes for drag reduction.

Thats the problem with rules of thumb, often the people using them
forget the assumptions that went into the rule.

> How 'bout a challenge: I can show you mathematically and using physical
> relationships why (without aerodynamic treatments like winglets or
> conjoined
> wings) two wings will produce more drag than a single wing of equivalent
> area but higher aspect ratio. Your challenge: Prove the physics wrong.
> Show how a second wing will result in less drag. Show me the math.

That sounds like a fun challenge. I think we're going to have to
speak in realtionships instead of mathematic expression because we're
using the usenet as our white board. Okay, why don't you start off by
showing me how span comes into the relationship of air moving over a
wing's airfoil.

> Dave 'usenet wind tunnel' Hyde
>

There was someone that commented that if 2 lifting surfaces made
sense, you'd see the 777 with 2 wings because they're Boeing and have
lots of money and super human engineers. I've worked for lots of
companies like Boeing (but not them because they tried to low ball me)
and they're made up of regular guys like you and me. Many of them
have interests and responsibility outside of designing the best
aircraft ever, and really just want to pay their bills and go home and
have a beer. You work as one guy in a huge machine where decisions
are often made on what's politicaly the best answer rather than what's
technically best. You get one tiny componant of this huge project.
These kinds of organizations often punish risk taking in that there is
no upside pay-off if you're right. But if you're wrong, and it was
because you did something different than before, you get hammered. So
the larger the project, the more conservative the approach tends to
be. Remember, bean counters hate risk of any kind.

[Del Rawlins]

On 18 Nov 2003 07:56 AM, Ben Sego posted the following:
> Dave Hyde wrote:
>
>> ChuckSlusarczyk wrote:
>>
>>
>>>"when did you ever see birds with their tails where
>>>their beaks oughta be?"
>>
>>
>> When I drove through a turkey at 65 mph.
>>
>> Dave 'last thing on his mind' Hyde
>>
>
> I got a chicken at 80 once. The weirdest part was cleaning the egg
> off the hood.
>
> B.S.

2 grouse, 1 canada goose, numerous crows, and a seagull.

----------------------------------------------------
Del Rawlins-
Remove _kills_spammers_ to reply via email.
Unofficial Bearhawk FAQ website:
http://www.rawlinsbrothers.org/bhfaq/

[Lpmcatee356]

>Imagine that you're an air molecule; how do you know if
>you're 5' or 10' along the wing? You don't, when the wing comes
>along, you just move along the bottom or zip across the top.

Those molecules are smarter than you might expect. <G>

There can be significant spanwise flow of the air. Like most things in nature
air finds the path of least resistance and sometimes this is not where it was
headed when the wing bounced into it.

Even if you take the same 40 ft high aspect ratio wing, saw it into 2 halves
and manage to attach it to the fuselage with no increase in interference drag
it's going to be less efficient than the 1 long wing - because of the spanwise
flow. Winglets help, flow fences help, joined wing tips help, elliptical
planform helps.

Look up W. Kaspar and his work on tip vortices.

[Ben Sego]

Del Rawlins wrote:
> On 18 Nov 2003 07:56 AM, Ben Sego posted the following:
>
>>Dave Hyde wrote:
>>
>>
>>>ChuckSlusarczyk wrote:
>>>
>>>
>>>
>>>>"when did you ever see birds with their tails where
>>>>their beaks oughta be?"
>>>
>>>
>>>When I drove through a turkey at 65 mph.
>>>
>>>Dave 'last thing on his mind' Hyde

>>
>>I got a chicken at 80 once. The weirdest part was cleaning the egg
>>off the hood.
>>
>>B.S.
>
>
> 2 grouse, 1 canada goose, numerous crows, and a seagull.
>
Gentlemen, I think we have a winner. Or dinner, perhaps, in the case of
the goose...

B.S.

[Bob Kuykendall]

Earlier, (Jay) wrote:

> Okay, why don't you start off by
> showing me how span comes into the
> relationship of air moving over a
> wing's airfoil.

That's generally covered in what they call "Theory of Finite Wings."
There's a chapter on it in Abbott and Doenhoff. This Desktop Aero page
is a good introduction to the topic:

http://www.desktopaero.com/appliedaero/potential3d/wingmodels.html

Bob K.

[Dave Hyde]

Jay wrote:

> Okay, I think you nailed the departure of my logic from yours. I
> don't believe that span is in the formula (at least not in high
> order).

The generally accepted definition of the induced drag coefficient
is:

CDi=CL^2/pi/e/AR,
where CL is the wing lift coefficient at the conditions under
consideration,
pi=3.14159...
e = Oswald's efficiency factor (typically 0.8 or so)
AR = aspect ratio

The _definition_ of aspect ratio is chord/span, or span^2/aero (they're
equivalent), so as area remains the same but aspect ratio increases,
induced drag decreases by 1/span^2. That's what I call a primary
effector.
If you add wing treatments like winglets, fences, etc, you can increase
the
effective AR, but the big effects are gained by working at the tips,
not across the span, as another wing typically does.

Look at the lift side. The formula becomes messier, but for a finite
wing:

CL,finite ~= CL,infinite*(1/(1+(dCL,inf/daoa)/pi/AR))

As span increases through increased aspect ratio, the finite
wing lift coefficient gets closer to the infinite wing CL.

Can we agree that this is a good thing?

In the lift case, there is *some* easily realizable benefit.
A forward surface like a canard can be used as a big vortex
generator to keep flow attached over the 'main wing' and
increase lift/delay stall. That's why you see a lot of close-coupled
canards on fighters these days.

There's also the trim drag benefit of another surface if
that surface can be configured to reduce the total downforce
required to trim. That's another reason for canards and
relaxed stability airliners. This benefit is usually
not as pronounced as the high AR benefit.

> Imagine that you're an air molecule; how do you know if
> you're 5' or 10' along the wing? You don't, when the wing comes
> along, you just move along the bottom or zip across the top.

Um...you might want to review some finite wing theory.
There can be quite a bit of spanwise flow at the root _or_
the tip. When subsonic you make a bow wake. The air is moving
before you hit it, and it's not just front-to-back.

> I know that the rule of thumb is higher aspect, higher efficiency
> (L/D), but this is only part of the story. That rule makes an
> assumption of a single wing.

That's not a rule of thumb, that's physics. All other things being
equal, the highger AR wing *will* have less drag.

> Okay, why don't you start off by
> showing me how span comes into the relationship of air moving over a
> wing's airfoil.

Done and done. Your turn.

> I've worked for lots of companies like Boeing...

Have you ever worked in conceptual design and/or
aerodynamics? Most of your risk aversion comments
were way off the mark. A trip to the Air Force museum
to see the Bird of Prey or the X-36 could be illuminating.

Dave 'misconceptual design' Hyde

[Del Rawlins]

On 18 Nov 2003 01:13 PM, Ben Sego posted the following:

>> 2 grouse, 1 canada goose, numerous crows, and a seagull.
>>
> Gentlemen, I think we have a winner. Or dinner, perhaps, in the case
> of the goose...

Unfortunately in Alaska roadkill belongs to the state and there was
somebody behind me. Up to that point I hadn't committed a crime, but
stopping and throwing it in the back would have been and I know people
who have gotten in trouble with the state fish and game dept. for dumber
things. That goose committed suicide; it and another goose had been
sitting at the edge of the road eating gravel. It's buddy flew away
from the road, and it flew right at my truck.

A few weeks ago I came home to a goose sitting in my front lawn, it let
me take pictures and even video of it before it got up and walked away.
Unfortunately there were too many eyes around. Had he shown the poor
judgement to land in my back yard, his next stop would have been my
freezer. Since I live under the pattern at Merrill Field I could always
claim I was enhancing aviation safety:

http://www.rawlinsbrothers.org/goose.avi

----------------------------------------------------
Del Rawlins-
Remove _kills_spammers_ to reply via email.
Unofficial Bearhawk FAQ website:
http://www.rawlinsbrothers.org/bhfaq/

[ChuckSlusarczyk]

In article t>, Ben Sego
says...


I don't know if he's the winner but I know he's an "Ace" :-)

Chuck ( one deer,1 pigeon and 1 bike rider) S


>>>>When I drove through a turkey at 65 mph.
>>>>
>>>>Dave 'last thing on his mind' Hyde

>>>
>>>I got a chicken at 80 once. The weirdest part was cleaning the egg
>>>off the hood.
>>>
>>>B.S.
>>
>>
>> 2 grouse, 1 canada goose, numerous crows, and a seagull.
>>
>Gentlemen, I think we have a winner. Or dinner, perhaps, in the case of
> the goose...
>
>B.S.
>

[Richard Isakson]

"Jay" wrote ...
> There was someone that commented that if 2 lifting surfaces made
> sense, you'd see the 777 with 2 wings because they're Boeing and have
> lots of money and super human engineers. I've worked for lots of
> companies like Boeing (but not them because they tried to low ball me)
> and they're made up of regular guys like you and me. Many of them
> have interests and responsibility outside of designing the best
> aircraft ever, and really just want to pay their bills and go home and
> have a beer. You work as one guy in a huge machine where decisions
> are often made on what's politicaly the best answer rather than what's
> technically best. You get one tiny componant of this huge project.
> These kinds of organizations often punish risk taking in that there is
> no upside pay-off if you're right. But if you're wrong, and it was
> because you did something different than before, you get hammered. So
> the larger the project, the more conservative the approach tends to
> be. Remember, bean counters hate risk of any kind.

Bull****, Jay.

I worked for several years as an engineer in Boeing's Aero Staff.
Everything you just said is wrong. The people that design wings at Boeing
use the best technology available that's consistant with the production
materials that are available. They don't design on the basis of some
political whim. They don't design biplanes because it's easy to show
mathematically that the mutual interference between the circulation of the
two wings decreases the efficiency of both wings.

You seem to have strange theory that just because something isn't done it
must be a good thing to try. Subsonic aerodynamics was well explored by
World War II. Much of transonic and supersonic flow was understood shortly
after. If you think that you've come up with something new that just means
you don't understand why thinks work. If you want do to something different
just to be different go ahead, but it will be an inferior product and
possibly dangerous. Your current design has at least three fatal flaws.
You need to open some books and understand the theory of flight before you
start designing airplanes.

Rich

[Del Rawlins]

Well, the seagull was only a probable since I was driving the '59 MG at
the time and not going particularly fast (honest). It hit the headlight
and bounced down the side of the car, so I didn't actually run it over.
For all I know it may have got up and flew away.

Now one of the grouse, on the other hand, was spectacular. I was south
of Delta heading north to Fairbanks, and as I topped a hill there it was
in the middle of the road. I had just enough time to notice it before
it went under, and in my rear view mirror there was just this big
indistinguishible cloud of feathers. I'm just lucky it wasn't a caribou
or a moose. Roadkill in Alaska can be grizzly at times.

Came close to nailing a porcupine a couple summers ago, which normally
destroys the tire. Since I had a full load of fresh Copper River salmon (
read: extremely time sensitive shipment) worth more than the truck on
board at the time, I would not have been amused. His number, which was
11.00-R22 (goodyear unisteel), just wasn't up that night.

On 18 Nov 2003 06:19 PM, ChuckSlusarczyk posted the following:
> In article t>, Ben
> Sego says...
>
> I don't know if he's the winner but I know he's an "Ace" :-)
>
> Chuck ( one deer,1 pigeon and 1 bike rider) S
>
>>>>>When I drove through a turkey at 65 mph.
>>>>>
>>>>>Dave 'last thing on his mind' Hyde

>>>>
>>>>I got a chicken at 80 once. The weirdest part was cleaning the egg
>>>>off the hood.
>>>
>>>
>>> 2 grouse, 1 canada goose, numerous crows, and a seagull.
>>>
>>Gentlemen, I think we have a winner. Or dinner, perhaps, in the case
>>of
>> the goose...

----------------------------------------------------
Del Rawlins-
Remove _kills_spammers_ to reply via email.
Unofficial Bearhawk FAQ website:
http://www.rawlinsbrothers.org/bhfaq/

[- Barnyard BOb -]

"Richard Isakson" wrote:

>You seem to have strange theory that just because something isn't done it
>must be a good thing to try. Subsonic aerodynamics was well explored by
>World War II. Much of transonic and supersonic flow was understood shortly
>after. If you think that you've come up with something new that just means
>you don't understand why thinks work. If you want do to something different
>just to be different go ahead, but it will be an inferior product and
>possibly dangerous. Your current design has at least three fatal flaws.
>You need to open some books and understand the theory of flight before you
>start designing airplanes.
>
>Rich
+++++++++++++++++++++++++++++++

WoW....
Sometimes, ya just gotta love a posting.


Barnyard BOb - if it's a duck, it's a duck

[- Barnyard BOb -]

>A few weeks ago I came home to a goose sitting in my front lawn, it let
>me take pictures and even video of it before it got up and walked away.
>Unfortunately there were too many eyes around. Had he shown the poor
>judgement to land in my back yard, his next stop would have been my
>freezer. Since I live under the pattern at Merrill Field I could always
>claim I was enhancing aviation safety:
>
>http://www.rawlinsbrothers.org/goose.avi
>
>Del Rawlins-
++++++++++++++++++++++++++++++++++

What happened to that goose?
Looked like a prime candidate for road kill...
heading for that very busy street.

BTW....
Are you sure you were in Alaska?
I didn't notice any snow, dirt roads,
mountains, huskies, eskimos or igloos. <g>


Barnyard BOb - which way to Iditarod

[C J Campbell]

"John Pelchat" > wrote in message
om...
|
| I looked at the NTSB site and gear design was mentioned in the
| findings for both Lionheart accidents. I'm not an engineer, so I
| leave it up to the rest of you to consider the information.
|

I actually saw the Lionheart crash at Bremerton. When he took off it was a
thing of beauty. The round engine coupled with the wind going through the
strutless wings made it sound like a giant dragonfly. He departed from
runway 19 at Bremerton and was gone, IIRC, about 45 minutes.

When he returned the wind had shifted almost 180 degrees. I guess he did not
check the AWOS or look at the wind sock. He made several low passes over the
runway, but he said later that he was having trouble getting lined up
properly. We went out to watch him land just as he was on short final.

He landed with a left quartering tailwind of about 9 knots. The Lionheart
started to weathervane. One main gear collapsed, then the other as he
groundlooped. The gear bolts were connected directly to the fuel tanks, so
when the gear collapsed the bottom of the fuel tank was ripped out. The
plane burst into a spectacular fire which was caught on film by several
cameras on the ground and a camera in the chase plane. It was pitiful
watching Bremerton's lone fire truck (a pickup truck with a water tank on
the back) try to put this thing out. The water would not even reach the
fire.

His wife was sure he was dead because we did not see him get out. As it
turned out he had only a cut on his thumb. The airplane was a total loss. He
did not have insurance and had spent much of his life savings on the plane.
He told me he had spent about $400,000 on building the plane. It had a
magnificent burlwood panel.

I believe his was the fifth Lionheart completed and the fourth to crash. The
pilot told me he did not plan to build another. I had first met the builder
a couple years before in a Belfair restaurant. A factory representative was
with him wearing a Lionheart t-shirt. I went over and introduced myself. The
rep was a professional builder who was going to spend about six months
working on the project with the owner.

[Del Rawlins]

On 18 Nov 2003 10:27 PM, - Barnyard BOb - posted the following:

> What happened to that goose?
> Looked like a prime candidate for road kill...
> heading for that very busy street.

I dunno. I went inside before my blood lust got the better of my
judgement.

> Are you sure you were in Alaska?
> I didn't notice any snow, dirt roads,
> mountains, huskies, eskimos or igloos. <g>

I left Alaska and moved to Los Anchorage 2 years ago. I really miss
Cordova (pop. 2500 and falling), but I don't really miss what I was
doing for a living there, and am happy to have gotten out before the
seafood based economy totally collapses. I just got word that one of
the major fish processing plants, and the only one which operates year
round (read: non seasonal workforce and a big part of the winter economy)
is going to be shutting down.

I can see the mountains from my house in the other direction, the only
"igloos" I have ever seen were loaded on an Alaska Airlines 737 (that's
what Alaska calls their containers), I don't like dogs, the windshield
of the Jeep in the video is covered with plenty of evidence of dirt road/
alcan usage, and if I want to see eskimos I can drive downtown (I'm
gonna get flamed for that).

There are 3 major differences I notice between living in a small town,
and living in the big ****ty:

1) More traffic on my 5 minute drive to school/work.

2) I can't drive or walk for 20 minutes and be the only human being
around.

3) When I needed some oddball part to accomplish some purpose on one of
my projects, in Cordova I would exhaust the local possibilities in the
space of 30 minutes and then just mail order the damn thing. Here, I
can spend 2 days and 3 tanks of gas driving all over hell and back,
explaining my needs to complete morons and then listening to their
wrongheaded opinions for doing what they think I want to do, and still
not find what I am looking for before mail ordering the damn thing.
Unless you are trying to perform the exact same task as Joe Dip**** in
the same exact manner, the world is set against you.

The best things which can be said of my current location, is that I am
working on my project again after a 3 year hiatus, and I live close to
the road out of Anchorage. When/if I ever finish the Bearhawk I'll be
an hour and a half away from my old haunts. That's the right word too,
since it's well on its way to becoming a ghost town.

----------------------------------------------------
Del Rawlins-
Remove _kills_spammers_ to reply via email.
Unofficial Bearhawk FAQ website:
http://www.rawlinsbrothers.org/bhfaq/

[Dave Hyde]

Del Rawlins wrote:

> There are 3 major differences I notice between living in a small town,
> and living in the big ****ty:

....

> 2) I can't drive or walk for 20 minutes and be the only human being
> around.

What, you don't have an ad agency within 20 minutes?

Dave 'didn't say law firm' Hyde

[Corky Scott]

On Tue, 18 Nov 2003 23:31:56 -0800, "C J Campbell"
> wrote:

>
>I believe his was the fifth Lionheart completed and the fourth to crash.

Wow. What's going on here? Too much airplane for too little
experience?

Corky Scott

[Fred the Red Shirt]

"C J Campbell" > wrote in message >...
>... One main gear collapsed, then the other as he
> groundlooped. The gear bolts were connected directly to the fuel tanks, so
> when the gear collapsed the bottom of the fuel tank was ripped out.

I'm still early in the learning stages of aircraft design but offhand
that design choice sounds rather ill-considered. Am I missing something?

> The
> plane burst into a spectacular fire which was caught on film by several
> cameras on the ground and a camera in the chase plane. It was pitiful
> watching Bremerton's lone fire truck (a pickup truck with a water tank on
> the back) try to put this thing out. The water would not even reach the
> fire.
>
> His wife was sure he was dead because we did not see him get out. As it
> turned out he had only a cut on his thumb. ...

--

FF

[C J Campbell]

"Corky Scott" > wrote in message
...
| On Tue, 18 Nov 2003 23:31:56 -0800, "C J Campbell"
| > wrote:
|
| >
| >I believe his was the fifth Lionheart completed and the fourth to crash.
|
| Wow. What's going on here? Too much airplane for too little
| experience?

Short coupled tailwheel airplane landing in a left quartering tailwind with
a serious design flaw in the landing gear. The pilot of the chase plane said
that the Lionheart's pilot was having enormous difficulty controlling the
airplane throughout the flight, with violent pitch excursions. He also had
not had much recent experience landing any tailwheel airplane and none at
all in the Lionheart. The pilot was an ATP currently flying for a major
airline.

It reminds me of a story Mike told me about a pilot at Tacoma Narrows who
finished his homebuilt aircraft after many years of loving work. He was
hesitant to fly it because he was not current and had not flown a tailwheel
airplane in a long time, but his family and friends wanted to see him fly
and so he and Mike worked out a careful plan to test fly it, beginning with
taxi tests, fast taxis, etc. Unfortunately, the man's entire family and many
friends turned out to watch the initial tests, expecting him to fly. Instead
of doing the fast taxi he took off, pitched up too high, and plopped back
down so hard that he jammed the landing gear up through the wings and
folding up the prop on the runway.

His buddies helped him move the plane back into the hangar, only now the
obsession was to get the thing flying again instead of creating a work of
art. Six months later the airplane was ready for another try. The same crowd
turned out and again the pilot was pressured into taking off before he was
ready. Mike said that the man was so fearful he was sweating, pale and
shaking before leaving -- he doesn't know how his family missed it.

He had an impossible time controlling the airplane. He could not land it and
finally the tower had Mike and others trying to talk him down. Mike said he
could hear from the pilot's voice that he was in terrible trouble. Finally,
with the airplane on fumes, the pilot managed a landing and the airplane
coasted to a stop at the end of the runway. But it never pulled off onto the
taxiway and the pilot did not get out. He was dead of a massive heart
attack.

No doubt at the funeral they said of him that he died doing what he loved to
do.

[Corky Scott]

On Wed, 19 Nov 2003 08:32:53 -0800, "C J Campbell"
> wrote:

>
>"Corky Scott" > wrote in message
...
>| On Tue, 18 Nov 2003 23:31:56 -0800, "C J Campbell"
>| > wrote:
>|
>| >
>| >I believe his was the fifth Lionheart completed and the fourth to crash.
>|
>| Wow. What's going on here? Too much airplane for too little
>| experience?
>
>Short coupled tailwheel airplane landing in a left quartering tailwind with
>a serious design flaw in the landing gear. The pilot of the chase plane said
>that the Lionheart's pilot was having enormous difficulty controlling the
>airplane throughout the flight, with violent pitch excursions.

I went to the Lionheart website to have a look. There was a section
that listed testimonials. Among those testimonials was one from none
other than Jim Campbell, he liked it...

Corky Scott

[Jay]

"Richard Isakson" > wrote in message > Bull****, Jay.
>
> I worked for several years as an engineer in Boeing's Aero Staff.
> Everything you just said is wrong. The people that design wings at Boeing
> use the best technology available that's consistant with the production
> materials that are available.

I suppose nobody ever approved using composites untill just recently
(wasn't on the QPL), so I guess it wasn't the engineer's fault that
they didn't get to use these materials until 30 years after the
homebuilt guys were using them in their garage. Right?

> They don't design on the basis of some
> political whim.

You must have had better luck working in large organizations than I
have.

> They don't design biplanes because it's easy to show
> mathematically that the mutual interference between the circulation of the
> two wings decreases the efficiency of both wings.

Ya sure, but for what airfoil, chord, span, stagger, flow model?

> You seem to have strange theory that just because something isn't done it
> must be a good thing to try.

No, the theory is just because someone else hasn't been able to do it
right, doesn't mean it won't ever work. Give yourself some credit.
Its happened before.

> Subsonic aerodynamics was well explored by
> World War II.

Ya, and we know what kind of advanced tools they had at their disposal
during that time. I think their computer was a group of ladies in a
room with adding machines.

> Much of transonic and supersonic flow was understood shortly
> after. If you think that you've come up with something new that just means
> you don't understand why thinks work.

When the Wright brothers came up with this idea of heavier than air
powered flight didn't mean they just didn't understand how things
worked. If they'd listened to the early 1900's version of people with
that attitude, we'd be celebrating some French guy inventing powered
flight. They had intuition that they may be something there, and
didn't give up just because lots of other people had failed.

> If you want do to something different
> just to be different go ahead, but it will be an inferior product and
> possibly dangerous.

I'm not building anything yet, I'm just discussing some ideas with
people interested in looking at old problems with new eyes.

> Your current design has at least three fatal flaws.
> You need to open some books and understand the theory of flight before you
> start designing airplanes.

Instead of running numbers on Excel with formulas filled with fudge
factors from experimental data taken 70 years ago, I think I'm going
to throw some wings on my FEA computer model and let the computer take
care of the algebra at 2.4GHz.

> Rich

[Ben Sego]

>
> I went to the Lionheart website to have a look. There was a section
> that listed testimonials. Among those testimonials was one from none
> other than Jim Campbell, he liked it...
>
> Corky Scott

Well, I'm sold then!

B.S.

[Jay]

Dave Hyde > wrote in message
> The generally accepted definition of the induced drag coefficient
> is:
>
> CDi=CL^2/pi/e/AR,
> where CL is the wing lift coefficient at the conditions under
> consideration,
> pi=3.14159...
> e = Oswald's efficiency factor (typically 0.8 or so)
> AR = aspect ratio

Okay, thanks for all that, I think you're missing some parentheses in
there because I'm getting a quad decker formula. I always love those
formulas with a constant that has some guys name that was alive in the
last 100 years.

> The _definition_ of aspect ratio is chord/span, or span^2/aero (they're
> equivalent), so as area remains the same but aspect ratio increases,
> induced drag decreases by 1/span^2. That's what I call a primary
> effector.
> If you add wing treatments like winglets, fences, etc, you can increase
> the
> effective AR, but the big effects are gained by working at the tips,
> not across the span, as another wing typically does.
>
> Look at the lift side. The formula becomes messier, but for a finite
> wing:
>
> CL,finite ~= CL,infinite*(1/(1+(dCL,inf/daoa)/pi/AR))
>
> As span increases through increased aspect ratio, the finite
> wing lift coefficient gets closer to the infinite wing CL.
>
> Can we agree that this is a good thing?

Okay I'm looking at things in the infinite wing theory where the
effects due to tip/root disturbance are very small compared to the
rest of the span. So with this theoretical wing of aspect approaching
zero, 2 non-interfering wings of half span, would be essentially the
same lift and drag as one.

Perhaps this is really a discussion of how large an effect the
root/tip distubance is for a practical wing (e.g. 30' span). You'd
pointed out that proper tip treatment can help make the shorter wing
behave as if it is part of an infinite span. Seems like a fence at
the tip would be the way to go to keep the high pressure air from
spilling over into the low pressure region.

> Um...you might want to review some finite wing theory.
> There can be quite a bit of spanwise flow at the root _or_
> the tip. When subsonic you make a bow wake. The air is moving
> before you hit it, and it's not just front-to-back.

Looks like the issue is I'm talking about this theoretical wing and
you're talking about a practical one. You know, in theory, practice
and theory are the same, but in practice, they are very different. =^)

> That's not a rule of thumb, that's physics. All other things being
> equal, the highger AR wing *will* have less drag.

I'm talking about 2 wings that have an aspect approaching zero, versus
a single wing with aspect approaching zero as well. So the lift and
drag per foot of wing are essentially the same.

> Done and done. Your turn.
>
> > I've worked for lots of companies like Boeing...
>
> Have you ever worked in conceptual design and/or
> aerodynamics?

Not of aircraft, have you? The closest thing I've done and got payed
for was the work I did on a DARPA program called FLASH. I was working
on the ailerons of the Dryden F/A-18 they were torturing.

> Most of your risk aversion comments
> were way off the mark. A trip to the Air Force museum
> to see the Bird of Prey or the X-36 could be illuminating.

Most if not all of those X planes were R&D payed for by the you and
me, the tax payers of America. Its extremely rare for a large company
to take a "flyer" with their own money and reach very far forward.

> Dave 'misconceptual design' Hyde
>

[Del Rawlins]

On 19 Nov 2003 08:19 AM, Corky Scott posted the following:

> I went to the Lionheart website to have a look. There was a section
> that listed testimonials. Among those testimonials was one from none
> other than Jim Campbell, he liked it...

No doubt he looped, rolled, and spun it.

----------------------------------------------------
Del Rawlins-
Remove _kills_spammers_ to reply via email.
Unofficial Bearhawk FAQ website:
http://www.rawlinsbrothers.org/bhfaq/

[Felger Carbon]

"Jay" > wrote in message
om...
>
> > Subsonic aerodynamics was well explored by
> > World War II.
>
> Ya, and we know what kind of advanced tools they had at their disposal
> during that time. I think their computer was a group of ladies in a
> room with adding machines.

That was at Los Alamos, NM. Not related to aerodynamics.

[Dave Hyde]

Jay wrote:

> Okay, thanks for all that, I think you're missing some parentheses in
> there because I'm getting a quad decker formula.

The formula is correct as written.

> So with this theoretical wing of aspect approaching zero,
> 2 non-interfering wings of half span, would be essentially the
> same lift and drag as one.

I think you have a fundamental misunderstanding of the basics here.
An infinte (span) wing has an aspect ratio of INFINITY, not zero.
LARGER aspect ratio is less drag.
Again, to make a successful break from the mouse-maze, you've
either got to have a sound grasp of the fundamentals or be
very lucky. Counting on luck does not instill confidence
(but sometimes produces interesting threads).

> Most if not all of those X planes were R&D payed for by the you and
> me, the tax payers of America. Its extremely rare for a large company
> to take a "flyer" with their own money and reach very far forward.

Who pays is irrelevant. There have been and will continue to
be radical departures from the 'box' even by giants in the aerospace
industry. The simple fact that you are not aware of them does not
mean that they do not exist.

Dave 'to infinity...and beyond' Hyde

[Dave Hyde]

Jay wrote:

*sigh*

> Instead of running numbers on Excel with formulas filled with fudge
> factors from experimental data taken 70 years ago, I think I'm going
> to throw some wings on my FEA computer model and let the computer take
> care of the algebra at 2.4GHz.

I give up. Good luck, and please post or publish your results
when you're done. The world awaits.

Dave 'Pontius Pilot' Hyde

[ChuckSlusarczyk]

In article . net>, Ben Sego
says...
>
>>
>> I went to the Lionheart website to have a look. There was a section
>> that listed testimonials. Among those testimonials was one from none
>> other than Jim Campbell, he liked it...
>>
>> Corky Scott
>
>Well, I'm sold then!

He likes anything that he thinks will lead to some ad money :-) He only stops
liking them when they stop the ads. zoom likes it and jaun will probably rebuild
it .....but never fly it. LOL!!!

Chuck(believer in 70 year old data) S

[Bob Kuykendall]

Earlier, Jay wrote:

> ...So with this theoretical wing
> of aspect approaching zero, 2 non-
> interfering wings of half span,
> would be essentially the same
> lift and drag as one...

The same drag as one very ineffecient wing, that is. So as L/D > 0, it
starts to not matter as much whether you've got a monoplane or a
venetian blind.

And please, nobody ask how you make a venetian blind. I do remember
when 16Kb was the size of a gym locker. BTDT, still got some of the
core beads.

On a slightly different topic: Jay, when I was pointing you towards
joined-wing concepts in the earlier thread and also in private email,
I really wasn't trying to be snarky. I was trying to point out a
configuration that:

* Suggests a practical application for something like a biplane
configuration

* Has been studied enough to suggest that it offers, in theory at
least, some advantages over other configurations

* Is not well explored in physical hardware (NASA canceled their
proof-of-concept aircraft and put the AD-1 it was based on in the
Hiller museum)

* Would look relatively cool and unusual

Thanks, and best regards to all

Bob K.

[alexy]

Dave Hyde > wrote:

>I think you have a fundamental misunderstanding of the basics here.
>An infinte (span) wing has an aspect ratio of INFINITY, not zero.
>LARGER aspect ratio is less drag.
Dave, to be fair to Jay, you did type

:The _definition_ of aspect ratio is chord/span

Of course, you immediately contradicted that by typing

:or span^2/aero (they're equivalent)

which should have clued anyone in that you had inverted the first
expression.

--
Alex
Make the obvious change in the return address to reply by email.

[alexy]

(Jay) wrote:

>"Richard Isakson" > wrote in message > Bull****, Jay.

>> You seem to have strange theory that just because something isn't done it
>> must be a good thing to try.
>
>No, the theory is just because someone else hasn't been able to do it
>right, doesn't mean it won't ever work. Give yourself some credit.
>Its happened before.
>
>> Subsonic aerodynamics was well explored by
>> World War II.
>
>Ya, and we know what kind of advanced tools they had at their disposal
>during that time. I think their computer was a group of ladies in a
>room with adding machines.
>
>> Much of transonic and supersonic flow was understood shortly
>> after. If you think that you've come up with something new that just means
>> you don't understand why thinks work.
>
>When the Wright brothers came up with this idea of heavier than air
>powered flight didn't mean they just didn't understand how things
>worked. If they'd listened to the early 1900's version of people with
>that attitude, we'd be celebrating some French guy inventing powered
>flight. They had intuition that they may be something there, and
>didn't give up just because lots of other people had failed.

It's funny, but I think you are both right. One beauty of experimental
aviation is the "experimental" part and the ability to break the mold.
But I'd also bet that 99 44/100% (conservative estimate) of the time
that well-established practice is forsaken, the builder finds out why
that practice was well established in the first place. And an
uninformed outsider's opinion of the engineering dome by professionals
on a project like an airliner is laughable at best. Somehow, I suspect
that Boeing knew quite a bit about composites 30 years ago, and I am
glad that the planes I fly on now that were designed at that time do
not have hot-wire cut foam wings <g>. Richard: I think it is good for
someone like Jay to come along and use his creativity to challenge
conventional thought. Jay: Remember that if you want to analogize what
you are doing here to the Wright Bros, they did a hell of a lot of
engineering and experimentation, not just out-of-the-box thinking.

>> Your current design has at least three fatal flaws.
>> You need to open some books and understand the theory of flight before you
>> start designing airplanes.
>
>Instead of running numbers on Excel with formulas filled with fudge
>factors from experimental data taken 70 years ago, I think I'm going
>to throw some wings on my FEA computer model and let the computer take
>care of the algebra at 2.4GHz.
Now THAT is scary. Someone who thinks a computer model is a substitute
for learning fundamentals (and is impressed by the speed if his PC's
processor<VBG>) is a huge danger to himself. If you do get into the
build mode, I hope you will try out your ideas on an RC model first.

--
Alex
Make the obvious change in the return address to reply by email.

[Ben Sego]

Felger Carbon wrote:
> That was at Los Alamos, NM. Not related to aerodynamics.

NACA and its successor, NASA, used "group[s] of ladies in a
room". The title for that job was "Computer." That work was most
definitely related to aerodynamics.

Here's a quote from the book "Engineer in Charge," subtitled "A History
of the Langley Aeronautical Laboratory, 1917-1958":

--start of quote--
As the test began, two researchers peered through small glass portals in
the side of the tank, operating a signal system that triggered different
lights as the airspeed became constant or when a problem arose. These
men called out their readings of the balance scales to a recorder who
simultaneously read aloud, from his panel of instruments, tank pressure
and temperature of the manometer liquid. For scale-effect comparisons,
the VDT staff made the tests at a constant airspeed (approximately 50
miles per hour) and at five different tank pressures (Usually 1, 2.5, 5,
10, and 20 atomospheres) and then tested airfoils of closely related
characteristics at 20 atomospheres only. Modifying a particular feature
of a model while keeping all its other characteristics constant enabled
the staff to compare the aerodynamic effects on each new shape with
those on the original. When all the necessary readings had been taken,
someone shut the drive motor off and opened a blow-off valve which
released the pressurized air. The calculation, plotting, and final
processing of data took weeks. "Computers" existed in those days--but
being human, they had to eat lunch, and wanted coffee breaks!
--end of quote--

This particular paragraph concerns work done in the Variable Density
Tunnel which began operation in 1922.

B.S.

[Ben Sego]

alexy wrote:
> (Jay) wrote:
>>Instead of running numbers on Excel with formulas filled with fudge
>>factors from experimental data taken 70 years ago, I think I'm going
>>to throw some wings on my FEA computer model and let the computer take
>>care of the algebra at 2.4GHz.
>
> Now THAT is scary. Someone who thinks a computer model is a substitute
> for learning fundamentals (and is impressed by the speed if his PC's
> processor<VBG>) is a huge danger to himself. If you do get into the
> build mode, I hope you will try out your ideas on an RC model first.
>

But learn about scale effects, or the model work isn't useful.

Ben "Osborne Reynolds" Sego

[Ben Sego]

ChuckSlusarczyk wrote:
> In article . net>, Ben Sego
> says...
>>>other than Jim Campbell, he liked it...
>>>
>>>Corky Scott
>>
>>Well, I'm sold then!
>
>
> He likes anything that he thinks will lead to some ad money :-) He only stops
> liking them when they stop the ads. zoom likes it and jaun will probably rebuild
> it .....but never fly it. LOL!!!
>
> Chuck(believer in 70 year old data) S
>

I understand it can be difficult to cancel an ad. Perhaps people aren't
speaking clearly and forthrightly enought to them...er...him.

Ben "governing myself" Sego

[- Barnyard BOb -]

>Jay wrote:
>
>*sigh*
>
>> Instead of running numbers on Excel with formulas filled with fudge
>> factors from experimental data taken 70 years ago, I think I'm going
>> to throw some wings on my FEA computer model and let the computer take
>> care of the algebra at 2.4GHz.
>
>I give up. Good luck, and please post or publish your results
>when you're done. The world awaits.
>
>Dave 'Pontius Pilot' Hyde
++++++++++++++++++++++++++++++++++++

Nice try, Pontius.
However, this outcome was inevitable.
Kinda like with his brother, Latchless. <g>


Barnyard BOb --

[[email protected]]

On 19 Nov 2003 10:56:41 -0800, (Jay) wrote:

:Instead of running numbers on Excel with formulas filled with fudge
:factors from experimental data taken 70 years ago, I think I'm going
:to throw some wings on my FEA computer model and let the computer take
:care of the algebra at 2.4GHz.

There you go. Exactly what Alan Shaw did with the Atlantica. It
turned out great. And the Prescott Pusher, designed entirely with
McDonnald Douglass CAD. A terrific airplane. A computer can't go
wrong.

BTW, if you aren't using a Pentium 4 3.06GHz 533Mhz 512K Xeon at a
minumum, you aren't even a serious amateur.

[Jay]

(Bob Kuykendall) wrote in message

> On a slightly different topic: Jay, when I was pointing you towards
> joined-wing concepts in the earlier thread and also in private email,

I did get your e-mail, thank you for that. I have actually seen, but
not run, the models that are configured the way you describe.

> I really wasn't trying to be snarky. I was trying to point out a
> configuration that:
>
> * Suggests a practical application for something like a biplane
> configuration
>
> * Has been studied enough to suggest that it offers, in theory at
> least, some advantages over other configurations
>
> * Is not well explored in physical hardware (NASA canceled their
> proof-of-concept aircraft and put the AD-1 it was based on in the
> Hiller museum)
>
> * Would look relatively cool and unusual
>
> Thanks, and best regards to all
>
> Bob K.

[Jay]

Thanks Alexy,

I wasn't sure what the convention was in aero work for defining
"aspect", it doesn't really matter as long as everybody agrees on the
same definition! So I just took David's definition and went from
there.

Then in his next expresion said "span^2/aero", so I figured "AERO"
meant something that he hadn't defined, but I should have implicitly
known, and figured at this point it wasn't crucial to the discussion.

But this is the reason why I was trying to discuss relationships
before we got into botched algebra. I'm seem to be continually making
those kinds of errors so I end up doing everything 2 ways just to make
sure.


alexy > wrote in message >...
> Dave Hyde > wrote:
>
> >I think you have a fundamental misunderstanding of the basics here.
> >An infinte (span) wing has an aspect ratio of INFINITY, not zero.
> >LARGER aspect ratio is less drag.
> Dave, to be fair to Jay, you did type
>
> :The _definition_ of aspect ratio is chord/span
>
> Of course, you immediately contradicted that by typing
>
> :or span^2/aero (they're equivalent)
>
> which should have clued anyone in that you had inverted the first
> expression.

[Jay]

Hey don't give up Dave, nobody said it would be easy. You haven't
convinced me not to run the model. But you have pointed out 2 things
I will look at more carefully:

1) Will the root/tip losses from 2 wings eat up any benefit from the
shorter/lighter spans? Are there tip treatments that diminish this?

2) What wing configuration can be used that minimizes mutual
interference between the 2 lifting surfaces.

Thanks!

p.s. I will post the results when I get them.

Dave Hyde > wrote in message >...
> Jay wrote:
>
> *sigh*
>
> > Instead of running numbers on Excel with formulas filled with fudge
> > factors from experimental data taken 70 years ago, I think I'm going
> > to throw some wings on my FEA computer model and let the computer take
> > care of the algebra at 2.4GHz.
>
> I give up. Good luck, and please post or publish your results
> when you're done. The world awaits.
>
> Dave 'Pontius Pilot' Hyde
>

[alexy]

Ben Sego > wrote:

>
>
>alexy wrote:
>> (Jay) wrote:
>>>Instead of running numbers on Excel with formulas filled with fudge
>>>factors from experimental data taken 70 years ago, I think I'm going
>>>to throw some wings on my FEA computer model and let the computer take
>>>care of the algebra at 2.4GHz.
>>
>> Now THAT is scary. Someone who thinks a computer model is a substitute
>> for learning fundamentals (and is impressed by the speed if his PC's
>> processor<VBG>) is a huge danger to himself. If you do get into the
>> build mode, I hope you will try out your ideas on an RC model first.
>>
>
>But learn about scale effects, or the model work isn't useful.

Alternate responses:
1) Doh, of course. I forgot about that.
2) Well of course. I thought that was obvious.
3) Why did you assume that by RC model I meant one at other than 1:1
scale?
4) Yeah, but he was talking about wings with infinite span, so I
figured scaling didn't apply.

Honesty compels me to #1. Good catch.
--
Alex
Make the obvious change in the return address to reply by email.

[Jay]

It looks like Atlantica is still in development, they're using the
same software as I am for my dabbling.

Prescott's Pusher looks like it was pretty ordinary in terms of the
trade offs made (high stall speed), the computer used for that
development looks like it was for manufacturability (CAM) rather than
conducting experiments in aerodynamics. The twitchyness in pitch
people write about is obvious because of the distance between the
center of lift and the elevator, no mystery there. If they'd had the
tools available to the hobbiest today, they'd have been able to see it
before they built it.

Computers aren't perfect, they're programmed by people, with the same
assumptions and errors. But the throughput allows a different type of
analysis to be done than was previously available. Instead of trying
to find a closed form aproximation for a particular parameter of
flight, it allows you to model lots and lots of very simple phenomenon
which come together to produce some high level behaviour like a stall
or another unanticipated effect.

wrote in message >...
> On 19 Nov 2003 10:56:41 -0800, (Jay) wrote:
>
> :Instead of running numbers on Excel with formulas filled with fudge
> :factors from experimental data taken 70 years ago, I think I'm going
> :to throw some wings on my FEA computer model and let the computer take
> :care of the algebra at 2.4GHz.
>
> There you go. Exactly what Alan Shaw did with the Atlantica. It
> turned out great. And the Prescott Pusher, designed entirely with
> McDonnald Douglass CAD. A terrific airplane. A computer can't go
> wrong.
>
> BTW, if you aren't using a Pentium 4 3.06GHz 533Mhz 512K Xeon at a
> minumum, you aren't even a serious amateur.

[Robert Bonomi]

In article >, Dave Hyde > wrote:
>Jay wrote:
>
>> Okay, thanks for all that, I think you're missing some parentheses in
>> there because I'm getting a quad decker formula.
>
>The formula is correct as written.
>
>> So with this theoretical wing of aspect approaching zero,
>> 2 non-interfering wings of half span, would be essentially the
>> same lift and drag as one.
>
>I think you have a fundamental misunderstanding of the basics here.
>An infinte (span) wing has an aspect ratio of INFINITY, not zero.
>LARGER aspect ratio is less drag.
>Again, to make a successful break from the mouse-maze, you've
>either got to have a sound grasp of the fundamentals or be
>very lucky. Counting on luck does not instill confidence
>(but sometimes produces interesting threads).
>
>> Most if not all of those X planes were R&D payed for by the you and
>> me, the tax payers of America. Its extremely rare for a large company
>> to take a "flyer" with their own money and reach very far forward.
>
>Who pays is irrelevant. There have been and will continue to
>be radical departures from the 'box' even by giants in the aerospace
>industry. The simple fact that you are not aware of them does not
>mean that they do not exist.
>
>Dave 'to infinity...and beyond' Hyde

AHA! *THERE's* the proper explanation.

Twin wings, with aleph-sub-one aspect ratio _should_ out-perform a
(merely) 'infinite' AR wing. *snicker* <chortle> =+GUFFAW+=

[Robert Bonomi]

In article >,
Jay > wrote:
>Hey don't give up Dave, nobody said it would be easy. You haven't
>convinced me not to run the model. But you have pointed out 2 things
>I will look at more carefully:
>
>1) Will the root/tip losses from 2 wings eat up any benefit from the
>shorter/lighter spans? Are there tip treatments that diminish this?

the big killer is the interaction in airflow pattern across the two
surfaces.

putting a 2nd surface "above" a lifting surface _decreases_ the available
lift from that first surface. you have a 'compression' effect on the
'ram air' passing between the two surfaces, due to the constriction from
the _reduction_ in cross-section of the space between the two surfaces,
as you proceed from leading edge of the lifting surface back to the point
of maximum rise in that surface.

To minimize these kinds of effects, the space between the surfaces has
to be relatively -large-, the velocity of the air _comparatively_ slow,
*and* you need to let that 'built-up' ram-air effect bleed off in the
only direction it can go -- i.e., _sideways_, towards the tips of the
wing(s).
>
>2) What wing configuration can be used that minimizes mutual
>interference between the 2 lifting surfaces.

One simple answer to -that- one is 'obvious' -- place them infinitely far
apart. <grin>

[alexy]

(Robert Bonomi) wrote:

>In article >, Dave Hyde > wrote:
>>Jay wrote:
>>
>>> Okay, thanks for all that, I think you're missing some parentheses in
>>> there because I'm getting a quad decker formula.
>>
>>The formula is correct as written.
>>
>>> So with this theoretical wing of aspect approaching zero,
>>> 2 non-interfering wings of half span, would be essentially the
>>> same lift and drag as one.
>>
>>I think you have a fundamental misunderstanding of the basics here.
>>An infinte (span) wing has an aspect ratio of INFINITY, not zero.
>>LARGER aspect ratio is less drag.
>>Again, to make a successful break from the mouse-maze, you've
>>either got to have a sound grasp of the fundamentals or be
>>very lucky. Counting on luck does not instill confidence
>>(but sometimes produces interesting threads).
>>
>>> Most if not all of those X planes were R&D payed for by the you and
>>> me, the tax payers of America. Its extremely rare for a large company
>>> to take a "flyer" with their own money and reach very far forward.
>>
>>Who pays is irrelevant. There have been and will continue to
>>be radical departures from the 'box' even by giants in the aerospace
>>industry. The simple fact that you are not aware of them does not
>>mean that they do not exist.
>>
>>Dave 'to infinity...and beyond' Hyde
>
>AHA! *THERE's* the proper explanation.
>
>Twin wings, with aleph-sub-one aspect ratio _should_ out-perform a
>(merely) 'infinite' AR wing. *snicker* <chortle> =+GUFFAW+=

You laugh, but there are planes of aleph-sub-two aspect ratio. At
least I assume that is what you need a complex rating for<g>.
--
Alex
Make the obvious change in the return address to reply by email.

[Dave Hyde]

alexy wrote:

> You laugh, but there are planes of aleph-sub-two aspect ratio. At
> least I assume that is what you need a complex rating for<g>.

And when Chuck Slusarczyk flies them as copilot they're
unstable.

Dave 'humor from the geek farm' Hyde

[slomo]

Aspect ratio on a wing without taper IS wingspan divided
by the chord. But few wings are strictly a rectangle. Many
have wingtips instead of being squared off. Many have
some taper, and the area covered by the fuselage is not
an extension of the taper, but figured
by straight lines connecting the left and right leading edge
points at the root and left and right trailing edge points at
the root. Not to mention airplanes with taper breaks and/or
other non-straight leading or trailing edges.

So, the easier way is to use the area and the square of the span.

Aspect Ratio (AR) is the square of the wingspan divided by
the area of the wing.

Now - to clarify the misreading of the note:

basic middle school math:
the upward arrow means to raise to the power

aero = a kindergarten form of area
also called fumble fingered the keys


Aspect Ratio is very much a part of the discussion. The biplane
has lots of area and not much span. Low aspect ratio. Inefficient.

Make the wing chord real skinny and Reynold's number comes
into play. But that's another story.





In article >,
(Jay) wrote:
>Thanks Alexy,
>
>I wasn't sure what the convention was in aero work for defining
>"aspect", it doesn't really matter as long as everybody agrees on the
>same definition! So I just took David's definition and went from
>there.
>
>Then in his next expresion said "span^2/aero", so I figured "AERO"
>meant something that he hadn't defined, but I should have implicitly
>known, and figured at this point it wasn't crucial to the discussion.
>
>But this is the reason why I was trying to discuss relationships
>before we got into botched algebra. I'm seem to be continually making
>those kinds of errors so I end up doing everything 2 ways just to make
>sure.
>
>
>alexy > wrote in message
> >...
>> Dave Hyde > wrote:
>>
>> >I think you have a fundamental misunderstanding of the basics here.
>> >An infinte (span) wing has an aspect ratio of INFINITY, not zero.
>> >LARGER aspect ratio is less drag.
>> Dave, to be fair to Jay, you did type
>>
>> :The _definition_ of aspect ratio is chord/span
>>
>> Of course, you immediately contradicted that by typing
>>
>> :or span^2/aero (they're equivalent)
>>
>> which should have clued anyone in that you had inverted the first
>> expression.

[Ben Sego]

alexy wrote:
> Ben Sego > wrote:
>
>
>>
>>
>>But learn about scale effects, or the model work isn't useful.
>
>
> Alternate responses:
> 1) Doh, of course. I forgot about that.
> 2) Well of course. I thought that was obvious.
> 3) Why did you assume that by RC model I meant one at other than 1:1
> scale?
> 4) Yeah, but he was talking about wings with infinite span, so I
> figured scaling didn't apply.
>
> Honesty compels me to #1. Good catch.

Three is really good. But I think #4 is best.

B.S.

[ChuckSlusarczyk]

In article et>, slomo says...

>Make the wing chord real skinny and Reynold's number comes
>into play. But that's another story.

Boy now you did it LOL!! I was wondering when Reynolds number would be
brought up and now they are. Let's see, I bet if we build an infinate span wing
biplane flying at infinatly high reynolds we can beat the monoplane flying in
the real world. :-)

Back to lurk mode .

Chuck (that ain't syrup,it's low reynolds air) S

[ChuckSlusarczyk]

In article >, Dave Hyde says...
>
>alexy wrote:
>
>> You laugh, but there are planes of aleph-sub-two aspect ratio. At
>> least I assume that is what you need a complex rating for<g>.
>
>And when Chuck Slusarczyk flies them as copilot they're
>unstable.

Hell, they wuz unstable before I got in!! It ain't the instability that
bothers me, it don't hurt till the crash ......and BOY that sometimes
hurts.

Chuck ( I built a biplane glider for Junkyard wars) S

>
>Dave 'humor from the geek farm' Hyde

[Ernest Christley]

Robert Bonomi wrote:

> To minimize these kinds of effects, the space between the surfaces has
> to be relatively -large-, the velocity of the air _comparatively_ slow,
> *and* you need to let that 'built-up' ram-air effect bleed off in the
> only direction it can go -- i.e., _sideways_, towards the tips of the
> wing(s).
>

So, are we looking for a delta wing bi-plane?

--
http://www.ernest.isa-geek.org/
"Ignorance is mankinds normal state,
alleviated by information and experience."
Veeduber

[Ben Sego]

Dave Hyde wrote:
<snip>

> Biplanes are a simple,
> but inefficient, way of getting more lift from wing area
> when an increase in span is not feasible. The are not, nor
> in general are they intended to be, "low drag."
>
>
>>You mentioned the interference drag, so how far do wings
>>need to be vertically separated for a given airfoil
>>and stagger for this effect to be negligable?
>
>
> *negligible?* Some *large* fraction of the span. At a minimum.
<snip>

> Dave 'usenet wind tunnel' Hyde
>

Here's some pretty pictures of biplane wing pressure interaction from
the CFD tool that Peter Garrison sells:

http://www.melmoth2.com/texts/CFD.htm

B.S.

[Ron Wanttaja]

On Wed, 19 Nov 2003 01:09:28 -0600, - Barnyard BOb - > wrote:

>Barnyard BOb - if it's a duck, it's a duck

....and if it tries to fly upside down, it quacks up....

Ron "Orville told Wilbur that one" Wanttaja

[Jay]

What I'm running now (in computer model) is a stagger between the top
and bottom wing with the bottom wing leading the top by a full chord.
The top has a dihedral of 5 degrees and the bottom wing has none so as
you move out on the span, the vertical distance between the surfaces
increaces.

This is actually flying quite nice although I have seen some drop off
in top speed. The flaps generate a strong pitching tendancy since the
wing with the flaps is no longer at the CG. The next step is I'm
going to adopt the airfoil from one the available glider wings and as
a result probably lengthen the stubby wings somewhat to recover the
lift with the goal of leaving behind some of the induced drag.

Regards

(Robert Bonomi) wrote in message s.com>...
> In article >,
> Jay > wrote:
> >Hey don't give up Dave, nobody said it would be easy. You haven't
> >convinced me not to run the model. But you have pointed out 2 things
> >I will look at more carefully:
> >
> >1) Will the root/tip losses from 2 wings eat up any benefit from the
> >shorter/lighter spans? Are there tip treatments that diminish this?
>
> the big killer is the interaction in airflow pattern across the two
> surfaces.
>
> putting a 2nd surface "above" a lifting surface _decreases_ the available
> lift from that first surface. you have a 'compression' effect on the
> 'ram air' passing between the two surfaces, due to the constriction from
> the _reduction_ in cross-section of the space between the two surfaces,
> as you proceed from leading edge of the lifting surface back to the point
> of maximum rise in that surface.
>
> To minimize these kinds of effects, the space between the surfaces has
> to be relatively -large-, the velocity of the air _comparatively_ slow,
> *and* you need to let that 'built-up' ram-air effect bleed off in the
> only direction it can go -- i.e., _sideways_, towards the tips of the
> wing(s).
> >
> >2) What wing configuration can be used that minimizes mutual
> >interference between the 2 lifting surfaces.
>
> One simple answer to -that- one is 'obvious' -- place them infinitely far
> apart. <grin>