Hershey bar wing vs composite wing - how much drag?

("Wayne Paul" wrote)
It is much easier to build a laminar flow airfoil and complex shaped
wing to fuselage transition using composite construction. These wing have
a better lift to drag ratio. The decrease in drag aerodynamic drag of
the wing and static drag decrease associated with the wing/fuselage
transition allow faster speeds.


Can you reword this (for some of us "Huh?" lurkers) especially the wing to
fuselage transition part?

How good/efficient are Cherokee, Ercoupe, Cessna (aluminum & rivet) wing
root fairings vs. what could be achieved with complex composite shapes?

Same question with the wing shape - to hold up the same plane, ALL else
being equal?

So ballpark - how much more efficient would the use of complex composite
construction (wings and wing root transition areas) make these planes - ALL
else being equal?

WAG - same power, weight, fuselage, etc - what improvements would these
planes see in speed, climb, stall, or fuel burn numbers?

Thanks.


Montblack

On Mar 28, 12:30 pm, Blanche wrote:
Robert M. Gary wrote:



A fast Cherokee is also known as a Mooney C model.

Hm...I always thought "fast cherokee" was an oxymoron...

And yes, I own a cherokee 180. Would I like faster? Sure! Wouldn't
everyone?

I think part of my point is that the price of the 180 and the M20C are
pretty close. I'm not sure why people choose the 180 when its a good
30 knots slower on the same fuel burn.

-Robert

Robert M. Gary wrote:
On Mar 28, 12:30 pm, Blanche wrote:
Robert M. Gary wrote:



A fast Cherokee is also known as a Mooney C model.

Hm...I always thought "fast cherokee" was an oxymoron...

And yes, I own a cherokee 180. Would I like faster? Sure! Wouldn't
everyone?

I think part of my point is that the price of the 180 and the M20C are
pretty close. I'm not sure why people choose the 180 when its a good
30 knots slower on the same fuel burn.

-Robert

I agree with you but I'd bet insurance and the cost of up keep added because
of the retrac gear has a lot to do with it.

On 03/28/07 14:19, Gig 601XL Builder wrote:
Robert M. Gary wrote:
On Mar 28, 12:30 pm, Blanche wrote:
Robert M. Gary wrote:



A fast Cherokee is also known as a Mooney C model.

Hm...I always thought "fast cherokee" was an oxymoron...

And yes, I own a cherokee 180. Would I like faster? Sure! Wouldn't
everyone?

I think part of my point is that the price of the 180 and the M20C are
pretty close. I'm not sure why people choose the 180 when its a good
30 knots slower on the same fuel burn.

-Robert

I agree with you but I'd bet insurance and the cost of up keep added because
of the retrac gear has a lot to do with it.



Not to mention I could fit in a 180, but not a Mooney (although that is
changing...)

"Montblack" wrote in message
...
("Wayne Paul" wrote)
It is much easier to build a laminar flow airfoil and complex shaped
wing to fuselage transition using composite construction. These wing
have a better lift to drag ratio. The decrease in drag aerodynamic drag
of the wing and static drag decrease associated with the wing/fuselage
transition allow faster speeds.


Can you reword this (for some of us "Huh?" lurkers) especially the wing to
fuselage transition part?

How good/efficient are Cherokee, Ercoupe, Cessna (aluminum & rivet) wing
root fairings vs. what could be achieved with complex composite shapes?

Same question with the wing shape - to hold up the same plane, ALL else
being equal?

So ballpark - how much more efficient would the use of complex composite
construction (wings and wing root transition areas) make these planes -
ALL else being equal?

WAG - same power, weight, fuselage, etc - what improvements would these
planes see in speed, climb, stall, or fuel burn numbers?

Thanks.


Montblack

Let me make this as simple as possible by simply giving you an example. My
HP-14 (http://www.soaridaho.com/Schreder/N990_Borah_Mt.JPG) has a 52 foot
wingspan. The wings were built with flush rivets and have been smoothed by
adding an epoxy/balloon mixture. This is mid 1960 construction techniques
using aluminum construction. My lift to drag ratio is around 36 to 1.
However, new modern sailplanes with composite construction and modern
airfoils that only have 15 meter (just under 50 feet) wingspan have glide
ratios of around 48 to 1.

So with both of my old HP-14 and an ASW-27 (http://tinyurl.com/8lecz) loaded
to have a gross weight of 800 lbs. At best glide speed my HP-14 would have
about 22 lbs of drag while the ASW-27 would have less then 17 lbs of drag..
So the ASW-27 is 30% more efficient then my 14. If my wings did not have
flush rivets and were not smoothed the difference would be even greater.

The same is true with power aircraft. Just compare the Flight Design CT
(http://www.flightdesignusa.com/) with a Cessna 152 or a Cirrus with any
earlier conventionally constructed aircraft of similar weight and
horsepower.

To take these in steps, the wing is the most important, the fuselage shape
is also important and the junction between the wing and fuselage. I am
familiar with a smooth wing metal sailplane that was re-winged with a modern
airfoil. The new wing, has the same area and span. The original
wing/fuselage combination produced a 38 to 1 glide ratio. The updated
combination produced a 42 to 1 glide ratio. That is a 10 percent
improvement. Going from a round riveted wing to a modern airfoil should
provide a 15+% improvement.

Wayne
HP-14 "6F"

On Mar 28, 2:27 pm, Mark Hansen wrote:
On 03/28/07 14:19, Gig 601XL Builder wrote:





Robert M. Gary wrote:
On Mar 28, 12:30 pm, Blanche wrote:
Robert M. Gary wrote:

A fast Cherokee is also known as a Mooney C model.

Hm...I always thought "fast cherokee" was an oxymoron...

And yes, I own a cherokee 180. Would I like faster? Sure! Wouldn't
everyone?

I think part of my point is that the price of the 180 and the M20C are
pretty close. I'm not sure why people choose the 180 when its a good
30 knots slower on the same fuel burn.

-Robert

I agree with you but I'd bet insurance and the cost of up keep added because
of the retrac gear has a lot to do with it.

Not to mention I could fit in a 180, but not a Mooney (although that is
changing...)- Hide quoted text -

- Show quoted text -

You do have to be a bit tall to fly a Mooney. I'm 6'4" and fit fine
but my partner is 5'10" and has a tough time reaching the rudders.

-Robert

Bill Daniels wrote:
Sailplanes are the key to understanding the advantages of composite
structures. Current sailplane design is several decades ahead of composite
airplane design in this area. Sailplane performance MUST come from
aerodynamics and structures since there is no other way to get it. (You
can't cover up a bad airframe design with more power)

Composites are indeed heavier than metal but if carbon fiber is used, not
that much heavier. The real payoff is in the extremely smooth surfaces that
promote natural laminar flow. The payoff is huge across the entire speed
spectrum but highest at the low speed end where the flow is less stable and
more likely to separate if the wing surfaces are rough.

The effect of weight and drag is easy to compute. Just divide the aircraft
weight by L/D ratio to get the drag. Weight has an effect but L/D has a
bigger effect. Slick, high aspect ratio wings are the future.

The trouble is that a little bit of dirt, bugs or ice and you can lose a
lot of lift in a hurry. This may not be a big deal for gliders, but for
powered planes that fly in real weather a more tolerant airfoil isn't
such a bad deal.

Matt

In article ,
"Montblack" wrote:

("Wayne Paul" wrote)
It is much easier to build a laminar flow airfoil and complex shaped
wing to fuselage transition using composite construction. These wing have
a better lift to drag ratio. The decrease in drag aerodynamic drag of
the wing and static drag decrease associated with the wing/fuselage
transition allow faster speeds.


Can you reword this (for some of us "Huh?" lurkers) especially the wing to
fuselage transition part?

How good/efficient are Cherokee, Ercoupe, Cessna (aluminum & rivet) wing
root fairings vs. what could be achieved with complex composite shapes?

Same question with the wing shape - to hold up the same plane, ALL else
being equal?

So ballpark - how much more efficient would the use of complex composite
construction (wings and wing root transition areas) make these planes - ALL
else being equal?

Paul,
Go to airliners.com or any other site that will have "new" and "old"
airplanes. Pay particular attention to the wing-fuselage junction.
On the old airplanes, the fuselage seems to be just stuck to the wing.
On the new aiplanes, there are HUGE fillets fore and aft of the wing.
This really became a design consideration in the mid-1980's.

On Wed, 28 Mar 2007 13:51:57 GMT, Nathan Young
wrote:

I have a Cherokee 180, with the short hershey bar wing. While I love
the plane, I always wish it could go a bit faster, or use a bit less
fuel to get to my destination.

With about 375 hours in a Cherokee 180 and about 1200 in a straight
tail Beechcraft (Debonair) my take it this.

I like the 180 better than the Archer even though the Archer lookes
nicer with that taper wing and is a bit faster.

That constant cord, thick wing makes the 180 one of the most docile
airplanes you will find and it still has pretty good performance. Very
good climb and tremendous at getting into short fields with the steep
descent.

I can't see as a gallon or two over the range of the Cherokee, or
Archer is going to be worth worrying about....although we did have one
guy land ours with 1/2 gallon of fuel on board (all in one tank). He'd
flown the same trip (St Louis Mo to Midland, MI) so many times he
never paid any attention to the time and this time coming home he had
one bodatios head wind. (and a LOT OF LUCK!

Having flown Both the 180 and the Deb in torrential rain I can say I'd
much prefer a thicker windsheild to prettier wings. It was deafening!

As to fuel, we flew the 180 down to Muncie IN to pick up the Deb. My
friend took off well ahead of me, but I passed him before we reached
Ft Wayne. I was back in Midland, had the Deb put away in the hangar
and was having a cup of coffee in the terminal building when I head
him call in. When they filled the Cherokee up, I found I had used
less than one gallon more to cover the same route at close to 190 MPH.

I had to ferry the Deb up to HTL to have some work done on the gear
which meant leaving it down. Now that's using gas. The speed was
about the same as the Cherokee but burning about 14 1/2 GPH.

I have followed the composite homebuilding movement for many years,
and am amazed at the sleekness of a composite wing. The wings on most
composites tend to be the complete opposite of a Hersey bar wing:
high aspect ratio, low thickness, no rivets, no screws for fuel

I'm glad you said most. I'm building a Glasair III and a high aspect
ratio it doesn't have. Wing span is a tad over 23' with a 4' wide
fuselage in the middle so that makes each wing about 9 1/2 feet long.
It also has almost 30# per square foot of wing loading on that tiny
wing but it sure does go. Built like a tank too. If you think the 180
has a steep descent you should fly a G-III once. :-)) Normal is about
2000 fpm power off.

tanks,smooth curves faired into airframe, and streamlined landing gear
structure.

So my question: How much drag does a wing on a Hersey Bar Cherokee
generate, and and hypothetically speaking, how much faster could the
plane go if it was retooled with a sleek, composite wing?

That's a diffiuclt question to answer because there are so many
variables. You could easily end up with a wing that could travel far
faster than the rest of the structure could handle. On the Cherokee
the landing gear presents a lot of drag. To maintain at least the
handleing characteristics of the Archer you probably ould not get much
faster than an Archer. To simply replace the wing with a composit one
of the same design would most likely make little difference.

All airplanes are a group of compromises. The 180 is the only plane
I've ever flown where I could put it into a full stall, hold the
elevator full up and still use the ailerons in turns. (with careful
application) Almost any changes are going to result in a plane that
is less forgiving. It's very difficult to hold the Deb in a stall
without having it drop a wing. It's like balancing on a tight rope and
if you touch an aileron to raise a wing, that wing will instead go
down (abruptly) and you will most likely roll into a spin.

Speed comes at a price.


Roger Halstead (K8RI & ARRL life member)
(N833R, S# CD-2 Worlds oldest Debonair)
www.rogerhalstead.com

("john smith" wrote)
On the new aiplanes, there are HUGE fillets fore and aft of the wing. This
really became a design consideration in the mid-1980's.


Wheel pants, gap seals, ....and HUGE new fiberglass fillets (fore and aft).
Are they part of everyday speed-mod packages?

If so, what is the "anecdotal" gain, after installing (just) them?

I've read reports on wheel pants, on gap seals, and on Power Flow exhaust
systems, but not on aftermarket fillets for the GA fleet.

http://www.powerflowsystems.com/


Montblack
airliners ...net? :-)