Hershey bar wing vs composite wing - how much drag?

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.

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
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?

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.

As a former PA28-180 owner, I can certainly agree with that.

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

I'm no aerodynamicist, but I have a usenet-opinion. I think at Cherokee
airspeeds the effect of the screw and rivet heads is probably unmeasurable.

I'm not sure whether you're using 'composite' to mean the material from
which the wing is constructed, or the blending of different airfoil shapes.

I don't think the construction material has any effect on the
aerodynamics, but 'composite' materials may make it more economic to
manufacture complex shapes, and may reduce the weight of the resulting
structure.

If you are referring to blended airfoil shapes, look at the difference
between the fat-wing Pipers and the Archer II, Arrow II, etc.

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?

I'm not volunteering to do the research, but I think with a little (or a
lot) of googling you can find the NACO airfoil on which the
constant-chord fat-wing Piper wing is based, and the NACO report has a
lot of detail about the characteristics of that airfoil. I've looked it
up before, but I've lost the reference.

Not news to you I'm sure, but there is more to wing airfoil choice than
minimizing drag.

On Mar 28, 8:51 am, 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.

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
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?

I can't remember if it was Kitplanes or SportAviation that had a
recent article on a Piper knockoff being produced as a kitplane in
South Africa. That might be a good starting point for the difference
in performance between the different planes as well as a discussion of
the differences in design and construction. Much of the difference
has to do with better airfoil designs being used but also weight
differences.

At these speeds I suspect surface condition is a small part of the
overall drag.

However!

If the new wing were a couple hundred pounds lighter, then you'd
see some inprovement in speed.

It takes power to stay aloft.

The heavier the plane, the more power is required just to stay up.


Lighter is mo' betta!


Richard

I have helped rig many sailplanes, both composite and conventional aluminum
construction. In almost every case the metal wing are lighter then the
composite. (1-35 and HP-18 aluminum wings are lighter then ASW-20, ASW-27,
and LS-6 composite wings.)

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.

Wayne
http://www.soaridaho.com/



"cavelamb himself" wrote in message
news
At these speeds I suspect surface condition is a small part of the
overall drag.

However!

If the new wing were a couple hundred pounds lighter, then you'd
see some inprovement in speed.

It takes power to stay aloft.

The heavier the plane, the more power is required just to stay up.


Lighter is mo' betta!


Richard

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.

Bill Daniels


"Wayne Paul" wrote in message
...
I have helped rig many sailplanes, both composite and conventional aluminum
construction. In almost every case the metal wing are lighter then the
composite. (1-35 and HP-18 aluminum wings are lighter then ASW-20, ASW-27,
and LS-6 composite wings.)

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.

Wayne
http://www.soaridaho.com/



"cavelamb himself" wrote in message
news
At these speeds I suspect surface condition is a small part of the
overall drag.

However!

If the new wing were a couple hundred pounds lighter, then you'd
see some inprovement in speed.

It takes power to stay aloft.

The heavier the plane, the more power is required just to stay up.


Lighter is mo' betta!


Richard

On Mar 28, 6:51 am, 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.

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
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?

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

-Robert

According to my copy of Aerodynamics, Aeronautics and Flight mechanics By
McCormick pub by Wiley 1979 page 192.
"The rectangular wing used on many light single-engine aircraft, the induced
drag is seen to be about 6% or higher than that for the elliptical wing for
aspect ratios of 6 or higher"

The elliptical wing produces the minimum induced drag.
OTOH its dam all expensive to manufacture in sheet metal

"Nathan Young" wrote in message
...
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.

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
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?

Nathan Young wrote:


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?

You may take the other side of your question.

You choose a composite plane (ie Lancair) with the same engine.
You take the 75% cruising speed of the lancair (V-lancair)
You take the Cherokee 75% cruising speed (V-cher)

If you want the same speed for your plane, you need more HP

The formula is HP=180 * (V-lancair/ V-cher)³

You may do the reverse: how many HP the lancair need for the Cherokee
speed....

You know the cost of drag....

But don't think all drag is from wing, part of drag is from fuselage and
a roomy fuselage will generate more drag.
But the comfort is in roomy fuselage


By
--
Volem rien foutre al païs!
Philippe Vessaire Ò¿Ó¬

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?