Hershey bar wing vs composite wing - how much drag?

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...)

Blanche wrote in news:1175110215.538586
@irys.nyx.net:

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?


Well there was an article about a guy in Sport Aviation a few years ago
who had his 140 cruising at some insane airspeeds. He had a 160 engine
in it IIRC, but more importantly he had done a lot of mods to the
airframe, particularly wingtips, vortice generators and fairings for the
gear, flap hinges and so on. Each mod multiplied the good of the other
mods, of course, so he was happily whistling along at speeds that were
simply amazing. As far as I know, he does sell the STCs he got for the
airplane, but I couldn't find him wiht a quick search. I think he was in
SA about three years ago but the wife will kill me if I pull the pile
out and go through it in the living room again. I'll post it if i see
it.


ALC

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¬

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

The composite construction makes a big difference in making
possible the use of supercritical airfoils. These airfoils need a
slick surface, so much so that flying in rain degrades their
performance to the point that they can become dangerous. You'd never
build a wing like that using sheet metal and rivets. Just the lap
joints or any waviness in the aluminum would cause trouble.
Composite looks nice, but I became allergic to some of that
stuff way back in the '70s. And in the cold winters here I've seen it
crack and delaminate. My preference is for something more resistant to
everyday life. Kinda like my old truck.

Dan