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Airfoil and wing design knowledge needed

#1
So I understand the basics of air foils and how the different shapes effect lift, drag and speed. But the one topic I have not learned or heard anyone talk about is what makes more lift a longer wing or a wider wing. I think the wider I mean is called the cord. I have seen gliders with very long skinny wings fly good and i have seen gliders with short wide wings fly good. Which one creates more lift? Or am I thinking about it wrong.

If I wanted a wing for the most lift and slow flight should it be a very long wing or a very wide wing?
 

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Hai-Lee

Old and Bold RC PILOT
#2
So I understand the basics of air foils and how the different shapes effect lift, drag and speed. But the one topic I have not learned or heard anyone talk about is what makes more lift a longer wing or a wider wing. I think the wider I mean is called the cord. I have seen gliders with very long skinny wings fly good and i have seen gliders with short wide wings fly good. Which one creates more lift? Or am I thinking about it wrong.

If I wanted a wing for the most lift and slow flight should it be a very long wing or a very wide wing?
WIng area is the real key though there are a few things to remember. Firstly when flying the air passing the tip of the wing is also attracted to the low pressure area of the wing, (and form tip vortices), so the longer the span the less the low pressure is lost to lateral airflow.

With short span and long cord wings the pressure centre can be greater in negative magnitude but the airflow from the tips quickly wants to swamp the lift pressure, (most short wing spans use tip end plates or winglets to manage the sideways airflow to enhance lift and reduce drag).

The lift is best if the cord is long and the span is great combined with fences or vortex generators to control the sideways motion of the airflow over the wing.

Its a bit of a juggling act actually!

Have fun!
 
#3
Long skinny wings have what is known as a high "aspect ratio" and short fat wings have a low aspect ratio. It is entirely possible to have two very different wings generating exactly the same lift. There are positives and negatives to both types and the choice to use one over another has to weigh these characteristics. Generally low aspect-ratio wings generate more drag and have more loss of lift due to span-wise flow than the high aspect ratio wings. There are more trade-offs, but I can't think of them at the moment.
 

TEAJR66

Flite is good
Mentor
#4
Wing area, as Hai-Lee stated. And different aspect ratios with equal lift, as Tench745 stated.

Now consider construction materials. High aspect ratios will require stronger spars. The desire to strengthen stuff usually means more weight. More weight requires more lift. Can you see the vicious cycle starting.

Folded foam really works well at a 5:1 aspect ratio for sportier planes. Think mechanically with the center of the wing being the fulcrum and the span the lever.

Gentler fliers can get away with 7:1 - 8:1 aspect ratio.

There is lots more to consider. Just sharing a few of my thoughts. In the end, I recommend "try and fly". Live and learn. Foam is cheap, electronics endure. Have fun!
 

Merv

Well-known member
#5
If I wanted a wing for the most lift and slow flight should it be a very long wing or a very wide wing?
For endurance, go for the high aspect ratio wing, 8-10:1 long and skinny, keep the thickness 10-12%.
For heavy lift, go for a lower aspect ratio 5-6:1 and increase the thickness of the wing, 15%+.
For speed, aspect ratio 5-6:1, keep the thickness 10% or less.
 

shadeyB

Well-known member
#6
am I thinking about it wrong.

If I wanted a wing for the most lift and slow flight should it be a very long wing or a very wide wing?
The lift is best if the cord is long and the span is great combined with fences or vortex generators to control the sideways motion of the airflow over the wing.

Have fun!
It is entirely possible to have two very different wings generating exactly the same lift..
There is lots more to consider. Just sharing a few of my thoughts. In the end, I recommend "try and fly". Live and learn. Foam is cheap, electronics endure. Have fun!

Everybody is partially correct however they are also partially wrong.
I have left a very detailed picture for you to look over, review and understand the principals of how planes fly

Hope this helps
BBE740A5-4CBD-4B11-A8F0-E41D86C36E98.jpeg
 
#8
Umm,,,,,, you forgot the wee fairies and flying unicorns piloted by wizards.

Seriously, high aspect wings tend to be tapered which lowers tip drag which improves overall efficiency. Plank wings are notoriously inefficient. High aspect wings also then have more square footage area which lowers the load a given area has to lift, thereby flying slower which reduces drag. More lift is generally derived from decreasing airflow over the top of the wing without incurring more turbulent flow. Some people call this a camber increase which is why thicker wings have a higher C of L, and , CoD, and why "high lift" wings tend to be upside down U /---\ shaped.
Everything is a compromise.
Arthur C. CLarke said science is indistinguishable from magic, so you COULD believe in science instead.
 
#12
Thanks a bunch guys I knew the wealth of knowledge here would have a productive conversation....and we all know it also takes a little magic too. LoL

I have a simple soarer coming and plan to do some wing experiments with it. Gonna do different shapes and sizes and may even play with the angle the wing sets on the fuselage, I think that is called wing incidence? And again I have no idea of the effect of angle changes to the flight and lift. So I am gonna learn.
 
#13
GotCox
Nothing wrong with experimentation but there is a lot of published information out there from folks that have already done this.
Doing some research or simply copying a proven design will get you into the right ball park.

It is worth remembering that RC models have to fly in a very restricted environment compared to full size so the aerodynamic control of the plane has a significant part to play to avoid, or at least limit, cases of "unwanted contact with the ground". ;)
 
#15
Thanks a bunch guys I knew the wealth of knowledge here would have a productive conversation....and we all know it also takes a little magic too. LoL

I have a simple soarer coming and plan to do some wing experiments with it. Gonna do different shapes and sizes and may even play with the angle the wing sets on the fuselage, I think that is called wing incidence? And again I have no idea of the effect of angle changes to the flight and lift. So I am gonna learn.
Easiest way to play with incidence changes is full flying horiz stab, but not many here understand the theory or how to build them. Imho, easy peasy
 

TEAJR66

Flite is good
Mentor
#16
Build the Simple Soarer as prescribed in the build video and resist the urge to modify anything. That will give you an excellent baseline. And, the SS is an excellent airframe to start with.

Once you have built and flown the SS, check out Experimental Airlines on YouTube.
An Armin Wing would be a great starting point for experimenting with the simple Soarer. Using a wing with the same cord and span, but folded EA style will produce a noticeable difference. This will help guide the direction of your experimentation. I.e., changes in chord and span, wing incidence, and wing shape (sweep, taper, tip shape, and undercamber).

Again, just my two cents. A little experience guides this advice. Try and fly.
 
#17
Build the Simple Soarer as prescribed in the build video and resist the urge to modify anything. That will give you an excellent baseline. And, the SS is an excellent airframe to start with.

Once you have built and flown the SS, check out Experimental Airlines on YouTube.
An Armin Wing would be a great starting point for experimenting with the simple Soarer. Using a wing with the same cord and span, but folded EA style will produce a noticeable difference. This will help guide the direction of your experimentation. I.e., changes in chord and span, wing incidence, and wing shape (sweep, taper, tip shape, and undercamber).
Again, just my two cents. A little experience guides this advice. Try and fly.
I tried an Armin wing on my Simple Soarer and kept the polyhedral of the original wing. It had a better top speed and better glide ratio than the FT wing. This came with a downside, however. Shallow turns were slow, but steep banks resulted in a wingtip stalling and the airplane diving at the ground. Eventually I cut away some of the bottom surface of the wing to form an undercambered wingtip like the FT wing. This decreased the top speed slightly, but greatly improved handling.
Hopefully this give you a couple rough data points for the start of your own experiments.
 
#19
I tried an Armin wing on my Simple Soarer and kept the polyhedral of the original wing. It had a better top speed and better glide ratio than the FT wing. This came with a downside, however. Shallow turns were slow, but steep banks resulted in a wingtip stalling and the airplane diving at the ground. Eventually I cut away some of the bottom surface of the wing to form an undercambered wingtip like the FT wing. This decreased the top speed slightly, but greatly improved handling.
Hopefully this give you a couple rough data points for the start of your own experiments.
Hmmm tip stalls.... bit of string tape from the tip front to the first poly break rear edge would add a bit of washout if you tweaked the panel while applying it even on a finished plane. The airfoil change works, too, but is a bit drastic. Click of down trim works, but you lose that sitting on the edge of imminent stall effect. Too hard to calculate min sink speed in a RC glider.