How to get greater lift from an aircraft wing

[T C]

I want to know about how to get more lift from aircraft wings without increasing engine power and wingspan.

 

[Greg Bernhardt]

What are your ideas so far?

 

[berkeman]

I want to know about how to get more lift from aircraft wings without increasing engine power and wingspan.

Welcome to the PF.

How about this?

http://www.airsceneuk.org.uk/airshow03/duxsept/triplane.jpg

 

[T C]

Welcome to the PF.

How about this?

http://www.airsceneuk.org.uk/airshow03/duxsept/triplane.jpg
View attachment 220387

I have said "without increasing wingspan" and you haven't noticed that part.

What are your ideas so far?

I think using Coanda effect can help but don't know about any real example of using that.

 

[berkeman]

I have said "without increasing wingspan" and you haven't noticed that part.

Of course I did. That's why I went "up" instead of "out"...

https://en.wikipedia.org/wiki/Wingspan

 

[berkeman]

I think using Coanda effect can help but don't know about any real example of using that.

How much reading have you been doing at the NASA pages on wing geometry and design for different flight profiles?

https://www.grc.nasa.gov/www/k-12/airplane/geom.html

 

[russ_watters]

I want to know about how to get more lift from aircraft wings without increasing engine power and wingspan.

Increase the angle of attack.

I'm going to guess you are going to reject my idea too because it violates a requirement you didn't specify. Point being: you need to try harder/do more work here. Explain in more detail the context of the question and describe the research you have already done.

 

[boneh3ad]

How about this?

That would increase engine power on account of increased drag.

I think using Coanda effect can help but don't know about any real example of using that.

I am not sure how you intend to utilized the Coandă effect without a jet of some sort. It doesn't apply to a typical flow over an airfoil.

 

[berkeman]

That would increase engine power on account of increased drag.

Nah, you just fly slower...

 

[anorlunda]

https://en.wikipedia.org/wiki/Airfoil#Thin_airfoil_theory

That is a good place to start. The references at the bottom of the article point to more advanced sources. The wiki article features "thin" as a strategy for better airfoils. I'm sure there are dozens of other ways too.

 

[boneh3ad]

https://en.wikipedia.org/wiki/Airfoil#Thin_airfoil_theory

That is a good place to start. The references at the bottom of the article point to more advanced sources. The wiki article features "thin" as a strategy for better airfoils. I'm sure there are dozens of other ways too.

Off topic: students hate thin airfoil theory when taught in a classroom.

 

[Dr.D]

Increase the angle of attack.

This works, up to a point, after which the wing stalls. Also, drag increases requiring more engine power.

 

[berkeman]

This works, up to a point, after which the wing stalls. Also, drag increases requiring more engine power.

We know. We're just trying to draw the OP out of his/her shell...

 

[jrmichler]

The OP said nothing about maintaining level flight, drag, or induced drag, so that opens possibilities. Flaps, leading edge slots, increase chord, lifting body fuselage. And more wings.

 

[berkeman]

Party boat! I assume it's a boat. Can it fly? Can the OP fly?

 

[T C]

I am not sure how you intend to utilized the Coandă effect without a jet of some sort. It doesn't apply to a typical flow over an airfoil.

How can you say that jets are necessary for Coanda effect?

 

[boneh3ad]

How can you say that jets are necessary for Coanda effect?

Do you know what the Coandă effect is?

 

[T C]

This wikipedia explanation is enough for me.

 

[berkeman]

This wikipedia explanation is enough for me.

If you have a propeller for your plane's propulsion, what is the source of all of that pressurized air for the wings? Some heavy air compressor added to the aircraft?

EDIT/ADD, a figure from the wikipedia article you cited...

https://upload.wikimedia.org/wikipedia/commons/thumb/a/a7/Buccanneer_blown_wings_diagram_%281%29.svg/375px-Buccanneer_blown_wings_diagram_%281%29.svg.png

 

[T C]

If you have a propeller for your plane's propulsion, what is the source of all of that pressurized air for the wings? Some heavy air compressor added to the aircraft?

Pressurised air is used in static application i.e. to get a flow of air. Do you want to mean that if the air flow is created by a blower, then Coanda effect wouldn't occur there?

 

[berkeman]

Pressurised air is used in static application i.e. to get a flow of air. Do you want to mean that if the air flow is created by a blower, then Coanda effect wouldn't occur there?

Sorry, I've tried a few times, but I'm not able to parse what you wrote there.

Since in this thread you seem to be asking for ways to increase the lift of a wing, and you have mentioned the Coandă effect, I'd assumed you meant the use of pressurized air to increase lift with blown flaps and similar techniques, as shown on the Buccanner aircraft above, and in this wikipedia article:

https://en.wikipedia.org/wiki/Blown_flap

 

[boneh3ad]

This wikipedia explanation is enough for me.

First of all, Wikipedia is not always a good source. In particular here, the Coandă effect is specifically related to the tendency of the a jet to cling to a surface and bend with it despite the fact that Wikipedia claims it is the tendency of any fluid to cling to any surface.

The Coandă effect requires a jet, meaning flow over a wing doesn't meet those requirements. Further, if you just want to talk about a fluid as a whole clinging to a surface, that is already how a wing works. That's just a feature of fluids in general.

 

[CWatters]

How about change the wing section for one with a better lift/drag ratio.

 

[FactChecker]

You haven't given any hint about what your current design is, so I will assume that this is just a general question. You also haven't specified what the flight condition is. There is a big difference between subsonic, transonic, and supersonic flight. In subsonic flight, if your wing design and angle of attack are correct, then I don't think there is not much more that can be done just with the wing. You can consider the interplay between the position of the engine and the wing. You can also consider blending the wing with the fuselage so that the body provides lift, but that depends on what type of airplane you are talking about, which you also have not specified. In transonic and supersonic flight, there are things that can be done to reduce separation.

In general, you should investigate the ongoing research efforts at NASA and DARPA to see what they are considering. They do a lot of work on this subject.

 

[Scargo]

And what about maneuverability and inverted flight? We need more direction. Does it need to carry passengers or any payload?
Didn't they try using the fuselage as a wing component as in "the flying wing"? Has that design been ruled out as too unstable, at least prior to computers and the B2?

 

[boneh3ad]

The flying wing isn't really used anymore except with perhaps stealth bombers. However, the next big leap in cargo/passenger aircraft design will probably be the blended wing body (BWB), which is a similar concept.

 

[pyroartist]

Fact: There are more flying wings in use today than all commercial aircraft combined. Hang gliders and paragliders are tailless, flying wings and are enjoyed all over the world.

 

[pyroartist]

TC - To increase L/D: for turbulent airfoils try this: https://www.eurekalert.org/pub_releases/2018-02/hjap-uss020618.php
or just use a laminar airfoil and very smooth surface finish.

 

[Tom Kunich]

Nah, you just fly slower...

This the actual point. You want to lift more with the same amount of power and the same wingspan the only way is to increase angle-of-attack and hence drag at any given speed. This is self defeating. At some point the airflow over the wing is limited by speed because the drag is too great for the available power.

 

[Joseph Patrick Kane]

I want to know about how to get more lift from aircraft wings without increasing engine power and wingspan.

TC, When you say wing span are you only referring to the width of the wing from root to outer wing tip, or you referring to all wing geometry?

 

[Dusan Stan]

You could optimize the lift loading to be elliptical. And as CWatters suggested use an airfoil that provide more L/D for your specific Reynolds number.

 

[Joseph Patrick Kane]

TC --- Just what is meant by Wing Span? Does it just mean the distance from wing tip to wingtip? Does it also include the other wing geometries?
I do not think the TC's original question was phrased correctly, because even basic grade school physics about wing geometry would include the variables of air speed, angle of attack, airfoil shape different shapes, (sweep, delta shape, flexibility, ETC.) and chord wise dimension.
Just what is TC looking for with his question, if he just means wing tip to wing tip length? Surely he must know that there are a great many variables that can affect the lift capacity of a wing. What is the purpose of the question?

 

[boneh3ad]

Fact: There are more flying wings in use today than all commercial aircraft combined. Hang gliders and paragliders are tailless, flying wings and are enjoyed all over the world.

Call me crazy, but I am pretty sure that wasn't the point of the question (and response).

To increase L/D: for turbulent airfoils try this: https://www.eurekalert.org/pub_releases/2018-02/hjap-uss020618.php

While a shark denticle may well prove to be an effective design for a vortex generator (VG), they still essentially work in the same manner as any other VG currently in use today. There's also the issue of the optimal placement being different depending on flight conditions. Further, that study was performed at a chord Reynolds number of $Re_c = 4\times 10^4$, which is two orders of magnitude less than that of a typical airplane.

or just use a laminar airfoil and very smooth surface finish.

This is not what a laminar flow (or, rather, natural laminar flow) airfoil is. There is a hell of a lot more to NLF than just a smooth surface. Further, most modern airliners already incorporate concepts from NLF into their wing design.

TC --- Just what is meant by Wing Span? Does it just mean the distance from wing tip to wingtip?

Yes, that is the meaning of wingspan. To incorporate other aspects of geometry, you'd talk about aspect ratio, OML, planform, etc.

 

[Sherwood Botsford]

Increase the density of air.

All those life equations have a term for density of air.

Pilots have to take this into account. On a hot day your max takeoff weight is much lower than on a cold day.

 

[CWatters]

+1

Many a pilot has flown up a high valley on a hot day only to find they don't have the lift to turn in the available space.