new wingtip design

[ND]

interesting article about a potential winglet replacement for jets.

I personally think that winglets have more sex appeal though, especially maughmer's.

http://www.gizmag.com/minix-wing-tip-vortex-aircraft-aerodynamics/15526/

[Jonathon May[_2_]]

At 20:24 27 February 2015, ND wrote:
>interesting article about a potential winglet replacement for jets.
>
>I personally think that winglets have more sex appeal though, especially
>maughmer's.
>
>http://www.gizmag.com/minix-wing-tip-vortex-aircraft-
aerodynamics/15526/
>
That's quite old ,has it moved on ?
Anything that improves performance is worth a try .And something that
makes it easier to fit the covers is a bonus.

[Charlie M. (UH & 002 owner/pilot)]

It's an almost 5 year old article.

Never heard of it before, it was so good, we all would have likely heard more about it.

My understanding is the tip vortex is based mostly on wingloading, the higher the loading the worse the vortex is (everything else remaining the same).
Some airfoils & aspect ratio's are worse than others in terms of vortex with a similar wingloading. And yes, speed has an effect as well.

I would like to see the actual tests performed between a "plain tip", winglet and this device.

[Charlie M. (UH & 002 owner/pilot)]

I did a Google search for "Minix wing tip"

Came up with....

https://www.google.com/search?q=%22Minix+wing+tip%22&rlz=1C1GGGE_enUS580US580&oq=%22Minix+wing+tip%22&aqs=chrome..69i57j0l3.5200j0j4&sourceid=chrome&es_sm=93&ie=UTF-8

This page (out of the 1st link) is sorta interesting (it's on page 3 of the above search).

http://www-mip.onera.fr/projets/WakeNet2-Europe/fichiers/pastEvents2005/bocaRaton/B13-Summary%20TLS%20Workshop%20Wake%20Alleviation%20%5 BDurston%5D.pdf

Most of the pages are old, the "newer ones" basically regurgitated the older info......

Curious on what others here think/feel/know......

[Bob Whelan[_3_]]

On 2/27/2015 3:20 PM, Charlie M. (UH & 002 owner/pilot) wrote:
> I did a Google search for "Minix wing tip"
>
<Snip...>

>
> Curious on what others here think/feel/know......
>

Think/feel...
These sorts of things are what happens when intuition is applied inaptly, kind
of like those early schemes proposing ways for making balloons dirigible, i.e.
steerable...you know, oars and sails and the like. How does this magical
"unwinding" device go about capturing the entire pressure differential between
bottom & top of the wing so's to prevent vorticity developing? Methinks at the
very least a considerably larger bell-mouth is in order to have potential for
ANY detectable vortical disruption. :-)

Quite Possibly/Presumably In the "Know Dep't." (Copied from comments)
"I tested this device for my university thesis and it done nothing at all but
to increase drag due to the extra skin friction drag caused by a greater
surface area. The vortices do not reduce because the design considers the
physics on too primitive and intuitive a level."
James Fletcher
26th March, 2012 @ 01:58 pm PDT

[Craig Funston]

On Friday, February 27, 2015 at 3:25:30 PM UTC-8, Bob Whelan wrote:
> On 2/27/2015 3:20 PM, Charlie M. (UH & 002 owner/pilot) wrote:
> > I did a Google search for "Minix wing tip"
> >
> <Snip...>
>
> >
> > Curious on what others here think/feel/know......
> >
>
> Think/feel...
> These sorts of things are what happens when intuition is applied inaptly, kind
> of like those early schemes proposing ways for making balloons dirigible, i.e.
> steerable...you know, oars and sails and the like. How does this magical
> "unwinding" device go about capturing the entire pressure differential between
> bottom & top of the wing so's to prevent vorticity developing? Methinks at the
> very least a considerably larger bell-mouth is in order to have potential for
> ANY detectable vortical disruption. :-)
>
> Quite Possibly/Presumably In the "Know Dep't." (Copied from comments)
> "I tested this device for my university thesis and it done nothing at all but
> to increase drag due to the extra skin friction drag caused by a greater
> surface area. The vortices do not reduce because the design considers the
> physics on too primitive and intuitive a level."
> James Fletcher
> 26th March, 2012 @ 01:58 pm PDT

Excellent discussion of "Common Misconceptions in Aerodyanmics" Worth the time to listen to the whole thing.

https://www.youtube.com/watch?v=QKCK4lJLQHU&list=PLCdGBvDMYlr8-tm7kQibn0iDCBbgpLbX6

Craig

[BobW]

On 2/27/2015 6:30 PM, Craig Funston wrote:
> On Friday, February 27, 2015 at 3:25:30 PM UTC-8, Bob Whelan wrote:
>> On 2/27/2015 3:20 PM, Charlie M. (UH & 002 owner/pilot) wrote:
>>> I did a Google search for "Minix wing tip"
>>>
>> <Snip...>
>>
>>>
>>> Curious on what others here think/feel/know......
>>>
>>
>> Think/feel... These sorts of things are what happens when intuition is
>> applied inaptly, kind of like those early schemes proposing ways for
>> making balloons dirigible, i.e. steerable...you know, oars and sails and
>> the like. How does this magical "unwinding" device go about capturing the
>> entire pressure differential between bottom & top of the wing so's to
>> prevent vorticity developing? Methinks at the very least a considerably
>> larger bell-mouth is in order to have potential for ANY detectable
>> vortical disruption. :-)
>>
>> Quite Possibly/Presumably In the "Know Dep't." (Copied from comments) "I
>> tested this device for my university thesis and it done nothing at all
>> but to increase drag due to the extra skin friction drag caused by a
>> greater surface area. The vortices do not reduce because the design
>> considers the physics on too primitive and intuitive a level." James
>> Fletcher 26th March, 2012 @ 01:58 pm PDT
>
> Excellent discussion of "Common Misconceptions in Aerodyanmics" Worth the
> time to listen to the whole thing.
>
> https://www.youtube.com/watch?v=QKCK4lJLQHU&list=PLCdGBvDMYlr8-tm7kQibn0iDCBbgpLbX6
>
> Craig
>

Great lecture - wish I'd had more like this in collich!

The aero engineer in me is still laughing at: "It's easy to explain how a
rocket works, but explaining how a wing works takes a rocket scientist."
Making it even funnier is that I used the degree for the first 4 years after
school in the solid rocket motor industry, where "rocket scientist" jokes were
rife...and decades later, non-aerodynamiscist-me is still trying to refine my
understanding/explanation for lift and its generation! Considering sailplanes,
I'm presently a fan of: gravity causes lift - after that things become
complicated! :-)

Bob W.

[Paul Villinski]

As a non-scientist/engineer, it baffles me that we are able to build amazingly sophisticated airplanes, yet, as the lecturer demonstrates, there is a huge amount of confusion over how to explain why a wing produces lift, and many of our common assumptions are simply wrong, i.e., the reason(s) for accelerated airflow over the top surface (which intuitively has never made sense to me). Engineers designing airplanes are themselves still arguing over whether it's more about Bernoulli or the downward-turning force or Coanda effect. Yet, I'm still able to get from one coast to another at 35,000 feet traveling at 600 mph, while sipping coffee and watching a movie.

[[email protected]]

I've been flying airplanes professionally for close to forty years and sailplanes for fun. I spend a lot of time looking at the wing trying to understand how it works. In the end, I conclude it's all magic. I kinda like that.

[Skypilot]

The biggest problem is trying to prove up the % saved. Then you have to convince the bean counters. :)


interesting article about a potential winglet replacement for jets.

I personally think that winglets have more sex appeal though, especially maughmer's.

http://www.gizmag.com/minix-wing-tip-vortex-aircraft-aerodynamics/15526/

[Martin Gregorie[_5_]]

On Fri, 27 Feb 2015 22:02:08 -0800, mmartin46 wrote:

> I've been flying airplanes professionally for close to forty years and
> sailplanes for fun. I spend a lot of time looking at the wing trying to
> understand how it works. In the end, I conclude it's all magic. I
> kinda like that.

I've never forgotten one cloudy day with a low overcast. I was in a car,
driving away from Heathrow toward Chobham Common, which put us directly
under the approach to Heathrow, when a 747 dropped out of the overcast on
finals. For a few seconds it was heading for us, grabbing the bottom of
the cloud and flinging it at the ground: it was like watching a waterfall
beneath its wing.

That sight made me realise two things: that a 747 really does weigh a
couple hundred tons and that the reaction from deflecting that huge mass
of air downward has more than a little to do with keeping it in the air.


--
martin@ | Martin Gregorie
gregorie. | Essex, UK
org |

[John Firth[_4_]]

At 04:59 28 February 2015, Paul Villinski wrote:
>As a non-scientist/engineer, it baffles me that we are able to build
>amazin=
>gly sophisticated airplanes, yet, as the lecturer demonstrates, there is
a
>=
>huge amount of confusion over how to explain why a wing produces lift,
and
>=
>many of our common assumptions are simply wrong, i.e., the reason(s) for
>ac=
>celerated airflow over the top surface (which intuitively has never made
>se=
>nse to me). Engineers designing airplanes are themselves still arguing
>over=
> whether it's more about Bernoulli or the downward-turning force or
Coanda
>=
>effect. Yet, I'm still able to get from one coast to another at 35,000
>feet=
> traveling at 600 mph, while sipping coffee and watching a movie.
>
A reasonable parallel is the dual nature of light, which can be treated as
both wave and particle. Both models
explain the result.

John Firth

[Kevin Neave[_2_]]

Glider wings work on faith.

It's easy to have faith at 4-5000ft so the wings work well & soaring is
easy.

'Tis more difficult to have faith at 1000ft so wings work less well &
gliding is more tricky.

Much below 1000ft I lose all faith & land shortly after.

This assumes UK feet where 5000 is "High" not American / Australian / South
African feet where 5000 is "Low".

KN

At 15:36 28 February 2015, John Firth wrote:
>At 04:59 28 February 2015, Paul Villinski wrote:
>>As a non-scientist/engineer, it baffles me that we are able to build
>>amazin=
>>gly sophisticated airplanes, yet, as the lecturer demonstrates, there i
>a
>>=
>>huge amount of confusion over how to explain why a wing produces lift
>and
>>=
>>many of our common assumptions are simply wrong, i.e., the reason(s) for
>>ac=
>>celerated airflow over the top surface (which intuitively has never made
>>se=
>>nse to me). Engineers designing airplanes are themselves still arguing
>>over=
>> whether it's more about Bernoulli or the downward-turning force o
>Coanda
>>=
>>effect. Yet, I'm still able to get from one coast to another at 35,000
>>feet=
>> traveling at 600 mph, while sipping coffee and watching a movie.
>>
>A reasonable parallel is the dual nature of light, which can be treated a
>both wave and particle. Both models
>explain the result.
>
>John Firth
>
>

[Dan Marotta]

I must admit that I didn't read the article thoroughly, but it seemed to
me by looking at the picture that the thing would enhance wingtip
vortices (the Windows spell checker did not like that word, BTW).
Anyway, I thought the idea was to reduce vortices since they're wasted
energy that could be used by the aircraft.

Aero engineers, please chime in.

On 2/28/2015 2:54 AM, Skypilot wrote:
> The biggest problem is trying to prove up the % saved. Then you have to
> convince the bean counters. :)
>
>
> ND;897867 Wrote:
>> interesting article about a potential winglet replacement for jets.
>>
>> I personally think that winglets have more sex appeal though, especially
>> maughmer's.
>>
>> http://tinyurl.com/37q5aeb
>
>
>

--
Dan Marotta

[BobW]

On 2/28/2015 10:19 AM, Dan Marotta wrote:
> I must admit that I didn't read the article thoroughly, but it seemed to me by
> looking at the picture that the thing would enhance wingtip vortices (the
> Windows spell checker did not like that word, BTW). Anyway, I thought the
> idea was to reduce vortices since they're wasted energy that could be used by
> the aircraft.
>
> Aero engineers, please chime in.

I had the same off-the-cuff gut reaction when I first looked at it, too. Upon
further cogitation, I'm still uncertain eggzackly what-n-how the designer was
seeking to achieve what I think he was seeking to achieve. I also noticed the
article said he was an aeronautics teacher, so this may be a case of: Those
who can't do, teach!

In any event, I'm not investing my retirement in any company trying to make
and sell these babies...

Bob W.

[Bob Whelan[_3_]]

On 2/28/2015 4:48 AM, Martin Gregorie wrote:
> On Fri, 27 Feb 2015 22:02:08 -0800, mmartin46 wrote:
>
>> I've been flying airplanes professionally for close to forty years and
>> sailplanes for fun. I spend a lot of time looking at the wing trying to
>> understand how it works. In the end, I conclude it's all magic. I
>> kinda like that.
>
> I've never forgotten one cloudy day with a low overcast. I was in a car,
> driving away from Heathrow toward Chobham Common, which put us directly
> under the approach to Heathrow, when a 747 dropped out of the overcast on
> finals. For a few seconds it was heading for us, grabbing the bottom of
> the cloud and flinging it at the ground: it was like watching a waterfall
> beneath its wing.
>
> That sight made me realise two things: that a 747 really does weigh a
> couple hundred tons and that the reaction from deflecting that huge mass
> of air downward has more than a little to do with keeping it in the air.
>

Agreed...and for the sake of pub discussions, I think it's entirely
sufficient. Where the explanation quickly becomes complex is when we attempt
to mathematically analyze lift, because so far no single approach numerically
addresses lift creation's entire problem. Bernoulli and Coanda are probably
the most commonly known "incomplete applications" among the pub set; both are
concisely eviscerated (more accurately, bounded) by Dr. McLean in his
conceptual assessment of each's ability to address the physical situation.
Anyhow, fun to contemplate for those so afflicted...

Bob W.

[Martin Gregorie[_5_]]

On Sat, 28 Feb 2015 16:54:40 -0700, BobW wrote:

> On 2/28/2015 10:19 AM, Dan Marotta wrote:
>> I must admit that I didn't read the article thoroughly, but it seemed
>> to me by looking at the picture that the thing would enhance wingtip
>> vortices (the Windows spell checker did not like that word, BTW).
>> Anyway, I thought the idea was to reduce vortices since they're wasted
>> energy that could be used by the aircraft.
>>
>> Aero engineers, please chime in.
>
> I had the same off-the-cuff gut reaction when I first looked at it, too.
> Upon further cogitation, I'm still uncertain eggzackly what-n-how the
> designer was seeking to achieve what I think he was seeking to achieve.
> I also noticed the article said he was an aeronautics teacher, so this
> may be a case of: Those who can't do, teach!
>
> In any event, I'm not investing my retirement in any company trying to
> make and sell these babies...
>
> Bob W.

I had good results with a form of Hoerner tip on my F1A competition
models (wings 2011mn span, 150mm parallel chord centre panels, short tips
tapering to 100mm chord by keeping the TE straight and sweeping the LE
back. The general tip design guidelines I used were:

- sweep the LE at least 10 degrees to promotee spanwise flow on the top
surface

- rake the edge of the tip about 30 degrees with a smooth,
rounded join to the LE and a sharp, acute angle join to the TE

- the tip's outside edge should follow the lower surface of the airfoil
with the upper surface smoothly blended down to meet the lower surface
at an acute angle.

The idea was for the spanwise flow to help move the tip vortex out from
the tip while the pointed TE would help stability by localising the tip
vortex.

My wings had carbon D-boxes with open structure behind that. The tips
themselves were carved from block balsa, finish sanded and covered with a
doped-on layer of 25 gsm glass-cloth. It all worked pretty much as I
hoped. The design flew well enough to be competitive and was extremely
stable and well-behaved in all sorts of air. There was an unexpected
bonus too: the glass covered tips were very tough. I lost count of the
number of times those models got overturned after landing and blown down
blacktop runways upside down, but always with remarkably little damage to
the tip blocks.


--
martin@ | Martin Gregorie
gregorie. | Essex, UK
org |