Venturi Airfoil

Putting aside the airfoil lift vs. angle-of-attack lift debate, the concept suggested will have:

front compression, rear expansion, net force (lift) = "0"

Added structures will only increase drag.

IF you "cap" your wing idea, inject and ignite fuel at the appropriate spots in the flow, you now have multiple ramjets distributed over the whole wing. If your goal is faster and higher, the scramjet is the way to go.

Hi mjb1962853,

I remembered about the scramjet when I was lying in bed after...

thanks

Chris

Hi Chris, Have a Quick View

Or here see 5 Glide slope control

There was at some point a glider air-brake system that raised little posts out of the upper surface - which is not unlike your design - but a the posts were lot smaller in scale than yours.

They were "devastatingly" good at breaking - but the system could fail only raising one side - which was "DEVAST-PRANG-ING".

Bernoulli's principal is - more or less - that the air must go faster because the distance is longer on the curved top, compared to the 'flat' under surface.

Messing with it on either surface is called "drag".

Hi 34point5,

I knew there would be an increase in drag on the vert surfaces, but also a decrease in drag because the thinner wing section. so overall, a small increase in drag. There is also efficiency loss in traditional wings due to the tip vortex effect. I think that this design might minimize that, and therefore gain back the efficiency it lost as drag.

I know we have had lengthy discussions on aerodynamics here before (on cr4), and that the differential flow/pressure between top and bottom is only part of the equation. I still think that this will speed up the air flowing over the top, and therefore have a measureable effect. the question is how much...

As for 'braking systems', these are streamlined venturi shapes, designed to pass the air. All braking systems are designed to interfere with the airflow and create turbulence and drag. I do not think they are the same, or will have exactly the same effects.

maybe experimentation is the only way to tell.... but you know I like to dispassionately discuss technical questions like this, whether i'm right or wrong... thank you for your insights.

Chris

Hi Chris, nice pic of a landing into a heavy multi-prop take-off wake.

The 'drag; of brakes is because they take power - as does a venturi.

I'm wondering what is behind your search. Shorter span? Lower take-off airspeed? You have had several like quests, it seems more than just your incurable curiosity.

I think the pic is a spray pattern of a crop duster.....

Heeheeee.

Found this - it's a bit "TV drama" for the firts 3 minutes, then "training slow"; but goes to several concepts, including the transfer of momentum (I got a wrap on the knuckles for on Bernoulli's behalf earlier) manifest in the depression of wake.

Hi Chris,

Google for "Custer Channel Wing". It is an actual application of a venturi (okay, half-venturi) to generate lift. Oh, and apparently it works really well too.

Lord Vader out.

Hi DVader1000,

I'm familiar with the Custer Channel Wing. I've got it on my favourites list. It is one of those ideas that worked well, but never had sufficient support to become mainstream. I don't get it.

and you are right.. it is a half venturi, which is exactly what I've shown.. but perhaps you are suggesting I should curve my venturii... I like it. harder to render and build, but may well decrease drag. (although, in fairness, the custer design also has the props blowing air through the channels, which directly increases the airflow too.)

Chris

Structure change and the addition of an engine w/pusher prop makes the Custer Channel Wing different than proposed concept. The CCW should have a low pressure area over entire top surface of the wing channel due to the action of the pusher prop. While the CCW concept seems to have improved lift characteristics at low speed, I suspect it has not become ubiquitous because there are some significant practical limitations.

That was a really interesting piece on the Custer Channel Wing.

Custer's concept of putting the airflow directly over the lifting surface I re-discovered when looking at a demonstration airfoil in the Brumigham UK technology museum, some 20 years back.

I noticed also that this concept of directing the airflow directly over the surface has been the subject of a patent from about 8 years ago!

I also understand that there are now further developments in hand regarding VTOL surfaces using a more innovative approach if,indeed, the authorities deem it to be innovative.

Hi Yusef,

As always, you make a lot of sense. I think that the depressurization of the upper side is about efficiency & stability, but is not more important than the wing area + AOA. One has only to stick your hand out the window of a moving car to see that. I'm more likely to build an RC prototype than to actually go into business, which would provide some validity to the concept.

As much as I'm a rabid Avro fan, I don't think the Avrocar performed as expected. It worked well as a ground effect vehicle, but remember they did want to be able to actually fly with it, and it never did. (or perhaps it didn't reach that stage of development)

On a side note, we went to the Reynolds Museum in Wetaskiwin AB a couple of weeks ago, especially because they (not toronto) have built a full scale replica of the Avro Arrow... but we were told it is no longer on display (no room) and that it will have to wait the funds for a new building.

Chris

There are similar concepts that is already out there. It actually uses whats called ground effect, which Flarecraft uses.

p911

I don't think the "Flare craft" uses a similar technique at all. No venturii at all, only ground effect. It is a wonderful machine in its own right though, and should become a contender in the aerospace world. I don't want to rain on such a great idea, but I think the flare craft might be too expensive for a boat, and does not perform as well as an airplane, so, it is neither fish nor fowl, and its applications are limited. (As are all aircraft designs come to think of it.) I rather like its ability to glide over marshland, doing even less damage than a hovercraft, and I can see how handy such a plane would be for, say, inspecting pipelines in the arctic and ferrying people into unimproved or rocky docks.

Do you know other advantages, like is it more fuel efficient than a speed boat, or is it faster than a hovercraft?

You nailed its use on the head.

Flare craft has been around a very long time, about 20 years ago the ship yard I worked at had developed some of the proto types..If I remember right, I think its was headed up by Sikorsky's nephews or relative....

...and it has some dangerous handling characteristics, as far as costs, with what was put into it, the only thing we could see its use was for drug running, it was a boat and a airplane, yet it was neither.........but it couldn't out run a radio.

It looked cool.

It used fuel simular to a plane.....only more. seas have to be calm, thats why we were developing it on the great lakes/bays. Other than that the only other use is a prop in a Batman or 007 movie

p911

Kalinin K-7

With a few tweaks like putting an engine in each venturis?