Russian Flying Saucer

cudabean · Post by **cudabean** » Wed Dec 24, 2003 1:47 am

This article at Wired is interesting. It describes a flying saucer that the U.S. Navy is interested in for reconnaisance drone and STOL cargo applications. It uses some sort of spooky vacuum trick to reduce the drag on an otherwise bulky draggy shape.

http://www.wired.com/news/technology/0, ... 81,00.html

There's a picture of the fat stubby-winged craft at their website:
http://www.ekip-aviation-concern.com/index.htm If you browse their brochure, you can see several grainy photographs of this hamburger-bun thing flying around. The photo's are color, but are so grainy that they remind one of western spy photos from the 50s. Maybe I'll contact the company and see if they want my old Kodak Instamatic for free!

cudabean

vhautaka · Post by **vhautaka** » Sat Jan 17, 2004 12:55 am

A Coanda lifter! Well, maybe just a Coanda drag-reducer.

If I understood correctly, the "spooky vacuum trick" is to use the engines with special, strategically-placed, flat nozzles to accelerate air on the wing surface.

This flow, moving fast and presumably being warm and turbulent, will stick to the surface and contribute to lift and thrust, and it will keep ambient air away from causing drag on the surface.

This is more straightforward than with regular jetplanes, which use engines to just propel gas out the back, to move the plane forward, to produce air movement around the airfoil and eventually both drag and lift

This technology of "making airflows stick" probably has the potential not only for STOL but VTOL.

Mmm... I wanna pulsejet powered vortex flying saucer. :)

- ville

nmasters · Post by **nmasters** » Sat Jan 17, 2004 6:53 am

The people actually involved with the project haven't published very much so most of what you can read about EKIP is uninformed speculation. There are several suction slots in the aft upper surface as shown in the attached drawing. As I understand it the idea is to get a vortex stabilized in each one of these slots by suction. These stable vortices turn the airflow to keep it attached to the thick airfoil and remove the boundary layer. This is not exactly Coanda effect which involves jets impinging on surfaces. This system sounds similar to the thick Griffith airfoil and the Goldschmied body that Bruce Carmichael talks about in "Personal Aircraft Drag Reduction" pp. 189- 192. Notice the quote from that Wired article "if we can make it work, it'll allow for new, radical concepts in aircraft design," said Dr. John Fischer, NAVAIR's director of research and engineering sciences. The thing was started 20 years ago and they're still not sure it will even work. There are photos of a large EKIP under construction but it was never finished. most of the images of EKIP type vehicles I've seen are definitely computer generated. As far as I know the only thing that ever actually flew was a 1 meter RC model. Don't hold your breath, this is a very long term project and it may have rather shaky foundations

vhautaka · Post by **vhautaka** » Sat Jan 17, 2004 10:09 am

www.ekip-aviation-concern.com wrote:The profile of the flying vehicle body ensuring laminar airflow in the boundary layer of the larger part of upper surfaces of the vehicle, permitting to install on the upper part of stern the vortex boundary layer airflow control system thus ensuring steady airflow around the vehicle body. The vehicle body airfoil allows to install an air cushion landing gear on the lower flying vehicle surface.

3. The vortex boundary layer airflow control system mounted on the stern surface ensures steady airflow around the body of the vehicles under all flight conditions, including take-off and landing at high angles of attack.

To me, this sounds like the Coanda effect being utilised.

The round holes in the front seem like air intakes, and on the prototypes there's arrays of flat nozzles/other orifices everywhere.. front of wing, on top of it and some in the back.

Very cool, this reminds me of Tesla's vision of aviation's future... just smart air pumping and flow control, no fast-moving wings or external propellors necessary. Can't remember the exact words, but something like that.

- ville

nmasters · Post by **nmasters** » Sun Jan 18, 2004 12:45 am

vhautaka wrote:
To me, this sounds like the Coanda effect being utilised.

- ville

It sounds like suction boundary layer control to me. But I'm often wrong. Care to enlighten me?
The relevant patent numbers are:
US Patent No. 5,417,391
Russian patent, date 14.10.1991, No. 2015941

And for your convenience the USPTO search page:
http://patft.uspto.gov/netahtml/srchnum.htm

vhautaka · Post by **vhautaka** » Sun Jan 18, 2004 8:22 am

Uh, I stand corrected. :) Thanks.

This seems to do exactly the opposite than I thought, using vortex chambers to suck in air at strategic places instead of blowing air over the airfoil. The effect, as I understand it, is essentially the same - causing steady flow over the plane's surfaces even when conventional aerodynamics wouldn't allow for it.

I would never have thought about using _suction_ to control anything in a bigass airplane. Nice!

- ville

Bruno Ogorelec · Post by **Bruno Ogorelec** » Mon Jan 19, 2004 10:37 am

vhautaka wrote:I would never have thought about using _suction_ to control anything in a bigass airplane.

Well, isn't suction just a form of blowing?

nmasters · Post by **nmasters** » Mon Jan 19, 2004 5:54 pm

brunoogorelec wrote: Well, isn't suction just a form of blowing?

Actually, no. Blowing adds material and energy to the boundary layer. Suction removes the boundary layer and the free stream material that moves in to form a new BL brings energy with it. Blowing is used to increase lift while suction is used to reduce drag by removing the turbulent BL. The two systems use opposite sides of an engine driven blower but the effects are completely different. Blowing increases the gross takeoff weight while suction improves top speed and fuel efficiency. On a thick airfoil like EKIP (or Griffith) it can get confusing because that thing wont produce any usable lift without the suction system. Without suction the EKIP is a bluff body, suction makes it act like an airfoil by removing the turbulent air aft of the minimum pressure point and puling the free stream down to the surface. The vortices that EKIP is supposed to trap in those complicated slots are formed from boundary layer material sliding off the section of skin ahead of the slot so a new, laminar, BL forms down stream of each slot. Some British researchers demonstrated ridiculously low drag on a 20% thick Griffith airfoil with 1 suction slot at 80% chord in 1948. Similar experiments have been performed several times since then and it works. But the drag numbers aren't so exiting when you factor in the engine power required to get a given drag reduction. As it turns out the thick sections with BLC offer similar performance to thinner natural laminar flow sections but they are expensive to build, expensive to operate and vulnerable to fowling by insects getting sucked into the slot. The maine attraction is that they apear to offer a lot of usable volume, not efficiency.

cbromano · Post by **cbromano** » Mon Jan 19, 2004 9:29 pm

As you might imagine the US Air Force has thought of all this long before. They have tried both sucking and blowing air around the airfoil. The ability to make the air â€œstickâ€

Post by **Mike Everman** » Tue Jan 20, 2004 6:58 am

I too very much want to avoid riding in something that greatly resembles a rock when the engines are not happy.