Can compressed air or steam provide lift?

[YuNoHu]

Dear Rotoheads,


Suppose compressed air is released at high pressure up a pipe eight feet high where it is diverted straight out to the sides to form circular jets of air in the form of disks that are four feet in diameter and a tenth of an inch thick. Now suppose the circular disks of air blow over metal surfaces that are like circular shelving that are aerodynamically shaped. Might this not generate significant lift?

In other words, couldn't compressed air generate lift for a device that would have no moving parts (and not require counter-rotation of any kind either.)

[Fareastdriver]

Thre was a project at the Jet Propusion Laboratory at Farnborough, United Kingdom during the 60s. It was in the form of a hollow rotating pole with high pressure air routing through the central pivot. It used the coranda effect; this was explained that if you hold a beer glass horizontly and push it under a running tap the water will spray over your trousers; and so the air could be influenced to provide lift.
They had a super model of a Trident with a rotating pole that brought it into the hover; the jet thrust built up airspeed; the pole was stopped,; (having no residual aerodynamics there wasn't a problem); and then stowed fore/aft in the fuselage.

The presentation was very interesting but I never heard anything about it afterwards. Probably because of the passengers complaining about the pole being stowed in the aisle.

[WASALOADIE]

As long as it causes a reduction in pressure above whatever is to be raised creating lift equal to or greater than above the body then it will work, but sustaining it is the problem.

[John Eacott]

Dear Rotoheads,


Suppose compressed air is released at high pressure up a pipe eight feet high where it is diverted straight out to the sides to form circular jets of air in the form of disks that are four feet in diameter and a tenth of an inch thick. Now suppose the circular disks of air blow over metal surfaces that are like circular shelving that are aerodynamically shaped. Might this not generate significant lift?

In other words, couldn't compressed air generate lift for a device that would have no moving parts (and not require counter-rotation of any kind either.)

Try researching blown flaps/boundary layer control, developed back in the 1950's and used in the Buccaneer, TSR2, and more recent the A380.

The TSR2 was credited with reducing the take off roll from 6,000 feet to 1,600 feet with BLC.

[topendtorque]

Not quite the answer you're looking for but I remember a funny story from these columns a few years back told by (Vee Any??? - apologies if not he ) some name like that.

Seems some sailors had been dispatched to get rid of some old gas cylinders. Soon thereafter was a strong clanging noise followed by a loud and disappearing whoosh.

Yes sir, the compressed gas was doing the trick alright lifting the bottle in a nice suborbital flight line after a standing start from leaning on the fence upside down and the hefty administration of a large wrench to the tap assy.

Must have had a fair effect that compressed gas because it also lifted said sailors into the slammer, if my memory serves me correctly.

[handysnaks]

Fareastdriver. Coriolis effect? Coanda effect surely....

[Fareastdriver]

Handysnaks

Correct, edited; it was a long time ago.

[handysnaks]

It's the old MD 902 driver in me;-)

[Gemini Twin]

"In other words, couldn't compressed air generate lift for a device that would have no moving parts (and not require counter-rotation of any kind either.)"

You mean like a aerofoil in a wind tunnel ;)

The "non moving" angle on the right side of the "non moving" tail boom of the AS350B2 and later models, produces a kind of lift, which reduces the power going to the T/R needed to counter torque.

[Fareastdriver]

The NOTAR is a good example of a stationary lifting surface.

[RVDT]

The NOTAR is a good example of a stationary lifting surface.

So is a wing on an aeroplane!

NOTAR is a good example is something only a Brit seems to think but I digress!

More up to date reading can be found here. (http://d188rgcu4zozwl.cloudfront.net/content/B002Q69B9M/images/cover.jpg)
Some of the old myth's/theories that were taught to protect the innocent are debunked!

[Fareastdriver]

Cannot be bothered; its not that important

[griffothefog]

I do recall a particularly good night once with my grandfather (RIP), when after we consumed enormous amounts of "Old Speckled Hen" we seemed to float home on the discharge of gases, but alas had little directional control and got quite lost:(

[Rigga]

Phantoms and Buccaneers used engine compressed air blown through approx 2mm slits/ducts along the length of wing and horizontal tail leading edges to enhance lift during Launches and Landings. This was called "Boundary Layer Control" and helped the airflow remain in contact with the lifting surfaces for much longer generating more lift. This worked in conjunction with Vortex Generators also along wings and tail surfaces.
On buccs (a 2-seat 40ton MAUM aircraft) it was said that the wings were each 6ft shorter due to this increased lift.

[Gemini Twin]

Can't be bothered either and WASALOADIE already answered the question correctly in post #3.

[[email protected]]

Hmmm. what about the newer theory that low pressure over the top is a myth and that the air being deflected downwards causing an equal and opposite reaction is lift?;)