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BAe Pilotless Demonstrator Flies - With CAA Auth'd Nil Control Surface Movement

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BAe Pilotless Demonstrator Flies - With CAA Auth'd Nil Control Surface Movement

Old 29th Jan 2012, 09:54
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BAe Pilotless Demonstrator Flies - With CAA Auth'd Nil Control Surface Movement

BBC News - First flight for 'flapless' plane

I'd still want reversion of some sort if the blowers failed. So you'd still need the plumbing?
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Old 29th Jan 2012, 11:03
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Presumably the blowers fail when the engine does. So no dead stick landings with this baby. MB one instead.
Bang! " 'ere where've you gone?". "I'm out here on the tail!". "No, stop messing about!". (Kenneth Williams/Tony Hancock in "The Test Pilot").
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Old 29th Jan 2012, 11:20
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Martin Baker? Pilotless? Am I missing something here?
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Old 29th Jan 2012, 12:03
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Hmm. They kept saying "jets of air" which made me think reaction control, like the Harrier. But then the slots looked a lot more like boundary layer control. For anything much larger than a model/drone/UAV I would think that would be BIG "puffer jets" to pitch/roll/yaw an aircraft at speed. So either way, that would be a lot of high pressure engine bleed air to do the job.

One has to think back to our days of having proper aircraft on a proper aircraft carrier - no, this isn't a BOF's nostalgia moment - and using boundary layer control to increase lift, reduce approach speed and improve controlability. All those bleed air ducts shifting hot air around inside the wings were fine as long as one of them didn't go wrong and started pumping very hot, high pressure air into the spaces where the fuel, hyd, electrics lived.

Bleed Air Duct failure was one of the nasty emergencies (in the F4), causing all manner of seemingly unrelated symptoms: fires, generator failures, hyd failures, instrument malfunctions, etc (someone help me out here). Careful crew diagnostic required and the only answer was, effectively, to turn off the bleed air and let as much of the hot air out of the aircraft as possible.

Of course, all that is probably irrelevant if you can't fly the aircraft any more.

BAeS seem to have a habbit of trying to improve on the traditional, tried and tested, control surfaces. Look at Tornado! We love it (and it was a workaround for VG, but I rather like "flaps" to fly with.

P.S. WHY oh WHY do reporters never think to ask someone to check that the words they are using are right?!?
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Old 29th Jan 2012, 12:11
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I think 'flapless' may be a misnomer. They're not talking just about flaps as in slow speed handling devices.

But the word 'flapless' is what BAES uses. Demon is part of the
FLAVIIR (Flapless Air Vehicle Integrated Industrial Research) programme
But they also explain that Demon is
designed to be able to forgo the use of conventional mechanical elevators and ailerons which usually control the movement of an aircraft in favour of novel aerodynamic control devices using blown jets of air
Nothing about rudder btw - and with this tailless delta-ish shape, we're presumably talking elevons anyway.

airsound
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Old 29th Jan 2012, 12:27
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I presume you do all realise this is old news? That film clip is dated 28 September 2010???
If you want to know more about the project, it has a home page at FLAVIIR
Its clearly very much a research project.
Description of the control jets at Aerodynamics
To quote:
"Control using blown air from the wing trailing edge is being investigated by Manchester. The basic principle is that blown air entrains the upper surface flow thus giving rise to an increase in lift.
The trailing edge has to be modified to become rounded, but in general the thickness of a typical trailing edge does not have to be altered.
Thrust vectoring utilising secondary coanda jets to enable deflection of the primary jet is also being investigated by Manchester. The principle is that deflection of the main jet can be achieved by switching on a higher pressure secondary wall jet which sticks to the geometry and bends the main jet with it.
Basic demonstrations have taken place on laboratory equipment and the research will focus on achieving an optimal design and build for a real aircraft.
Synthetic jets, or zero mass jet actuators are a novel means of controlling flow separation and hence can be used to augment lift and control an air vehicle. These jets are typically around half the boundary layer height (approximately 5mm diameter) in size and it is envisaged that many hundreds of such devices would be enabled on a flying surface to affect control. In order to understand the fundamental principals in using such devices and explore how to use and design with them Imperial College are looking at computational modelling using large eddy simulation (LES). The end goal is to achieve sufficient understanding to enable simpler and faster computational models to be built such that they can be used within the design cycle.
Another form of synthetic jet using small-scale surface deformations is also being investigated experimentally by Imperial College. Here the benefits of such devices over cavity oscillators are being studied.
The bridge between developing novel flow control mechanisms and actually utilising such devices in an aircraft is in the flight dynamics and control required. Hence research is being undertaken both at Cranfield and at Manchester in developing suitable experimental techniques to both develop and test control system software."


There are other pages describing the other research topics within the project
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Old 29th Jan 2012, 12:28
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Hot air duct leaks are extremely dangerous as has been said.

A Vulcan was on its way to Goose Bay once and had a significant hot air leak which caused considerable damage; the aircraft could have been lost. And that was with relatively minor need for such air.

Certification of a manned aircraft with a bleed air control system, including sufficient redundancy, wouldn't be a simple task. Maintaining sufficient bleed air pressure during a protracted descent or on a typical low drag airliner approach would be.....interesting. I recall the dire threats we were given on the Buccaneer OCU about reducing thrust below about 86% NH on a 45-25-25 approach...

No. Although this BWOS idea might work for drones, you can forget about it for aeroplanes.
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Old 29th Jan 2012, 12:30
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Crikey, this one's old news. Demon flew about 16 months ago - why are we dragging this up again? The CAA authorisation is also a joke, just like it was with their bold claims with HERTi being CAA approved - no sense and avoid = no flying outside of segregated airspace (see CAP722 for further).

I guess the biggest utility of these types of control are for low observability, but would we be able to fly this in peacetime UK airspace over populated areas (I think not!).

LJ
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Old 29th Jan 2012, 14:00
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Originally Posted by Mach Two
P.S. WHY oh WHY do reporters never think to ask someone to check that the words they are using are right?!?
Exactly. They could have also verified it with the manufacturer; or maybe not!

Showcase UAV Demonstrates Flapless Flight - BAE Systems

In Cumbria last Friday, DEMON successfully demonstrated flapless flight when, for a planned portion of a test-flight, the conventional flap control system was turned off
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Old 29th Jan 2012, 14:31
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Of course the Americans have already been demonstrating their own flapless Landing techniques in Iran with theirs.
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Old 29th Jan 2012, 15:27
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M2 and BEags,

F4 Bleed Air Duct Malfunction = air at up to 410C and 100-200 psi in the fusealge and wings. Ducts also ran underneath the fuselage fuel tanks.



Which makes it hard to diagnose and shows how much stuff it could damage.
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Old 29th Jan 2012, 21:42
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A little info

It has normal controls as well as the flapless ones - I was told that this allows them to get into situations of interest and then "flip over to fluidic control" for a while and then back to conventional.

Here is a video from a lecture about it which might be a bit long and rambling but I found it interesting:

I saw "DEMON" at Farnborough and asked about it. I was told that it effectively converted the usual mechanics for ailerons into a mere ball valve to control the flow of air and that this made it extremely reliable and easy to maintain.

I attempted to suggest some possible stealth advantage as I was wondering what happens to a stealth aircraft's visibilty, given that they seem so smooth, when an aileron lifts up. That idea was shot down quickly but I am not smart enough to understand the reasons.

The video indicates one of their big problems - the cost and difficulty in getting permission to test something like this in the UK.
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