 Thank you. Hopefully the audio is working. I can hear it. I'm changing slides because of my nose. A bit of an introduction. As we heard there, I'm a volunteer at Aerospace Bristol, which is a museum in the north of Bristol that covers a lot of the history of Aerospace in Bristol and the future of Aerospace in Bristol as well. It's very, very much worth a visit, and I will give you a little bit more detail on that. If you need to ask questions, if you're interested in more details about it, I can talk about this for hours. I'll be probably hanging around afterwards and you can ping me on Twitter if you want to ask there as well. This is our aircraft. This is the aircraft that our wing came from. You can just about see the highlighting on the wing there, the one that's nearest to us. That's the chunk of wing that we've got, and this was an aircraft that we had... It was born in north Wales, as with all of the wings from Airbus aircraft. It grew up, I'm told, in either Hamburg or Toulouse. I thought it was Toulouse, but it may have been delivered from the sighting thing converter, and I've had some information where I wasn't sure about that recently. This is where it lives now. It's an interactive exhibit. As you can see, it's behind glass, and we'll talk about why. It sits there, it has interactive elements on the screen in front of it, and the idea is that it shows you a little bit about why the movable surfaces on the leading edge and the trailing edge at the front and the back, why they are there, what they do, and this talk is going to talk a little bit about that, but also it's going to go through a little bit more of the detail of actually how we made it work. That's not something which we would normally do in the museum, but we thought it might be of interest here. Before we really get into it, I need to go through some thanks. Obviously huge thanks have to go to Airbus. They gave it a lot of hardware, support, direct aid, indirect support. It really was thanks to Airbus that this is actually possible, and I was by no means the leader. That credit very much goes to Judy, but also Stuart, Keith, Doug, Steve, there was John and Andy who gave us a lot of support on-site as well in many others including Gosher and lots of other early careers people at Airbus who gave huge help to help the planning and the setup and the cleaning and the fabrication and everything. Also the other volunteers and the staff at Aerospace Bristol including Paul you will see in the video if it works and all the visitors and the patrons and the sponsors and the funders and everything that actually lets the museum function and keep it open and running. As I said, it's well worth a visit. It's in North Bristol. It's only about maybe over an hour away from here. It's just off the M4. So as I said, if you have time and you're looking for somewhere to go on the way back and if you're heading in that direction, I would recommend it. So we'll start off a little bit because the principle that the rig tries to show and it's really talking about how the wing can act a bit bigger than it actually is. The principle is that a wing for cruise will be relatively small. A wing that's sized for cruise is going to be relatively small because the aircraft flies very fast. It is very high up usually, but the speed is such that it wouldn't need to be particularly large. However, if we didn't have any of these moveables we would need the wing to be significantly larger to allow it to actually perform at landing. There is a limit to how hard the wing can work and if we were to size the wing for landing with it being clean with no moveables at all, you'd end up with something that looks something like the funny looking aircraft on the side to the right there and it wouldn't be particularly practical. One of the things that's useful is that if we have the high lift devices what that means is that we can actually get much, much closer to a wing that really is optimised for cruise. It allows the wing to work much, much harder and to allow the aircraft to fly slower which gives you significantly safer operations at low speed for takeoff and landing and it also means then that you can optimise the wing for performance where you really need it to be optimised which is in the cruise where it's going to burn most of its fuel and spend most of its time. We're going to a little bit about how that actually works because lift and stall are the bits that we very much have to come next. What you're seeing when the aircraft is flying is that it's changing the momentum of the air. Now I should point out this is the explanation that I've tend to found most useful to explain these concepts to people. There are a million and one different explanations of how lift is produced and it is frequently wrong even in physics textbooks perhaps especially in physics textbooks. Many of these things are actually all true at the same time, some of them are not so accurate. But the way I've tend to found most useful is that fundamentally what you're doing is you're taking some of the air and if we consider the air to be static as the wing moves through it, often at an angle you're deflecting the air down a little bit you're changing its momentum and when you change the air's momentum down a little bit you're pushing down on it you're changing its momentum that means there's a force there and Newton's third law tells you that there's an equal and opposite force in the opposite direction and that is lift. It's also a little bit of the drag that you would see as well. The amount of lift that you're generating is for any given set of conditions going to be proportional to the angle of the wing to the air and as you increase that angle you're going to up to a certain point see that the lift increases but it is only up to a certain point beyond that point the wing isn't going to work the same way it's not going to be able to have the flow following the surface and as a result you're going to see certain changes happen number one is that the rate of which the lift is increasing with the angle starts to drop off you're also going to see that drag starts to increase this is where the aircraft is stored strictly what it means is if you're doing it in flight test you slow down, you slow down, you slow down you increase the incidence increase increase increase at some point the aircraft can no longer maintain straight and level flight it will start to descend and that's the stall that's where you reach your peak of lift an airliner normally oh crikey excuse me an airliner will normally never want to operate in that regime you need to keep a long way away from it because it's not particularly safe and what the high lift devices do is that they actually delay the onset of that point if we go a little bit into what's happening this is an example of there are many different types of stall but this is an example of one of the things that you can see in the chart what you can see is that the lift as I said is increasing as the incidence, the angle to the flow is increasing if you're at A, the flow is pretty much smooth as you're going up to the point where it starts to get to point B there is some separation to the flow the flow is no longer following the surface it's very stirred up and as you get up to C that is the maximum lift there's a significant amount of separation there but it is still producing a huge amount of lift when you get to D the wing is fully stalled and most of the flow is not following the upper surface at all so what we see is that we want to do if we want to fly slower is we want to push that point C up as high as we can get it and this is what you can see here this is from a book by Egbert Torrenbech Aerospace Initial Design Books and what you see is the clean wing is the one that you would see if you don't have the movables you can see that characteristic of the lift increasing and lifting increasing up to a point if you deploy slats this is the leading edge devices and you'll see some examples of what they look like in the next slide to come when you have those slats deployed what happens is that the maximum lift that you can achieve goes up quite a lot and that's very useful because that means that you can generate more lift or more usefully you can generate the lift you need to fly at a lower speed flaps do something slightly different flaps are deployed from the trailing edge from the rear of the wing and they give you more lift for any given incidents and they're useful because what that means is that the pilot can actually get a significantly better view of the runway because if you have it tipped up like that you might recall Concord which is also Aerospace Bristol the last Concord to fly Alpha Foxtrot is Aerospace Bristol as well the droop knows is one of the things that they had to use for that aircraft because Concord has an enormous angle to the flow and that allowed the pilots to actually see the runway flaps on a conventional aircraft allow the aircraft to be at a lower incidence when it's approaching into landing and that gives you a significantly better view of what's going on and so what you can see is when you have both the flaps deployed the lift is very very significantly increased and it happens at a relatively low angle all of this means that you get significantly better performance at takeoff so if we have a look at actually what that looks like the slats are deployed with on this aircraft along a circular track and you have a drive cog which will literally just grind forward and push the flap down the track what's happening is it's coming out it opens up a slot between the nose of the airfoil that's fixed and the movable slot and this slot is what re-energises the flow over the top of the wing and allows it to retain attachment to the surface the other thing that happens is that it increases the camber it increases the it increases the the bend of the airfoil at the front again it means that you're not having a very very sharp transition around that nose it spreads it out a little bit which means that it's easier for the wing to retain its function on the trailing edge the flaps have and again there are many many different types of these devices this is what's used on this aircraft what you see is that there is a lever that's driven by a shaft and the lever pushes forward and pushes the slap sorry the flap down a track and so you can see as it goes from clean down to deployed the flap is both moving down the track and changing in its angle and again you can see one of these slots that you've got now my drawing isn't particularly precise there I've actually drawn the I don't know whether the pointer is going to be visible yes it is but here I've actually done something wrong which is I've got a convergent divergent slot there which is not a good thing to have it will tend to produce bad effects but this slot is also there so again you can see it's making the wing physically bigger but it's also increasing the angle and it's creating this multi element wing which allows it to break down the lift into multiple chunks which allows it to keep working and keep effective significantly longer it's quite interesting when you see the kinematic if you'll see a little bit of it on the video I have coming up what you'll see is that the aircraft that the flap comes back when it comes back it actually gets to the end of its travel and as it gets to the right bit it actually comes back up the track a little bit as well so it isn't a uniform motion down the track it actually comes back slightly when it gets to its final position that's all the theory this is all a little bit about the a little bit about the practicalities of making this work this exhibit has to run 24-7 it's one of these things that we didn't want to have to spend a lot of time doing maintenance because we're the volunteers that are going to have to do it and we didn't want it to come to a lot of cost for the museum on the aircraft the movements are powered hydraulically and because we're not stupid we decided that we weren't going to use that because hydraulic control is crazy complicated what we did instead was to go with something electrical but we do use all of the existing driveshaft hardware that's on the aircraft and all of the other parts are genuine genuine aircraft parts one of the things that we had to do when we were preparing this was to actually get a hold of parts to replace the parts that weren't there because when this aircraft was taken out of service like every aircraft that's taken out of service nearly everything that's reusable is taken off and effectively not recycled but reused on other aircraft and that qualification process is what allows you to reuse those parts safely everything has to have the paperwork done the inspections have to be done to make sure that they're safe we managed to get a hold of one of the parts we had to buy it on the open market and we were very lucky and that we managed to get a hold of it before someone had done the paperwork which meant that it was significantly cheaper than if we had to buy a real aircraft part but what we need to be able to do is to actually drive these surfaces to specific positions we want to be able to show people the position that's similar to what you'd have on takeoff where the flap is not fully deployed and on landing where both the flaps and the slats are fully deployed we want to make sure that we don't bounce off the end of the hard limits that wouldn't harm the aircraft parts at all but our parts might well explode because suddenly going from moving to being stopped we weren't convinced that was good for something that was going to run and run and run and run because our parts aren't anywhere near as expensive and heavy duty as the aircraft parts so the control system had to be set up for that this is where the control boxes are they live on the wall underneath the root of the wing there are two control boxes and they're both completely identical the only difference is that the software is different and as you can see they're transparent so everybody can have a laugh at our wiring and it also means that the museum can actually explain to people as part of their education activities what the different parts do you can see two sets of power supplies two sets of controllers and so on and we'll talk a little bit about our experience with those at the end probably the most important part of this is that though this is the emergency stop this is on the wall it's accessible from outside of the enclosure safety was one of the things that we really really really had to think about with this rig it is potentially extremely dangerous it has parts that move powerfully and without warning it has rotating shafts which give me shivers it has parts that come very close together such as crush hazards normal operation is that no one will be inside the enclosure at all and ideally you only go in to start it there's a timer where you can then exit and then when it's running there's no one there at all obviously there are people who are going to be there for maintenance but these are only going to be authorised and trains people so basically myself and the other members of the team start up does require access you actually have to push a button to confirm that you want it to go and again one of the reasons we did that is to make sure that that person can ensure that there is no one in a position to be harmed by it when it starts moving and again one of the other things we had is that there's no volt release switches on both of the systems so if the power goes down it will shut down but then when the power comes back up it will not start again you have to go in and start it manually this is a little bit about the control system logic I've been visited by the famous EMF spiders the hard limits are what we don't want to hit so in advance of those we have soft limits that are set up by homing switches those are actually directly attached to the motor controllers it's a Polulu simple motor controller that's actually quite nice because it means that even if our control system was broken we were never going to violate that soft limit because the control system with the firmware built into the controller would simply stop it what happens is that when you switch it on the system will look for a inductive proximity sensor which will detect whether it's in a home position and there's a metal plate on both of the surfaces that will tell you whether you're in this homing range that we've got there what it will do is if it detects the presence of that plate it will go out until it doesn't and then refine the edge and if it doesn't have the edge there if it's not active it will grind in until it finds it this means that we always know however you start it up as long as the motor is wired with the correct orientation it's always going to be able to find its way to home and then the cruise position is a little bit in board of that homing position the takeoff setting is a bit further out and then the landing position is near to the end of the soft limit of travel and then the ground shaft rotations to do that so there's nothing particularly unusual in there but we'll talk a little bit about how we actually do that this is the inboard edge of the slat looking out towards the rest of the museum you can see there a section of BA146 fuselage so you can see the cross section of that with all of the stuff that's under the floor and all of the things that you normally can't see behind the lining of the cabin you can see there also the tube which is what supplies hot air for the anti-icing system which obviously we don't need because it sits in the museum in board of that is where the motor is and this is probably one of the first bits that we were initially really doubtful about these are motors that we bought from a company that supplies motors for robot building there may well be ones that are very similar to that running around the site they're basically just cordless drill motors attached to a planetary gearbox and we expected these to be incredibly unreliable and difficult to deal with and they do fail but not very often those are just keyed into the existing shaft which you can see starts where that four lugged part is here this is the first slat gearbox when you move outboard of the motor and this then feeds into the gear slowing it down significantly which drives the slat itself but the shaft movement is continuous along the whole of the leading edge one of the things that you'll be able to see if the video works is that there's a little bit of the slat shaft which is still running right at the end because our wing is only a section of wing and it actually goes further out this is the slat track itself and this is where you can see some of the control hardware on this side you can see the the homing switch this is just a micro switch which is attached to the motor controller and this is the inductive proximity sensor with the home plate so that is active right up until the end of the travel and so this basically it will retract if you were to start it up in this position it would come back until it found the edge of that plate there this is the slat rotation counter we originally did that optically and it worked perfectly in our rig but with the usual integration hell problems that you always have something like this we found it didn't work on site we didn't really ever chase down why we thought it was an interaction with the lighting system that they had there because it seemed to cause a problem even if we were running things just on the bench the other problem we had was that the shaft actually bounces around quite a lot so maintaining the alignment for the optical sensors was a little bit hairy as well this basically just uses another one the proximity sensors and we were able to use the fact that the slat shaft actually has these four bolts holding the different sections together we could simply mount it there and use the fact that we had effectively four counts per rotation which was actually a very good resolution for us so we simply use one of those those have been very good as well they are designed for PLCs so they don't run at five volts and that's a problem because as the title says we were using hard winos but a voltage divider did sort that out and it was actually very very useful first of the shaft you can see going outboard and there are multiple tracks per slat this is the outboard edge and what you can see here this is the bit of the drive shaft which would go out to the remaining bits of the wing that aren't there on the rig this is the flap and again going inboard so we've just come across from the leading edge to the trading edge and you can see all of the hardware we showed so this is the track it's all labelled up on the rig so people can see what it is there's a lever in the gearbox here and then this is the rest of the hardware the carriage slides up and down this is one of the outboard gearboxes you can see it's a really really substantial piece of kit it's very very heavy because it has to take enormous flight loads and then there's another one inboard what you can see here is you're starting to see some of the extra hardware we've had it and there'll be a detail of that here this is the motor and you can see it's another one of exactly the same type although it does have a slightly different gearing because the number of rotations for a full travel is not the same leading edge to trading edge this is the flap home sensor and it's the same thing that we had before where there's a plate attached to the lever which allows it to find that edge and on this slightly different angle that's the home sensor again but also the stowed limit switch and that's again just fascinating to hear we did at various points try to drill holes into the rig because it's never going to fly again and we have after blunting many many many many many very expensive drill bits we found that there is some kind of alien technology alloy being used and we decided that we were just going to glue it in place instead and that's been fairly reliable with appropriate surface treatment this is a video that I hope will work showing the slats moving and the flaps moving in the background you can see John there who's holding the brand new pendant controller, manual pendant controller who's going to be able to who's actually controlling this movement you can see the shaft spinning and it's continuous all the way from the inboard right out to where you can see at the outboard edge the socket for where the drive shaft would continue and then this is the flaps moving inboard you can see that that movement just starts to move out a bit before it starts to pull it in because it's an over centering link as it comes up we move around to a different angle you can see underneath the spoilers which we had initially thought that we might have moving as well and then decided that that was going to be extremely complicated and decided not to but you can see the shaft rotating and the remains of the systems the wires and the pipes which are all there from the actual aircraft hardware and that's the movement finished oh thank you it wants to play again what did we learn we power it with an Arduino Mega and it's actually really reliable we didn't expect it to be we thought that hobbyist hardware wouldn't really work for this kind of length of time we only killed the only ones that died were the ones that we killed by doing something stupid as we mentioned there are some parts which use 9 volts logic and applying those to pins doesn't help the motor controllers have been really really good you can talk to them via USB there's a really really good configuring program that you can use to set the limits and the speeds and acceleration for something that's driving a brushed motor it's really really flexible and the fact that you have these firmware limit switches which gives an extra layer of the protection onion that we might wish to exploit is really really handy because it meant that even if we did something really bone headed with our code it was actually going to not break the rig these displays that we had attached to the shield that provides the interfaces into the arduinos they do die after a couple of years we found that the backlights failed and that was on everyone that we'd used they also when that happened seemed to start causing some hard to trace glitches that went away when we took the displays off we can diagnose the rig with USB when we're there and so having these displays was kind of not really required anyway so both of them run in quotes headless now and so we've never really needed them but those were not a brilliant choice these inductive sensors are absolutely excellent I think they're designed for PLCs for prologic controllers for factory automation they're very very reliable they work very well we were glad that we decided to use those for all of our position sensing really the power supplies were LED lighting power supply drivers they're 24 volts they were also very very reliable the fans did fail after I think 3 or 4 years so the fans were replaced by the the electricians at the museum and then the supplies are fully functional again and the motors this was probably the bit that we were most nervous about to begin with we were really concerned that those were going to die their brushed motors there was going to be a lot of electrical noise and that was something which we did have to deal with but appropriate use of jokes and capacitors and so on dealt with that we also had quite a lot of shielding of the wiring as well which basically meant that the problems in normal operation were fine we really expected though that we were going to have to go to maybe a brushless system for something that was going to be running this long and in the end what we found is it works pretty much flawlessly they do die the brushes do fail but they are very very very cheap which means it's very easy for the museum to just go and buy another one and then swap it out so a little bit about the museum I'm not going to go into a huge amount of detail but one of the big aims of the museum is that they want to actually advance learning skills and training in science technology engineering design showing the conservation of the heritage of aviation that Bristol has which goes back a very very long time right back it's very pretty much to the dawn of aviation they've got the new conservation centre which is now open where you can go in and see some of the conservation work that the museum does actually happening there's a freighter, there's a Bristol bowling brick around the place as well there's other things which they're working on to do with Concord one of the other things obviously that is there is the last Concord to fly Concord Alpha Foxtrot I think the nose actually droops and they were braver than us and I think actually did use the original hydraulic systems to make it work there's also a lot of other things there there's far too much for me to list so I would very much recommend a visit and thank you for your attention as I say I'll be around if you have questions or ping me on Twitter