Master Lecture: Helicopter Flight Dynamics and Controls w/ Leonardo Helicopters' Dr. James Wang

morning everyone and welcome to the go fly master lecture series to get us started I'll have Glen Leiter CEO of go fly introduce the go fly prize and our speaker today Glen thank you Paul and greetings to everyone and thank you for joining us we are so very pleased today to welcome dr. James Wong dr. Wong is senior vice president of Leonardo helicopters and dr. Wong holds many patents and many international major awards including the UTC gold neat award the AHS Grover Bell award the AHS fellow award and the Royal Aeronautical Society Gold team award in 2013 Wired magazine named dr. Wong the Steve Jobs of rotorcraft for his ability to think outside of the box he has pushed the transportation technology boundaries by inventing and designing the AgustaWestland project zero which is the world's first all-electric VTOL technology demonstrator aircraft and we are so very pleased to welcome dr. Wong and thank him for our next master lecture dr. Wong ok good afternoon mark good morning everyone from adequate around the world today I would like to give everyone in the audience some insight to how helicopter operate the concentrate on the flight dynamics in the control portion there will not be too much math or equation I would like to focus on the physics of how they operate and how they fly because I have some wonderful teachers a professor when I was studying in the university I found some of the best professor had and one they were able to explain the fundamental of the physics behind how things operate and they work and then I feel very calm lightened but once I believe you understood the physics how do things work you were able to then also look up resources to find the equation the mass and the description should catalyze what are you seeing now on the picture on the front page is something I'm very proud of which is the booster whistle project zero the world first all-electric 8000 aircraft that I started designing and 2010 and that put together a team inside it rooster wisdom and we were able to succeed Lee design build and operate this test to this and just less it's six-month and you can find out more about this interesting vehicle if you just do a Google under Agusta Westland project zero change one you'll see many interesting story now let's begin the our presentation today agenda for today I'll explain how helicopter flies why helicopters are difficult to fly because they have instability explain the four controls the for integration inside the human brain and why the smaller more difficult they now briefly talk about the history of helicopters and then finally I will explain the helicopter rotor system because the rotor system is what controls the helicopter and makes the helicopter unique explain water articulated Angela's airless and rigid rotor first let's thought was hot helicopters fly many people you might be pilots out there but let me quickly go through this for a helicopter there are basically four controls you have the collective stick you have the pedals and you also have the cyclic sticks each one's serve different function now the former cyclic control it control multiple things let's just limit to the joystick before at first the four F cyclic controls pitch rotation four back translation and hover also climb and be sent in forward flight there left-right cyclic control it controls banking left right translation in hover and in control fearing left or right in fourth line as you can see each one of this control it control more than one function by moving the joystick left and right in hover you make make the helicopter sliding left or right waiting for fly become different it causes the helicopter to bank and fear the left if you're right you could do it quick enough you can roll the whole helicopter the third one is collective control collect the controls by marrying the blade pitch angle of the rotor blood and that changes the thrust the lift of the helicopter and you allow the helicopter to climb up or go down and in for flight to climb or descent and the force one is a young control the young axis is controlled by the children it rotate the helicopter left or right and this is controlled by the foot pedal now why is tail rotor required on a helicopter as we seen the picture when the helicopter let's assume the main rotor is spinning in a different top o'clock and counterclockwise direction that's going to produce a torque on the fuselage the causes to spin in the clockwise which is the opposite rotation direction the main rotor therefore you need a tail rotor to produce a tail rotors thrust to counteract the main rotor to balance it to keep the heading steady some of these controls could be used may not be used on the fly machine that you will be building you may build a helicopter you may not the regardless what kind of flying device you will be creating they will all have three axes a rotating motion and three axis translation motion you'll find you need to find a way to control it now let's take a look go back to the helicopter example a helicopter we just said it needs a tail rotor to produce a thrust to counteract they tort the yelling because this tail rotor is also produced a lateral force by the sight force is going to drag the helicopter was in hover in the direction of tail rotor thrust to counteract that the main rotor also needed tilt a little bit in the opposite direction to produce a side force to cancel to cancel the Toro distressed and end result is you have a couple if you look the picture from the front view of the helicopter the tool really stress the sky force now we need to tilt the rotor to the slightly opposite direction to produce a sight force from the resultant stress to counteract by doing so because there is a distance between the children center shaft and what a simple rotor main rotor this will cause the helicopter to produce a torque and in hover that's why I usually don't see the helicopter hovered level it always tilted slightly to one side the solution for the helicopter is some helicopter designer choose to raise the tail rotor upward to the same height as the main rotor for example like the AgustaWestland aw139 the Sikorsky blackhawk as some other helicopter a raising the total thrust line now they're both on the same level if we take a look the picture from the front view again there's no more coupling so this in fact cancel the sight force directly and the helicopter was sitting in a little position now I always like to go back refer how does that affect your project you may or may not build a helicopter you may or may not have a rotating lifting device like a rotor to generate lift if you do you have some kind of torque produce you need to find a way to cancel that torque and depend on how you cancel it it may cause a tilting of your body or fuselage it may or may not be important to you now let's take a look at the rotor forces in hover in hover it's very simple we have this rotor thrust must balance the weight so regardless of how you're going to build up your device power by your rotor system or power by a jet pack or spring water out you need a thrust of balance to weight go back to the helicopter you go into for flight first transitioning from hover for a helicopter the mainland orders thrust the red color is always perpendicular to the main rotor and by tilting the helicopter order rota for that will produce a horizontal propulsive force component and that will cancel the drag for a flight and that's what provide a steady equilibrium steady velocity flight and horrify so whichever device you've built you have to think about how to generate a thrust how to cancel that drag and the weight this is an interesting part now how does the helicopter go into for a flight this is where helicopter is quite unique in order to make a helicopter going to Flora flight it must rotate a fuselage or the rotor and then accelerate leniently and then it continues translating this is also one of the reason why helicopter difficult to fly and now I'm going to detail in a few slides from now how do you produce a moment on a helicopter to rotate the body for four helicopters are two ways to produce a moment on the fuselage first method many rotor design use what we call a hinge offset hinge off says that distance measured between the main rotor shaft and where the flapping hinge of the blade is this is an articulated rotor type design and usually this is called an e for hinge offset because there's the distance between the hinge point and the main or Center once the helicopter blade produced of lift but tilting will produce a moment this lift will convert to here and then won't rotate about the rotary cinder hub that's one way to produce a rotor moment the longer the hinge offset II the more control moment you can generate for your fun device you will need some method to steer your flying vehicle so it could be through translation like by a puff of jet air or you may want to rotate and tilt the body of your vehicle and such that the thrust within till and pull for or post sine wave your vehicle so one thing you need that considers how do you generate the moment if you depend on the rotating the vehicle to move the thrust leather way second way of the helicopter to produce a moment is what we call a thrust tilting method here we show the rotor thrust the red color is again perpendicular to the rotor tip path plane and that produce a vertical component which is to balance the weight of the helicopter in a little horizontal propulsive force component there's little horizontal component has a moment arm of balance that helicopter CG and that will also produce a moment usually this method to produce the moment is weaker because the propulsive force is quite small very slow four times in the arm give you a small moment while the previous method we have a very large force lift almost equivalent to the weight of the helicopter multiplied by a distance in Java which could be small using around three or four percent of the rotor radius but because the large lift you have a very powerful moment now I'll go into the second topic why helicopters are difficult to fly whichever device you'll be designing it's important to make sure it's it easy to operate it's a stable it's a controllable for helicopter number one reason why they're difficult to fly because each control the cyclic the client the young it has multiple thing unlike an airplane and helicopter there a lot of cross coupling for example an airplane has shown the picture on your screen the bottom left the helicopter has a for flight control they basically control the four degrees of freedom but rudder controls a yellow the elevator controls the pitch and then the aileron controls the roll and the engine power controls the velocity they're pretty much uncouple in for flight one of the reason also they're on compass because airplane they don't really cover to simpler on a helicopter we take a look the right side the four flight controls they have to control six degrees of freedom three room and three translation let's take a look at the four aft cyclic stick it has to control pitch rotation and then is to also control the four back to installation in hover and the for a cyclic he also controls together with the collected the climb and descent in for flight the lateral cyclic controls the road rotation and also left and right translation in hover and fearing to left and right for flight rudder is the only one that sliding uncouple less for less couple it control mainly the left and right rotation the yelling as you can see by cross couple all that one control effects result in the other direction pitching rolling translation that has some complexity to the flying control so one of the question to consider what kind of flight control system do you require inside your vehicle such that to help it can reduce the cross coupling to make the operator job simpler another reason why helicopter difficult to fly is a helicopter pilot has to anticipate his reaction inks his head even just to go from point A to point B in his Brian the Oaks of the owner to do four orders of integration mathematically we sell him a wearing it let me explain what does that mean for example when the helicopter pilot he want to do a simple translation in hover from a to moomoomath distant X to point B the X could be say a hundred feet Hey first he pushed cyclists ik floor den number two what happened is the helicopter rotor momen will produce a moment about the fuselage to rotate the helicopter forward let's call it theta double dot as it produces an angular acceleration from the engine acceleration is the rotate accelerate angular Lee it produce an angular velocity a steady pitch rate theta dot and then because it started rolling forward eventually you will reach a steady data angle the helicopter once you reach the end of theta now because the rotor is pointed tilted for you produce a thrust generate and longitudinal acceleration X double dot you need to celebrate to reach linear velocity it's not and then the velocity will convert after while to a distant X so therefore level integration method from theta double dot theta dot to Engel to linear acceleration theta is equivalent to inflation accelerated integrate together velocity integrate the velocity to get the displacement so just for the one moving to flight this the x1 Durfee if the pilots anticipate and do all this in his head we still haven't really realizing this is well one reason makes the anticipation and prediction think forward what makes the helicopter slightly challenging to fly for example if you don't have a rotor you know you simply have a jet propulsion and simply puffing the air on the side then you have an you can eliminate maybe the first to order integration the theta double dot and the theta dot you may start with a simply a linear acceleration leaning velocity Danish translation to get it X that could make your control easier number two helicopter challenging the flight because they're inherently unstable airplanes are inherently unstable but not that that they're actually generally pretty well behaving you make a paper airplane you throw it it pretty much of flying in a straight line myself helicopter on the other hand will sell any other pilot sense they built into the system mechanically or electronically if the product takes it hands off the helicopter it will veer away in some manner then it could crash so there's always require some type of pilot feedback or stable stability augmentation system to make a helicopter manageable number three helicopter mini axis of instability three rotations three translation 63s of freedom the human can easily control two or three degrees of instability but controls 6 DOF simultaneously is challenging for example the balancing boons that in your hand is relatively easy because it does not have six degrees of instability that's why even there's an unstable system but it's doable now number four the more difficult to control usually for any control system sure something we call a time constant big items usually longer time constant for example the plumes take example again he has longer time constant then trying to balancing a pencil the balance of broomstick is relative easy to balance a pencil in your hand Trident is almost impossible because the time constant is shorter that's why bigger airplane seven four seven the big six 53k helicopter are a little bit more stable and easier to control in a smaller airplane that's also quite model airplane and radio control helicopters are more difficult to fly because they're smaller reaction times quicker next topic the history of helicopters there are many early rotorcraft pioneers one of the most famous one in Igor Sikorsky and mainly people get the credit to Igor Sikorsky for the inventor of the helicopter when Igor Sikorsky first immigrated from Russia to us around 1910 he already came up with a helicopter idea to fern : however it discovered at that time around nineteen nine 1910 the engine are very heavy and they don't produce the power required to produce a vertical lifting vehicle that is what Igor Sikorsky decided to pursue designing airplane first it was until 1930s that's when Igor were able to use more modern engine to produce just barely sufficient power it was successfully produced the vs-300 to the top so power is one of the most important thing for you to consider how would you generate the power in a minimal weight Leonardo da Vinci right many hundreds of years ago he also generated the spinning corkscrew the lifting VTOL device idea what even now could have to come as a power back few hundred years ago to produce the lifting vertical machine that's why the ultra general was invented came about before the helicopter because although djaro does not rely purely on horse power to vertically lift the vehicle it has propeller on the front engine and the rotor is unpowered and it by producing the for flight it can produce enough lift from the rotor by windmill also rotating to general generate the lift to take off so they doesn't rely purely on engine power the vertical lift now we go back to the controller of it in the early pioneer helicopter are difficult to fly as we have learned earlier that is why I offer young he invented the bell stabilizing bar around 1945 the Bell stabilizing bar is the horizontal bar on the top I wrote ahem if functions like mechanical feedback system to stabilize the helicopter in my having this it basically increased the time constant slow down the helicopter to more manageable so one of the considerations you may be thinking is whatever device you have do you need some kind of mechanical sensor feedback system or electronic general accelerometer to help you stabilize the vehicle nowaday the MEMS germs are so cheap that's so small you can get a complete 6th axis Bend feedback system for only under twenty thirty dollars so that may be one thing for you to consider and they're extremely lightweight they only weighs one ounce or less stanley hillier brought the flower idea from mr. Hiller one step sorry for the flight of offering on the one step forward by adding a pedal aerodynamic shape pedals on the fly bar order stabilizing bar such that he can gain some extra control so this is what we often see on radio-controlled model helicopter you can see on the bottom left corner a small RC helicopter has a pedal fly to help stabilize and to add the control power nowaday if you do some Google and look at the modern radio control helicopters RC helicopter than on the market they're stone in last five years this pedal stabilizer ization bar has disappeared why because now is a relying this mechanical bar people are using MEMS and small sets stability augmentation system way more than one less than one ounce inside these RC helicopters to stabilize it so that may be something you go shop around under internet to learn about it you may want to use far along one of those when it causes a fine lines list could flybarless controller or mmm that was controller used by quadcopter Frank P sake another pioneer he he was the one originated the Boeing tended rotor helicopter idea now let me talk about a little about power required for human power because very similar problem and challenge to what you have your challenge is to provide a lifting design carrot one person was a relative amending power to weight ratio and it had to be compact size was the human power airplane competition which was first set up by the industrialist called herring Kramer 1959 he and le's did not put a size limitation his rule was simple build a human power aircraft fly figuring that was it for a mile so people could be as big as possible this is the result 1977 dr. McGrady and dr. Lisa Minh that produced the gossamer Condor as you can see from the picture it is huge if you're like they're able to achieve the power to weight ratio needeth for human power fly to win the kramer price unfortunately you have much more challenging target there is this cubic size the go prize is I must fitting so you know have the luxury to make a very huge wing very huge rotor the second creamer price a hundred thousand pound against Ella by an agreement this was to set up a course who can be the first one to fly across the English Channel this was again won by dr. McKray D in 1979 let's take a look it took him two hours 45 minutes to to fly across because I was very slow speed in the weight only 32 kilogram was a 30 meter almost a hundred feet wingspan that is definitely outside by the rule the boundary allowable by the go fly price and there was another human this airplane distance record set in 1988 MIT Dallas team flew across from Greece to great was that weight of only 31 kilo again very impressive now we talk vertical width let's erase the bar 1988 HS created the Igor Sikorsky price was a person $20,000 nobody achieved that for many many years I spent two thousand nine agents convinced Sikorsky Aircraft raise the prize money to a quarter million dollar the rules was very simple human power only was hovered for 60 seconds minimum altitude must maintain over three meters about ten feet must remain was seeing a hovering box 10 by 10 meters Hey minutes ride 1989 University of Cal Poly Luis Obispo tried it they're only able to reach 8 inches for each second Hummer not quite the one minute and a 10 feet 1994 Japanese Nihon at our University also try able to achieve 20 centimeter and nineteen point four six second only and look at how huge the road Ernest each one were ten meter diameter 30 feet spitting at 20 rpm only that's the kind of efficiency you need to produce a human power helicopter and you will have to equal challenge to lift one person finally after 33 years that's how long it took it was not until 2013 from Canada the air low low atlas human power helicopter team they were able to capture the quarter million dollar prize and cover for 64 second reach the elders altitude just three point three meters barely cleared a three meter and now the go fly flies I think it's quite a bit more interesting and challenging but technology has changed electric performance you don't you're not a human you could use the electric any kind of jetpack whatever there's a very few restriction number four because my expertise is helicopter a rota graph the vertical lift if you do choose to go into the direction of some kind but rotor lifting device let me now explain what are the various type of rotor system you may want to consider or that are available today here are some of the the helicopter configuration that had been proven successful over the last hundred year we have the classical single main rotor and pillar kindom rotor coaxial rotor single rotor with no tail rotor side by side like the K max tip jet propulsion tilt rotor like the v-22 40 infinite wisdom aw609 pusher prop propeller like design by piaseki children tradition single main rotor and tail rotor that might not be a Bible choice because to generate the the lift the thrust it may require a bigger sight than my fit in a dimension that you're allowed in the Gulf go flight price but there's something for you to calculate in the last two lectures Paul never like want and also Dan Raymer they produce a very good math equation helping you how to calculate and then also has a sizing code can help you calculate so it may be something for you just try an exercise if you do go this night go down to the read of a spinning main rotor lifting vehicle do you want to have a tail rotor in this helicopter design make McDonald is is called no car they direct the jet out of the side of the helicopter to eliminate a runner and now the design is rather than because you do have to fly that you have a horizontal distance requirement in a go fly price do you won't have a tail rotor or maybe have the timber like the piasecki to produce for propulsive force and then they use like a rudder a guy bang to direct it site way frontier owner to produce to come to at the time that may be another possibility can then rotor more efficient than the main motor because you don't have a tumor that use up twenty percent of your total horsepower just for counteracting the counteracting the main or reporter here both main rotor are used toward lifting the vehicle so it's more efficient but we do need to make sure the two rotor are spitting up assist direction to counteract the torque on the project zero which I have designed a few years ago on this one I went and design was a twin and rotor side by side design and again it usually must be an even number because that's how you cancel the torque and I decided at a wing to it because one of my goal is not just to fly perfectly takeoff vertical ending is I also want to be able to go for flight efficiently so this case the wing also produce majority of the lift we can split down the center bond each of the progeny reproduce around 30 percent of the lift it's like a lifting body out War wing produced the rest balanced that these percent sixty percent of the list and then the two rotor they're able to turn 90 degree become like a tiltrotor in for a fly but if we don't turn them 90 degree really turn into you eighty degree and the two duct they can contribute you over ten percent of the lift in forward flight that's another consideration this one this case the project zero would designed it for carrying one human passenger or can be unmanned so this requirement same as the go go fly price carry one person but we designed it for speed and higher efficiency side by side and an option coaxial and the way to cancel to your torque the supports it came out was a coaxial plus the pusher prop just to make the floor fly more increase the speed but in this case you are not worried about us feet however but you may want is just an extra small propeller just to help push you forward to meet the horizontal distance requirement so you're separating out the lift component from your vehicles for propulsively and you may be a turn off the for propulsive power during the hover to save your power tiltrotor you as to rotor I can tell you from hovers to 90 degrees horizontally become four fly this I police is too complicated you will not be able to have to wait luxury to build something like this cuatro der that's another possibility but they never think about the power whether you'll be powered by electric or whatever source challenges you have the power disappea energy density from the lithium battery to provide a 20-minute flight in a bus the x3 is a another interesting idea they separate a lift in the main rotor and the propulsive force by the Chu propeller and the two propeller also can produce differential thrust to produce a yelling force to keep the vehicle straight speed that's one thing we don't have to water about here in the Gulf light price on the sakura CX queen in hover the rotor spins the helicopter one second for flight the rotor stops it become like an x-wing cheap jet that's another possibility it blows air out of the blade tip that the benefit is you can eliminate the Aurora maybe is the design could be you jetpack blow air directly downward or could be using a jet to produce it to propose and rotors spinning there then use the lift for the rotor to generating the vertical force in me that may be more efficient the last topic of it is discussing is the different rotor type on the helicopter they're basically four types articulated hinges fearless and reach the rotor first let me describe the blame motion yeah anytime you're gonna use a propeller or rotor you will have some kind of blade involved any roller blade for the helicopter there are three motion of the blade lead lagging flapping and torsion first let me explain the torsion that's the simplest you change the blade angle to increase the lift that's how you control the thrust Nick by changing the lift this is the first time we will see a question on this presentation there's something called angular momentum the conservation of angular momentum is what dictates when that ice skater bring his arm saying he spins faster okay I think most of them we all learned this in our high school physics how does this apply to helicopter blade but changing the blade torsion you're increasing the blade lift now the Blay will flap upward because there's a flapping hinge or all also even there's no flapping can simply because the blade is elastic the bend upward now is the blame will upward by bending or flapping they're reducing the effective radius just like the spinning skater pulling his arm inward now you have a conservation ingre momentum will cause the blade to go up and move forward that's kind of leading if there's no me like hinge right this point if this is rigid then there'll be a lot of stress build up every time the blade flat out flat then you will want to lead or lack about this point the hint down will build the stress invented crack the blade recruit that is why the lead lack hinge is required to alleviating the court why spending moment the wiser flapping change needed with the answer discover mice one Sierra when he designed the older journal every time try to take up the ology are you always roll over in crash let's take a look here's a helicopter main rotor spinning for a top view in a counterclockwise direction if the blade tip velocity Omega R equals 800 kilometers an hour now let's say the helicopter is flying forward at 200 kilometers an hour on the top side which was called a retreating site velocity will be 800 minus 200 becomes 600 that'll be 600 km/h be the true velocity that the airfoil see the blade tip on the advancing side which on the bottom side it become 800 climbs an hour the blade spinning the to meeting the uncoming here at 200 times an hour it becomes now total one thousand clubs an hour that is what the interval will see here the advancing side now we can see this more lift generated on the best inside in the retrieving side the end result is the helicopter will want to roll over that is why by having a flapping hinge that help alleviate allow the helicopter to balance out so especially although John is very important because the blank pigeon was fixed so you must allow the blade of flat in order to alleviate at rolling moment that is the nice thing for you to consider when if you're designing any type of flying go fly vehicle whistle rotor do you want what type of lifting blade is a rigid what type of hinge and how do you accommodate the stress so here we have funds articulated lots of moving parts hingeless fewer parts to bear less rotor sophisticated composite design fewer parts now let me just quickly give you some example with a different type of rotor Alleluia helicopter the French he has articulated rotor was a lack hinge and this is the flap hinge the Russian kind 24 again quite complicated articulated over lots of hinges there's a torsional hinge there's a flapping hinge that's a mechanically like hinge ch-53 it's a g6 plane it articulated order quite complex sitch 47 is shinobi three blade articulated white complex also this is the hingeless now on the Agusta Westland Lynx on the hingeless rotor we can see quite simple there's no flapping lagging engine is a virtual li-like hinge basically got a rod or bent slightly because long enough so you don't have this stress build up from flapping the center hump is made of titanium plate and that plate is allowed to tube it to produce an effective flapping cage the benefit of a hingeless design is if you give you that large hinge offset eat that we talked about before it give you a very good control moment and did you give you a Fergus control firing so if you find your vehicle that having a control power that you may won't have to think about how to increase the moment control moment of your vehicle it has a rotor that you may have to go more original he's like PL 105 by intervals helicopter is another design we say hingeless rotor no mechanical flapping hinge no mechanically like hinge is provided effectively by the composite blade elite this is a close-up of the composite bleh root of the bo 105 the benefit the hingeless rotor allows give that control moment to do the acrobatic such as we see on the ripple team and also on the inner of us tiger as a hingeless rotor allows you to do that acrobatic finally the pyramus rotor this is the ec135 you can see the benefit is extremely clean aerodynamically and fully composite rotor design rotor blade is the first you lean like and you're the first you'll flap hinge it gives you excellent control power the Comanche also have a bearing list main rotor bell 230 now we go to the other way to blade teetering rotor this thing give you the lowest amount of control power the teetering time because there's no restraint of the root the players allowed to Teeter myself and how do you get a control moment this is where in the beginning of the video I mentioned you produce a site force that you multiply by the vertical shift all the way to the CG and that produce a moment about the center of the vehicle to give you the thrust tilting effect on the project zero we choose which do you say rigid rotor si this is the rigid rotor no flapping hinge no lean back hinge we only have a torsional hinge the change of pitch why because rotor diameter is relatively small to the vehicle size only three million I ammeter therefore we don't add a placement quite region so you don't have the kind of flapping allowance for the blade so you won't develop that Court wise motion and also because the design object is quite different on the projects that we also want to have an aircraft they can tilt forward and rotor and then they'll allow the fly a few hundred kilometer forward high-speed so basically in full fly that when a rotor tilts 90 degree it becomes like an airplane that is why the rotor must have a rich aha so again you have to think about the design criterion what do you want to do to pick the right rotor design the rotor control characteristic for your go flying design this the projects are quite big 12 meter wing tip to wing tip and the final advice I'd like to provide to everyone is imagination is boundless one of my favorite phrase I tell my sculpting my the people we work on this give it can be dream it can be built so wish everybody the best of luck and lots of success thank you very much great thanks James looks like we've got just a very few minutes for questions so we'll take just a couple so one is uh you talked a little bit about the efficiency differences between an electric tilt rotor and a traditional rotor between a okay there's no efficiency difference between a lettre killer or any other like the v-22 engine power tilt rotor the power required is physics it's fixed is purely dependent on the weight and the amount of drag you have in the system the reason why you may want because they're using electric like when I did the project go electric is because electric is very simple because you can get rid of gearboxes transmission gear reductions because you get there many electric motor you can choose from you can choose if you have the right kV rating the motor rpm so the project surfers that we cover the whole gearbox the main rotor is connected directly to the electric motor and that is why we went to electric one of the reason great thanks and then as you know the the go fly price has a nose requirement as a part of it do you have any advice for people competing about the noise requirements yes one of the benefit of course for the electric is the it's quiet you don't have to indian exhaust engine exhaust it was a muffler it can be very quiet now let me have two part first why do we put a shroud on the project the shroud is there SS mentioned before it produced some lifting for flight but in hover it can increase the efficiency of your rotor in hover that is what and also for the noise we found out that having this round actually increase the noise so you may want to think about it before adding us around and the second part I would like to mention is that if you decide use a jet jet is very very noisy if you design and use a jet propulsion because by reducing the lifting Divine's like helicopter rotor which is very big here move down slow velocity then if you move to a small nozzle the jet noise usually proportional to - I believe the fifth or sixth power of the exhaust velocity come out of the jib tip so that is a consideration you will have to experiment with to find them great thanks and then final question before we end if you were entering the go fly competition how would you begin to tackle the let the competition what would be your first couple steps ok first couples that is the challenge here is the sight because you have to fit in the design side that is what's going to make it difficult for you to chew have the freedom in design the human power helicopter compounder plane no size limit it's quite easy so that's why you can use minimum power minimal wing very less small electric motor human produced 1/3 horsepower that once their horsepower it's tiny it only weights about half a pound right but then you need a big motor so you need a trade-off the trade-off is that you need to reduce the rotor size the lifting device sight on reducing the size the power required will rise very rapidly so there's a trade-off the size physical dimension versus the power required one good story therapy for was think out of the box one of the story who was okay a panel was trying to help a his his children going the science project price and that the requirement was to drop an egg from three floor high building was a break who can who didn't break the egg shell will win and only tool they're given is toilet tissue co-head and wire everybody's trying to see if they can make a parachute or something except this one father he came out as an idea how about used the cold hanger wire and the toilet tissue to fabricate an auto general ruler and then for the ink in the middle and then they left that down from third floor but the entire thing come down slowly but also rotating and they won the price we stop breaking the day hmm so think out of the box great thank you very much and then just with a couple concluding remarks I'll pass it back over to Gwen open me Oh Glenn's gonna give us just a parting word hello everyone thank you so much dr. Wong we greatly appreciate your insightful presentation and look forward to seeing all of the wonderful creations that the innovator group has given and we'll be providing thank you very very much all thanks Emma great day thank you

Channel: GoFlyPrize

Views: 40,336

Rating: 4.9156628 out of 5

Keywords: Dr. James Wang, Leonardo Helicopters, gofly, jetpack, helicopter, lecture, technology, flight

Id: tZr7lTJPQu8

Length: 56min 50sec (3410 seconds)

Published: Wed Nov 29 2017