AutoGiro Lessons – Part 1 of 3 – "Autogiro Theory"



alright Here I am it Texas Taylor to be exact and I'm walking out my room heading over to my lesson literally here's the hotel where that Luscombe is that's where my lesson is so anyway so I'm off here to meet Dayton dabs met him at the wings over Houston Air Show hmm I guess about almost a year ago and he had a daughter gyro on the flight line I thought oh my god that's pretty cool I got to get a rating me on one day for the Pitcairn sup anyway we're starting very early the sun's just barely coming up because we're trying to beat the Texas heat so all right so here's the gyro great timing having a senior soon yeah I poked my hand in here yesterday I arrived early and you were already gone but here we're playing with assessment so that's ought to be fun yes I ran all the material coming out on the deal and it was interesting I didn't realize that you know there was you know a difference on the blade thing of three different sections you know I mean the helicopter thing is pretty much everything's kind of lifting but Brad and I knew I knew about you know the autorotation principle and all that stuff but what I didn't realize is there was three distinct separate you know blending situations on those on the wing there absolutely is in each in flight each section is constantly changing riding on what your rotor rpm is odd and your speed and stuff right exactly your speed your loading everything is going to adjust that how the rotary acts however naturally the interesting thing about gyroplanes or auto-rotating rotor to begin with is a rotor and auto rotation will never exceed three teams now why is that miss miss the centripetal force against the coning affect the way the ruler works did win it when it pulls in over three g's it's actually going to bleed off that's own load so you'll you'll speed it up it'll it'll pick up a lot of speeds you start pulling more ie so when you come in right right well yeah that's naturally gonna come so we don't we can't put us like a ballet dance pin and they pull themselves in my spin fast exactly exactly but once if you pull more than that what it's going to do is it's just going to slide through slide through that's going to bleed off its own load oh yeah and it has to do with those three sections constantly changing so when you pull more G's you're what's happening is is you're you're driving thing becomes bigger and you're lifting becomes a lesson so it just goes through it well or not necessarily not necessarily really what happens is the faster you go the driven portion of the blade comes in more the driving portion the blade comes in more in the stall portion of the blade gets smaller right so there we go so we have this blade here okay so this blade is turning in this direction yeah in this direction we have a stall portion rotten inside we have the driving portion this is there and there you have the driven portion yes so this this section of the blade stalled because it's not rotating fast enough it's got a high angle of attack this thing here is actually using the process of auto rotation because of the angle it's got a forward forward vector that drives the blade forward and then this part out here is actually what maintain or creates your lift while you're flying and that's correct the driving portion is also creating a lot of lift right so what happens let me break this down a little bit more in every portion of the the rotor you have the same force from under the alright yeah because the because it takes upward flow to MIT to right that's way an autogyro flies right and it doesn't matter if you're on the stove portion or the driven portion rar the same amount of airflow is coming up from under the rotor system right but this difference is the speed increases as it goes out to the tip so it effectively lowers the angle of attack of the blade because it's going faster against the the basic same relative wind to the gyros okay so this actually has a has actually has an airfoil this particular one well you can see it right it's cambered on the the top is flat on the bottom right it's got a little bit of reflux and basically what that does is it allows it it's most efficient okay now I am seeing something here that I questioned when I was reading in theory okay and this actually has got twists in it so as as the as the angle comes out it rotates leading edge down doesn't it or not or is that just a optical illusion I don't have the proper welcome here and look at it yeah it flat there it appears that way the rotor is also though oh yeah yeah yeah yeah yeah well maybe it's hard to tell well you know maybe it doesn't have any maybe is an optical illusion yeah I don't think maybe it doesn't huh now would it make any difference if it was rotated 90 degrees basically yeah yeah reacts 90 degrees later and so on a helicopter on the cyclic they the inputs ninety degrees before the action it looks like damn flimsy yeah from the back here I I think it's straight I don't think there's any twist built on through and it's kind of a Oh you know it's an optical illusion because if I look at it from here it looks like that's flatter the angle that I'm seeing it out and when I come out here that looks flatter it's just an optical illusion I think it's straight there's very very little pitch in these blades the basically you get your angle of attack by that rotor constantly being backwards to the the blade itself is very little kitchen kitchen not each other right like Lauren collective on a helicopter that don't have a collective like like a helicopter all of your all of your list generated simply by when we add power that will put more air flow going forward through the through the system or it'll push us further forward which drives every action there's an equal opposite oh yeah right the air comes the comes through the rotor system you get a greater amount of air the rotor is going to turn faster you're going to get well in effect it's like putting hand out at a certain angle going down the road and then going fast but it's going to create more like this what a lot of people don't realize is a gyroplane is nothing but an airplane with a rotating wing right more more or less this this is your wing up mm-hmm so it's it's not that complex with the as far as the complexities of a helicopter right you don't have to worry about torque because there is no torque going to the to the rotor because you're not driving the rotor system exactly which when you're doing a helicopter or what happens is when you drive the rotor up there then the helicopter wants to go the other way because this freak wheels it doesn't it can it can fly with just a you know kind of a vertical stabilizer which kind of dampens the also as long as it's moving forward that you know stays trailing but with the helicopter when you increase and decrease rpm and change the collective and stuff you're always monkeying with the with the RPM because the tail rotor on a helicopter is what it's an anti torque rotor is really what exactly yeah and there's always a positive pitch back there because once you hover you know the helicopter wants to go opposite the deal so you've got a positive pitch on your blade and if you basically want to go one way you increase the pitch and if you want to go the other way you decrease the pitch but you never actually I've actually got a I've got a helicopter fantasy flight one of those Hill okay yeah and it actually has a has a ramjet engine out at the tip that drives the rotor system so because you're not actually driving the deal you don't have to you don't have to have a tail rotor they put a little one in the back there but it's actually set up in effect there's only one blade there's the counterbalance on the other side and on the one blade it's totally neutral and so it goes one way for left and the other way for right Christy very interesting and the only way they added it originally they didn't have it on there but they wanted to be able to make Crossman you ought to be able to rotate into the wind and they cross me right you know adjustments and it low forward to airspeed I'm sure it's very helpful to have like you said it's like grabbing a fan if you have a fan you grab the blade the body of blades going to turn on that that's the content time to helicopter on this one there's no there's no motor going up there so if you grab the blade the blade would turn the desire a little time okay now you were you were about to say something about precession and I know in a helicopter the blades spin around and of course you're having done bump the rotor head to make it do what you want to do and because of precession it always acts is 90 degrees after you you know you put the input which actually is a great example is like on a p-51 when you take off you've got 3000 rpm on a big heavy aluminum propeller and when you tip that nose up in effect that gyro you've punched you push the time right it reacts 90 degrees later so what happens is the airplane swings to the left and it takes a lot of right rudder on takeoff before you know and once you get the tail up you know then then it kind of goes away and that's one of the reasons why because the propellers turn to the right on like American airplanes right that's why the conning towers are on the right side of an aircraft carrier debt because the airplane wanted to swing off to the left interesting is that never never knew that absolutely everything yeah well we're what we're talking about with the gyroscopic precession and gyroplane focus blade here for so basically when we turn right you'll see that the the rotor actually changes pitch there this rotor is a counterclockwise rotating rotor so yeah now you can see when we turn right that increased the angle of attack on that that rotor in the front right yeah when we turn left that decreases the angle of attack on the rotor in the front okay okay so as we turn right here well that's doing is that's creating lift here in the front by increasing the angle of attack of the rotor in front of the gyro plane so the lift is created at this point so it's pushing up there that doesn't react until we get over here okay so when we turn where you got to the right got it to the right okay so we turn to the right that means we want this to tip over here so we've actually increased the lip there that it doesn't actually it doesn't actually react here so it tips it over there and it goes for the ride because when we turn right let's the left side of the rotor and decreases the angle of attack on the right side of the road so you can see because that blade is facing the opposite direction because it's going the opposite way right so that one's low that one's that one's high okay now move to stick back to neutral and go back to the right oh that's to the left you okay yeah so that's neutral go to the right okay back to the neutral okay I'm back to the left and neutral okay pretty cool I tell you what man that looks pretty Mickey Mouse to me yes so this this in effect is like a helicopter it's what got what they call it Jesus bolt okay every bolt up in that rotor system is very um yeah the system is what we call a semi rigid rotor system so which gets into complexities of a rotor craft and Coney and Coriolis effect all of that has to be taken into effect with the rotor system there's three different types that rotor systems out there there's rigid there's semi rigid and there's fully articulating the Pitcairn has a fully articulated rotor which means it'll flap up and down and forward and backward exactly so then explain to me why because I know when Juan Sierra C ever developed a thing the biggest Bugaboo that they couldn't figure out was the the blade stuff they couldn't figure out how you know once they started moving forward it continued to roll on so they eventually solved that by having the blades flap up and down and forward and backwards so this one doesn't have they flap up and down because of the Flex of the blades but why not forward and back the is it's only a two bladed sister right yeah two blades systems we're not having to happen to worry about that because the they're physically attached to each other so you don't have to worry about one balances the other one okay so when you get anything over that a three or even a four I guess as well then they've got to be able to kind of find their little ray and the blade does that by moving forward and backward and going up and down on its own correct it's now it also adds a little bit of complexity to an aircraft a semi rigid rotor system is not going to get into what they call ground resonance the ground resonance is an issue there's all kinds of videos on YouTube about it where if the rotor craft lands or gets any sort of a bump that those flat those hinges put the rotor out of balance with itself right will actually break itself it'll lose its a flutter problem right exact letter ratio yeah in fact there are times when I'm slowing down my bell 47 which is a two bladed system right it doesn't think it does I can't remember anyway I bleed leg engines yeah I I can't remember I'll have to go back and look at it but basically there are times when it's slowing down when you can feel it one to go and you're having to adjust the cyclic like into the wind to keep it from hopping around and destroying us that I it's kind of a scary feeling well the the proper way whenever as far as ground residents and in the definition that I'm speaking of the as far as ground residence is concerned the best way to get out of ground resonance lift the aircraft back off the ground anything with a helicopter so what do you do with this right and this if you have the rotor rpm to take off take back off if you if you don't have it to then shut the aircraft down alright there's a typically when that's going to happen is right after you touchdown so you should have a lot of energy still stored up in that rotor system hmm so if if that's the case got full power that's assuming you're making kind of a smooth like an airplane kind of landing but if you're coming in and trying to stop in 50 60 feet right you're not gonna you're gonna lose all your but but then maybe you go through it fast enough that it's not it the other thing is just make a smooth plan exactly there you go make a smooth landing and everything's okay not an issue anymore right so that's the the basic principles of the gyro claim it's very very simple mechanically aerodynamically it appears simple there's there's a number of complexities with it you

27 thoughts on “AutoGiro Lessons – Part 1 of 3 – "Autogiro Theory"”

  1. Ground resonance is not a flutter issue it is when one or more blades becomes out of phase with the other and it causes adiyssymetry of rotational mass across the plane of rotation while the rotor disc is in motion. this sets forth an extreme out of balance condition and transmits this negative energy throughout the entirety of the airframe

  2. I considered gyros last year, but think I will stick to my microlight, for now at least. Thanks for your videos. Please check out my trike flying channel.

  3. Seems like a pretty complex way to describe lift vectoring. The rotor disc is being tilted left and right which, yeah it makes the trailing blade decrease in pitch while the forward blade increases in pitch but overall, you're just tilting the rotor disc which throws more lift to one side.

  4. Great stuff Kermit! I always thought the rotor on an autogyro was generating lift all along its length, in some proportion as long as its turning (being an airfoil) – now I know! Fascinating!

  5. LOL i pity this poor guy. Trying to educate Kermit on any kind of flying must be a daunting task.

    Anyway Kermit, another awesome snapshot into the world of flying. Cheers mate!

  6. Kermit, for shame… How long in the aviation industry and can't spell autogyro (with a Y)? You must live in central Flerda (Florida). πŸ˜‰

  7. Kermie, I swear I could sit with you, share a fine rum and pick your brain for hours. You are unbelievably full of aviation information that is so intriguing to me. Maybe, if I'm lucky, somehow that will happen some day. Love the videos, keep them coming. Ps, sir you are inspirational.

  8. Fascinating, looking forward to the rest in this series but, man, doesn't that rotor head and mast look flimsy :-0

  9. Fascinating stuff. I've read about autogyros for years, seen them in museums, etc., but wasn't familiar with the theory behind the rotors. Thanks for the familiarization, and I'm looking forward to seeing your flights!

  10. I have 26 years experience in fixed wing flying and took a demo flight in a Magni M16 gyroplane last week. It was incredible and I'd like to continue with lessons but I'm concerned about learning how to land it. It would be great if you could comment on your learning experience and any challenges you might have encountered in transitioning from fixed wing aircraft to the gyroplane. Thanks in advance.

  11. I fly these gyro’s and i have to say i loved the refresher on the Theory. cant wait for you to post the follow up to this first part of the Gyros

  12. The gyroplane has it's blades twisted downward 1.5 deg, where the Helocopter has it's blades twisted UP the oppposite direction from the gyroplane.

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