Glad to hear that the video is appreciated! I never thought this video would get this much attention. It was just a insyrument/video experiment for me. This also motivates to make more such video's.
i came down here to write the same thing. yes obiousliy it's coupled to a gyro... but especially seeing the manual reset progress really helped me to fully grasp the mechanical working.
I love this old tech. I do guided stuff for a living, so these days we use MEMS magnetometer, gyro, and accelerometer to provide our inertial platform. But there's nothing to see, the two devices together are the size of a grain of rice. I'd love to have one of these, but I'd rather rely on electronics when my life depends on it.
Hehe, the technology is indeed improving luckily. But old tech is nice to discover. Like mechanical calculators that can integrate. Old stuff, but very wel thought trough and very well built. 😎
Yes. Avionics is quite noisy. Well, when the housing is installed the noise is less, but still rather good to hear. Also 400Hz instruments have usually 400Hz servo loops built in that makes the well known 400Hz hum. So the avionics bay and a cockpit is rather noisy. The good thing is that the noisy gyro's nowadays are in the avionics bay and the indicators are displays. So the noisy servo loops are not needed anymore. Probably the only noisy instrument is this type of back up horizon.
That's true! I'm a mechanical engineer and even after years I'm still amazed how these precision masterpieces are designed and made. Eventually it's a crude physics principle that's used in it's raw form. I'm also busy trying restarting a Honeywell/Sperry 311 vertical gyroscope. (www.polytech.nu/index.php?artikel=440) My main concern is how to build a powerful enough 115 VAC 400 Hz power supply... The gyroscope is even a more spectacular masterpiece. There is some 'simple' electronics for managing the device. At power on the gyro is brought to it's start position for example. Even more interesting is that it you're flying a long time straight ahead, there is a correction for the earth curvature. (Otherwise the horizon would be upside down at the other end of the world...) A video will follow when the power supply is ready. ;-)
This is really cool. Thanks for sharing this. I'm curious if it would remain it it's current position as the earth turns or will it drift as time goes by? Again, great stuff.
A gyroscope can drift to it's home position. The drift is (luckily) very slow. I a gyroscope is placed upside down, after a while the gyro will drift to 'normal' position due to the self correcting mechanism affected by gravity. Since a plane is usually flying straight forward, the self correcting mechanism doesn't affect the reading. If a plane would fly upside down for a very long time, the gyroscope will drift to it's 'normal' position. Under normal circumstances this wouldn't affect the usability. In fact, if there was no self correction of a long time, the horizon would be upside down eventually when flying halway around the earth. Update: I planned to do the experiment to see how long it takes to autocorrect the horizon, but this video has to me made yet... But someone else did this exeriment already: ua-cam.com/video/kTXTCqMHyhg/v-deo.html
@@Thebasicmaker Not accurate. Precession (the Earth turning) is a problem for the artificial horizon. Old versions of it had a weight in the bottom of the device to keep it level, these days it has pendulous veins to compensate for the Earth turning and traveling over the curve. The mechanism is necessary for the artificial horizon to work correctly, otherwise it would drift out of true as the Earth turned or you traveled over its surface.
The weight is used as an auto correct to send the gyro axis perpendicular to the earth's surface. If this 'auto correct' is not in place, the gyro is eventually upside down when flying to the other side of the world. The desired situation is that the horizon is represented, so while flying long distances the gyro is corrected to 'follow' the earths curvature. - The rotation of the weight is mechanically derived from the gyro motor rotations by using a 'gearbox'. - The weight is off center, so the weight is 'pulling' to send the gyro axis perpendicular to the gravity axis. Due to the gyroscopic effect the movement is very slow. - If the gyro axis is perpendicular to the gravity axis of the earth, the mean position of the movable weight is centred. - If the gyro axis is NOT is perpendicular to the gravity axis of the earth, the weight stays a little bit longer at one side of the gyro axis. The result is that the gyro axis is pulled every weight rotation a little bit to send the gyro axis upright. Since the 'auto correct' is very slow, the short time effect is negligible. By 'pitching and rolling' the offset dus to the 'auto correct' is nil. The (very) long term effect is that the gyro is always sent upright eventually. Practically an airplane flies most of the time 'straight forward'. When following the curvature of the earth, the 'auto correct' matches the 'error' introduced by the earths curvature. The long term result is that the horizon stays level when flying around the earth when flying most of the time straight forward. If the airplane 'pitches and rolls', there will be a very small error introduced due to the 'auto correct'. This is very minor.
A gyroscope can drift to it's home position over time. The drift is (luckily) very slow. I a gyroscope is placed upside down, after a while the gyro will drift to 'normal' position due to the self correcting mechanism affected by gravity. Since a plane is usually flying straight forward, the self correcting mechanism doesn't affect the reading. Well, the curvature of the earth than the self correcting system so the horizon is always matching with the curcature of the earth. If a plane would fly upside down for a very long time, the gyroscope will drift to it's 'normal' position. Under normal circumstances this wouldn't affect the usability. In fact, if there was no self correction of a long time, the horizon would be upside down eventually when flying halway around the earth. So the curcature of the earth is a much smaller challenge... I planned to do the experiment to see how long it takes to autocorrect the horizon, but this video has to me made yet... But someone else did this exeriment already: ua-cam.com/video/kTXTCqMHyhg/v-deo.html
I want one of these just as a memo from my training (since most modern airplanes are digital now and training airplanes usually use these), where could I get one! I love the system :), Also, is there a way I could get one that works (the gyro)?
The idea of a weight isn't that bad. In fact, if the plane was not affected by forces (other than gravity), a pendulum with a weight would work for a directional gyroscope. But since a weight at the end of a pendulum is affect by forces due to increasing and decreasing speed, the result isn't usable. The gyroscope is 'steady' in space, like a pendulum only affect by gravity. ;-)
This gyroscope can drift to it's home position over time due to the self balancing weight. The drift is (luckily) very slow. If a gyroscope is placed upside down, after a while the gyro will drift to 'normal' position due to the self correcting mechanism affected by gravity. Since a plane is usually flying straight forward, the self correcting mechanism doesn't affect the reading. Well, the curvature of the earth than the self correcting system so the horizon is always matching with the curvature of the earth. If a plane would fly upside down for a very long time, the gyroscope will drift to it's 'normal' position. Under normal circumstances this wouldn't affect the usability. In fact, if there was no self correction of a long time, the horizon would be upside down eventually when flying halfway around the earth. So the curvature of the earth is a much smaller challenge...
Pendulous vanes are associated with vacuum driven gyros. They alter the airflow coming out of the gyro. Electronic gyros use electrical sensing of some sort to figure out the local vertical.
Will this gyro be prone to error after the use for a certain amount of time due to wear and tear of bearings and such, how would you know if there is an error ?
Hehe, I collected almost 100 indicators last year. (Don't tell my wife.) ;-) I planned to document all of them. Since spare time is rare and there's a lot to do, the process takes time. But eventually the information will be shared. Usually I write articles with photo's, but since the large audience for avionics on UA-cam I inteded to make more video's. Since this is different than articles I have to optimise the wya of publishing video's though. ;-) Thans for our enthousiasm!
So ist requires you to be level when resetting? So that would mean that should it lose power during flight it basically be impossible to get it working correctly again in-flight (unless you calibrate it against a second one)
In an ideal world you want indeed a level plane for a perfect reset. This standby gyro is therefore started directly (and later caged/resetted) at startup of the airplane when it's still leveled. Whe power is lost nothing serious happens as long as the primary horizon still works. Ok, it loses it's orientation, but it's not used unless the primary horizon fails. If it loses power for a long time, the orienation is lost. (The default position is a vertical horizon to indicate clearly that the reading is wrong and there is some malfunctuon or the horizon is not caged/reset yet.) Is power is back again and the plain flies straight ahead (what is probably does most of the time), the gyro is caged and the orientation is restored. There might be a little offset, but that won't affect the use of the instrument. If there's a significant pitch/roll during caging, the reading is wrong after caging. The likelyhood that the back up system fails also is rather small since the instrument is very basic. It's just a 'motor and some gears'. The chance the primary system fails and if the secondary system fails ánd the visibility is poor, is rather small. Luckily. 😅
@@TheStiepen Yes, there's a lot of information 'missing'. This video was just a simple test of the gyro. I never thought this video took of witch such amount of views! So this motivates to make other (better) video's. ;-) I wrote an article with additional photo's and related information here: polytech.nu/index.php?artikel=499
Thats true. The idea is that there's a heavy weight spinning realy fast in the midde of the gimbals. Tue to the spinning, the spinning weight don't want to change it's direction of the axis. So you created a reference. When the outer shell rotates, the gimbal axis rotation is used to display the horizon's position. 😎
This is de 'all in one' package. The limitation is that the 'zeroing' has to be done manually and there's no derived signal for other instruments. But it's self correcting, rather small and doen't need 400 Hz power. More high end systems hve the indicator and gyro connected by wires. Mainly using resolvers/synchro's via a 400 Hz connection. A bigger and more complex gyro can be used and more instruments can be controlled. Even an error feedback system can be used to compare the real gyro position and the real indicator position. The system is therefore more reliable, but also bigger andmore expensive. Usually high end planes like fighter and big airliners use the seperate indicstor and gyro system. The all in one package is usually for more simple planes. (One exception is for example the Panavia Tornado fighter jet. That plane has the ADI42 all in on horizon.)
I've got a very similar unit from an Airbus - the pinout is the same and the PCBs look very similar. When I put 28V on the flag disappears but then reappears very quickly and the motor doesn't start. Am.i right in assuming the motor in yours is 28v or is the voltage stepped up?
The device is powered by 28VDC. There's an electronics circuit that likely creates a three phase signal for powering the motor. I haven't measures the motor voltage/frequency. It could be possible that the voltage is stepped up to 115VAC for example since this is a common voltage for gyroscope motors. I think your device needs some service if the motor doesn't start and is a 28VDC version. Some broken components may be there...
That's a huge editing mistake makijg the video. 😉😎🙈 Originally the text was copied from a 200 VAC 400 Hz three phase video. I can't change this anymore unfortunately. ☺
The fact that the pilot can see they're losing altitude means they knows that his standby is not correct. By referencing the altimeter and the vertical speed indicator, and making sure those is no change, they can then reset their standby artificial horizon.
See the video comment: "Note: There's '28VDC single phase' mentioned, this should be '28VDC' since direct current has no phase shift. Oopsie. This is an editing mistake."
Hi, I have purchased a JET Horizon Indicator model A1 804 and later a SFEN power unit but do not have the pin outs. Can you help with the wiring pin outs ? Cheers
Well, documentation of these devices is very hard to find, so reverse engineering is needed... This is rather hard to do remotely but I can help maybe with some ideas. If there's a (toroid) transformer in the intrument, the instrument is probably fed with one or three phase AC power. Measure where the resistance is low/(near)zero between the connector pins and the connections of the transformer. If there is one winding, the device is fed with a single phase 400 Hz signal. First try 28VAC and increase the voltage to 115VAC depending on the device's reaction. Of there are three of four wires connected between the transformer and the conector, the device is probably fed with 400Hz three phase (120 degrees apart) power. Also start with 28VDC and increase to 115VAC depending on the reaction. If there is no (toroid) transformer, the device is probably fed with a DC voltage. Look for the biggest electrolytic capacitor (in the rear of the instrument). It's likely that this capacitor is the buffer capacitor for the incomming power. It's likely that the voltage is 28VDC. I think this helps, but remind that some electronics experience is needed for reviving these 'obscure' devices. (I'm certainly not an expert, but it's also a lof of learning by doing.) Update: I found the type plate of the JET A1 804. The needed power is 115VAC 400Hz three phase. So the information above is not that relevant anymore. ;-) The trick is to find three pins with the same mutual (rather low) resistances. And there will be probably/maybe a pin with the same mutual resistance between this and the other three pins. This is de neutral pin. You need a three phase 400Hz 115VAC power supply for activating the device. If you're lucky, a single phase 115VAC 400Hz supply (with an extra capacitor for phase shifting) will work also. The capacitor value is a matter of some experimenting. Follow the test setup as shown here: ua-cam.com/video/5eD8IkY5TII/v-deo.html For testing I didn't use the inductor in the schematic... These 28VDC instruments are luckily much easier. :-D I try to revive a Tornado MRCA TV TAB display unit that needs 115VAC+N 115VAC 400Hz and 28VDC. :-$ Avionics is more complex than regular electronics.
I bought this one via eBay. If you look long enough, nice stuff appears someday. It works also on 24 VDC. Although, the maximum speed of the gyro is a little bit less. Usually 28VDC avionics equipment works also on 24VDC in real life.
I did some measurements, but untill now I don't know what the other pins are used for. The gyro motor and illumination are powered by the two 28 VDC pins. Although the backlight is not working since two incandeacent bulbs are broken. I still have to fix that... The function could be determined by the full reverse engineering of the pcb, but I haven't planned this yet. I can imagine that one or two pins are used to confirn that the gyro is op to speed.But this is an educated guess since I don't have documentation os this device.
I want to use it for a car, will the degrees and inclination be seen graphically well without connecting the 28 vdc for a long time? Is it mandatory to use the gyro motor?
Expect that the drift without power will happen after one or two minutes, so unpowered operation is not practical. My advise is using a standard DC/DS step up converter to obtain 28VDC (or 24VDC) from the 13,8VDC battery voltage. Don't expect much movement of the horizon unless you want to go offroad. A car moves primerely around it's vertical axes, so not that much roll and pitch. For offroading the view will be interesting! For a regular street car a directional gyro instrument will be much more interesting. I wonder wat your intentions are for the project. ;-)
@@polytech_nu Hi, good afternoon. Thank you very much for your prompt response. I want to use it for a supermarket cart powered by a 36 vdc scooter motor, it is modified for any terrain but I have a problem, I need to know the front inclination (up, down) to increase or decrease the speed of the motor when necessary necessary for a great battery efficiency and can travel more km. The lateral inclination (left and right) is necessary when I have heavy loads, the cart tends to tip over very easily and with the artificial indicator I can foresee any accident 
@@carlosenciso8036 I think using such a artificial horizon wouldn't be my choise. This instrument has only a visual output and no electronic output. A 'vertical gyrosope' has a synchro or resolver output that may be more convenient. But my choise would be a simple 'Arduino gyro' board. That's an electronic gyro. It's small, cheap, has an output for simple electronics. Ok, a mechanical gyro is way cooler, but for your purpose a cheap Arduino gyro is probably the way to go.
Yes. To be precise, the gyro stays in the same orientation but due to the earth's rotation the position relative to the earth changes. This gyroscope can drift to it's home position over time due to the self balancing weight on top of the gyro center. The drift is (luckily) very slow. If a gyroscope (with a self balancing mechanism) is placed upside down, after a while the gyro will drift to 'normal' position due to the self correcting mechanism affected by gravity. Since a plane is usually flying straight forward, the self correcting mechanism doesn't affect the reading. Well, the curvature of the earth is 'corrected' to get a good reading. If a plane would fly upside down for a very long time, the gyroscope will drift to it's 'normal' position and the reading would be eventually wrong. Under normal circumstances this wouldn't affect the usability. In fact, if there was no self correction of a long time, the horizon would be upside down eventually when flying halfway around the earth. So the curvature of the earth is a much smaller challenge... The trick is that there's a weight on top of the gyroscope that can move around the axis for a certain angle. There's a second movable part that can limit the angle of movement of the weight. In upright position, the weight is rotating slowly and therefore the weight pulls the gyroscope in every direction. This means that the gyroscope is vertical as desired. If the gyro is not perfectly centred, the weight stays a little bit longer at the highest point. Therefore the gyro is pulled slightly to one side until the gyroscope axis is perpendicular to the gravity to the earth.
I have had one of these in a storage box for a while now, It came from a Boeing 747-400 and would love to see it working again, Are you using an inverter to power this? Great video by the way!
The price may vary a lot. In A condition with documentation the price is probably €900...€2.220. But you may be lucky to find a used one for approximately €200.
Unfortunately I haven't the equipment to measure/determine the exact speed. The higher the speed is, the more stable the gyroscope is. Usually the speed is between 10.000 and 22.000 rpm.
I wonder, can AI handle loop maneuver (aka deathloop) ? Then I did stright loop on Cessna in flight simulator attitude indicator suddenly become broken (hanged in inverted bank and stopped responding to actual attitude). As I understand, it was simulation of actual malfunction.
This model can handle an infinite roll, but limited pitch. The maximum is straight up and down. So a looping results in a loss of 'calibration'. When flying straight forward, the instrument can be reset again. This won't destroy the instrument but induces a spin or hitting the mechanical end stop. But more advanced horizons for fighter jets can handle loopings.
Cool! Luckily it's easier to find a 28 VDC power supply than a full flight deck. 😂 Note: Check the instrument before applying power. It's possible that the instruments need 115VAC 400 Hz or even three phase 200 VAC 400 Hz...
Yes, I’ll check it. I seem to recall though that this being a STBY instrument it’s powered by the aircraft HOT Battery Bus in case of total generator failure or loss of all three engines. Thats why you could hear it spinning up as soon as main battery power was put on the aircraft. I have the primary ADI’s as well but they are driven by the ring lasers via the black boxes so they don’t function the same way as the STBY attitude indicator seen here.
That's right. This gyro has a self correcting mechanism at the top. The balance weight slowly compensates drift. There are 'split' horizons where the gyro is mechanically separated and there's only a electrical link. The instrument is only an indicator and the gyro is located elsewhere. These type of gyro's have usually a 'reset mechanism'. My applying some signal, the (starting) gyro is pulled to it's default position.
German bombers also had gyro powered navigational instruments. When British soldiers approached crashed bombers, they mistook the spooling-down Gyros for ticking time bombs. So they got German pilots to "defuse" their bombs lol.
I'm not sure. But these instruments have high RPM's. I expect 10.000+ rotations per minute. I want to write an article about this instrument and than I want to make a measurement on the three phase signal to determine the rotation speed. Untill then it's guessing for me...
Гироскоп очень сильная вещь, его невозможно обмануть, всегда показывает правильное положение, даже если ты этого не хочешь, всё равно он будет это показывать.
A gyroscope can drift to it's home position over time. The drift is (luckily) very slow. I a gyroscope is placed upside down, after a while the gyro will drift to 'normal' position due to the self correcting mechanism affected by gravity. Since a plane is usually flying straight forward, the self correcting mechanism doesn't affect the reading. Well, the curvature of the earth than the self correcting system so the horizon is always matching with the curvature of the earth. If a plane would fly upside down for a very long time, the gyroscope will drift to it's 'normal' position. Under normal circumstances this wouldn't affect the usability. In fact, if there was no self correction of a long time, the horizon would be upside down eventually when flying halfway around the earth. So the curvature of the earth is a much smaller challenge...
A gyroscope can drift to it's home position. The drift is (luckily) very slow. If a gyroscope is placed upside down, after a while the gyro will drift to 'normal' position due to the self correcting mechanism affected by gravity. Since a plane is usually flying straight forward, the self correcting mechanism doesn't affect the reading. If a plane would fly upside down for a very long time, the gyroscope will drift to it's 'normal' position. Under normal circumstances this wouldn't affect the usability. In fact, if there was no self correction of a long time, the horizon would be upside down eventually when flying halway around the earth. Update: I planned to do the experiment to see how long it takes to autocorrect the horizon, but this video has to me made yet... But someone else did this exeriment already: ua-cam.com/video/kTXTCqMHyhg/v-deo.html
I'm not sure. But these instruments have high RPM's. I expect 10.000+ rotations per minute. I want to write an article about this instrument and than I want to make a measurement on the three phase signal to determine the rotation speed. Until then it's guessing for me...
This gyroscope can drift to it's home position over time due to the self balancing weight on top of the gyro center. The drift is (luckily) very slow. If a gyroscope (with a self balancing mechanism) is placed upside down, after a while the gyro will drift to 'normal' position due to the self correcting mechanism affected by gravity. Since a plane is usually flying straight forward, the self correcting mechanism doesn't affect the reading. Well, the curvature of the earth is 'corrected' to get a good reading. If a plane would fly upside down for a very long time, the gyroscope will drift to it's 'normal' position and the reading would be eventually wrong. Under normal circumstances this wouldn't affect the usability. In fact, if there was no self correction of a long time, the horizon would be upside down eventually when flying halfway around the earth. So the curvature of the earth is a much smaller challenge... The trick is that there's a weight on top of the gyroscope that can move around the axis for a certain angle. There's a second movable part that can limit the angle of movement of the weight. In upright position, the weight is rotating slowly and therefore the weight pulls the gyroscope in every direction. This means that the gyroscope is vertical as desired. If the gyro is not perfectly centred, the weight stays a little bit longer at the highest point. Therefore the gyro is pulled slightly to one side until the gyroscope axis is perpendicular to the gravity to the earth.
THAT IS SO COOOL DUDE... I DONT EVEN CARE WOT ITS USED 4....LOL... ITS JUST A MARVERLAS BIT OF AIR PLANE .. AND LOOKS VERY INPORTANT,,, I JUST LIKE THIS VIDEO... GOOD WORK,,, AND I LOVE THE FACT THAT PEOPLEL.. PUT THIS OUT THERE,,,, COZ I WOULD OF NEVER SEEN IT... IN MOTION..OUT OF A PLANES COKPIT..... THANK U,,,,BTW
Nice to read that the videois well received! 😎 This is a so called standby artificial horizon. This is the most important navigation instrument for and airplane. If the regular (more advanced) navigation instruments fail, this is a standby backup instrument.
By pulling the knob the default state is obtained. In that case the gyro is caged and forced to the upright position. the result is that the displayed horizon is matching with the real horizon. Remind that this reset has to be done when the plane is on the ground to prevent a wrong reading.
There are several for sale on eBay. Remind that there are also 115 VAC 400 Hz versions. Usually the standby horizon like this one is powered by 28 VDC. Also check is there's a cage knob at the front. If there's no cage knob, the instrument is a 'repeater'. That means that there's no gyro built in and an external gyroscope is needed. So check the needed power and the reset knob before buying...
Why? I can imagine that there's an extra force on the bearings, but the bearings should be able toe handle this. All the automated gyro systems are caged when spinning up: ua-cam.com/video/QjmO9-8EApE/v-deo.html
@@polytech_nuexactly. Best maintenance practice is to cage it before power up so you aren’t forcing it into place. I can’t comment on how an automated gyro cages I’ve never (knowingly) used one but experience would tell me that it cages before spin up.
Hehehe, jeps, oopsie... The original text was '115 VAC single phase' and I forgot to change that part. I made this video on the couch om nu phone in half an hour for fun and I didn't expect this nuber of views. 😅 I'll try to be more carefull editing video's in the future.☺
The inner working is very simple. There's a rather heavy core that spins very fast. Due to the rotation, you need a lot of force displacing the core axis. Like a motorcycle wheel that becomes much harder to stear at higher speeds. The core is mounted in a gimbal so the instrument can rotate in almost every direction and the core axis stays 'always' in the same orientation. The graphical representation is obtained by linking cogs that are connected to the gimbal. When the gimbal moves, the display moves also.
The gyro core spins very fast, but is fully enclosed so that's no risk. The slow spinning weight is a larger risk. There are gears connecting the gyro core to the slow rotating weight. The result is that the wirht spins slow, but the force is large! So you don't want to stick your fingers in there...
The device isn't broken so there's no use of repairing it. And the video title is that this is a test of the instrument, not a repair video. The video is to show the inner mechanics of the instrument. I wanted to share the beauty of the working and design of the instrument. And it looks like 300.000+ other viewers agree with me. 😅
If the earth were a globe or round ball, an airplane taking off from Germany, should then dip its nose quite often to eventually go land down under in Australia upside down! When an airplane takes off, you feel the pitch, when we go in for landing, you feel the pitch downwards, but not once on an 10 hour flight you feel a slight pitch downwards?????! Like the saying goes, it is easier to fool somebody than to convince him that he has been fooled! Love the proof in that spinning Gyro!!
The earth is (approximately) a round ball. The circumference of the earth is approximately 40.000km. If you start flying parallel to the earth for approximately 111,2 km (one degree of the circumference of the earth) in a straight line, you'll end up approximately 4,548 higher then where you started. So if you follow the curvature of the earth and fly parallel to the earth's surface (like a regular flight), after flying 111,2 km your descent is approximately 2,3 degrees. So in theory during a flight there is a constant small pitch down to follow the earth's curvature. Since this pitch is constant, it isn't felt as a pitch downwards but in can in theory be felt as a slight lower gravitational force. But this is expected to be so small that it isn't detected by human senses. During take off the pitch can be even 15 degrees over a much shorter distance and therefore be felt much better. Concerning the gyro: Gyro's tend to drift. If you have a gyroscope placed on a fixed surface of the earth, the gyroscope will drift due to the earth's rotation. So if you fly to the other side of the earth, the horizon can be presented upside down for example. To prevent this unwanted drift, a correction is needed.This gyro has a self correcting mechanism at the top. The balance weight slowly compensates drift. The weight is due to gravity always a little bit longer at one side pulling the gyro upright. This correction is very small, slowly and is based on the idea that the airplane/vertical gyro axis flies most of the time perpendicular to the earth's surface. If the gyro axis is perpendicular to the gravity, the weight doesn't shift and the gyro axis is therefore not corrected. There are also 'split' horizons where the gyro is mechanically separated and there's only a electrical link. The instrument is only an indicator and the gyro is located elsewhere. These type of gyro's have usually a 'reset mechanism'. By applying some signal, the (starting) gyro is pulled to it's default position. I made a video about the initial auto correct here: ua-cam.com/video/QjmO9-8EApE/v-deo.html. In this case spirit levels and torque motors are used as sensors and actuators to control the startup position of the gyro. You started the comment with: "If the earth were a globe..." This implies that you think that the earth is not a sphere. In that case there's almost nothing I can do for you... My only advice would be to test this using a gyro without the automatic drift correction. Take a gyro and fly to the other side of the world. If the earth is a sphere, there will be drift. If the earth is flat, the gyro will indicate everywhere the same position no matter where you travel to. Oh yeah, and beware of flying over the edge... ;-)
@@polytech_nuyeah there is nothing that can be done to help this guy, he’s a flat earther or what we call a “Flerfer”. He truly believes that the ENTIRE REST OF THE WORLD has been fooled while HE knows the truth. It’s ridiculous
The spinning weight is for self leveling the gyroscope. If the gyroscope is too much to one side, a bracket is lifted so the weight is blocked. The result is that the weight is always the longest to the highest side of the gyroscope. The weight pulls the gyro very very slightly down due to the unbalance by the weight. So if the gyroscope core drifts, this weight corrects this drift. This is only used on high quality gyroscopes where the gyro is built into the instrument itself like the ADI42. Note that the effect of this self balancing weight is only noticable on a long term scale.
Every pilot or enthusiast learns how this instrument works through the gyroscope, but I never got to visualize it how. Thanks for showing
Glad to hear that the video is appreciated! I never thought this video would get this much attention. It was just a insyrument/video experiment for me. This also motivates to make more such video's.
i came down here to write the same thing. yes obiousliy it's coupled to a gyro... but especially seeing the manual reset progress really helped me to fully grasp the mechanical working.
and here i thought the sound was the planes engines spooling up, and it was the gyro the whole time.
Hehe, gyro's and 400 Hz avionics are indeed noisy!
@@polytech_nugotta love that 400hz whine, music to my ears not even kidding
Its a very interesting startup but still a wicked looking piece of tech, never thought this is how it would function with the error checking too
I love this old tech. I do guided stuff for a living, so these days we use MEMS magnetometer, gyro, and accelerometer to provide our inertial platform. But there's nothing to see, the two devices together are the size of a grain of rice. I'd love to have one of these, but I'd rather rely on electronics when my life depends on it.
Hehe, the technology is indeed improving luckily. But old tech is nice to discover. Like mechanical calculators that can integrate. Old stuff, but very wel thought trough and very well built. 😎
Amazing piece of machinery
Love the mechanics of it
I repair and overhaul sfena gyros like this. They all have the same distinctive sound when you power them on!
Fun way of levelling your shelves
Honestly, I had never thought about how these worked. Thank you for showing me, this is fascinating.
The picture of the back explains why it was slightly off sitting on the bench.
Thank you.
Indeed. Sometimes the know can also be rotated to send the marker up and down, but this one is fixed. Therefore the angle is given. 👍
Very nice instrument. It looks like the algorithm is recommending your video
Haha, indeed! It' fun to see the comments and subscriptions pour in. 😎
Indeed it is and im glad
@@Maxikxng yes, there are only a few people (including myself) on this platform that makes videos about av avionics. It’s a very small niche.
@@Maxikxng Same, there are only s few avionics channels including mine
Do you think it makes that noise inside the cockpit?
Yes. Avionics is quite noisy. Well, when the housing is installed the noise is less, but still rather good to hear. Also 400Hz instruments have usually 400Hz servo loops built in that makes the well known 400Hz hum. So the avionics bay and a cockpit is rather noisy. The good thing is that the noisy gyro's nowadays are in the avionics bay and the indicators are displays. So the noisy servo loops are not needed anymore. Probably the only noisy instrument is this type of back up horizon.
@@polytech_nuhopefully when you're in the air you're never able to hear them haha.
Simple amazed how our human brain is smart. How could someone be capable of creating such things. Unbelievable
That's true! I'm a mechanical engineer and even after years I'm still amazed how these precision masterpieces are designed and made. Eventually it's a crude physics principle that's used in it's raw form.
I'm also busy trying restarting a Honeywell/Sperry 311 vertical gyroscope. (www.polytech.nu/index.php?artikel=440) My main concern is how to build a powerful enough 115 VAC 400 Hz power supply... The gyroscope is even a more spectacular masterpiece. There is some 'simple' electronics for managing the device. At power on the gyro is brought to it's start position for example. Even more interesting is that it you're flying a long time straight ahead, there is a correction for the earth curvature. (Otherwise the horizon would be upside down at the other end of the world...) A video will follow when the power supply is ready. ;-)
yes, it's not invented by black peoples
@@polytech_nuthe PSU you buy
A committee of different engineers: electrical, mechanical, aerospace and possibly physicists to my knowledge amongst other things
It's not that complicated tbh, the early missile guidance systems really amaze me tho
This is really cool. Thanks for sharing this. I'm curious if it would remain it it's current position as the earth turns or will it drift as time goes by? Again, great stuff.
it signal the up and down , doesnt matters if the earth is turning
A gyroscope can drift to it's home position. The drift is (luckily) very slow. I a gyroscope is placed upside down, after a while the gyro will drift to 'normal' position due to the self correcting mechanism affected by gravity. Since a plane is usually flying straight forward, the self correcting mechanism doesn't affect the reading. If a plane would fly upside down for a very long time, the gyroscope will drift to it's 'normal' position. Under normal circumstances this wouldn't affect the usability. In fact, if there was no self correction of a long time, the horizon would be upside down eventually when flying halway around the earth.
Update: I planned to do the experiment to see how long it takes to autocorrect the horizon, but this video has to me made yet... But someone else did this exeriment already: ua-cam.com/video/kTXTCqMHyhg/v-deo.html
@@Thebasicmaker Not accurate. Precession (the Earth turning) is a problem for the artificial horizon. Old versions of it had a weight in the bottom of the device to keep it level, these days it has pendulous veins to compensate for the Earth turning and traveling over the curve. The mechanism is necessary for the artificial horizon to work correctly, otherwise it would drift out of true as the Earth turned or you traveled over its surface.
What is the purpose of the two weights that are flopping around in it?
The weight is used as an auto correct to send the gyro axis perpendicular to the earth's surface. If this 'auto correct' is not in place, the gyro is eventually upside down when flying to the other side of the world. The desired situation is that the horizon is represented, so while flying long distances the gyro is corrected to 'follow' the earths curvature.
- The rotation of the weight is mechanically derived from the gyro motor rotations by using a 'gearbox'.
- The weight is off center, so the weight is 'pulling' to send the gyro axis perpendicular to the gravity axis. Due to the gyroscopic effect the movement is very slow.
- If the gyro axis is perpendicular to the gravity axis of the earth, the mean position of the movable weight is centred.
- If the gyro axis is NOT is perpendicular to the gravity axis of the earth, the weight stays a little bit longer at one side of the gyro axis. The result is that the gyro axis is pulled every weight rotation a little bit to send the gyro axis upright.
Since the 'auto correct' is very slow, the short time effect is negligible. By 'pitching and rolling' the offset dus to the 'auto correct' is nil.
The (very) long term effect is that the gyro is always sent upright eventually.
Practically an airplane flies most of the time 'straight forward'. When following the curvature of the earth, the 'auto correct' matches the 'error' introduced by the earths curvature. The long term result is that the horizon stays level when flying around the earth when flying most of the time straight forward. If the airplane 'pitches and rolls', there will be a very small error introduced due to the 'auto correct'. This is very minor.
@@polytech_nu wow thank you for the very detailed answer!
@@DoRC Glad I could help! (This reminds me also to finally write an article about this nice device for my website www.polytech,nu.) ;-)
How does it deal with the curvature of the earth?
A gyroscope can drift to it's home position over time. The drift is (luckily) very slow. I a gyroscope is placed upside down, after a while the gyro will drift to 'normal' position due to the self correcting mechanism affected by gravity. Since a plane is usually flying straight forward, the self correcting mechanism doesn't affect the reading. Well, the curvature of the earth than the self correcting system so the horizon is always matching with the curcature of the earth. If a plane would fly upside down for a very long time, the gyroscope will drift to it's 'normal' position. Under normal circumstances this wouldn't affect the usability. In fact, if there was no self correction of a long time, the horizon would be upside down eventually when flying halway around the earth. So the curcature of the earth is a much smaller challenge...
I planned to do the experiment to see how long it takes to autocorrect the horizon, but this video has to me made yet... But someone else did this exeriment already: ua-cam.com/video/kTXTCqMHyhg/v-deo.html
Pendulous vanes
I want one of these just as a memo from my training (since most modern airplanes are digital now and training airplanes usually use these), where could I get one! I love the system :), Also, is there a way I could get one that works (the gyro)?
Gotta love Gyro and Gyro Precession!🎉
I didn't know it had a gyroscope, I thougt it used a weight (but thinking of accelerations maybe a weight is not a good Idea)
The idea of a weight isn't that bad. In fact, if the plane was not affected by forces (other than gravity), a pendulum with a weight would work for a directional gyroscope. But since a weight at the end of a pendulum is affect by forces due to increasing and decreasing speed, the result isn't usable. The gyroscope is 'steady' in space, like a pendulum only affect by gravity. ;-)
I would love to understand what purpose those loose pieces serve as it spins around. I assume some sort of drift correction?
I‘d be interested about it as well
Maybe it is the pendulus vanes. They dont rotate at the gyros speed, and they seem to have an effect only if the gyro is not vertical, that's why....
This gyroscope can drift to it's home position over time due to the self balancing weight. The drift is (luckily) very slow. If a gyroscope is placed upside down, after a while the gyro will drift to 'normal' position due to the self correcting mechanism affected by gravity. Since a plane is usually flying straight forward, the self correcting mechanism doesn't affect the reading. Well, the curvature of the earth than the self correcting system so the horizon is always matching with the curvature of the earth. If a plane would fly upside down for a very long time, the gyroscope will drift to it's 'normal' position. Under normal circumstances this wouldn't affect the usability. In fact, if there was no self correction of a long time, the horizon would be upside down eventually when flying halfway around the earth. So the curvature of the earth is a much smaller challenge...
Pendulous vanes are associated with vacuum driven gyros. They alter the airflow coming out of the gyro. Electronic gyros use electrical sensing of some sort to figure out the local vertical.
Will this gyro be prone to error after the use for a certain amount of time due to wear and tear of bearings and such, how would you know if there is an error ?
This is so cool. Now please show us the inside of Turn coordinator and VS indicator🤓
Hehe, I collected almost 100 indicators last year. (Don't tell my wife.) ;-) I planned to document all of them. Since spare time is rare and there's a lot to do, the process takes time. But eventually the information will be shared. Usually I write articles with photo's, but since the large audience for avionics on UA-cam I inteded to make more video's. Since this is different than articles I have to optimise the wya of publishing video's though. ;-) Thans for our enthousiasm!
So ist requires you to be level when resetting? So that would mean that should it lose power during flight it basically be impossible to get it working correctly again in-flight (unless you calibrate it against a second one)
In an ideal world you want indeed a level plane for a perfect reset. This standby gyro is therefore started directly (and later caged/resetted) at startup of the airplane when it's still leveled.
Whe power is lost nothing serious happens as long as the primary horizon still works. Ok, it loses it's orientation, but it's not used unless the primary horizon fails.
If it loses power for a long time, the orienation is lost. (The default position is a vertical horizon to indicate clearly that the reading is wrong and there is some malfunctuon or the horizon is not caged/reset yet.) Is power is back again and the plain flies straight ahead (what is probably does most of the time), the gyro is caged and the orientation is restored. There might be a little offset, but that won't affect the use of the instrument. If there's a significant pitch/roll during caging, the reading is wrong after caging.
The likelyhood that the back up system fails also is rather small since the instrument is very basic. It's just a 'motor and some gears'. The chance the primary system fails and if the secondary system fails ánd the visibility is poor, is rather small. Luckily. 😅
@@polytech_nu ah, I was missing the context that this is a backup system!
@@TheStiepen Yes, there's a lot of information 'missing'. This video was just a simple test of the gyro. I never thought this video took of witch such amount of views! So this motivates to make other (better) video's. ;-) I wrote an article with additional photo's and related information here: polytech.nu/index.php?artikel=499
@@polytech_nu I'll have to check that out later, definitely a fascinating piece of technology.
So it's got like a flywheel or something in it that needs charged up basically?
Thats true. The idea is that there's a heavy weight spinning realy fast in the midde of the gimbals. Tue to the spinning, the spinning weight don't want to change it's direction of the axis. So you created a reference. When the outer shell rotates, the gimbal axis rotation is used to display the horizon's position. 😎
Cool device!! First time I see an AH naked.
Me as well, didn't realize they were so big.
It's not just a screen, it's a whole damn Unit 😳
Indeed. There's some magic behind the display. ;-)
Thanks for video 👍 ( good construction idea, one frame for gyro and second for dial ). Two separate mechanism I think.
This is de 'all in one' package. The limitation is that the 'zeroing' has to be done manually and there's no derived signal for other instruments. But it's self correcting, rather small and doen't need 400 Hz power. More high end systems hve the indicator and gyro connected by wires. Mainly using resolvers/synchro's via a 400 Hz connection. A bigger and more complex gyro can be used and more instruments can be controlled. Even an error feedback system can be used to compare the real gyro position and the real indicator position. The system is therefore more reliable, but also bigger andmore expensive. Usually high end planes like fighter and big airliners use the seperate indicstor and gyro system. The all in one package is usually for more simple planes. (One exception is for example the Panavia Tornado fighter jet. That plane has the ADI42 all in on horizon.)
What's 28V DC SINGLE PHASE? DC has no phases or frequencies.
I've got a very similar unit from an Airbus - the pinout is the same and the PCBs look very similar. When I put 28V on the flag disappears but then reappears very quickly and the motor doesn't start. Am.i right in assuming the motor in yours is 28v or is the voltage stepped up?
The device is powered by 28VDC. There's an electronics circuit that likely creates a three phase signal for powering the motor. I haven't measures the motor voltage/frequency. It could be possible that the voltage is stepped up to 115VAC for example since this is a common voltage for gyroscope motors. I think your device needs some service if the motor doesn't start and is a 28VDC version. Some broken components may be there...
Does it need 400 Hertz AC?
Very cool, but what is single phase DC?
That's a huge editing mistake makijg the video. 😉😎🙈 Originally the text was copied from a 200 VAC 400 Hz three phase video. I can't change this anymore unfortunately. ☺
Is it bad he tilted it twice and it started reading high, then a pilot in cloudy conditions would level off and lose altitide?
The fact that the pilot can see they're losing altitude means they knows that his standby is not correct. By referencing the altimeter and the vertical speed indicator, and making sure those is no change, they can then reset their standby artificial horizon.
What are the two rotating pieces on top of the giro for?
There is a technical wrong in description. "28VDC singe phase" DC current has not phase!
See the video comment: "Note: There's '28VDC single phase' mentioned, this should be '28VDC' since direct current has no phase shift. Oopsie. This is an editing mistake."
Hi, I have purchased a JET Horizon Indicator model A1 804 and later a SFEN power unit but do not have the pin outs. Can you help with the wiring pin outs ? Cheers
Well, documentation of these devices is very hard to find, so reverse engineering is needed... This is rather hard to do remotely but I can help maybe with some ideas. If there's a (toroid) transformer in the intrument, the instrument is probably fed with one or three phase AC power. Measure where the resistance is low/(near)zero between the connector pins and the connections of the transformer. If there is one winding, the device is fed with a single phase 400 Hz signal. First try 28VAC and increase the voltage to 115VAC depending on the device's reaction. Of there are three of four wires connected between the transformer and the conector, the device is probably fed with 400Hz three phase (120 degrees apart) power. Also start with 28VDC and increase to 115VAC depending on the reaction. If there is no (toroid) transformer, the device is probably fed with a DC voltage. Look for the biggest electrolytic capacitor (in the rear of the instrument). It's likely that this capacitor is the buffer capacitor for the incomming power. It's likely that the voltage is 28VDC. I think this helps, but remind that some electronics experience is needed for reviving these 'obscure' devices. (I'm certainly not an expert, but it's also a lof of learning by doing.)
Update: I found the type plate of the JET A1 804. The needed power is 115VAC 400Hz three phase. So the information above is not that relevant anymore. ;-) The trick is to find three pins with the same mutual (rather low) resistances. And there will be probably/maybe a pin with the same mutual resistance between this and the other three pins. This is de neutral pin. You need a three phase 400Hz 115VAC power supply for activating the device. If you're lucky, a single phase 115VAC 400Hz supply (with an extra capacitor for phase shifting) will work also. The capacitor value is a matter of some experimenting. Follow the test setup as shown here: ua-cam.com/video/5eD8IkY5TII/v-deo.html For testing I didn't use the inductor in the schematic... These 28VDC instruments are luckily much easier. :-D I try to revive a Tornado MRCA TV TAB display unit that needs 115VAC+N 115VAC 400Hz and 28VDC. :-$ Avionics is more complex than regular electronics.
how did you get one? also does it work on 24dv too?
I bought this one via eBay. If you look long enough, nice stuff appears someday. It works also on 24 VDC. Although, the maximum speed of the gyro is a little bit less. Usually 28VDC avionics equipment works also on 24VDC in real life.
Do you know what other pins of connector are used for? I guess it can be backlight or sth
I did some measurements, but untill now I don't know what the other pins are used for. The gyro motor and illumination are powered by the two 28 VDC pins. Although the backlight is not working since two incandeacent bulbs are broken. I still have to fix that... The function could be determined by the full reverse engineering of the pcb, but I haven't planned this yet. I can imagine that one or two pins are used to confirn that the gyro is op to speed.But this is an educated guess since I don't have documentation os this device.
Just beautiful.
I want to use it for a car, will the degrees and inclination be seen graphically well without connecting the 28 vdc for a long time? Is it mandatory to use the gyro motor?
Expect that the drift without power will happen after one or two minutes, so unpowered operation is not practical. My advise is using a standard DC/DS step up converter to obtain 28VDC (or 24VDC) from the 13,8VDC battery voltage.
Don't expect much movement of the horizon unless you want to go offroad. A car moves primerely around it's vertical axes, so not that much roll and pitch. For offroading the view will be interesting! For a regular street car a directional gyro instrument will be much more interesting.
I wonder wat your intentions are for the project. ;-)
@@polytech_nu Hi, good afternoon. Thank you very much for your prompt response. I want to use it for a supermarket cart powered by a 36 vdc scooter motor, it is modified for any terrain but I have a problem, I need to know the front inclination (up, down) to increase or decrease the speed of the motor when necessary necessary for a great battery efficiency and can travel more km. The lateral inclination (left and right) is necessary when I have heavy loads, the cart tends to tip over very easily and with the artificial indicator I can foresee any accident

@@carlosenciso8036 I think using such a artificial horizon wouldn't be my choise. This instrument has only a visual output and no electronic output. A 'vertical gyrosope' has a synchro or resolver output that may be more convenient. But my choise would be a simple 'Arduino gyro' board. That's an electronic gyro. It's small, cheap, has an output for simple electronics. Ok, a mechanical gyro is way cooler, but for your purpose a cheap Arduino gyro is probably the way to go.
Souvenirs, j’en ai dépanné quand je travaillais à SFENA/DAV en 1975/1976.Ca ne me rajeunit pas !
Merci pour cette vidéo.
Thankt for your story! 👍
Will it drift due to the earths rotation?
Yes. To be precise, the gyro stays in the same orientation but due to the earth's rotation the position relative to the earth changes.
This gyroscope can drift to it's home position over time due to the self balancing weight on top of the gyro center. The drift is (luckily) very slow. If a gyroscope (with a self balancing mechanism) is placed upside down, after a while the gyro will drift to 'normal' position due to the self correcting mechanism affected by gravity. Since a plane is usually flying straight forward, the self correcting mechanism doesn't affect the reading. Well, the curvature of the earth is 'corrected' to get a good reading. If a plane would fly upside down for a very long time, the gyroscope will drift to it's 'normal' position and the reading would be eventually wrong. Under normal circumstances this wouldn't affect the usability. In fact, if there was no self correction of a long time, the horizon would be upside down eventually when flying halfway around the earth. So the curvature of the earth is a much smaller challenge...
The trick is that there's a weight on top of the gyroscope that can move around the axis for a certain angle. There's a second movable part that can limit the angle of movement of the weight. In upright position, the weight is rotating slowly and therefore the weight pulls the gyroscope in every direction. This means that the gyroscope is vertical as desired. If the gyro is not perfectly centred, the weight stays a little bit longer at the highest point. Therefore the gyro is pulled slightly to one side until the gyroscope axis is perpendicular to the gravity to the earth.
I have had one of these in a storage box for a while now, It came from a Boeing 747-400 and would love to see it working again, Are you using an inverter to power this? Great video by the way!
See 2:36. Pin B is the ground and pin D is +28VDC. No 400Hz inverter is needed. Just a simple DC power supply. +24VDC also works. 👍
@@polytech_nu Super, thanks for the helpful information! I will let you know how it goes!
The 748 uses a 400hz AC power source.
How much money to have in US dollars? Used is also not a problem
The price may vary a lot. In A condition with documentation the price is probably €900...€2.220. But you may be lucky to find a used one for approximately €200.
How fast does it need to spin?
Unfortunately I haven't the equipment to measure/determine the exact speed. The higher the speed is, the more stable the gyroscope is. Usually the speed is between 10.000 and 22.000 rpm.
I wonder, can AI handle loop maneuver (aka deathloop) ?
Then I did stright loop on Cessna in flight simulator attitude indicator suddenly become broken (hanged in inverted bank and stopped responding to actual attitude). As I understand, it was simulation of actual malfunction.
This model can handle an infinite roll, but limited pitch. The maximum is straight up and down. So a looping results in a loss of 'calibration'. When flying straight forward, the instrument can be reset again. This won't destroy the instrument but induces a spin or hitting the mechanical end stop.
But more advanced horizons for fighter jets can handle loopings.
@@polytech_nuIt's basically 180 degree on vertical...right?
@@The_Touring_Jedi Indeed. 90 degrees to straight up and 90 to straigth down. So 180 degrees pitch angle. (Roll infinite...)
Fantastic,thanks!
I love the gyroscope
Yes, but now turn it sideways. Does it precess?
I have an entire DC10 flight deck here with a couple of these lying around. Now to find a 28V DC Power supply
Cool! Luckily it's easier to find a 28 VDC power supply than a full flight deck. 😂 Note: Check the instrument before applying power. It's possible that the instruments need 115VAC 400 Hz or even three phase 200 VAC 400 Hz...
Yes, I’ll check it. I seem to recall though that this being a STBY instrument it’s powered by the aircraft HOT Battery Bus in case of total generator failure or loss of all three engines. Thats why you could hear it spinning up as soon as main battery power was put on the aircraft. I have the primary ADI’s as well but they are driven by the ring lasers via the black boxes so they don’t function the same way as the STBY attitude indicator seen here.
Awesome!! Probably prone to some error/drift right? I am guessing it doesn't self-correct from external nav?
That's right. This gyro has a self correcting mechanism at the top. The balance weight slowly compensates drift.
There are 'split' horizons where the gyro is mechanically separated and there's only a electrical link. The instrument is only an indicator and the gyro is located elsewhere. These type of gyro's have usually a 'reset mechanism'. My applying some signal, the (starting) gyro is pulled to it's default position.
Which phase of 28VDC is that again?
I made an editing mistake. The phase information should be removed. 🤐
German bombers also had gyro powered navigational instruments. When British soldiers approached crashed bombers, they mistook the spooling-down Gyros for ticking time bombs. So they got German pilots to "defuse" their bombs lol.
how fast is that thing spinnin?
I'm not sure. But these instruments have high RPM's. I expect 10.000+ rotations per minute. I want to write an article about this instrument and than I want to make a measurement on the three phase signal to determine the rotation speed. Untill then it's guessing for me...
I have this one from Fokker 100, perfect condition, would you like to buy ?
That may be interesting. Please contact me via polytech.nu/index.php?navid=4
Гироскоп очень сильная вещь, его невозможно обмануть, всегда показывает правильное положение, даже если ты этого не хочешь, всё равно он будет это показывать.
this is so cool
amazing!
Amazing ❤❤❤
Oh so its not the jet engines making that annoying sound lol
For what are the two flaps on the top of the gyro??
A gyroscope can drift to it's home position over time. The drift is (luckily) very slow. I a gyroscope is placed upside down, after a while the gyro will drift to 'normal' position due to the self correcting mechanism affected by gravity. Since a plane is usually flying straight forward, the self correcting mechanism doesn't affect the reading. Well, the curvature of the earth than the self correcting system so the horizon is always matching with the curvature of the earth. If a plane would fly upside down for a very long time, the gyroscope will drift to it's 'normal' position. Under normal circumstances this wouldn't affect the usability. In fact, if there was no self correction of a long time, the horizon would be upside down eventually when flying halfway around the earth. So the curvature of the earth is a much smaller challenge...
Very cool❤
Does it drift ?
A gyroscope can drift to it's home position. The drift is (luckily) very slow. If a gyroscope is placed upside down, after a while the gyro will drift to 'normal' position due to the self correcting mechanism affected by gravity. Since a plane is usually flying straight forward, the self correcting mechanism doesn't affect the reading. If a plane would fly upside down for a very long time, the gyroscope will drift to it's 'normal' position. Under normal circumstances this wouldn't affect the usability. In fact, if there was no self correction of a long time, the horizon would be upside down eventually when flying halway around the earth.
Update: I planned to do the experiment to see how long it takes to autocorrect the horizon, but this video has to me made yet... But someone else did this exeriment already: ua-cam.com/video/kTXTCqMHyhg/v-deo.html
I worked at fokker aircraft and overhauled/repaired these. Nice to see
Cool! Overhauling is a speciality I guess since the parts are very small and sensitive. I don't want to risk it overhauling one. :-D
A cuantas RPM gira eso?
I'm not sure. But these instruments have high RPM's. I expect 10.000+ rotations per minute. I want to write an article about this instrument and than I want to make a measurement on the three phase signal to determine the rotation speed. Until then it's guessing for me...
How it feels the Earth curvation?
Pendulous Vanes
This gyroscope can drift to it's home position over time due to the self balancing weight on top of the gyro center. The drift is (luckily) very slow. If a gyroscope (with a self balancing mechanism) is placed upside down, after a while the gyro will drift to 'normal' position due to the self correcting mechanism affected by gravity. Since a plane is usually flying straight forward, the self correcting mechanism doesn't affect the reading. Well, the curvature of the earth is 'corrected' to get a good reading. If a plane would fly upside down for a very long time, the gyroscope will drift to it's 'normal' position and the reading would be eventually wrong. Under normal circumstances this wouldn't affect the usability. In fact, if there was no self correction of a long time, the horizon would be upside down eventually when flying halfway around the earth. So the curvature of the earth is a much smaller challenge...
The trick is that there's a weight on top of the gyroscope that can move around the axis for a certain angle. There's a second movable part that can limit the angle of movement of the weight. In upright position, the weight is rotating slowly and therefore the weight pulls the gyroscope in every direction. This means that the gyroscope is vertical as desired. If the gyro is not perfectly centred, the weight stays a little bit longer at the highest point. Therefore the gyro is pulled slightly to one side until the gyroscope axis is perpendicular to the gravity to the earth.
THAT IS SO COOOL DUDE...
I DONT EVEN CARE WOT ITS USED
4....LOL...
ITS JUST A MARVERLAS BIT OF
AIR PLANE ..
AND LOOKS VERY INPORTANT,,,
I JUST LIKE THIS VIDEO...
GOOD WORK,,,
AND I LOVE THE FACT THAT PEOPLEL..
PUT THIS OUT THERE,,,,
COZ I WOULD OF NEVER SEEN IT...
IN MOTION..OUT OF A PLANES COKPIT.....
THANK U,,,,BTW
Nice to read that the videois well received! 😎 This is a so called standby artificial horizon. This is the most important navigation instrument for and airplane. If the regular (more advanced) navigation instruments fail, this is a standby backup instrument.
Instruments, instruments.. That’s the artificial horizon, which is better than the actual horizon…
...and why buy one if you can have two for just double the price... ;-)
Как он понимает нулевую точку? Чем определяется?
By pulling the knob the default state is obtained. In that case the gyro is caged and forced to the upright position. the result is that the displayed horizon is matching with the real horizon. Remind that this reset has to be done when the plane is on the ground to prevent a wrong reading.
where can I buy one one of them
There are several for sale on eBay. Remind that there are also 115 VAC 400 Hz versions. Usually the standby horizon like this one is powered by 28 VDC. Also check is there's a cage knob at the front. If there's no cage knob, the instrument is a 'repeater'. That means that there's no gyro built in and an external gyroscope is needed. So check the needed power and the reset knob before buying...
Interesting, i always assumed thet were just a bubble...kind of like a magic 8 ball.
A bubble would not work in a turn
Shouldn’t cage a running gyro
Why? I can imagine that there's an extra force on the bearings, but the bearings should be able toe handle this. All the automated gyro systems are caged when spinning up: ua-cam.com/video/QjmO9-8EApE/v-deo.html
@@polytech_nuexactly. Best maintenance practice is to cage it before power up so you aren’t forcing it into place.
I can’t comment on how an automated gyro cages I’ve never (knowingly) used one but experience would tell me that it cages before spin up.
28VDC single phase ? 😁
Hehehe, jeps, oopsie... The original text was '115 VAC single phase' and I forgot to change that part. I made this video on the couch om nu phone in half an hour for fun and I didn't expect this nuber of views. 😅 I'll try to be more carefull editing video's in the future.☺
Muito legal!!! O sistema de ereção com pêndulos é interessante!
cool👍
I always thought they had a sphere on the inside and not a cylinder
Glad to hear that this video may be helpfull. Theoretical physics gyroscopes are drawn as a sphere, so the idea is not bad at all...
Something is rotating, something is nosing, something is indicating 😅
“28vdc single phase” x3
I just put my water leveler on my glider.
😂
So cooooooool! But l really wanna know exactly how it works!!
Google gyroscope
The inner working is very simple. There's a rather heavy core that spins very fast. Due to the rotation, you need a lot of force displacing the core axis. Like a motorcycle wheel that becomes much harder to stear at higher speeds.
The core is mounted in a gimbal so the instrument can rotate in almost every direction and the core axis stays 'always' in the same orientation.
The graphical representation is obtained by linking cogs that are connected to the gimbal. When the gimbal moves, the display moves also.
Buenas tardes, hubiera jurado que era del tamaño de un auto (para un barco o algo así) y después vi la mano! 🤦🏽♂️
Hahaha. 😅
That gyro discs sounds fast :D DO not put finger inside !!! :D
The gyro core spins very fast, but is fully enclosed so that's no risk. The slow spinning weight is a larger risk. There are gears connecting the gyro core to the slow rotating weight. The result is that the wirht spins slow, but the force is large! So you don't want to stick your fingers in there...
Proof we live on a plane not a spinning ball .
Can you point out the part of the proof?
Maybe interesting to have seen: ua-cam.com/users/shortscd_tsW2kNSk
Crazy to think this is just a little chip now.
Indeed. But I prefer the noisy mechanical stuff. I also wonder what the accuracy is of the gyro in a chip...
Я даже телефоном не шевелил, чтобы не сбить авиагоризонт😂
😅
Зачем это показывать? Лучше рассказали бы как отремонтировать этот агрегат.
The device isn't broken so there's no use of repairing it. And the video title is that this is a test of the instrument, not a repair video. The video is to show the inner mechanics of the instrument. I wanted to share the beauty of the working and design of the instrument. And it looks like 300.000+ other viewers agree with me. 😅
@@polytech_nuI can't understand some of the negative comments...beautiful piece of mechanic.
@@The_Touring_Jedi I totally agree. ;-)
Looking at all these machines make me feel stupid, how could anyone even think of this
Sorcery!
😅
Very, nice.. but next time "watch the attitude"
😆
Арритировать надо прибор перед выключением
No. Just remove the power. The gyro will spin down and eventually goes to the default 'sideways' position.
Мы улетаем...
Now this whole thing resides inside a 2mm chip
Indeed. But I prefer the noisy mechanical stuff. I also wonder what the accuracy is of the gyro in a chip...
Так вот как он работает ой Спасибо ))))))))
Rip
?
Я по такому уровню стиралку дома устанавливал
😉😛
шумный,через чур,я так думаю.
Додумался же ктото
Прошлый век
If the earth were a globe or round ball, an airplane taking off from Germany, should then dip its nose quite often to eventually go land down under in Australia upside down! When an airplane takes off, you feel the pitch, when we go in for landing, you feel the pitch downwards, but not once on an 10 hour flight you feel a slight pitch downwards?????! Like the saying goes, it is easier to fool somebody than to convince him that he has been fooled! Love the proof in that spinning Gyro!!
The earth is (approximately) a round ball. The circumference of the earth is approximately 40.000km. If you start flying parallel to the earth for approximately 111,2 km (one degree of the circumference of the earth) in a straight line, you'll end up approximately 4,548 higher then where you started. So if you follow the curvature of the earth and fly parallel to the earth's surface (like a regular flight), after flying 111,2 km your descent is approximately 2,3 degrees. So in theory during a flight there is a constant small pitch down to follow the earth's curvature. Since this pitch is constant, it isn't felt as a pitch downwards but in can in theory be felt as a slight lower gravitational force. But this is expected to be so small that it isn't detected by human senses. During take off the pitch can be even 15 degrees over a much shorter distance and therefore be felt much better.
Concerning the gyro: Gyro's tend to drift. If you have a gyroscope placed on a fixed surface of the earth, the gyroscope will drift due to the earth's rotation. So if you fly to the other side of the earth, the horizon can be presented upside down for example. To prevent this unwanted drift, a correction is needed.This gyro has a self correcting mechanism at the top. The balance weight slowly compensates drift. The weight is due to gravity always a little bit longer at one side pulling the gyro upright. This correction is very small, slowly and is based on the idea that the airplane/vertical gyro axis flies most of the time perpendicular to the earth's surface. If the gyro axis is perpendicular to the gravity, the weight doesn't shift and the gyro axis is therefore not corrected.
There are also 'split' horizons where the gyro is mechanically separated and there's only a electrical link. The instrument is only an indicator and the gyro is located elsewhere. These type of gyro's have usually a 'reset mechanism'. By applying some signal, the (starting) gyro is pulled to it's default position. I made a video about the initial auto correct here: ua-cam.com/video/QjmO9-8EApE/v-deo.html. In this case spirit levels and torque motors are used as sensors and actuators to control the startup position of the gyro.
You started the comment with: "If the earth were a globe..." This implies that you think that the earth is not a sphere. In that case there's almost nothing I can do for you... My only advice would be to test this using a gyro without the automatic drift correction. Take a gyro and fly to the other side of the world. If the earth is a sphere, there will be drift. If the earth is flat, the gyro will indicate everywhere the same position no matter where you travel to. Oh yeah, and beware of flying over the edge... ;-)
@@polytech_nuyeah there is nothing that can be done to help this guy, he’s a flat earther or what we call a “Flerfer”. He truly believes that the ENTIRE REST OF THE WORLD has been fooled while HE knows the truth. It’s ridiculous
And?
?
Ok now im thankful for the boring lcd screens on planes today. At least i dont have to listen to that
Hehe, indeed. Although I like the 'old style' instruments, the noise is not the best. ;-)
What are the spinning things on the top?
The spinning weight is for self leveling the gyroscope. If the gyroscope is too much to one side, a bracket is lifted so the weight is blocked. The result is that the weight is always the longest to the highest side of the gyroscope. The weight pulls the gyro very very slightly down due to the unbalance by the weight. So if the gyroscope core drifts, this weight corrects this drift. This is only used on high quality gyroscopes where the gyro is built into the instrument itself like the ADI42. Note that the effect of this self balancing weight is only noticable on a long term scale.