USB Vibration Spectrum Analyser

Mike G

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In post #32 of this thread :

https://www.rotaryforum.com/threads/rotor-vibrations.1145740/

I wrote about a simple accelerometer with a USB port that could be linked to a smartphone to allow vibration measurements to be made simply and cheaply and recorded via an app. I proposed to analyse the results for owners so that I would be able to build a database for each gyro model and be able to tell an owner if his vibrations were good, bad or ugly. There was very little reaction from members here on the RWF but there was more interest on FaceBook, so we’ve progressed a bit with this idea and here's an update.

We’ve made a different version of the case to allow it to be easily bolted to the mounting bracket and made a simplified mounting bracket for the Calidus/Cavalon, which I sent to Jeff Harrison to try out on his Calidus. Here is a photo of the accelerometer mounted on another Calidus I used for testing in France.
IMG_20210220_121927661 resized.jpg

Jeff had to struggled a bit because this is all new and prototype stuff. My idea was that he took some screenshots of the spectra for me to look at while flying at different airspeeds, but he found that awkward and used an interesting app that allowed him to record a video screenshot. This meant he could start the app before TO and stop it on landing which was a safer solution than messing about trying to take screenshots while flying.

Here’s an edited video of his rotor vibrations.


From these I could tell him that his horizontal 1/rev vibrations were between 0,4 and 0,6 IPS and that his 2/rev vibrations were between 1.7 and 3.0 IPS which are fairly low 2/rev values compared to other 2 seat eurotubs. His vertical vibrations were quite low suggesting that his tracking was probably reasonable.

The interesting question (and the reason I’m trying to develop this device) is, of course, does this rotor require track and balance (RTB)? When the 1/rev vibrations are around 0,5 IPS it’s always a bit difficult to decide whether to RTB or not, If I got these results with a balancer attached to the gyro I’d say let’s do it because I’ve already traveled to the site and the balancer is already installed. Using this new device I’d be tempted to say leave it alone.

So I advised Jeff that this rotor would benefit from an RTB because, properly done, the vibrations should all be below 0,1 IPS and if a dynamic balancer and competent operator were available locally go for it. If however it meant considerable expense bringing in someone from a great distance with travel expenses etc then it’s probably not worth while because he won’t feel a great difference between 0,5 and 0,1 IPS.

Jeff is in the process of sending this prototype to Florida where we hope another guinea pig tester will try it out on his Cavalon and feedback the results and any suggestions for improvements.

Mike G
 

fara

AR-1 gyro manufacturer
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Mike have you gotten your vaccination yet? Are they allowing you to come over from France to the US without a quarantine period if you are vaccinated? I could use a review myself with PB-4 and would not mind trying this gizmo out too. Probably not interested in a generic class for all, it always seems to not work in favor. May be just AR-1 owners who want to attend
 

JETLAG03

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@Mike G will you be making this accelerometer with a USB port and which app did Jeff use to record the data.


phil
 

Mike G

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Abid

I’ve had my first vaccination and the second is due early June.

I hope to receive the first MkIII prototype Gyro Warning System (GWS) some time in May and hope to have fully tested it on my gyro by the time I get my second vaccination. As soon as I can after that I’ll bring it to Florida to let you try it and to get your feedback. I’ll also do whatever PB4 track and balance training we can organise.

For this USB Spectrum accelerometer, there are only 3 prototypes in existence because the chip used now has a ridiculous lead time (6 months+) and Mark Burton of Smart Avionics is still doubtful there will be enough demand from gyro owners to justify him going into production.

I have one prototype, Mark has another and the 3rd is in the USA and should be on its way to Florida for further testing. I’ll bring mine with me to show you but the only thing it gives you over your PB4 is that it shows the vibration in the 3 axis (X,Y & Z) at the same time. It cannot be used for balancing,

My thinking was that this would be cheap enough so that every owner could have one in his tool box and it would allow him to regularly monitor the evolution of his rotor and prop vibrations and give him some actual numbers for me (or his manufacturer) to advise him if all was OK or not and to allow me to create a database. Judging by the lack of response here on the RWF I fear that Mark Burton will be proved right. I will continue to try to get feedback from users in the hope that I can prove him wrong. A suggestion from Jeff Harrison is that it could be fitted as standard to factory machines and used at each maintenance period to record vibration status.



Phil

The accelerometer is made by Smart Avionics (who make the PB4 balancer), it comes with an app to create the spectra, The app that Jeff used to video a screenshot is here:

https://play.google.com/store/apps/details?id=videoeditor.videorecorder.screenrecorder

I haven’t tried it yet but it looks interesting.

The major application for this device is probably for factory machines because if we get a big enough database we can compare data for each type and be more precise about how good or bad a rotor is. For unique gyros like yours it would still be interesting because for any rotor regardless of make we know what vibration levels are acceptable or not.

I fear it will be some time (perhaps never) before this ever gets to market,

Mike G
 
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JETLAG03

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Thanks @Mike G probably be easier for owner/pilots to give an opinion on the interest of ownership of the GWS if the price range was known.

Even for amateur built machines like mine there may be an interest in being able to "health check" the rotor vibrations periodically if, as they say on TV "if the price is right".
 

Mike G

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Phil
In your thread
https://www.rotaryforum.com/threads/rotor-vibrations.1145740/
that I quoted at the begining it says:
"The question you’re all going to ask is “how much?”. The prototype was cobbled up out of bits Mark had laying around the workshop so if he went into production he’d have to source better quality parts, organise manufacturing, develop the app, plus write the manual and I’ll have to do the testing to ensure that the app was user friendly in the cockpit. So we don’t know how much but have agreed that if the price exceeds 100 pounds/Euros/US dollars it would be too much and we’d not go any further.

Brian
This isn't the PB4, it's a new simple device that we're prototyping and having difficulties with the supply of the chip. The PB4 is still in production and fully supported. The PB3 is no longer in production but is still fully supported.
Contact Mark Burton at smartavionics.co.uk.
If you have any questions about the PB4 I'm always ready to answer, I have no financial interest in smart Avionics.

Mike G
 

JETLAG03

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Mike .. personally, at £100 or there abouts, I would certainly be interested.
 

fara

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Abid

I’ve had my first vaccination and the second is due early June.

I hope to receive the first MkIII prototype Gyro Warning System (GWS) some time in May and hope to have fully tested it on my gyro by the time I get my second vaccination. As soon as I can after that I’ll bring it to Florida to let you try it and to get your feedback. I’ll also do whatever PB4 track and balance training we can organise.

For this USB Spectrum accelerometer, there are only 3 prototypes in existence because the chip used now has a ridiculous lead time (6 months+) and Mark Burton of Smart Avionics is still doubtful there will be enough demand from gyro owners to justify him going into production.

I have one prototype, Mark has another and the 3rd is in the USA and should be on its way to Florida for further testing. I’ll bring mine with me to show you but the only thing it gives you over your PB4 is that it shows the vibration in the 3 axis (X,Y & Z) at the same time. It cannot be used for balancing,

My thinking was that this would be cheap enough so that every owner could have one in his tool box and it would allow him to regularly monitor the evolution of his rotor and prop vibrations and give him some actual numbers for me (or his manufacturer) to advise him if all was OK or not and to allow me to create a database. Judging by the lack of response here on the RWF I fear that Mark Burton will be proved right. I will continue to try to get feedback from users in the hope that I can prove him wrong. A suggestion from Jeff Harrison is that it could be fitted as standard to factory machines and used at each maintenance period to record vibration status.



Phil

The accelerometer is made by Smart Avionics (who make the PB4 balancer), it comes with an app to create the spectra, The app that Jeff used to video a screenshot is here:

https://play.google.com/store/apps/details?id=videoeditor.videorecorder.screenrecorder

I haven’t tried it yet but it looks interesting.

The major application for this device is probably for factory machines because if we get a big enough database we can compare data for each type and be more precise about how good or bad a rotor is. For unique gyros like yours it would still be interesting because for any rotor regardless of make we know what vibration levels are acceptable or not.

I fear it will be some time (perhaps never) before this ever gets to market,

Mike G

Yeah I am having a hell of a time getting avionics myself because of chip shortages supposedly. Even had to change vendors of avionics even for current orders.
I got my second shot for Pfizer a week ago and no fangs so far but I did start dreaming of Bill Gates trying to sell me a new Windows laptop for SolidWorks. Not sure if its connected to the vaccine.
Yes as soon as you get the GWS I am in for trying it in an AR-1 here and you can come over help us install it and test it
 

Sv.grainne

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Fara:

The crazy dreams are part of getting OLDER, I'm older than dirt and have some wildass dreams!

At around $100 I am certainly interested in one of the analyzers. Hope to start construction of my single place machine this summer and think it would be nice to have.
Bobby
 
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Bosko

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Belgrade, Serbia
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Phil
In your thread
https://www.rotaryforum.com/threads/rotor-vibrations.1145740/
that I quoted at the begining it says:
"The question you’re all going to ask is “how much?”. The prototype was cobbled up out of bits Mark had laying around the workshop so if he went into production he’d have to source better quality parts, organise manufacturing, develop the app, plus write the manual and I’ll have to do the testing to ensure that the app was user friendly in the cockpit. So we don’t know how much but have agreed that if the price exceeds 100 pounds/Euros/US dollars it would be too much and we’d not go any further.

Brian
This isn't the PB4, it's a new simple device that we're prototyping and having difficulties with the supply of the chip. The PB4 is still in production and fully supported. The PB3 is no longer in production but is still fully supported.
Contact Mark Burton at smartavionics.co.uk.
If you have any questions about the PB4 I'm always ready to answer, I have no financial interest in smart Avionics.

Mike G
Mike,
I am interested as well.
Bosko
 
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