Flite Test - Laser Balancing Props - FLITE TIP

Many multirotors suffer from vibration. Lasers can help you visually see the vibration that your motors and props are creating on your R/C plane or multirotor. By reflecting a laser off of a mirror that's attached to your plane or multirotor you can easily see and and correct unbalanced props!
More details and photos in the write up on the website:
flitetest.com/a...

[@SAFbikes]

Glad you guys started giving credit to the original youtube or forum thread author. I enjoy looking back at the old videos and seeing how you guys have evolved as a channel.

[@backyardfarmer5618]

Guys, great video as always. As a beginner in this hobby, your videos are a wealth of information that would have probably taken me years to figure out on my own (not to mention the expense of learning the hard way). I am pretty good at reading and retaining information, but to actually see concepts happen in real life (on video) really helps and brings the point home. Thanks again for making this hobby more enjoyable for me by removing some of the frustrations that I would have experienced if it wasn't for your educational videos!

[@seancsnm]

I feel like this can't really help balance a prop very well, but it can confirm whether your prop is balanced or not.

[@paulb8188]

UHHH watch other videos as to how to sand prop to balance it! EZPZ

[@seanjuan1973]

I laughed so hard at the beginning I had to pause the video and come back to it a few minutes later... You guys are nuts, and I love you for that! Keep up the great work! :)

[@zfotoguy71]

Another awesome way to do this is using the iSeismometer free application for your smart phone. I have it on my iPhone 5. Put the phone on the table with application running and use the 3 different graphs to adjust motor and prop as needed. Free and easier than using the laser beam method.

[@TheDefinitiveAirgunReview]

At the end LOL Josh as Doctor Evil brilliant!

[@mikedrz]

I thought, I was the only one who noticed that his voice changes when he say "Hi!" haha. It's cools, like a genuine happy to see you Hello!

[@kdknitro]

You shined a lazer in my eye, ahhhhh im sueing you but i will settle out of court for a new episode of Flite Test lol

[@redkb]

I'd like to see you guys fix the H quadcopter with this method and show a before and after. Lets see you remove the Jello.

[@LdHrothgar]

This is checking to see if a particular motor/prop combo is balanced, he mentions at 4:20 in that you would, once you determine your combo is unbalanced, then apply or remove whatever substance you wish to balance your prop, once you've balanced it then check it again, if it's out then check the motor, once both are balanced you get a dot and move to the next one.

[@coldbluefire]

I would recommend using a prop balancer first (old school glow guy speaking) and then using the laser trick to further isolate possible engine balance issues. Since you copter types use much lighter props then us glow engine types you could easily just use two neodymium magnets and a shaft that equals the prop hub diameter to rig a up prop balancer.

[@CrashPilot1000]

Nice tip! Without reading all the comments, there is an easier way if you have a multiwii FC. Just connect the gui and click everything away except for the acc lines than increase the scale to x10. With unbalanced motors you will see the "flatlines" shaking. Others put their i/android phones with somekind of vibration monitoring app on the copterarms.I like the starwars - laserapproach the most - of course. The dark side of vibration becomes a red line of vibration.. hehe. So long Crashpilot

[@XrayMike]

Let me get this straight: This is a method for figuring out which one is unbalanced/balanced. If you find an unbalanced prop, you have to take it off to actually balance it. I like the method, because I can't easily tell if a prop is balanced or not.. (I do pre-balance, as a crash of mine was caused by an unbalanced prop). (it is possible to balance this way too, by adding tape to specific sides and looking at the effect, being worse or better)

[@FlorianHorsch]

Great tip - really like the comment on the mirror.

[@wyatthassel8341]

The mirror helps to amplify the vibrations visually. If you where to just mount the laser on the arm, then the visual vibration would be much less. The mirror makes it much more precise.

[@eastcoast78]

next flite tip.. How to wrap your friends arm with your T shirt to stop bleeding lmao

[@hawkskyflier]

Nice tip!! Thanks. Just built David's Tri Copter.. Gonna have fun, gotta figure out a few things, but I like this tip. Thanks a bunch... for all the videos!

[@DadHav]

Hi, I don't usually reply on other peoples channels but I hear these guys are really cool and their in my neighborhood so maybe they won't mind. Last I heard you can buy any laser you want (in the US) as long as it is 5 mw or less. That's plenty to do the vibration test. Anything over that and you may find it won't ship to certain countries. Some manufacturers ship no matter what and I know of many people still buying 50-500 mw lasers but you might loose it in customs if something goes wrong. J

[@johnangeleri7336]

The "laser beam" trick shows that the prop is not in adequate balance, but guessing at where to put tape is NOT the answer. Something like the Du-Dro Tru Spin is a more realistic and effective approach. PS- This video presents as if you guys had been inhaling paint fumes just prior to filming… That said, My son and I love your videos.

[@c4pt1n54n0]

if you have a cat, a broken mirror, and an aicraft, you can have balanced props. i think that was more the aim of this vidyao

[@zillah7599]

Great guys. Love the show. keep doing what you do. Try to be funny or not it's all good. I have only been flying for 5 months and these guys have helped tremendously. keep your spirits up as high as your plans are.

[@IamKillerB]

This is very freakin cool. Never seen this approach but I love it!! Can't wait to try it out and see if it tunes my quads better!

[@Ubernator]

He added the tape before the episode started just to show you that you could "see" the vibrations. You need to add tape when you see vibrations in the prop, but if you add tape and the vibrations get worse take that tape and put it on the other side of the prop. Then you should get a vibrations reduction.

[@LeftFlamingo]

Obviously, to keep the video length decent, they had pretested and balanced out the prop, then added a big weight to mess it up so that they can demo the effect. Naturally you would use your favorite balancing method (they have vids for that too on the channel) to get it near perfect, and then check with the laser and tweak it out to get a perfectly balanced prop. Oh, and balance your motor first as well, especially if it's an outrunner.

[@1nfowars]

This guy really shined the laser in your eye!

[@truglodite]

Nice idea, but as shown it only measures movement in 2 directions. For example, take the 'balanced' motor, remount the mirror horizontally, and you may still see bad vibes. I suggest using a prism, more mirrors, and/or additional lasers to make a couple more dots to monitor the other axis. ;)

[@truglodite]

Andrew Crews I Apologize for not being clear... by 2 directions I meant 2 axis... really it's 4 directions if you count rotation... that is only 4 out of 6 possible vectors. Motion (either translation or rotation) in a direction that is orthogonal to the mirror will not move/distort the spot. OTOH, you can use 2 reflected beams (oriented ~90* apart), or more ideally 3 beams (forming sort of an "XYZ axis", with it's origin on the part) to resolve ALL possible motions. 2 beams will resolve most of the nasty vibes we care about. If you want to go the distance with 3 axis, you can see the more subtle structural modes (because 2 beams can be fooled by singular interactions between rotation and translation ). A 2 can be implemented with 2 parallel lasers and 2 mirrors, or a prism... though I suppose you could also split a single laser beam by wedging 2 surfaces together in the middle. Does that make any more sense?

[@atomgonuclear]

That would be a waste of time. You can only balance these in 1 axis. In order to do the other axis you would have to modify blade pitch. It's a thrust axis. They are never balanced..... It's how you create thrust. I think your talking about flex anyway. That's not the same as balancing. Lastly... This laser method is flawed bc it doesn't say which side to balance. You have to guess and check until you get it close.

[@truglodite]

As vibration travels through a structure, it 'reflects' to create interference patterns in various directions... think of sound in an imperfect room. I was simply thinking multiple axis could determine this motion, which is likely to lead to better balance. I know perfect balance is only theoretical... just thinking out loud. If I had a prism on me I would slap it and see if it helps.

[@brantremenda3537]

Awesome production!!!

[@XrayMike]

The reason you only take one prop at a time is because (especially with cheap) props tend to come unbalanced. it is easy to figure out if one prop isn't balanced this way, and adding tape will tell you if it becomes better or worse (from that you can judge whether to add or remove the tape (and add on the other side). When you have multiple motors running, it is harder to find unbalances in props, as vibrations come from all motors.

[@silentseawolf]

as a red/green colorblind person, what dot? never saw it until the last close ups, lol.

[@dagobb]

Thank you guys! I'll definitely try this out. Have a lot of props to balance.

[@08ds]

This process is typically used to balance the MOTOR, not the prop. Your supposed to balance your props first, THEN do this and add tape to the motor to balance the motor.

[@Frankdubbsfpv]

Looks like good a way (kind of dangerous) to check your whole setup in the end after traditionally balancing stuff. You could just look at your gyro readings in the flight controller software while running one motor up at a time to get this same information.

[@Billy_Darley]

"those beeps are driving me crazy". my first thought, what beeps? XD selective hearing is so nice.

[@jordanhuusy]

couldn't stop laughing in the beginning........ ahhahahahah "hiiii!"

[@ReneNieuwenhuis]

I'm using 'Vibration' on my iPhone. Put it on the place of your cam and go from there. Placing it on the arms is also a good way to telll if the motors are balanced.

[@pintail120]

please can you elaborate, not sure what you mean ? how does the iphone assist in balancing ?

[@Ian-Hall]

I've just done my Tri this way and the footage is much better....So yes...Its works.

[@Moosetraks21]

built a monster quad but flew it out of sight andnever saw it again it had a full fleged naza v2 on it and weighted 3.5lbs fully loaded, just hope no one got hit with the crbon fiber props on its way down :(

[@sammystriano]

That sucks

[@Perry_Wolf]

Why'd you fly it out of sight?

[@nordemoniac]

Tip: Buy a cheap GSM GPS tracker from Bang good or similar stores. They're about $12 and with a cloned SIM card or a cheap prepaid plan, you'll get coordinates on your phone with the set interval, which shows where your plane is.

[@Saschabrix]

You make a great team!

[@aesoft2009]

The laser is shone onto the mirror, and since the mirror is stuck to the tricopter it will vibrate with the tricopter. The laser beam reflected by the mirror will be distorted by the vibrations and it will stretch the dot into an oval or line.

[@bearospace]

laser beams on their heads!!!!! great episode!

[@MrCasehatter]

Hey guys keep em coming and need some fresh stuff.. good job good advise Mt. Dew

[@ewaltruts833]

U forgot to mention this also improves alot of other factors like , more power , less hot esc's , longer battery life etc.. cool way to balance them props tho ^^

[@markryan3018]

Lasers are very bad for the sensor in the camera.

[@CustomcrowdMitroc]

Mark Ryan your right

[@Prestonesfpv]

Forget about the lazer, it only makes things more complicated for newcommers! Balance your motors with tape and use a prop balancer for the props, thats all you need for a smooth flying rig.... it can all be found on the tube.

[@nandakoryaaa]

And what to do if props are foldable?

[@seanjuan1973]

Totally agree... got a new Bixler with a HK prop and it blew up on the second flight. Replaced it with a APC prop and everything is cool again. I have never had a APC fail and only broke one due to stupid human error.

[@hughhemington9559]

I wonder if a strobe would be a more useful tool to visualize vibration? Especially if the strobe were adjustable for frequency. (maybe an automotive tuning strobe could be used?) If you shot a strobe at the motor/prop/arm against a background with a black grid drawn on a white surface, not only would vertical prop oscillation be visible, but so would motor/arm motion, and both could be measured in a linear way. This might be more useful if the RPM could be determined and recorded at any point. The motor without the prop could be spun up first, to isolate non-prop vibration. The only thing I don't know is, would any video camera actually catch the motion? Would it be able to focus? Even at 60fps, I don't know if it could be a useful part of the test, or if only direct visual inspection could be used. Alternatively, performing the same test shown here, but bouncing the laser onto a white background with a black grid would yield more useful results.

[@Oshbotscom]

By using a strobe, you'd be losing all the data while the light isn't lit. It would be possible for the balance to be far off, but the frequency of the oscillations and the frequency of the strobe could match at the center of the target and give you a false reading.

[@ramradhakrishnan9382]

You could probably use a small square of self adhesive Aluminum (Aluminium?) tape in lieu of the front surface mirror.

[@WafflePlaneRC]

top flite ballencer is good, but this method is also good. Just because you dont like it dosen't mean that it is horrible

[@MetHerInBaghdad]

Cool way to balance the props. A later show mentions balancing the motors as well. How can you tell if you need to balance the motor, or is this just a different way to do it? Seems this is the easiest method.

[@SolarPoweredGardener]

Put a zip tie around the motor and the zip part will act as the weight to balance it. Just slide it around until you find the balance point, mark it, pull off zip tie and put your tape there...

[@Swallabat]

Downwards facing LED laser on each motor base, and you could do all four at once simply by hovering it high over a relective surface...

[@NevinWilliams71]

To make a first-surface mirror out of an ordinary household mirror, is pretty easy: Apply a chemical paint & varnish remover to the mirrors backing, per product instructions. Wipe off gently with a non-abrasive cloth; the protective coating should come off, leaving a reflective surface . A second treatment may be required to get all of the paint off.

[@VoidedWarranty]

HI!! Loving this tip. Gonna try it on some EDFs.

[@NUeB_net]

Great tip ... and works with planes, too! :)

[@georgeaura]

How do you know where to put the tape using that procedure?

[@DominoSixO]

george aura It's your own decision put it where you like till is balanced

[@georgeaura]

Oh ok

[@Fahnder99]

+Domino SixO You use a prop balancer. A real one. This cool gadget is only for measurement of wobble.

[@feefeee]

I really like your channel and the presenters shame you don't do more videos of helicopters

[@maylanemassive]

I think you should compare this balancing a tyre that's not on the rim. The tyre (prop) can be well balanced but it will need balancing again when its on the rim (motor), and for this you need to spin it up SImply, balance your prop using methods mentioned here, the balance prop and motor with laser, iphone of whatever and tape, then when you are happy, you can if you like remove the tape and sand or scrape if you prefer. No idea why you are all so angry there is some great info here!

[@IDoNotLikeHandlesOnYT]

Using a stationary laser and vibrating mirror produces twice the deflection so it's easier to see small vibrations.

[@BMSWEB]

Need a MASSIVE Thumbs up for this one!!!!

[@zero00tolerance]

thankyou so much I got it now ! have a good day.

[@dominicrobillard7273]

Love your videos! Would be great if you could do a review of our thrust stand at RCbenchmark. We have a USB interface and powerful scripting to do automatic testing. We support up to 5kg of thrust. Our Series 1580 also has an onboard accelerometer allowing vibration testing. So you can do trial and error balancing like you do with the laser. You can also do vibration VS RPM plots.

[@Borntobeme1931]

Hey Could you make a short video on how to build a folding flying wing out of an existing one? Ty lots, love your videos.

[@cknopik]

For the first time ever, Josh Bixler made me laugh more than Josh Scott.

[@Eaglebird]

I can't seem to find the video for that clip in the intro of the helicopter hitting the dummy (@0:23). Was it ever posted, or removed? I wanted to share it with friends to help describe how dangerous these machines can be.

[@vipero00]

You got the idea from KZbin? If you did shouldn't you give credit to the source. You guys do pro level work you should give credit like pros. Cite your sources.

[@Beng177]

Have a look at their article in the description, they did cite the source. :)

[@AirborneMediaPros]

I balance my motors using this technique and then balance my props on a prop balancer. It's more work, but a heck of lot safer.

[@7jsm7]

cool, I hadn't thought of doing that but it makes complete sense.

[@biglon62]

That is very effective and smart! Thanks guys!

[@johnwarren1079]

Do you find that the motor shaft is out of balance? I balance my blades by sanding them on the heavy side on a blade, using a blade balancer, will that do the same thing?

[@AegeanEpiphany]

Hardest part is deciding what tape to put on which prop and where on that prop. Is this in the next episode?

[@weeliano]

Especially the prop mounted on the tilting tail servo on a Tricopter. The HK generic GWS clone prop material is not very strong. Aggressive yaws will rip the blades apart after a while. I had it happen to me on my Tricopter. Now I use only Gemfan carbon nylon props.

[@willd.8040]

Should consider using wax paper to sand down the weight on the heavier side rather than adding tape, which can change the air-flow over the prop

[@cam_3d]

Nice vid guys! One thing...which side of the prop do you put the tape on?

[@Gig540]

So with conventional aircraft to do point nose in air and mirror on wing or on fuse under the prop? Also I would guess the laser would be set on table away from plane?

[@basebilljr07]

you can also do this without the prop to balance the motor first use tape on the outside of the motor to balance it and then put the prop back on and do it again to balance the prop for the best results

[@jordyb323]

Lazer beams attached to your fricken props

[@MyMona27]

Pre test....you could mount a motor on A rubber base with the laser and a servo tester and test each prop .

[@TOPHAT1966GS]

This maybe a silly question, but, this will work on an electric but what about nitro or gas engines? How would this test compare to a nitro or gas engine with all of the fundamental and harmonic frequencies being spawned off through out the throttle ranges and mechanical noise IE vibrations? Altogether, its very interesting.

[@daverbmxer]

I'm thinking a hard drive platter should work pretty good for the mirror.

[@fredvs79]

It likely would work great, my idea as well.

[@spokehedz]

Yeah, you are right! I mean, there was only one prop spinning when they did this--so how DO you know which one is actually causing the vibration? I mean, the other two are not even moving at all so you wouldn't be able to tell at all!

[@chriskhosravi2140]

Excellent Tip!

[@lancethrustworthy]

Sheesh, guys, what's the deal with having the laser bounce (off the mirror) onto a nearly black surface? it was too hard to tape a piece of white paper there? This would have been a fine video, if someone with a critical eye had taken a moment to look at the shot. Phooey. We expect more from you, because you've often done good stuff. You dropped the ball here.

[@Jasoninee]

It's a flippin' laser! There was never a point in the test where I was like "OMG! where did that super bright red laser dot go!" They have always made videos for the masses. You know who the masses are? Non-professional RC pilots enthused about their hobby that usually have normal jobs and a normal place residence. If I wanted to follow this test I could. My dot would shine on the wall or wherever, because in reality all I did was tape a mirror on my copter, set it on the table, and run it. They always have a nice "It's not rocket science" feel to them. How much more do you expect? Should they make a brand new room with special high reflective projector paint just like everyone at home has? YOU dropped the ball here. They did exactly what they always do. Are you going to go on all of their other videos and say they should have more pro tape and pro tape dispensers?

[@AlexJoneses]

Dan Lewis turn your brightness up

[@kdstunts_641]

Can u guys do a video on the pros and cons of 2blade vs 3blade props

[@hughhemington9559]

I use a laptop hard drive platter as a mirror. I used epoxy to attach a large alligator clip to it.

[@c4pt1n54n0]

Like a laser guitar tuner! right on, boys.

[@LoveRC]

It's Entertaining and informative. Love it!!!

[@leviathan19]

a lot easier to use a prop balancer that will show you if its the hub that is not balanced or the prop

[@stevec5000]

So you can use the mirror to check if it's balanced but HOW DO YOU BALANCE IT?

[@jatu3683]

The Josh Bixler word of the day = Singlarizing

[@moonchildoforcamoon6272]

I nearly lost a finger last night so if you have throttle lock USE IT, I got lucky with a tiny paper cut and minor bruising but it could have been much worse

[@RemodNC]

Brilliant idea!

[@joeyscustoms]

Awesome tool! Thank U guys!

[@Isuzuwhat]

Josh Scott, is he a NAVY VET? (clicks the laser pointer on and off) "for all you non Navy vets out there, that means..."

[@agentbertram4769]

This is not really showing you how to balance the prop just how to display the effects of an out-of-balance prop. Do you have another video on how to balance the prop blade?

[@Stambo59]

Using the same theory, could you not just mount the laser where the camera is going to mount and get the same result. Come to think of it my mini HD camera has a laser for aiming it. May have to aim it a little further away for the same resolution. I'll give it a try on my quad and let you know.

[@LTT.Official]

Copters with fricken laser beams attached to their fricken heads.

[@heliscat]

One can simply feel whether or not the motor is out of balance when running full power. Trial and error, feel for vibration, it takes a long time. Pain in the bootay.

[@sonick808]

why'd you do that. LMAO. As a ham, I always love to see morse being repped.

[@parapentetropical]

Hi guys , regards from spain. Could you let me now which camera are you using in this video? Thanks antonio

[@panther105]

I've been watching all these prop balancing videos showing various high tech static and dynamic balancing systems and all you guys add weight by folding electrical tape over the leading edges of your props. Makes me wonder if this is causing some aerodynamic imbalance even though the props are (apparently) dynamically balanced. Is this a concern? If not, should it be? Is there another way to alter the blade weight, possibly by subtraction rather than addition.....? Thanks.

[@exoditegrayc]

Nice tip! Thanks!