Micro RC Plane Magnetic Actuator DIY

A little how-to for making your own magnetic actuators for micro RC planes
Basic info: 0:00
Making a coil: 3:05

[@microbuilder]

Skip to 3:05 to get to the actual making of the actuator coil.

[@athenovae]

This video couldn’t come at a better time for me. I been flying on and off for 10 years and just started picking it up again. Thank you for the video! Much appreciated 😊

[@microbuilder]

Glad you enjoyed it, thanks for watching!

[@technoingenious]

I love your content and appreciate your job, I feel your content is more enhanced with your voice-over.

[@microbuilder]

Thanks! Yeah there was a bit too much information to have just a song playing over it, glad you liked it.

[@Friendroid]

I made one of these years ago - there's a video in my channel. I learned that in theory it's a simple mechanism, but they are tricky to build to specification. There is a 1/96 spitfire on youtube that uses several of them and there are a few threads on rcgroups from a gentleman who build very tiny ducted fan "jets" with coil actuators as well. Recently i found some led candles that use them to create a flickering effect.

[@microbuilder]

I know exactly which planes youre talking about, and they are amazing little works of art!

[@kopparsulfat]

I must say i am impressed with your work. I love the look of the twin engine plane.

[@microbuilder]

Thank you!

[@vinnieg2009]

great video. thanks for sharing!

[@microbuilder]

Thank you!

[@kangsterizer]

these videos that popup sometimes make me glad i subbed 10y ago haha. hope you show new micro planes sometimes, these are so cool.

[@microbuilder]

Thanks for sticking with the channel all these years! I do in fact have a couple more videos coming up in the near future, so stick around just a bit longer lol

[@georgehiotis]

I look forward to watching how the magnet works within the coil. Thank you for sharing your knowledge.

[@microbuilder]

Youre welcome. I will be doing a video on installing the coil and magnet in a plane hopefully this coming week.

[@promess]

@@microbuilder any hope?

[@microbuilder]

@@promess I do have a project in the works using actuators!

[@promess]

@@microbuilder slick! I'll watch when you post it! :) While I'm an absolute novice, I've got this fantasy of building a ~10 inch stol high wing? I'm in the planning phases now of trying to build it 5 channel slow flier that i can hopefully jam around my living room. Kinda thinking ugly stick, maybe polyhedral, at least di... with a 8-10 inch wing span? I was under the impression that I was going to have to go w/ the 1.3g servos then I saw your video on actuators and while fiddly, it absolutely seems way more possible than I'd have thought previously. How hard is it to build 2 sided actuators(I've seen the examples, but i can't think of how they work DIY style, in this the mag attracts based on polarity, but with pass through... huh? how? )? Any suggestions on how I build materials? I was thinking of trying to make some spars to bend some damp balsa over and cover the bottom with tissue... I also saw a really small affordable small scale "dental vacuum former"(search it in amazon, it's like 115? :o wild right, so many ideas! ) that wouldn't be too hard to make some more rigid airfoils/fuselages with, but I don't know a.) if the actuators could potentially get hot enough to weaken the plastic, and b.) how would i place them in the wings for ailerons? Thanks for your content, I didn't even know any of this was possible before your lil red sports plane. :)

[@microbuilder]

@@promess Living room flying is really fun, the only downside is wingloading (how many grams per square inch) becomes the most important factor for how slow it'll fly, which will strongly dictate how big/small/complex your build can be. For instance, the ParkZone Mini Vapor has roughly an 8x5" wing and weighs around 12 grams, which gives it a wingloading of around 0.3 grams per square inch. My last LRF was a 5" version of the Mini Vapor and its wingloading was 0.2g/sq in. So, either building as light as possible, or building bigger are the two typcal ways to go about it, only downside with building bigger is your living room starts feeling pretty small lol Theres definitely a bit of an art to indoor/living room builds, but I have a few videos on my channel that show some of my past living room flyers if youre looking for examples. As for a dual arm actuator, I actually havent tried building one of those, mostly because its super fiddly work, and I'd rather just buy one and save the time/frustration lol but they work the same as a single arm actuator, its just a matter of which way the polarity of the power is sent through the coil, which changes the polarity of the magnetic field, so the magnet moves in accordance with the change of the coils field...its just like taking single arm actuator and adding another arm on the other side. As for materials, forming wetted balsa and using tissue as a covering is usually the go-to way of doing indoor flyers, though the bottom of the wing typically isnt covered since at the size/speed of indoor flyers it really isnt needed and just adds extra weight. The actuators coils definitely shouldnt be getting hot, at least not hot enough to melt anything. For mounting them in a wing, you'd do it just the same as you would a servo, right in the middle of the wing with a couple small push rods joining the actuators arms to the ailerons control horns. Check out the Scratchbuilt Indoor and Micro Models forum over on RCGroups, you'll find a ton of info on all this sort of stuff, its a wealth of info!

[@Snipermac99]

Thanks the an interesting and instructive video!

[@microbuilder]

Thanks for watching!

[@NitroCharged]

Great to see you back again! :)

[@microbuilder]

Hey Nitro, long time no see! Any new micro EDFs?

[@NitroCharged]

@@microbuilder Yes indeed! Will PM you about it all soon.

[@Phoenixsims.02]

You dont even under stand i check your channel like one a week for a vid and this is a video i really wanted to see

[@microbuilder]

Thank you!! Got a couple more coming soon too.

[@charlesmaulion3014]

nice video 👍

[@microbuilder]

Thank you!

[@evanlane1690]

Very cool. Can you do a follow on video of the arm and magnet assembly? I'm interested in using these but I'm still a little fuzzy on how they go together with the magnet.

[@microbuilder]

Yep, will be installing the coil and magnet in an upcoming video...wouldve done it in this one, but the plane wasnt quite ready yet.

[@cyberneticinterfacemodular3996]

Nice micro stuff.Do you do rubber power model radio control.

[@terminsane]

i absolutely love these little things. I wish there was more information on making em. Have you looked into elrs? I think there's a ton of potential for custom rx boards for things like this. I saw a github project with elrs rx + brushed ESC + servo integrated

[@microbuilder]

Thanks! I hadnt heard of ELRS, but it does look interesting...micro RXs, especially ones for magnetic actuators, are few and far between, and it would be really cool to be able to make my own, ultra lightweight servos would be great too. Looks like its a whole hobby unto itself though, but definitely something to look into. Thanks for the heads up!

[@terminsane]

@@microbuilder its entirely opensource rx design. i think it would be a great match for these things, as you could make the rx do whatever you want, and very cheaply

[@whatelseison8970]

Can I get a link to that repository?

[@bebopBiGsHoT]

They could be centered with another smaller magnet on the outside of the coil , or with 2 actuators side by side so they attract each other .. I remember you from the forums a decade ago, glad to see you back at it. I guess I should bust out the old plantraco gear.. Ornithopter ?!?! You can get a mini FPV Drone for less then $20.00 nowadays. Crazy .. Where are the cheap *micro* 4ch scale planes / jets ??

[@microbuilder]

Yes indeed, in fact the actuator with the arms actually has a little slot to mount such centering magnets...completely forgot about that... A decade ago sure sounds like a long time ago, feels like it too lol I never did end up getting a Plantraco plane, I did have their micro Blimp though which was surprisingly fun. And yeah, electronics have come a really long way, much cheaper and much smaller/lighter...could probably build a pretty tiny orni these days...

[@whatelseison8970]

>>You can get a mini FPV Drone for less then $20.00 nowadays. Crazy .. Where are the cheap micro 4ch scale planes / jets ?? YES! I've been saying this for some time now. with some clever programming and thrust angles/thruster positioning it should be possible to build a 4 channel fixed wing with exactly the same electronics that go into a micro quad and no control surfaces. I've been messing with microcontrollers for a little while now and I suspect it may be possible to flash custom firmware onto one of those cheapy all-in-one boards.. A lot of them even have tx and rx pads labelled. Unfortunately, it seems that very few folks are attempting this and those that are don't seem to be documenting it.

[@neilsaeroadventures1116]

I see a pitts in the making!

[@microbuilder]

If youre referring to the unfinished fuselage, you have good eyes! I'm also really glad that you were able to tell it was a Pitts...wasnt sure I had really gotten the shape right lol

[@neilsaeroadventures1116]

@@microbuilder it has a very distinctive look to it, always wanted to try to build one myself. I’m just trying to get better at curving balsawood instead of building box fuselages. Very nice work, I can’t wait to see it done!

[@simone12russo]

Can you make a video that explain from start to finish all the process to build a little airplane like this? Also all the electronic part..

[@microbuilder]

If you go back one video on my channel you'll find a build video of simple micro 2 channel DH.88 Comet. Its about 45 minutes long, but it covers just about everything...I think...

[@nathanbarraud4349]

Thanks for the video, it is super interesting ! I have one question, how do you power these ? Like how do you control it from your receiver? I have tried to make one of these some time ago actually, but it did not performed well enough to put on an actual plane, the wire diameter was too large ha ha

[@microbuilder]

Thanks! The receiver powers the coils like they were a regular brushed motor, since theres no potentiometer like on a servo, it just sends current straight to it, and RX gets the signal from the transmitter like any regular RX. There will be a video coming installing and setting up everything, so hopefully that'll clear it up.

[@whatelseison8970]

If you had a very small servo with the gears stripped or something you could take the circuit board out and connect the coil where the motor used to go and either glue the pot in the centered position or replace it with a pair of fixed 2.5k resistors. Then you'd just drive it like a regular servo.

[@microbuilder]

@@whatelseison8970Yeah I've considered that a few times, theres also servo to actuator conversion boards...not the lightest way to do it, but its definitely a useful option to have.

[@Andreasporsche]

👍🤝👍

[@microbuilder]

Thanks!

[@anirudha1984]

Where do 2 leads of coil connect into?.....directly into +ve and -ve of one of the channels of receiver leaving signal terminal unconnected?.....

[@microbuilder]

You need a receiver thats meant for driving actuators rather than servos, those receivers have only two outputs that the actuator leads connect to

[@mfsmgame]

How do they work?

[@pironiero]

Is there any lightweight fpv plane on your project list?

[@microbuilder]

As a matter of fact there is, I want to build an FPV plane that I can fly in the house...pretty sure its possible, but we'll see lol

[@adam.gibson]

Can you use a normal PWM channel to control this somehow? I would really like to make a micro DLG... even though I know it wouldn't perform well, It would be neat to have one.

[@microbuilder]

Should be able to, the RX drives the coil like it would a regular brushed motor. As for a micro DLG, definitely go for it, I made an 18 gram 2 channel one using micro servos many years ago that worked quite well, the couple times I was able to catch a thermal it climbed like a tissue in a tornado lol

[@adam.gibson]

@@microbuilder I am a bit confused by that. PWM normally controls servos and not motors directly. I assume there is some power differences between servo throws as PWM varies how long voltage is applied, but I wouldn't expect it to be that much of a difference. I could be way off though. I am no electronics guy.

[@microbuilder]

@@adam.gibson I could be completely wrong too lol

[@whatelseison8970]

​@@adam.gibson You are right, you cannot drive these directly from a _servo_ PWM signal; not just because there's no current driving capability on the signal wire, but the pulse width only ranges from 5-10%, so even with an amplifier it still wouldn't work. If you had a very small servo with the gears stripped or something you could take the circuit board out and connect the coil where the motor used to go and either glue the pot in the centered position or replace it with a pair of fixed 2.5k resistors. Then you'd just drive it like a regular servo. The circuit board inside the servo does the job of translating a servo PWM signal with pulse width of 1-2ms (5-10%) to a high current motor PWM with pulse width between -100% and 100% depending on the position of the pot. With the pot fixed in the center the board basically becomes a tiny, bidirectional, brushed esc.

[@adam.gibson]

@@whatelseison8970 Thanks for the reply. I kind of suspected that but I wasn't sure if the pulse width had enough space between signal to change voltage. It makes sense that isn't the case otherwise there wouldn't be enough power in the servos at one of the extremes. I want a micro DLG about 6 or 7 inches that has movable surfaces. Just not enough need for something that small to get companies on that bandwagon I assume as I am sure there has to be some way to do it given enough smarter people than me on the task :).

[@fmsmodelRC]

Really enjoyed your video, can you add your business contact email address to your profile?

[@microbuilder]

Thank you, and you guys have some great RC stuff too! Email added...swear I had that on there already, but apparently not lol

[@microbuilder]

I just realized I had posted my old email account that I no longer have access to, so if you sent one in the last hour I wont be able to see it...just updated the email to the proper one, sorry about that!

[@fmsmodelRC]

@@microbuilder Thanks for the reply! I will send an email to you ASAP. Your hand-building is impressive.

[@fmsmodelRC]

@@microbuilder No worries, I'm just checking in now. LOL

[@fmsmodelRC]

Hey, I sent the letter, can you see if it went into your spam?@@microbuilder