Multi-rotors: Aerial Filming

by ericmonroe74 | May 1, 2012 | (52) Posted in Projects

Multi-rotors: Aerial Filming

The "Perfect" Aerial Platform

By: Eric Monroe  (Shadow74)


I have seen this topic discussed many times across several different forums.  While there is more than one way to "skin a cat" the following is a collection of things that I have learned first-hand in my successes and failures with multi-rotors.



My 2 cents…..

(okay its probably more like 10 cents)  :)


Achieving this happens with quite a few things going on at once.  First and foremost (from what I have found) you have to start with a stable copter. You can have the most awesome mount in the world and with the wrong copter you are still gonna get the typical bumpy/shaky/jello Youtube crap when it comes to your footage.  Start with a good copter. One copter that I believe fits this category (as far as one that can be purchased from a company) is the Cinestar Revolution by Quadrocopter. They make a Cinestar 6 and 8 with optional GPS, position hold, and the best 3 axis gyro stabilized gimbal (IMHO) that I have ever seen. These machines are state of the art, and have the power to carry everything from a GoPro up to a RED EPIC cinema camera. Here is a video featuring this setup:

(Enjoy because this is STELLAR piloting/camera work....Tabb is one of the best in the business)

 

The Cinestar copters, are unfortunately currently out of my price range. Ranging anywhere from $8,000 to over $15,000 depending on options.  Since I still want to produce quality aerial video I set out to invent my own platform. (admittedly however, with all the R/D I have put into doing this I could have probably bought a Cinestar 6 and been done with it.)

Here are some pics of a few copters that I have designed, re-designed.....and then redesigned again.  :)





A few things I have learned about obtaining great footage:

The copter cannot have a small footprint. A Gaui 330 for example is just too small.  So are most of the out-of-the-box copters.

Here is the copter that I started with:


Most of what I have learned early-on about aerial filming came from flying this little guy.  In a near-perfect dead calm situation I was able to gather a handful of nice shots, add the slightest wind and the footage was not usable.  The small footprint and lack of mass just makes things that much more difficult in terms of flying characteristics.


The more motors, the more stable. Tricopters are awesome to fly, but cannot compare to a quad for gathering smooth footage especially when doing slow stuff in a hover, they just won't sit still enough. (tri-copters excel at faster follow footage such as chasing a motorcycle etc.)  A quad cannot compare to a hexa.... and so on.

The heavier your multi-rotor is (within reason) the better and more rock solid that they seem to fly....problem then is powering it for more than 4-5 minutes. For filming, I will no longer fly anything setup to fly with a 3-cell.  Of course I am not saying that it can't be done, however if you build a machine that is meant to carry anything more than a GoPro forget it.  My latest quad design (the angry bird) measures 38" from motor to motor, weighs 6 1/2 lbs, flys the Cinestar's motors swinging 14x4.7 props and is powered by a 50C 5-6 cell lipo. This machine will carry a GoPro for close to 15 minutes.  For GoPro only machines you can make a 3 cell system work, but you will get WAY more power and flight time if you go with at least a 4-cell setup.  FPV Manuals sells a Delrin version of David W's tri-copter and advertises 28 minute flights with a GoPro using two 3300mah 4S lipos running in parallel. It is not the prettiest machine to look at IMHO, it has wooden arms etc. but flies for a LONG time which FPV guys love....still a bit too lightweight for filming. 


The more rigid the frame, the better footage you will get. This is because fewer vibrations are able to transfer throughout the copter frame itself.  I discovered this when I built my first big quad using metal arms.  I built another duplicate frame using wood arms and it was full of vibrations that are not present in my metal armed version.


Prop balancing is an art.....one that you MUST not only get "good" at, but AMAZING at. I have spent as long as 30+ minutes a piece precision balancing my props for my multi-rotors. You have to static balance not only the blades, but also the center hubs…..then dynamic balance after that. Prop balancing is CRITICAL to good footage.  Balancing the motors is also extremely important.  Precision takes patience……but yields fantastic end results.  When everything is balanced properly, fewer vibrations make it to the camera and the flight controller.  The gyros on a multi-rotor flight controller are extremely sensitive.  The fewer vibes that make it to the controller, the smoother and more stable your flying/filming experience will be.



Enough about copters…….let's talk camera mounts:

Once you have a nice WIDE copter platform to carry your camera, mounting it to the copter is next. (Would be nice if cameras just flew themselves….that would save us all a lot of hassle.)  I have experienced that keeping the weight that you are carrying in line with the forward flying plane of the aircraft keeps it from penduluming the copter around and making it "pitchy" when it flies.  A number of pilots mount their cameras (especially the larger ones) under the copter.  This can make your copter fly goofy at high speeds. In a hover it is usually not too bad, but there will be times where you will need to accelerate to follow a boat or a motorcycle and when transitioning from fast forward flight back to a hover the weight hanging underneath wants to keep going forward causing the nose of the copter to pitch up.  When using a camera with a wide angle lens like a GoPro Hero, hanging it underneath will most often times cause the landing gear, the props and the boom arms to show up in your shot.  Putting the camera out on a boom up front and counterbalancing with the battery(s) in the back keeps everything in line and gets the camera out front where it can do what its supposed to…….capture great footage.


There are 2 things to do about vibration.....minimize what the copter is creating through a rigid frame, proper balancing of props etc. and then dealing with the inevitable vibrations that are left over. Vibrations (from what I have experienced through trial and error) must have a path to travel. Minimizing the contact point between your camera boom and the copter helps tremendously to deal with existing vibrations. Once the few existing vibrations manage to get through that point and travel out the boom, the next step is up the risers to the secondary camera boom. Most all of them dissipate before reaching the secondary boom.


If you do choose to mount your camera under the copter, make sure that the measurement from motor to motor is significantly larger than the distance from the top of your copter to the bottom of your camera mount.  If the latter distance is the same or greater than the motor to motor measurement you will have an extremely unstable machine and a crash waiting to happen.



Some of my work:

Here are two videos that I put together using my multi-rotor designs. The first is filmed entirely with the GoPro Hero and the second with a Canon 5D MK2 HD-DSLR camera.  Enjoy!



 

 


An additional 2 cents…….  :)

Multi-rotors have fast became my favorite machines to fly.  I have designed and flown several and have had an absolute blast learning how to tweak these amazing machines for gathering awesome aerial video.  I can honestly say that my feet are firmly planted in this area of flying and I am looking forward to the continual growth of multi-rotors in the R/C world.  Sharing each of our experiences whether positive or negative helps everyone.  Make sure to post on the forums!  Happy flying!


Multi-rotors FTW!  :)


Cheers!


Eric Monroe (Shadow74)


COMMENTS

ilovefpv on May 4, 2012
Great article... 5 stars...
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ericmonroe74 on May 6, 2012
Thanks a bunch! :o) there will be more to come soon.
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Capello1986 on May 8, 2012
Amazing video and totally love the tricopter with the gopro mount sticking out there front!
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.Joel on May 8, 2012
Some incredible footage there, thanks for sharing!
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Jake Wells on May 11, 2012
"The heavier your multi-rotor is (within reason) the better and more rock solid that they seem to fly....problem then is powering it for more than 4-5 minutes."

I found this very encouraging. The first version of my quad I tried to make it as light as possible. It was tough to hover it "being light" It either wanted to climb of stall. After adding more weight with the camera it became much more stable and easier to maintain altitude. Thanks. I haven't weighed mine but I'm getting 7.5 to 8 min on a 2200mAh battery.
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SkySlayer on May 2, 2012
Thanx man that helped me alot.
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ericmonroe74 on May 2, 2012
Glad to hear! :)


Cheers!

Eric
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dege13 on June 21, 2012
The art of Prop Balancing... Can you please do a video or article (or both) on prop balancing?
Most people say 'put a piece of tape in it' and that's all the detail you get. I am looking for more information than that. It sounds like you have a lot of ideas, tips and suggestions for prop balancing and I am sure that everyone with vibration issues would love to hear about it from a master. Thanks!!
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juniorrc on May 9, 2012
Thanks for sharing your knowledge.
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Larry_AK on May 8, 2012
Thanks great article!
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stonekap on May 2, 2012
I really dig your footage Eric!
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ericmonroe74 on May 2, 2012
Thanks a bunch! That truly means a lot. :o) I am excited to see where this path leads.

Cheers!

Eric
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ycopter on May 22, 2012
Thanks for sharing your considerable experience.
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EvilAl on May 16, 2012
Hey Shadow74, do you have a build thread or detailed pics of your angry bird quad?

And curious...if you say hexas are more stable than quads, why haven't you experimented with them yet?
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ericmonroe74 on May 23, 2012
I will be doing a build-log of my angry bird quad, as soon as i get caught up with some of my work :o)

I am also going to write an article on how to build my camera mount for the GoPro

Eric
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ericmonroe74 on May 22, 2012
Hey Evil,

I have a hexa, just had a motor issue and I am waiting on a warranty replacement. Here is a link to my hexa's maiden flight.

http://www.youtube.com/watch?v=1I3Ds6gloUo&feature=g-upl


Here is the thread i started about my hex a on the flattest forum ;o)

http://forum.flitetest.com/showthread.php?1370-My-Hexa-copter-o)&highlight=hexacopter


(Oh, and I am starting an Octo-copter in the next couple weeks....stay tuned)


Cheers!

Eric
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DejaD on May 8, 2012
Very nicely done article. You have a wealth of knowledge on the whole quad-copter thing. I'll be re-reading this in the future.
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Jake Wells on May 9, 2012
Very Cool man thanks for posting.
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yamark on June 6, 2012
Man you are a talent!! luv your work!!
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JuggNugg on December 22, 2013
Amazing footage! What city/town did you shoot in?
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Grearson on February 4, 2015
i cant give more then 5 Stars, awesome and yet way to go for me. Just started with a DJI Style Spider Quad.. aiming to upgrade it to a F550 as soon as i can afford it =)
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StereotypicalBrit on April 12, 2015
hello from England,
Just wondering if the FT Electrohub would make a good aerial photography platform? Would it be possible to put a gimbal on it?
kind regards, Finn.
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Multi-rotors: Aerial Filming