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Old 09-28-2014, 12:04 AM   #1
Mapoff
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Default here we go. single vs multirotor

Currently flying a trex 800 with a brushless gimbal. Its doing really well. I'm wondering if anyone has tried both single rotor and multirotor? I don't have any vibrations from the blades, just movement from quick craft movements. I'm wondering if multi's have any advantage as far as gimbal performance while on the two different crafts. I recently attempted a shoot in 30+ mpg winds. Maybe more like 20 with 30 gusts. From what i've seen multis cost more, and can't handle wind as well.
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Old 09-28-2014, 01:23 PM   #2
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Multis are the goto platform for smooth video and easy to use. A first time user has a good chance of success the first time.
A friend has a quad he's used at 400 feet.
And in windy conditions.
They are both aircraft they both cost a lot of money.
Multis sound disgusting and it's no wonder these amateur "videographers" have caused laws to be enforced like now in our national parks. Amateurs.
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Old 09-28-2014, 04:29 PM   #3
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A multirotor is like a Segway. Anyone can quickly get moving with little skill or effort. A single rotor is like a Hyabusa. It's performance in the hands of a skilled rider is amazing. Here were my thoughts on the subject

http://aerial-video.blogspot.com/201...-platform.html

Also I don't trust any current flight controller flying $75K in camera equipment.
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Old 09-28-2014, 07:25 PM   #4
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The right tool for the right job.

Having been involved in aerial for the last 15 years and experience with both multi and single rotor I can say that both have there place.

It was my experience that I could shoot about 90% of what I wanted and needed with a heli. At the same time I could shoot about 75% of those same wants and needs with a multi. Not one can do it all regardless what any fanboy tells you.

The gap is due to the fact that a multi cannot handle swift wind changes and winds that blow up as seen when flying over a cliffs edge or over a large object. I am not saying the multi could not do these requirements it is just a better result when doing 100's of runs in the same conditions with a single rotor.

When people say multi are safer, take that with a grain of salt. Here in Hawai we had a multi hit a persons face and left them blind in one eye and impaired vision In the other. Would a single rotor done more damage......perhaps but that is all speculation which is what most of the comments of multis being safer come from.

Often people are comparing a small multi that carries a gopro to that of a 800 single rotor carrying a serious load. Of course the single rotor is going to look more dangerous and perhaps it is in that comparison. As we see the multi sector grow so does the size needed to compete with a 800 sized single rotor.

Also cost difference is not in favor of the multi at all occasions. A serious large and heavy duty built multi carrying a serious camera load can cost the same if not more than a single rotor carrying the same weight.

I have personally seen 5 serious AP multis go into the Pacific Ocean at the hands of 4 different skilled and seasoned pilots. Only one of them fly multis exclusively anymore.

Let's not forget about fly always that are all too common in the multi world when using a auto controller. This is reesponsable for at least two of the above 5 mentioned.

Let's not forget that a multi cannot be auto'd down like a single rotor and thus can be more prone to going "down" in a place not intended when something goes wrong.

I am partial to a properly designed, built and flown single rotor but do recognize the shift in our AP world to multis and also recognize the ability of these small and cheap multis to be flown with professional results.

A big thing to consider with the shift in out AP market to mostly multis, we will see the advancements hit the multi world first... Just because more companies are cashing in on the multi boom at the moment. Competition brings pricing down and advancements faster.

In the end "the right tool for the right job"....both are great platforms.
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Old 09-28-2014, 08:43 PM   #5
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Very impressed with the responses. I started with the trex 700. Then I stretched to a 800 with the kit which was only $35. The original 700 was the f3c which only cost $750. An Octo with the same lifting capacity was over $2k. I've been more than happy with using a single. It sure gains a lot of good attention. I do use tha Naza H which is almost an artifact now. My GPS puck came off mid flight the other day when I was really far away. It dipped forward hard. Switched to manual and brought her in. I've never practiced an auto in real life. It should be done. I'm scared of getting it wrong. I'm piecing a second 700 together for flying only and will get more daring with that.

I was curious mostly of the high wind ability. I recently went FBL and the wind conditions seemed to cause a lot more rocking than it did with the flybar setup. The flybar produces too many vibrations for me.
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Old 09-28-2014, 09:04 PM   #6
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I have seven single rotor AP machines. My FB helis have no more vibration than the FBL versions. The FB must be perfectly straight, aligned and balanced however, emphasis on perfectly.

The only thing harder than getting a flybar happy is not bending it moving it around!
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Old 09-28-2014, 09:54 PM   #7
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I should have been clear. I had the v2 f3c head that had no vibrations. Overtime I had vibes. I bought a whole new head and I just couldn't get it to stop vibrating. I thought about putting it back on. Would you say flybar is better due to its passive reaction or FBL? Speaking on winds. I hated flying flybar manual. It required extreme attention. I can fly the FBL with ease.

That flybar always seemed to get hit but it also has a carbon fiber sleeve over to give it some strength.
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Old 09-28-2014, 10:39 PM   #8
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In gusty winds over 25 mph my FB helis are more stable. You have to know how to properly set up the delta mixing, paddle design, blade airfoil, flybar length, and so on all work together. It's easy to blame vibrations on the flybar that are really another issue on the head. Having several helis of the same identical design makes isolating the bad actors much easier as you can trade parts.
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Old 09-28-2014, 11:38 PM   #9
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The manual is somewhat lacking on the more precise adjustments. I may go back. I got a big opportunity that came up so I went with what I could make work, and work it did except the wind made it tough.

How about a FB heli to a multirotor? There is a guy in NC who flies an octo mostly and he has a video that says flying in 35mph wind. The video looks perfect and you can see the trees shaking all over. There has to be some software stabilization. I think most demo feels are software stabilized which is deceptive.
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Old 09-29-2014, 02:39 PM   #10
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Yep, two excellent posts. Completely agreed xfc3dcd, nice blog posts with point-form. Though I actually find a that multirotors can be 5 times the price of a heli, not just double. You can built a pretty nice 7-800 heli for about $3000. But you can easily spend $15k building an Octo that can lift the same payload.

And as for reliability, I find that the larger multirotors seem to be unreliable. I think the problem is they are pushing the high-power systems too hard. ESC's burn out, lose sync, etc.

I've seen a number of huge multirotor, with 28" props built in the last year, but I have not seen one in use yet.
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Old 10-04-2014, 07:00 AM   #11
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Indenpendent of flying characteristics, cost etc. - there are a lot of advantages by fly the camera with a multirotor.
For professional work with separate pilot and camera operator - will the freedom of camera movement be the most important.
In a typical single rotor setup is the gimbal with camera mounted on front of the heli.


In multirotor setup is the camera underneath the copter.

This solution give the camera operator a lot more of freedoom a dramatically enlarges the efficiency of the work. This means - you can do more complicaded shots easilly and faster. And the shots are what you get pay for.
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Old 10-04-2014, 08:36 AM   #12
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I am equally comfortable flying my SR helis in all orientations. This, combined with working with the same camera Op for the last 10 years, allows getting any shot a multirotor can get, all without the worry of getting booms in the shot. We also have SR rigs with underslung 360 mounts just like MR.
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Old 10-04-2014, 11:20 AM   #13
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Yes, having an under slung camera does make some shots easier and in the multi universe typically allows it to be a one man operation. However like noted previous by others...everything has a tradeoff or compromise in performance in another area. Ease of use for complicated shoots may become moot if the shot requires high speed agility as a first priority.

Underslung cameras present a design challange if flight agility is a top priority over ease of use or signle operator capabilities. Ideally to achieve top flight agility one needs to not only pay attention to CG but also the moment force or "swing weight" of the various components masses in relation to the yaw, roll and pitch axis.

Underslungs tend create sluggish response in both pitch and roll while yaw is unaffected. It is just a result of the physics involved hanging that mass so far away from the COG in the roll and pitch axis

Properly designed front mounts can increase pitch and roll agility however at the expense of yaw response.

Again their is no such thing as blanket statements when it comes which platform is better than the other. Everything is a trade off depending on what your top priority performance factor is. Some applications will favor one platform over the other but neither platform came be claimed universally superior.


Quote:
Originally Posted by Ivamos View Post
Indenpendent of flying characteristics, cost etc. - there are a lot of advantages by fly the camera with a multirotor.
For professional work with separate pilot and camera operator - will the freedom of camera movement be the most important.
In a typical single rotor setup is the gimbal with camera mounted on front of the heli.


In multirotor setup is the camera underneath the copter.

This solution give the camera operator a lot more of freedoom a dramatically enlarges the efficiency of the work. This means - you can do more complicaded shots easilly and faster. And the shots are what you get pay for.
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Old 10-04-2014, 11:39 AM   #14
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Quote:
Indenpendent of flying characteristics, cost etc. - there are a lot of advantages by fly the camera with a multirotor.
For professional work with separate pilot and camera operator - will the freedom of camera movement be the most important.
In a typical single rotor setup is the gimbal with camera mounted on front of the heli.
This is only because historically we've had pretty unimaginative AP helicopter platforms that are little more than standard RC helis with camera booms strapped on.

Look at some of KopterKids designs, and see what is possible.
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Old 10-04-2014, 01:33 PM   #15
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Quote:
I am equally comfortable flying my SR helis in all orientations. ...
Quote:
Look at some of KopterKids designs, and see what is possible.
I know i know...
I am speaking about MY Experience and typically setups.
I did change to to multirotor (but i am still enthustiastic helicopter pilot) and i can only say - it works better for me.
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Old 11-11-2014, 01:20 PM   #16
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Quote:
Originally Posted by R_Lefebvre View Post
This is only because historically we've had pretty unimaginative AP helicopter platforms that are little more than standard RC helis with camera booms strapped on.

Look at some of KopterKids designs, and see what is possible.


Look what those guys have recently done with the CK800 airframe AXS Gimbal. This was shot between 9,000 - 10,000 feet in elevation carrying RED camera and assorted downlink gear. Pretty stoked to see the rig make a cameo in couple shoots.

We are working on version 3 of the CK airframe with the key difference being an integrated gimbal/airframe concept. Gone is the traditional forward tube mount dampening system that is wildly used in various forms. It will be a hydrid underslung/forward placement to get the swing weight as optimized as possible to maintain high performance as to cyclic and yaw response. It will also make the FBL controllers job much easier with one more cohesive mass rather than two loosely connected masses ! Weird interaction can happen between the fbl rudder and gimbal yaw controlers when you get a large mass like a RED forward on tubes.

This is a 9min teaser, tune in to ABC on November 30th at 2pm for the full 44 minute presentation. Aerial shoots start at 1:50 and are rather frequent from that point to the end.


Copter cameo shot
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Old 11-12-2014, 03:25 PM   #17
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Heh, somebody just posted this on my Facebook page, cause I'm into off-roading I guess. Anyway, what I really cared about was the UAV footage.

Then I saw the copter at 1:08, I knew it was you guys. Multi's can't do that stuff!



I've been working on a design sort of like yours, but in 500 size, for Go-Pro class cameras.
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Old 11-12-2014, 08:04 PM   #18
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I've always wanted to make a 500 like that but never had the time. It would be such a great platform to bridge the gap between Phantom size quads and larger hexa/oct/700s!

Good luck with it and post pictures
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Old 11-12-2014, 11:31 PM   #19
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So what does a set of those custom frames cost? I like how the camera is shifted closer to center of gravity. Keeps things working better than all the weight far out at each end.
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Old 11-13-2014, 12:16 AM   #20
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A lot of the components are off the shelf at normal retail price before any of the custom work comes into view. Goblin, DJI retracts plus a good hand full of other bits and pieces. I only use 3K CF nowadays so the raw materials(AF & AL) easily equal the cost of the stock components. That's the total hard cost before factoring in the roughly 200hrs spent in CAD, CAM and cnc machine time to go from CK700 V1 to CK800 V2 to now CK800 V3! There has only been one of each so far so unfortunately no economy of scale has factored into the equation as of yet. For V3 Im tinkering with Firgelli linear actuators and cnc alloy landing skids vs the custom carbon wrapped skid/dji combo. That would knock off a huge chunk of $$$
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