# Why are there no full sized multicopters? **URL:** \ **Category:** Factual Questions\ **Created:** [February 5, 2012, 4:08am UTC](https://boards.straightdope.com/t/why-are-there-no-full-sized-multicopters/611827 "2012-02-05T04:08:25Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![chacoguy](https://avatars.discourse-cdn.com/v4/letter/c/50afbb/32.png) [@chacoguy](https://boards.straightdope.com/u/chacoguy)\ **Post date:** [February 5, 2012, 4:08am UTC](https://boards.straightdope.com/t/why-are-there-no-full-sized-multicopters/611827/1 "2012-02-05T04:08:25Z")
[Multicopter](https://www.google.com/search?tbm=isch&hl=en&source=hp&biw=1366&bih=592&q=multicopter&gbv=2&oq=multicop&aq=0&aqi=g4g-S6&aql=&gs_sm=c&gs_upl=2146l13124l0l17104l10l10l1l0l0l0l153l1272l0.9l9l0) I recall a disastrous video of several helicopters and a blimp from years ago; but still, why does it work so well on a small scale and yet, isn’t even attempted at full scale? I’ll define full scale as a rotor diameter of ten meters. ---
**Author:** ![Joey\_P](https://avatars.discourse-cdn.com/v4/letter/j/919ad9/32.png) [@Joey\_P](https://boards.straightdope.com/u/Joey_P)\ **Post date:** [February 5, 2012, 4:16am UTC](https://boards.straightdope.com/t/why-are-there-no-full-sized-multicopters/611827/2 "2012-02-05T04:16:17Z")
How many rotors does it have to have to be a multicopter? The chinook has two horizontal rotors. I see on wiki, the chinook (while looking for a picture) is called a Tandem Helicopter. The [wiki](http://en.wikipedia.org/wiki/Tandem_rotors) page gives a list of others as well. ---
**Author:** ![TriPolar](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tripolar/32/3008_2.png) [@TriPolar](https://boards.straightdope.com/u/TriPolar)\ **Post date:** [February 5, 2012, 4:17am UTC](https://boards.straightdope.com/t/why-are-there-no-full-sized-multicopters/611827/3 "2012-02-05T04:17:38Z")
There was an English three rotor copter tested once. It had a triangular air frame. I saw a small clip of it many years ago, but otherwise I’ve never found any more info. The main problem is that multicopters are uneccesarily complex. The single screw with tailrotor design has dominated the helicopter industry because of it’s simple, basic design. Counter-rotating co-axial rotors and intermeshed rotors have been used, but they are still more complex, and as a result have a higher failure rate than the simple single screw. Tandem rotors have been used with success, but they have the problem of transmitting power to 2 rotors space far apart. For model helicopters multiple rotor systems are easy, and they are more stable than the single screw. But translating that into a full size helicopter is more difficult and costly, and introduces safety issues. The multi-rotor blimp disaster is an example of what can go wrong. ---
**Author:** ![chacoguy](https://avatars.discourse-cdn.com/v4/letter/c/50afbb/32.png) [@chacoguy](https://boards.straightdope.com/u/chacoguy)\ **Post date:** [February 5, 2012, 4:19am UTC](https://boards.straightdope.com/t/why-are-there-no-full-sized-multicopters/611827/4 "2012-02-05T04:19:45Z")
I’m pretty sure ALL helicopters have at least two; so, a multicopter would be one that has more than two. I’m happy to be educated either way. ---
**Author:** ![Robot\_Arm](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/robot_arm/32/18280_2.png) [@Robot\_Arm](https://boards.straightdope.com/u/Robot_Arm)\ **Post date:** [February 5, 2012, 4:34am UTC](https://boards.straightdope.com/t/why-are-there-no-full-sized-multicopters/611827/5 "2012-02-05T04:34:05Z")
> [@TriPolar](#): > > There was an English three rotor copter tested once. It had a triangular air frame. I saw a small clip of it many years ago, but otherwise I’ve never found any more info. > > The main problem is that multicopters are uneccesarily complex. The single screw with tailrotor design has dominated the helicopter industry because of it’s simple, basic design. Counter-rotating co-axial rotors and intermeshed rotors have been used, but they are still more complex, and as a result have a higher failure rate than the simple single screw. Tandem rotors have been used with success, but they have the problem of transmitting power to 2 rotors space far apart. > > For model helicopters multiple rotor systems are easy, and they are more stable than the single screw. But translating that into a full size helicopter is more difficult and costly, and introduces safety issues. The multi-rotor blimp disaster is an example of what can go wrong. It looks like most of those multicopters have fixed-pitch propellers. I suspect they’re controlled by speeding up or slowing down some of the props relative to others. At full size there’d be a lot more rotational inertia; maybe the control response would be too slow. ---
**Author:** ![garygnu](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/garygnu/32/2924_2.png) [@garygnu](https://boards.straightdope.com/u/garygnu)\ **Post date:** [February 5, 2012, 4:44am UTC](https://boards.straightdope.com/t/why-are-there-no-full-sized-multicopters/611827/6 "2012-02-05T04:44:41Z")
Some things don’t scale. ---
**Author:** ![TriPolar](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tripolar/32/3008_2.png) [@TriPolar](https://boards.straightdope.com/u/TriPolar)\ **Post date:** [February 5, 2012, 5:04am UTC](https://boards.straightdope.com/t/why-are-there-no-full-sized-multicopters/611827/7 "2012-02-05T05:04:43Z")
> [@Robot\_Arm](#): > > It looks like most of those multicopters have fixed-pitch propellers. I suspect they’re controlled by speeding up or slowing down some of the props relative to others. At full size there’d be a lot more rotational inertia; maybe the control response would be too slow. Not at full size. Rotor speed is a terrible way to control a helicopter. It just isn’t responsive enough. It works for light tiny models, but the only full size copters I’ve ever heard of that use rotor speed control are small tip jet models. All full size machines run their engines in a narrow operating range varying fuel to maintain that range based on load. The non-linear output of engines makes this a necessity. ---
**Author:** ![PlainJain](https://avatars.discourse-cdn.com/v4/letter/p/5daacb/32.png) [@PlainJain](https://boards.straightdope.com/u/PlainJain)\ **Post date:** [February 5, 2012, 5:10am UTC](https://boards.straightdope.com/t/why-are-there-no-full-sized-multicopters/611827/8 "2012-02-05T05:10:30Z")
Lack of need? ---
**Author:** ![Gagundathar](https://avatars.discourse-cdn.com/v4/letter/g/a183cd/32.png) [@Gagundathar](https://boards.straightdope.com/u/Gagundathar)\ **Post date:** [February 5, 2012, 5:13am UTC](https://boards.straightdope.com/t/why-are-there-no-full-sized-multicopters/611827/9 "2012-02-05T05:13:29Z")
Too bad, those things look very cool. I wonder how much an RC version would cost. ---
**Author:** ![bldysabba](https://avatars.discourse-cdn.com/v4/letter/b/ecccb3/32.png) [@bldysabba](https://boards.straightdope.com/u/bldysabba)\ **Post date:** [February 5, 2012, 7:02am UTC](https://boards.straightdope.com/t/why-are-there-no-full-sized-multicopters/611827/10 "2012-02-05T07:02:56Z")
> [@Gagundathar](#): > > Too bad, those things look very cool. The also do some [very](http://www.youtube.com/watch?v=MvRTALJp8DM&feature=mfu_in_order&list=UL) [cool](http://www.youtube.com/watch?v=YBsJwapanWI&feature=player_embedded) [things](http://www.youtube.com/watch?v=YQIMGV5vtd4&feature=player_embedded) (in some labs anyway). ---
**Author:** ![Broomstick](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/broomstick/32/246_2.png) [@Broomstick](https://boards.straightdope.com/u/Broomstick)\ **Post date:** [February 5, 2012, 12:19pm UTC](https://boards.straightdope.com/t/why-are-there-no-full-sized-multicopters/611827/11 "2012-02-05T12:19:09Z")
> [@Gagundathar](#): > > Too bad, those things look very cool. > I wonder how much an RC version would cost. They start around $150 USD and go up from there. $200-400 would be a mid-range price. ---
**Author:** ![gunnergoz](https://avatars.discourse-cdn.com/v4/letter/g/e95f7d/32.png) [@gunnergoz](https://boards.straightdope.com/u/gunnergoz)\ **Post date:** [February 6, 2012, 1:43am UTC](https://boards.straightdope.com/t/why-are-there-no-full-sized-multicopters/611827/12 "2012-02-06T01:43:12Z")
Just my opinion, but if a multi-copter was to really be built full-size, it would be best if it had several units of dual, contra-rotating, coaxial rotors such as found on Russian Kamov military and civilian models. This would at least eliminate rotor torque strain on the assembly. But who knows. The only aero-stat to ever try the configuration (a blimp bearing a frame holding four h-34 helicopers) failed, apparently due to mechanical stresses on the steel truss structure holding it together, killing at least one of the H-34 pilots. ---
**Author:** ![kanicbird](https://avatars.discourse-cdn.com/v4/letter/k/5f8ce5/32.png) [@kanicbird](https://boards.straightdope.com/u/kanicbird)\ **Post date:** [February 6, 2012, 2:15am UTC](https://boards.straightdope.com/t/why-are-there-no-full-sized-multicopters/611827/13 "2012-02-06T02:15:53Z")
Another factor may be size needed for landing/takeoff and storing. Those things seem to need a lot more area which negates some of the versatility of a helicopter. ---
**Author:** ![Joey\_P](https://avatars.discourse-cdn.com/v4/letter/j/919ad9/32.png) [@Joey\_P](https://boards.straightdope.com/u/Joey_P)\ **Post date:** [February 6, 2012, 2:28am UTC](https://boards.straightdope.com/t/why-are-there-no-full-sized-multicopters/611827/14 "2012-02-06T02:28:01Z")
> [@bldysabba](#): > > The also do some [very](http://www.youtube.com/watch?v=MvRTALJp8DM&feature=mfu_in_order&list=UL) [cool](http://www.youtube.com/watch?v=YBsJwapanWI&feature=player_embedded) [things](http://www.youtube.com/watch?v=YQIMGV5vtd4&feature=player_embedded) (in some labs anyway). I wonder how many lights they smashed before they put that giant net in. (Actually, I’m guessing it was more to keep them from hitting the wall) ---
**Author:** ![Mangetout](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mangetout/32/19_2.png) [@Mangetout](https://boards.straightdope.com/u/Mangetout)\ **Post date:** [February 6, 2012, 7:31am UTC](https://boards.straightdope.com/t/why-are-there-no-full-sized-multicopters/611827/15 "2012-02-06T07:31:46Z")
> [@chacoguy](#): > > I’m pretty sure ALL helicopters have at least two; so, a multicopter would be one that has more than two. I’m happy to be educated either way. I’ll bite. I believe there is a design that uses a jet exhaust instead of a tail rotor. ---
**Author:** ![Sizzles](https://avatars.discourse-cdn.com/v4/letter/s/e480ec/32.png) [@Sizzles](https://boards.straightdope.com/u/Sizzles)\ **Post date:** [February 6, 2012, 12:14pm UTC](https://boards.straightdope.com/t/why-are-there-no-full-sized-multicopters/611827/16 "2012-02-06T12:14:08Z")
How about the Moller flying car; [http://www.google.co.uk/imgres?imgurl=http://hackedgadgets.com/wp-content/\_flying\_car.jpg&imgrefurl=http://hackedgadgets.com/2007/07/27/moller-flying-car-enters-production/&usg=\_\_LFSzEqZ1maTYCCweNxVTVvAOIdE=&h=340&w=500&sz=58&hl=en&start=8&zoom=1&tbnid=Q48rIL45chalgM:&tbnh=88&tbnw=130&ei=rcMvT9DvOJTn8QOX7pj1Dg&prev=/images%3Fq%3Dflying%2Bcar%26hl%3Den%26sa%3DX%26gbv%3D2%26tbm%3Disch&itbs=1](http://www.google.co.uk/imgres?imgurl=http://hackedgadgets.com/wp-content/_flying_car.jpg&imgrefurl=http://hackedgadgets.com/2007/07/27/moller-flying-car-enters-production/&usg=__LFSzEqZ1maTYCCweNxVTVvAOIdE=&h=340&w=500&sz=58&hl=en&start=8&zoom=1&tbnid=Q48rIL45chalgM:&tbnh=88&tbnw=130&ei=rcMvT9DvOJTn8QOX7pj1Dg&prev=/images%3Fq%3Dflying%2Bcar%26hl%3Den%26sa%3DX%26gbv%3D2%26tbm%3Disch&itbs=1) Looks like it has 8 rotors. ---
**Author:** ![CalMeacham](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/calmeacham/32/35_2.png) [@CalMeacham](https://boards.straightdope.com/u/CalMeacham)\ **Post date:** [February 6, 2012, 1:00pm UTC](https://boards.straightdope.com/t/why-are-there-no-full-sized-multicopters/611827/17 "2012-02-06T13:00:10Z")
Heck, Robur’s \*Albatross \* had dozens of 'em: [http://www.allposters.co.uk/-sp/The-Albatross-Illustration-from-Robur-Le-Conquerant-by-Jules-Verne-Paris-Hetzel-1886-Posters\_i1589761\_.htm](http://www.allposters.co.uk/-sp/The-Albatross-Illustration-from-Robur-Le-Conquerant-by-Jules-Verne-Paris-Hetzel-1886-Posters_i1589761_.htm) [http://www.eccentric-cinema.com/reviews2011/master\_world.htm](http://www.eccentric-cinema.com/reviews2011/master_world.htm) [http://ohomemilustrado.blogspot.com/2011/06/albatross-sketch-from-robur-conqueror.html](http://ohomemilustrado.blogspot.com/2011/06/albatross-sketch-from-robur-conqueror.html) ---
**Author:** ![Reply](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/reply/32/15952_2.png) [@Reply](https://boards.straightdope.com/u/Reply)\ **Post date:** [February 6, 2012, 1:06pm UTC](https://boards.straightdope.com/t/why-are-there-no-full-sized-multicopters/611827/18 "2012-02-06T13:06:33Z")
> [@Gagundathar](#): > > Too bad, those things look very cool. > I wonder how much an RC version would cost. Ever since the [AR.Drone](http://ardrone.parrot.com/parrot-ar-drone/usa/) was released, there’s been a growing [DIY quadrocopter scene](http://diydrones.com/). Not a bad time to get involved, what with the technology (namely control interface and remote imaging) evolving so rapidly and the legislation on civilian UAVs still virtually non-existent. Who knows if they’ll still be legal in a few years… ---
**Author:** ![Reply](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/reply/32/15952_2.png) [@Reply](https://boards.straightdope.com/u/Reply)\ **Post date:** [February 6, 2012, 1:11pm UTC](https://boards.straightdope.com/t/why-are-there-no-full-sized-multicopters/611827/19 "2012-02-06T13:11:15Z")
> [@Mangetout](#): > > I’ll bite. I believe there is a design that uses a jet exhaust instead of a tail rotor. [NOTAR](https://en.wikipedia.org/wiki/NOTAR)? (no tail rotor) ---
**Author:** ![CalMeacham](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/calmeacham/32/35_2.png) [@CalMeacham](https://boards.straightdope.com/u/CalMeacham)\ **Post date:** [February 6, 2012, 1:52pm UTC](https://boards.straightdope.com/t/why-are-there-no-full-sized-multicopters/611827/20 "2012-02-06T13:52:06Z")
> [@Reply](#): > > [NOTAR](https://en.wikipedia.org/wiki/NOTAR)? (no tail rotor) They should start their own nation. They could call it the NOTAR Republic. (d&r) [Next page](https://boards.straightdope.com/t/why-are-there-no-full-sized-multicopters/611827.md?page=2)