What is with the recent surge in quadcopters?

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All of the sudden in the past 5+ years there seems to have been a surge in the popularity of quadcopters. My question is why? because the technology for this has to have existed for awhile considering we've had remote controlled helicopters place etc. Why are quadcopters such a big fascination? I just don't get why people act as if they are so remarkable and new.

Thank you
 
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Can't see anything in that link. I wanted more personal input than links..
 
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the revolution is in the various advances that allow robots to fly autonomously, hence the link to a course in autonomous flying vehicles. The quad rotor is one of the simplest designs that can do precise movement.

The other advances include but are not necessarily limited to
Image Analysis
Advances in microprocessor and microcontrollers to do the image analysis
smaller but strong permanent magnet motors
better batteries
AI and Machine Learning algorithms
 

russ_watters

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I think the main issue is cost. Cheaper electronics and cheaper batteries have brought the cost down to where consumers are willing to start buying them as toys and tools.
 
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Also, battery energy density per mass is much better right? (at any cost) When I was a kid people would fly toy airplanes that needed a gas motor. Now they can be run on batteries.
 

russ_watters

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Not sure. Lion batteries have been around for a long time, but have gotten much cheaper in the past few years. But it can't come anywhere close to matching the energy density of a gas powered plane.
 

AlephZero

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A control system for a "model sized" gas engine powered helicopter would be a huge engineering challenge, compared with a variable speed electric motor.

With a fixed wing gas engine model, you are not too bothered about precise control of forward speed, so you don't need accurate control of engine power. But that isn't good enough for hovering.

The smaller the model, the better the control needs to be. The greater mass and inertia of a big model is your friend, slowing down the response to inaccurate force inputs.
 
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I wouldn't credit control systems because at the same time we've seen a rise in popularity of electric RC helicopters which have mechanical balancing and no electronic control system. It must be the energy/weight ratio of batteries together with the power/weight ratio of motors and/or the cost of those.

The motors depend on the stronger rare earth permanent magnets which only became widespread 10-20 years ago. I guess battery technologoy was driven by phones and laptops.
 

cjl

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A control system for a "model sized" gas engine powered helicopter would be a huge engineering challenge, compared with a variable speed electric motor.

With a fixed wing gas engine model, you are not too bothered about precise control of forward speed, so you don't need accurate control of engine power. But that isn't good enough for hovering.
But model-size gas engine powered helicopters have existed for quite some time now, and they have very precise control.

http://youtu.be/sBY3b2b25E8
 

mheslep

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Also, battery energy density per mass is much better right? (at any cost) When I was a kid people would fly toy airplanes that needed a gas motor. Now they can be run on batteries.
Right, and those gas power aircraft could not be practically used indoors with the emissions. Batteries facilitate indooor use, so perhaps that, in part, explains the sudden onset. The other piece, I suspect, in the case of quad copters is the stability provided by much improved (size, cost, capability) controllers that was not available ~15 years ago.
 

AlephZero

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But model-size gas engine powered helicopters have existed for quite some time now, and they have very precise control.

http://youtu.be/sBY3b2b25E8
From what I see on Google, the cost of that model in kit form is about 10 or 20 times as much as the cheapest battery powered helicopters. That seems consistent with the increased engineering complexity.

Of course you don't need any form of automatic control system to successfully fly a vertical-thrust machine...
https://www.youtube.com/watch?v=f8W2SI4c93s
 

cjl

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From what I see on Google, the cost of that model in kit form is about 10 or 20 times as much as the cheapest battery powered helicopters. That seems consistent with the increased engineering complexity.

Of course you don't need any form of automatic control system to successfully fly a vertical-thrust machine...
Sure, but that's far from the cheapest gas (actually nitromethane) powered option as well. They definitely are more expensive than electrics, but the difference in price isn't very large (for a comparable size and performance). Of course, electrics are available that are much smaller than any available nitro powered helicopter, which does allow for a much cheaper entry into model helicopters than internal combustion would allow (and I do think that it's the proliferation of these micro-sized models and components that has caused the great increase in quadcopters that we've seen recently).
 
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mheslep

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Isn't nitro $25/gallon?
 

cjl

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Something like that, but an engine that displaces one cubic inch or so doesn't burn it that fast (and they run a mix of nitromethane and methanol, if I remember right).
 
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Hey,
to get back to the original point,

This surge is mostly due to safety reasons :
smaller propellers mean smaller kinetic energy akin
you are less likely to get beheaded by a quad than by an heli.

Add it the mentioned stunning mechanical simplicity over helis, in exchange for increased computing complexity, due to quad inherent instability.
The latter was made negligible by the recent progress in superlight closed-loop control systems embedded in the aircraft frame.
 

russ_watters

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Aerodynamically, the idea has been around a long time. But adding to what I said a year and a half ago, as of about 5 years ago, everyone in the western world now carries an inexpensive but complete avionics computer, sensor package and telemetry package in their pockets.
 

CWatters

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Fully functional RC Model helicopters are difficult to fly and beginners frequently crash. The type with two contra-rotating main rotors are easier but quad rotor drones are even easier to fly.
 
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It seems that the lithium-polymer battery and the "gyrostabilizer-on-a-chip" became widely available.
 

mheslep

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It seems that the lithium-polymer battery and the "gyrostabilizer-on-a-chip" became widely available.
Yes, and one more: the neodymium permanent magnet DC motor which enables four lightweight motors, so that the vehicle total mass and moment is reasonable. Take away any of those and the quad fails to take off. Ba-dump-dump.
 

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