Quadcopter long flight time - RC Groups
Oct 06, 2012, 04:18 AM
renasis
Discussion

Hello,

I have been thinking about making a quadcopter that can run for a very long time. Why not use helium for the buoyancy needed to offset the weight of the quadcopter components? I googled this and found very little, I am surprised, why not?

Thanks,

-ren
 Oct 06, 2012, 04:25 AM always looking for clouds i think that would make it a blimp!?
 Oct 06, 2012, 08:04 PM Registered User Blimpcopter! Uploaded with ImageShack.us
Oct 06, 2012, 11:39 PM
Posted as eflightdude 06-07
Quote:
 Originally Posted by renasis Hello, I have been thinking about making a quadcopter that can run for a very long time. Why not use helium for the buoyancy needed to offset the weight of the quadcopter components? I googled this and found very little, I am surprised, why not? Thanks, -ren
Simple physics, that's why. To lift 2.15 lbs you need a balloon with a diameter of 4 feet. What about lifting less weight? Well, to lift only 0.93 lbs, you still need a balloon with a diameter of 3 feet. http://www.stevespangler.com/in-the-...ysics-science/ As you can see, this gives you a blimp, not a quad, as socommk23 already said. And then there is no point in having the motor arrangement of a quad, you would be better suiting to mounting your motors vertically to provide forward and sidewise thrust, and only keeping one mounted vertically to allow easy ascent/decent. If you want a blimp, there's a section of RCG dedicated to that.

If, however, you want a quad, then your max flight time is obtained when the weight of your battery equals the weight of your quad minus the battery. In other words, the battery is half the ready to fly weight of the quad. Any more and you lose flight time do to the battery weighing too much, any less and you lose flight time because you aren't carrying as much battery as you could. Of course that's just the batteries, you also have to factor in motor efficiency, prop efficiency, proper prop size, etc.

Lots of good info here, you just have to have the time and willingness to sort through it all.

Also, to quote my physics teacher when I asked if making a small, autonomous line following speed robot if the best turning ability used more mass for a heavier weight for more tire friction but a larger inertial factor, or less mass which gives less tire friction but less inertia: "That has a lot of variables, many of which we haven't covered yet. Is it something you're going to build?" "Well, yes." "Then experiment." He smiled, and turned back to his work as I left. Needless to say, me and another guy will be experimenting quite a bit on the line follower for the competition in March, as we both plan on being the winning team.
 Oct 07, 2012, 12:32 AM Registered User lol blimpcopter
 Oct 07, 2012, 01:03 AM User To get a high endurance vehicle (several hours+) with VTOL capability using today's technology, you'll have to go with a single rotor design powered by a fuel burning engine (internal combustion or perhaps gas turbine). No multi-rotor configurations or batteries will cut it. Be aware, however, that you will basically need to design a flying fuel tank. Actually, there is one other option - the blimp that you are proposing.
Oct 08, 2012, 09:42 PM
Registered User
Quote:
 Originally Posted by rmteo To get a high endurance vehicle (several hours+) with VTOL capability using today's technology, you'll have to go with a single rotor design powered by a fuel burning engine (internal combustion or perhaps gas turbine). No multi-rotor configurations or batteries will cut it. Be aware, however, that you will basically need to design a flying fuel tank. Actually, there is one other option - the blimp that you are proposing.
Not correct if you have the money you can get one of these 4 to 8 hours of flight time

http://uniteddrones.com/products/aether-aero/
Oct 08, 2012, 10:00 PM
Mosquito 6
Quote:
 Originally Posted by gitit20 Not correct if you have the money you can get one of these 4 to 8 hours of flight time http://uniteddrones.com/products/aether-aero/
Luv the ladders .. for miniature police persons .. damn cute I'd say
Oct 08, 2012, 10:13 PM
User
Quote:
 Originally Posted by TayNinh68 Luv the ladders .. for miniature police persons .. damn cute I'd say
Good one!!

And if you really have the money then one of these will give you 14 hours of endurance with a payload capacity of 600-700lb.

Oct 09, 2012, 12:00 AM
Mosquito 6
Quote:
 Originally Posted by renasis Hello, I have been thinking about making a quadcopter that can run for a very long time. Why not use helium for the buoyancy needed to offset the weight of the quadcopter components? I googled this and found very little, I am surprised, why not? Thanks, -ren
Well, certainly it would fly, if you disconnect the dern tank silly Just joking Ren

Advantages: Long flight time .. long linger time .. payload dependent on balloon size .. very easy to see at great distances .. big enough balloon maybe sell ad space .. event managers may look more kindly at overhead videos with your future proven technology .. visa-vi; airworthiness.

Disadvantages: Very slow .. hard to maneuver .. even harder to maneuver with any wind .. can't do aerobatics or evasive manuevers .. clean air restricted to rotors reducing lift .. zero stealth during moonlight or brighter flights .. if your balloon fails your rotors will briefly churn balloon skin as the aircraft plummets to the ground while your left thumb instinctively attempts to burn stuff up .. and as mentioned previously, very easy to see at great distances .. which makes for some slightly challenging target practice for some nefarious person if so inclined .. even a .22 at 400 yards.

We do have a Lighter than air section here .. https://www.rcgroups.com/blimps-62/ but meanwhile, this guy would probably love for you to build him one

www.youtube.com/watch?v=Z7437gB3Cxo (video is argueably germane to this post, but OT for rcgroups in general, so c/p into u-tbe; .22@400 yds 2:33 .. my apologies)

How about making some large bird like balloons soo the gunners wouldn't have to blast away at (Cheneyerize) quail. While I make this post tongue in cheek, albeit with many truisms, serious marksmen want challenges and someone's gonna do this and make a business of it (using LiFeP04 of course)
Jul 15, 2013, 10:17 AM
rc blimp manufacturer
Quote:
 Originally Posted by WonderKing Blimpcopter! Uploaded with ImageShack.us
hello i have tried that solution with a 2.3m sphere
mk basis with 2 x fww engines

 test ball cam (7 min 12 sec)

pretty hard to go straight but very long flight time with 2.5 kg payload
+ 2 hours ...

but max wind less than 20 km/h !

shall be improved

cheers phil

P.S i dont work for minizepp anymore