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Old 03-24-2011, 06:14 PM   #1
LilWilly
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Default Variable Pitch Quad Copter Build

Starting a new project of splicing together 4 guai 425 kits into a quad copter. Basically all i am using is the tail end of each kit and creating a hub for them all to be attached to. I am not using traditional RC electronics but rather an arduino board as a receiver so that it is able to fly autonomously. When in manual mode it will be flown using an xbox controller plugged into my computer. I am trying to go with a single engine design but have questions on which engine to use.
It will be running 4 sets of 315 blades off of one motor. I have a scorpion HK-4020-1100KV motor laying around and would like to use it if possible however im thinking it may not be able to handle it.

When completed it should weigh in around 5-6.5 lbs with battery and all however i would like to eventually lift a camera and other payloads with it

the way im thinking of it is i have 4 sets of 450 heli blades so i need 4 times the motor of a 450 heli.

the 450 equivalent motor from scorpion has a max power of 525W
while the motor that i have has a max power of 1640W

im not sure if the power is the correct stat to be looking at or not any tips,comments, references to similar builds or anything at all would be much appreciated
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Old 03-25-2011, 05:03 PM   #2
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4 sets of 450-sized rotors?! Talk about a flying lawnmower... That thing is going to be HUGE!

I've never seen anything similar. I've heard of people using variable pitch airplane props on their quads, but not full-sized helicopter rotors.

Personally I would prefer a hexa or octocopter to lift an SLR camera, as you get redundancy should a motor fail, it's a lot simpler mechanically (thus easier to repair), and it's probably going to fit in your car.

Then again I'm quite curious to see something like that fly, and wish you the best of luck with this project
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Old 04-04-2011, 02:37 AM   #3
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hi, i had the same idea, how are u going to counter the torque from the motor?
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Old 04-05-2011, 03:01 AM   #4
LilWilly
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I plan on using a simple control surface attached to each boom to act as almost a rudder

I decided to downsize and i just got 4 EXI 450 entire tail assemblys for $25 each you cant beat it im going to use 250 size blades on each one

currently im designing a main hub which will be 8 CF plates to hold everything together and house the motor gears brains and what now
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Old 05-19-2011, 07:50 AM   #6
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Wow Douxyeti

Thats amazing, great workmanship you have shown there.

I have studied teh pictures on Flicker but i cant work out how you keep the arms attached to the airframe.

could you show some more pictures of how that area assembles?

Have you had chance to fly it yet?

What flight controller will you be using?

Great project keep us posted

Thanks
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Old 06-04-2011, 08:33 PM   #7
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Yes .. great craftsmanship ... and a great idea ... keep the updates coming ... I want to see this puppy fly ... should be some serious lifting power ...
Also .. what is the idea behind the floating arms ... I assume since there are gears on the arms that you plan on it having a wing and doing a conversion into airplane mode ?????
Keep up the great work
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Old 06-05-2011, 01:04 AM   #8
Wazzer
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Im pretty sure the floating or rotating arms are for yaw control

now that the quad has variable pitch they wont be changing teh motor rpm to vary to torque to give you yaw the same way a normal quad would

rotating the arm to give you yaw will give you huge yaw authority andpotentialy insane piro speeds!!

I too am looking forward to more info on this build

Ben
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Old 06-05-2011, 09:22 AM   #9
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Quote:
Im pretty sure the floating or rotating arms are for yaw control

Yep ,, I think you are right as now that I watch the vid again ,,, the props don't swivel forward but sideways ... I was just mislead by his moving them all the way over .
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Old 06-06-2011, 08:16 AM   #10
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Looks like this project was dead before it even started. Been over 2mos since the OP posted. Just a word of advice from anyone thinking of doing this. Make sure you learn about multirotors and can fly them well before building something complicated like this. If not you are just wasting your time.
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Old 06-06-2011, 08:53 AM   #11
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He isn't wasting his time ... he may have learned another way that they don't work ... nothing ventured ,, nothing gained . 2months is nothing when dealing with something like this ... he may have run into a problem that needed to be worked out or went on vacation ,,etc.
Besides that is what this hobby is about ,, and especially VTOL ,,, trying something different and having fun doing it ... who cares if it works or not .... did you learn something and did you have fun doing it
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Old 08-01-2011, 12:07 AM   #12
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Quote:
Originally Posted by v22chap View Post
He isn't wasting his time ... he may have learned another way that they don't work ... nothing ventured ,, nothing gained . 2months is nothing when dealing with something like this ... he may have run into a problem that needed to be worked out or went on vacation ,,etc.
Besides that is what this hobby is about ,, and especially VTOL ,,, trying something different and having fun doing it ... who cares if it works or not .... did you learn something and did you have fun doing it
"LIKE"...!
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Old 08-26-2011, 10:47 AM   #13
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To control yaw, the variable pitch quad would operate in a similar way to a conventional quad. Instead of increasing rpm on 2 sets of motors and reducing rpm on the other 2, you would increase/decrease pitch on the 2 pairs of rotors.
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Old 09-24-2011, 08:10 PM   #14
v22chap
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any updates on this build ???
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Old 10-06-2011, 10:42 PM   #15
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I think if I were doing this I'd use the tails from helis as shown, but drive each rotor with a separate motor using a fixed rpm gov mode, then use servos to control the pitch (mount the servos out at the end of the arms with the rotors so the control rod is short).

I'd use tail blades from a 600 or 700 rather than main rotor blades, and have direct drive from the motor. I'm not sure what the correct kv would be, probably 1200 or 1500 if you want to spin the rotors at the same speed they typically spin on a 450 class heli.

Chris Bergen is building an AP heli that's using a motor driven tail on. I'm not sure how he has the motor mounted on the tail, but compared to that drone shown above with the dual motors and main/autorotate gears, mounting motors on the tail seems like an easy task.
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Old 12-29-2011, 08:21 PM   #16
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Great job on the fabrication OP , that modular system looks great. Hope you persue it further.

I'd really like to see how the maingears inter lock with one another to drive all the arms, inner workings between the plates as i'd like a single motor also.


I've been thinking of this for a while also.

I'm leaning towards a tricopter myself.

I'd use a vbar to run each of the legs (3 legs would be the same configuration as a swashplate) , you'd need to run tailbooms and tailrotors from a helicopter (i'm going to go with the trex 500 size myself).
Driving them would take a bit of designing. One option is how the OP did it , another would bo some kind of a direct drive off the end of the TT shaft (TT drives seem the easiest). Another design aspect i'd like to include is a rotating boom.
I have the scarab tricopter right now and the yaw rate with only one boom rotating it is slow. I'm wanting 3 booms to rotate to make a fast yaw rate.
Obviously i'm looking for a 3d quad and it won't have any camera gear on it.

For the rotating boom i'm currently imagining a similar system to the scarab v2 camera gimble/tricoter rear leg ( www.multiwiicopter.com ). A larger bearing system on the outer side (trex500 boom) , then a modified TT drive gear driven directly off the motor shaft. Then have 2 more bearings inside the boom to keep the modded TT gear centered and steady.


------------------

My Quad thoughts

I'd run up the motors in a throttle curve bypassing the mulitwii control board. Then connect the outputs of the mulitwii board to the servo's. This would be an idle up setup.

Arm board , bring up to center stick (0 degrees) then fire motor/motors (some kind of reduced throttle throw (like landing gear on a 9303 radio) or govenor mode for the esc/esc's to smoothly bring up to speed. After that it would fly like a normal helicopter in idle 1

For the tail , you'd need to mount 4 servo's and connect them all in parallel to the rudder output of a gyro.

Martin
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Old 01-26-2012, 10:52 PM   #17
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All good stuff... man you guys are into the full-on expensive Quads, and doing custom builds to boot. In reading this I was thinking if someone wants a very inexpensive simulator before talking an expensive Quad in the air, the new Blade mQX at just over $100 may be the ticket. Small but incredibly fun to fly and like the Blade mCPx for 3D helicopters is much cheaper to learn on then a 500 class machine (wish they'd had these when I started - would have been a much less expensive learning curve. I did a review that has some interesting comment from fellow HeliFreak types at: http://www.helifreak.com/showthread....02#post3574902
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Old 01-28-2012, 01:07 PM   #18
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I've done a lot of thinking and talking about this idea in the past, and really the only difficulty is the yaw problem. Did you decide to do it with tilt-rotors or control surfaces or what?
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