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Variable Pitch Quad Copter Using single Motor

VPP Quad

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#41 azrin_aris

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Posted 26 February 2012 - 04:01 AM

Congrats on doing this, it looks amazing!

I've seen a similar design but cannot find the link right now. They used belt driven tail assemblies and a dual motor setup on a sort of planetary gearing in the middle. Could have one motor fail and still fly.

Dumb question I guess, does the OP code have support for inverted flight on VP airframes?


Yes I did came across a couple of sites before and both are using 2 motors. That's motivates me to make the single motor system.

#42 BigpatAus

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Posted 26 February 2012 - 07:13 AM

Your link is broken..

I attempted a fix..it failed....you may want to re-link


Thanks for that I just updated the link. Hope it works now
P

http://diydrones.com...-implementation

Edited by BigpatAus, 26 February 2012 - 07:14 AM.


#43 Drifter

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Posted 26 February 2012 - 07:37 AM

Might be the ground effect is causing the instability, try between 1 and 2 meters altitude.

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#44 azrin_aris

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Posted 26 February 2012 - 07:59 AM

Might be the ground effect is causing the instability, try between 1 and 2 meters altitude.


You are right, test flight #2 this morning shows much better stability. However I guess I've set the head speed too low hence the sluggishness of the response.

#45 Mat Wellington

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Posted 26 February 2012 - 09:52 AM

first off - well done ! great machine man, very cool

second, looks like it needs a bit more inner Kp to tighten it up

Third, - i cant see any reason why you couldnt go inverted, i assume you set up a curve on the throttle channel to control the motor the same as a heli, (full throttle at about 25%, drop it down to maybe 85% at mid and 3/4 position and back up to max at full stick ) and set up a linear pitch curve, and feed that to the CC as a throttle input, then on the CC do a throttle curve of 0=0, 25=0, 50=33, 75=66 and 100=100

that way the 4 servos will travel from full negative pitch to full positive pitch as you go from 25% to 100% throttle position, and from 0 to 25% is just to spool the motor up (controlled direct from the throttle curve on the TX )

very cool project anyways, cant wait to see it developed

#46 Gentle Lady

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Posted 26 February 2012 - 11:42 AM



Don't know if you have seen this. Pretty amazing stuff.

#47 azrin_aris

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Posted 26 February 2012 - 11:58 AM

Test Flight #2 Video uploaded



#48 azrin_aris

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Posted 26 February 2012 - 12:00 PM

first off - well done ! great machine man, very cool

second, looks like it needs a bit more inner Kp to tighten it up

Third, - i cant see any reason why you couldnt go inverted, i assume you set up a curve on the throttle channel to control the motor the same as a heli, (full throttle at about 25%, drop it down to maybe 85% at mid and 3/4 position and back up to max at full stick ) and set up a linear pitch curve, and feed that to the CC as a throttle input, then on the CC do a throttle curve of 0=0, 25=0, 50=33, 75=66 and 100=100

that way the 4 servos will travel from full negative pitch to full positive pitch as you go from 25% to 100% throttle position, and from 0 to 25% is just to spool the motor up (controlled direct from the throttle curve on the TX )

very cool project anyways, cant wait to see it developed


Thank you so much for the guidance. I'm studying the settings tonight.

#49 Adverse Effects

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Posted 26 February 2012 - 12:21 PM

dam it was flying really well

i was worried about the gears :( i just didnt think they would strip from use, i thought it would take a crash

the only i can see around it is bigger and heaver gears
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#50 Guest_dankers_*

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Posted 26 February 2012 - 12:25 PM

That was flying so well, I agree with your comment at the end of the video, perhaps clearance is a bit too large?

#51 Adverse Effects

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Posted 26 February 2012 - 12:27 PM

you do have to remember the gears are made to turn like 50mm blades not 200mm+ blades

Edited by Adverse Effects, 26 February 2012 - 12:27 PM.

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#52 azrin_aris

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Posted 26 February 2012 - 01:01 PM

That was flying so well, I agree with your comment at the end of the video, perhaps clearance is a bit too large?


Another possible cause is the material of the gear itself. It is not the original Align Trex Pro but from HK450 Pro. I'm buying align parts next to test it out.

#53 azrin_aris

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Posted 26 February 2012 - 01:06 PM

dam it was flying really well

i was worried about the gears :( i just didnt think they would strip from use, i thought it would take a crash

the only i can see around it is bigger and heaver gears


You got me thinking there to use Trex 600 tail unit. But how to shorten the torque tube - I have no idea at the moment. Or I just have to keep up sizing the frame, and the same problem will occur again 😜

#54 Adverse Effects

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Posted 26 February 2012 - 01:19 PM

hehe this is why i am making the motors directly connected to the props ;-) nothing to strip out
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#55 Adverse Effects

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Posted 26 February 2012 - 01:29 PM

just thinking about the problem

if you got a 2nd gear (the big one) and turned it upside down and had a spring pushing it down

Attached File  1 motor center drive.jpg   20.28KB   37 downloads

no drive going to it

its just there to push the drives down in to the main drive gear

Edited by Adverse Effects, 26 February 2012 - 01:30 PM.

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#56 K Wells

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Posted 26 February 2012 - 01:51 PM

I would suggest metal drive gears with proper pitch diameter spacing...I've simply used paper between gear mesh to achieve this...

Here are custom metal gear suppliers I use...many are stock!

http://www.rushgears...CFQReTAoduhgaMg

http://www.wmberg.co...ucts/Gears.aspx
Looking Forward to the Maiden

#57 v22chap

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Posted 26 February 2012 - 04:34 PM

Congrats on a job well done . Look forward to seeing more research on this one motor idea as I have been thinking the same thing , but have run into a problem of time as we moved and both houses need a lot of work ,,, one to sell it and the other to meet what the wife wants :) .
I was using the gearing to a Gaui 500 and going to use belt drive to props .. But would probably have the same problem with belts slipping pulling such large rotors as the 200 mm ones .

I love the idea of not having 4 motors that one motor or esc can go bad ... and if the single motor idea worked , I was going to try and put another motor on the drive unit ,,, just idleing as a back up motor .

Best of luck and please keep going with your great bird . Maybe bigger pitch gears or steel will fix the problem ... but maybe you may need to think about using gear reduction at the drive end of the tubes as to relieve some of the gear presure .

#58 LeeS

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Posted 26 February 2012 - 05:54 PM

Are the belt driven tail units less efficient than the gear driven ones?

Seems like with belt driven you could have it with no angular conversions on the force and an overall lower part count. Plus you get the benefit of not having bent drive shafts in the event of a crash.

#59 azrin_aris

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Posted 26 February 2012 - 11:15 PM

just thinking about the problem

if you got a 2nd gear (the big one) and turned it upside down and had a spring pushing it down

Attached File  1 motor center drive.jpg   20.28KB   37 downloads

no drive going to it

its just there to push the drives down in to the main drive gear


This might work but currently I'm using HK450 pro tail mount and there is not enough space for another



#60 azrin_aris

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Posted 26 February 2012 - 11:18 PM

I would suggest metal drive gears with proper pitch diameter spacing...I've simply used paper between gear mesh to achieve this...

Here are custom metal gear suppliers I use...many are stock!

http://www.rushgears...CFQReTAoduhgaMg

http://www.wmberg.co...ucts/Gears.aspx


Thanks K Well, I've look at the website and I simply got lost. There are too many types of gears. 😊



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