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Old Jan 07, 2012, 03:03 PM
AP-stick
ggtronic's Avatar
Montreal
Joined Nov 2005
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Quad Saucer - UFO - RCG R&D - read this before making a saucer !

hello

I own a quad since spring 2011 and it fly nice

wanted to built a safer & strange look quad ...
with the exact same component layout... just want to add the donut...

made the body with white bead foam... lots of hole
to save weight... cover top & bottom with 3mm depron...
the thing endup at 1.9 kilo... my previous quad reach
1.4 with FPV gear+GOPRO and fly OK

--these 750kv 60g motor
--plush 30A esc
--multiwiicopter PARIS V3 board (work great !)

EDITED : Warthox & Erknie & other user find great answers ! thanks all

it fly, but prop tunnel need special attention and the airframe will slow down all maneuver

RCgroups Saucer ... (1 min 8 sec)
Soucoupe volante = Saucer (1 min 44 sec)

.
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Old Jan 07, 2012, 03:15 PM
Member FPV UK
IWCoburg's Avatar
Isle of Wight, UK
Joined Apr 2010
729 Posts
There are heavier quads so I recon it should and I do hope so as that looks a real beastie.

Mike.
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Old Jan 07, 2012, 03:21 PM
No thrust...It'll bust...
troynh's Avatar
Troy, NH
Joined Sep 2006
4,316 Posts
Nice GG! It'll fly but it may be straining a little. Orientation?
I've got the perfect LED's for this setup when you're ready.

-Tim

Maiden flight of the UFO Quad - 12-1-2011 (2 min 9 sec)
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Old Jan 07, 2012, 03:30 PM
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UK, Buckinghamshire, High Wycombe
Joined Feb 2007
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in a windless environment it will fly just fine but ANY wind and you will find you have made a kite also a quad can told to some strange angles and yet still feel level to the eye when you build a frame like this every angle your quad flies at normally will look exaggerated due to the body and may put you off a bit with orientation
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Old Jan 07, 2012, 03:45 PM
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Hawaii
Joined Feb 2003
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Looks good. Like Nemisis said, make sure you test fly in calm days.

Also make sure you round off the edges on the top of the inlets. Nice smooth and large radius.
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Old Jan 07, 2012, 03:59 PM
AP-stick
ggtronic's Avatar
Montreal
Joined Nov 2005
1,624 Posts
thanks IWCoburg & all

troynh : amazing setup ... you are always many foot step ahead !
Believe me, if my toy fly good, look is the next step
Orientation : will go 100% fpv = solve...
OH, couldnt think of any better sound thrack !
i'v got there... amazing spot to fly !


n3m1s1s : agree with the wind=may cause lots of problem
dont worry with orientation...

SeismicCWave : thanks... EDIT you find a good answer= tunnel air flow

RESULT : see by yourself first attempt.. maiden
ovni = saucer = soucoupe (1 min 37 sec)


With all these empty foam holes, this thing
sounds lound ! amplifying all vibration & airflow ...

Pool noodle on the bottom are temporary...
if this thing fly OK , next step is top & bottom CONE
+nice legs+troynh LED kit !
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Old Jan 07, 2012, 04:22 PM
AP-stick
ggtronic's Avatar
Montreal
Joined Nov 2005
1,624 Posts
biggest problem is the lack of YAW (rudder) authority
... ounce airborne... it always start to turn clock wise and
100% left rudder is not enough to get it back ? when i use
aggressive rudder... the saucer start to loose control on the roll+pitch
(lack of thrust on 2 motor)

-- all ESC are trimed/scaled together to match throttle span (throttle calibration done)
-- some motor has little alignement problem... has fix it ... still no good
-- the frame is pretty well balanced (scale check on all motor corner=ok)
-- need around 300W to hover... 400W peak recorded
-- easy to take off & hover at 50% throttle...

i suspect these problem
-- wind tunnel around propeller reduce the tork/roll effect thus yaw authority?
-- airframe too heavy ? may need lot more gain on the PID ?
-- PID settings : i'v changed the YAW rate from 0.51 to 1 with no success

any clue ?
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Old Jan 07, 2012, 04:23 PM
Tri-Quad-Hexa-Octo-copters!!
United States, TX, San Antonio
Joined Feb 2007
14,418 Posts
Hi,
Fun project It looks like your pitch and roll P's might be a bit low since it is appears it is having trouble wobbling with angle inputs. Try increasing them and see if it holds angles and level better.

An important suggestion is that I could hear your ESCs beep four times indicating you have the settings on lipo and not NiMh. You need to set the ESCs to NiMh, lowest voltage and no or soft cut-off. If you don't you will see that thee lipo setting will cause you some unintended flips. The lipo LVC will cause this when it cuts power to one or more of the ESCs as the power demand dips them into that cut-off level. Use a lipo balance plug alarm.

You can increase your yaw authority by increasing the dual rate of your yaw channel and increasing your yaw channel expo and or tilting your motors properly so the arms that increase speed are tiled to pull the model in that direction. It will be the same tilt on the same arm FB and RL, but opposite tilts on different arms. The info on this is in the Props section under --TIP 8: in the Quadrocopter and Tricopter Mega Link Index
Cheers,
Jim
Quadrocopter and Tricopter Mega Link Index
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Old Jan 07, 2012, 04:26 PM
Registered User
Hawaii
Joined Feb 2003
5,952 Posts
1) Please change the battery type on your speed controller to NiMH.
2) You are now maxing out your hardware. Rounding out the edge on the top lip of your propeller inlet hole will give you a little more efficiency. The sharp edge is creating a lot of airflow turbulence before the air is hitting the propeller.
3) Check the alignment of your motors. They should be perfectly vertical. You may have to shim some of them off center from vertical to get the yaw control back to neutral.
4) You are using some small propeller diameter compare to the total diameter of your machine so your yaw control is less sensitive. You may have to enlarge the propeller hole and use larger diameter propeller.
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Old Jan 07, 2012, 04:27 PM
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Isle of Wight, UK
Joined Apr 2010
729 Posts
Just something that used to work on kk controllers and may help. Tilt the motors over a little (about 5 degrees), as you can use some of the thrust to counter torque as that was an old trick on the kk quads in the earlier days to improve yaw.

Blooming good effort though, love it.

Mike.
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Old Jan 07, 2012, 05:51 PM
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Australia, QLD, Brisbane
Joined Nov 2011
949 Posts
Looks like a giant flying asprin! It's going to have problems with the wind. You might have to go to 3 blade props to get more low speed thrust.
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Old Jan 07, 2012, 06:24 PM
Clear skies and calm winds...
United States, NC, Wilmington
Joined Nov 2011
793 Posts
Very Cool! Have you seen this?
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Old Jan 07, 2012, 06:27 PM
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VA
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You need to look at the surface area you are trying to yaw (twist) in the air. Looking at the ratio of total surface area/prop surface area you will see that your design is relatively high compared to a standard quad. Larger broad blade props, more of them or tri blades may give you more blade drag to move it quicker.
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Old Jan 07, 2012, 06:39 PM
RTFM // copter damaged
warthox's Avatar
Joined Aug 2009
1,724 Posts
i made such a body last year. wasnt that fun to fly.
had to increase the p values by more than factor 3 to fly more or less stable.
had the same problem with yaw. the windtunnels were the problem. i 'rounded' the edges of the tunnels on top and bottom side and that helped.
i used my acro quad with keda 20-26m motors for that, normally pretty aggressive, but with the body it flew very slow. the body has an enormous air resistance.

i can upload a video of flying it if you are interested.







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Old Jan 07, 2012, 07:04 PM
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Quote:
Originally Posted by ggtronic View Post
i suspect these problem
-- wind tunnel around propeller reduce the tork/roll effect thus yaw authority?
Try to increase holes diameter ?
It seems that your props don't have enough room to work efficiently.
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