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Old Feb 26, 2012, 08:41 AM
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South Africa, GP, Krugersdorp
Joined Aug 2011
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Question
Wind and .. +quad, X quad, spider

Hi all

My first quad was 60cm M2M + quad, and it flew OK in light to moderate wind. My second project was a spider of same dimension, and it seems that it is not wind tolerate at all?

So, my question is: when flying in "light wind", which of +,X or spider will be most stable?

Looking forward to hear your opinion!
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Old Feb 26, 2012, 10:18 AM
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Sunny Phoenix, AZ
Joined Feb 2004
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Quote:
Originally Posted by TheZero View Post
Hi all

My first quad was 60cm M2M + quad, and it flew OK in light to moderate wind. My second project was a spider of same dimension, and it seems that it is not wind tolerate at all?

So, my question is: when flying in "light wind", which of +,X or spider will be most stable?

Looking forward to hear your opinion!
I would think it would have most to do with how much surface area the frame presents to the wind. If the multicopters all have the same motor-to-motor spacing and the same props, I suspect all that is left is what is called "wetted area"...

Jon.
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Old Feb 26, 2012, 10:52 AM
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South Africa, GP, Krugersdorp
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Yes, same motors and props and more or less same frame area?
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Old Feb 26, 2012, 11:04 AM
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Sunny Phoenix, AZ
Joined Feb 2004
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Originally Posted by TheZero View Post
Yes, same motors and props and more or less same frame area?
Do you think the frame area, as presented to a wind blowing horizontally is about the same? If so, then it might have more to do with how much one frame vibrates as compared to the other, and then how much that vibration affects the flight controller... I know I've seen very different levels of stability in the same quad, depending on how well the props are balanced and how much the frame vibrates...

Anyway, just a few thoughts...

Jon.
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Old Feb 26, 2012, 12:19 PM
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Hi jmdhuse

Yes vibration might be a problem, I agree. However, with no wind, the spider is VERY stable.

That's why I asked the question. Want to know if it is a problem with my spider, or is spiders in general does not like wind.

If it is a problem with my set-up, how do you counter wind induced vibrations?
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Old Feb 26, 2012, 12:39 PM
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Hawaii
Joined Feb 2003
5,956 Posts
Quote:
Originally Posted by TheZero View Post
Hi all

My first quad was 60cm M2M + quad, and it flew OK in light to moderate wind. My second project was a spider of same dimension, and it seems that it is not wind tolerate at all?

So, my question is: when flying in "light wind", which of +,X or spider will be most stable?

Looking forward to hear your opinion!
It should not make a difference. What you have may be arm flex issue with different length arms on a spider. It may not be an issue in calm wind but when the flight controller and motors are buffeting in moderate wind the longer arms may now be flexing.
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Old Feb 26, 2012, 02:17 PM
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South Africa, GP, Krugersdorp
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Hi SeismicCWave

Good to hear from you again!

My arms are 12 mm square aluminium with 1.2mm wall thickness - just checked after your mail, they are stiff!

You are an experienced guy, let me ask you the following question: Let's say that my props and/or motors are out of balance - could it be that the vibration problem may only become noticible in wind, but not when it is calm?

Have a nice day!
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Old Feb 26, 2012, 02:52 PM
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Hawaii
Joined Feb 2003
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>>My arms are 12 mm square aluminium with 1.2mm wall thickness - just checked after your mail, they are stiff!<<

That is fairly thick arm. Flex should not be the issue.

>>You are an experienced guy, let me ask you the following question: Let's say that my props and/or motors are out of balance - could it be that the vibration problem may only become noticible in wind, but not when it is calm?<<

Doubt it. Vibration will cause problem in any wind.

Did you check the center of gravity of your spider. The center of gravity is different on a spider. It should be the center of where the four motors intersect.
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Old Feb 26, 2012, 03:51 PM
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South Africa, GP, Krugersdorp
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Yep, COG is correct, and the machine is in nice balance.

Did a lot of thinking on the matter - the only logical reason I could come up with is that the spider is around 150g lighter than my previous quad, maybe that could be the cause. Next time the wind is up (I am sure that will be tomorrow - LOL) I will add anouther battery for the extra weight and check it out.
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Old Feb 26, 2012, 04:12 PM
let's brm together!
Czech Republic, Prague
Joined Nov 2011
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Spider = hexa or just a spider quad?

I think because it is lighter and has a larger surface area it will be more suspectible to wind. If it has 6 props that is even more surface.
And comparing behaviour in wind is tricky - when I flew with the same configuration in wind, it behaved different every time, sometimes there is constant wind near ground but gusts at 5m above - sometimes there is wind at ground but only a breeze at altitude - you can't just compare it subjectively...
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Old Feb 26, 2012, 04:37 PM
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Hi, just spider quad.

I had a normal quad, could not lift the thing off the ground under 80% throttle, but it flew well. Built the spider quad, using everyting the same, including motors (but new motors) and it is about 150 grams lighter - his thing is a monster! Hover at just over 40% throttle ...

So yes, comparisons ...
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Old Feb 26, 2012, 04:42 PM
let's brm together!
Czech Republic, Prague
Joined Nov 2011
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40% throttle is nice but still doesn't tell the whole story - you can achieve the same with higher kV motors even if they are not more powerful nothing linear here...
I think it's 150g that's making a big difference - personally I prefer them beefy and heavy though...
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Old Feb 26, 2012, 06:32 PM
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I'm not sure why but I have 2 quads with KK boards, the main difference between the two is one is + and one is X. Although the X mode quad is better suited to AP, the + quad handles wind better. Not sure why though.
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Old Feb 27, 2012, 02:09 AM
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Hi Randall

Your two quads - are they more or less the same size?
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