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Old Oct 06, 2012, 02:02 PM
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Originally Posted by Stenkryparen View Post
Thanks for clarity.

I think testing always override engineering and theoretical reasoning.
Well, it's nice to have a theory first that you want to prove / disprove. It's when people go directly from theory to conclusion that you get problems.
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Old Oct 06, 2012, 02:57 PM
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Originally Posted by Brandigan View Post
I think you'll still get the gusts problem with the Hubsan. All these Micro LB sized quads fly better in wind than a v929 or an MQX because of the direct drive props and because they have a smaller 'sail' area to be affected. It's how the gyros etc. react afterwards that's the clincher and it will be interesting to see if the Hubsan is any better than others.

I was going to get one from Banggood, they had it on backorder, but now it's gone from their site completely.
From James' review, it looks as if the Hubsans accelerometers help fight wind gusts (as well as the other 6-axis quads). I agree with your other points, but it's the accelerometers that make the difference over just gyros.
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Old Oct 06, 2012, 03:32 PM
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Quote:
Originally Posted by Brandigan View Post
I think you'll still get the gusts problem with the Hubsan. All these Micro LB sized quads fly better in wind than a v929 or an MQX because of the direct drive props and because they have a smaller 'sail' area to be affected. It's how the gyros etc. react afterwards that's the clincher and it will be interesting to see if the Hubsan is any better than others.

I was going to get one from Banggood, they had it on backorder, but now it's gone from their site completely.
This in incorrect. There is no 'sail area', any size aircraft flying in a 5mph crosswind will be pushed sideways at a rate of 5mph.
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Old Oct 06, 2012, 03:50 PM
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Originally Posted by Gerry__ View Post
This in incorrect. There is no 'sail area', any size aircraft flying in a 5mph crosswind will be pushed sideways at a rate of 5mph.
So you're saying aerodynamics has nothing to do with it. An 8x11" piece of paper is going to blow in the wind just as fast\slow as a bullet in the same wind gust if both are dropped off the top of a high building (both being of equal mass)?

Heck we should quit making airplanes and cars aerodynamic and just make them like boxes..........get alot more storage out of them.
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Old Oct 06, 2012, 04:02 PM
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Originally Posted by MassiveOverkill View Post
So you're saying aerodynamics has nothing to do with it. An 8x11" piece of paper is going to blow in the wind just as fast\slow as a bullet in the same wind gust if both are dropped off the top of a high building (both being of equal mass)?

Heck we should quit making airplanes and cars aerodynamic and just make them like boxes..........get alot more storage out of them.
The bullet is being blow sideways at 5mph, but of course it only takes a second to travel to its target, so it isn't pushed very far in that time. Anyway, a small quad, or one four times the size, being flown into a headwind of 5mph, will both have to attain an airspeed of 5mph to stay in the same position in relation to the ground, there is no 'sail' effect with the bigger one.

Basic stuff.

BTW, a sheet of paper isn't aerodynamically stable so it's not a sensible comparison.

Wind (steady movement of air horizontally across the ground) has no effect on aerodynamics, it only affects landing, take-off and navigation.

Don't confuse wind with turbulence.
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Old Oct 06, 2012, 04:14 PM
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Don't agree. Explain why coaxials can't handle wind as good as single props.
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Old Oct 06, 2012, 04:21 PM
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Originally Posted by Gerry__ View Post
Don't confuse wind with turbulence.
Why not? You are. I said that larger quads were more affected by gusts. If gusts aren't turbulent, what are they?
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Old Oct 06, 2012, 04:23 PM
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Originally Posted by MassiveOverkill View Post
Don't agree. Explain why coaxials can't handle wind as good as single props.
Drop one large and one small rubber duck into a river flowing at 5mph, they will bother float down the river at 5mph.

Fluid dynamics is what this is and the air works in the same way.

Before arguing with me any more ask yourself:

1. Have I read any books, scientific papers, or authoritative articles on this subject?

2. Am I qualified in this field?

3. Would I bet my life I'm right.
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Old Oct 06, 2012, 04:27 PM
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Originally Posted by Brandigan View Post
Why not? You are. I said that larger quads were more affected by gusts. If gusts aren't turbulent, what are they?
If anything, the larger one has more mass and therefore more inertia and stability. A small plane and a large plane both flying through the same degree of turbulence at the same speed. Which will be bounced around the most?
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Old Oct 06, 2012, 04:27 PM
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Originally Posted by MassiveOverkill View Post
From James' review, it looks as if the Hubsans accelerometers help fight wind gusts (as well as the other 6-axis quads). I agree with your other points, but it's the accelerometers that make the difference over just gyros.
Assume my Gyros etc. covered accelerometers and we agree.

BTW, didn't know James had reviewed a Hubsan, so thanks for the info.
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Old Oct 06, 2012, 04:29 PM
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Originally Posted by Gerry__ View Post
If anything, the larger one has more mass and therefore more inertia and stability. A small plane and a large plane both flying through the same degree of turbulence at the same speed. Which will be bounced around the most?
Is this 20 questions? Hmmm.. OK, the one that relies on the aerodynamics of the medium it is travelling in more, so the one most like a glider will get bounced around more.

My turn. Which one is that?
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Old Oct 06, 2012, 04:30 PM
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Originally Posted by Gerry__ View Post
Drop one large and one small rubber duck into a river flowing at 5mph, they will bother float down the river at 5mph.

Fluid dynamics is what this is and the air works in the same way.

Before arguing with me any more ask yourself:

1. Have I read any books, scientific papers, or authoritative articles on this subject?

2. Am I qualified in this field?

3. Would I bet my life I'm right.
4. Are you a troll?
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Old Oct 06, 2012, 04:32 PM
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I haven't read any papers and I'm not qualified to get into this argument, but I will say I've been in rivers many times with my friends using different canoes and have watched us follow the same route never anyone staying together. And no I'm not talking about paddling. I'm talking about being side by side in a slow portion of the river and just sitting there and ending up at completely different differences before hitting the next ride through. Aerodynamics absolutely have effect because with your comment regarding the two ducks try it and I guarantee they won't stay side by side.

I personally don't know all of the science behind it and I don't really care to too much. All I know is my ladybird absolutely destroys my mqx in windy conditions.
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Old Oct 06, 2012, 04:32 PM
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Originally Posted by Brandigan View Post
4. Are you a troll?
I know what I'm talking about.
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Old Oct 06, 2012, 04:33 PM
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Exactly. Wind cancels out of the equation. There is no way for the autopilot to even detect wind as it does not exist for a flying object of any size or configuration within the environment of the air. Therefore all planes fly equally well in the wind as do all copters of any description.

When you are talking turbulence or wind shear, THEN you are talking about an instantaneous impulse upon the flying vehicle. This induces an acceleration, which is exactly what the gyro senses. "Sail area" can have everything to do with the magnitude of the acceleration experienced in a wind gust, turbulence or shear. And that is why some gyros perform better than others and why a gyro might perform well in one vehicle but not in another.

So: wind is laminar, having speed but not acceleration. It affects all flying vehicles equally, even bullets. It is not detectable by any means by the flying vehicle, which strictly senses an environment at rest, regardless of any wind.

Turbulence, wind shear or wind gusts produce instantaneous forces which can be sensed by gyros. Differing vehicles will indeed react differently due to "sail area," length of moment arms, mass and mass distribution. Gyros CAN detect these effects, which is good, because these bad guys are what crash our stuff.

We aren't talking theory here. These are fully understood aerodynamic facts and have been for almost 100 years. They aren't subject to contradiction, having been well tested and verified over a stretch of time beyond our own lifetimes.
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