Birds in outer space

[Beanbag]

Similar work has been done back in the Skylab days. They boosted goldfish up to Skylab to see how they would adapt to zero gravity. The initial boostees would swim around in random loops and positions, because their sensory gear was used to having a gravitational pull to orient itself with. Fish hatched in orbit adapted quite nicely, however, and would swim normally.

Flying animals would probably adapt better to zero gravity than non-flyers, since they are used to working in a three-dimensional environment and have a propulsion system that isn't dependent on having a solid surface to push against. They wouldn't so much fly as swim through the air. Birds taken from a 1-g environment would probably flail around like mad, since they no longer have gravity to work against and provide a reference for orientation. Birds hatched in zero g wouldn't have the same preconditioning, and should adapt in nicely. They'd be overdesigned physically, since most of the energy needed in flight is to overcome gravity and stay aloft.

Regards;
Beanbag

 

[Grommitt]

This all depends on what you mean by "flight". The four forces acting upon an airfoil are:

1. Lift
2. Gravity
3. Thrust
4. Drag

Straight and level, unaccellerated flight is maintained when:

1. Lift is exactly equal to Gravity
2. Thrust is exactly equal to Drag

When a bird flaps its wing (airfoil), lift is generated perpendicular to the chordline of the wing. When the amount of lift is greater than gravity (weight of the bird), altitude increases. When the bird adjusts it's wing movement so as to generate lift energy that is equal to it's own weight (gravity), then it is in level flight. Descending is just the opposite of this.

The point is that in 0-gravity there can be no lift because lift is defined by gravity by virtue of being opposite to it. It follows, then, that with no lift there is no flight.

What would occur, is simply Newton's 'equal and opposite reaction' as a result of the birds flapping wing 'pushing' against the air molocules in the cabin. The bird would keep moving in a direction 90 degrees to the logitudinal axis of it's body with a slight horizontal component due to angle of incidence of the wing.

In other words, it would keep banging against the relative "ceiling", of the cabin. In effect, there would be no difference between the bird's wings pushing against the air and the human crewman pushing against some part of the cabin to get moving.

I have doubts as to whether a bird could adapt to the absence of gravity and still "fly".

As to the assertion that a bird "learns" how to fly I also have doubts. I think that birds, like all creatures, are "hardwired" to function in the environment in which their species has thrived. It's just a matter of practicing what you already know how to do through genes.

The REAL question is: "Can a 5 ounce bird carry a 1 pound coconut?"

 

[espritch]

I read a while back that some bees were taken into space to see how they would adapt. They died.

Note: I read this a long time ago and I don't know if it is accurate.

 

[xouper]

Grommitt: What would occur, is simply Newton's 'equal and opposite reaction' as a result of the birds flapping wing 'pushing' against the air molocules in the cabin. The bird would keep moving in a direction 90 degrees to the logitudinal axis of it's body with a slight horizontal component due to angle of incidence of the wing.

That seems like a reasonable hypothesis to me. If we use Aristitole's approach to truth, we could stop there and skip the empirical step.

A point I'd like to add is that the lift of an airplane wing is also a result of Newton's Law - a wing's lift is defined by and is directly opposite to the momentum imparted to the air around it. Which leads to your other point -

The point is that in 0-gravity there can be no lift because lift is defined by gravity by virtue of being opposite to it.

Perhaps I am misunderstanding your point here, but lift generated by an airfoil is not defined by gravity, nor is it dependent upon it. For example, a helicopter rotor works by generating lift, and a helicopter in zero g would still move in the direction the rotor pulls it, due to the lift force generated by the rotor. Another example, an airplane making a level, coordinated turn with a 60 degree bank generates lift at twice the force of gravity, and here the lift vector of the wing is not directly opposite to the gravity vector. Perhaps, then, I have misunderstood your point.

 

[Grommitt]

[

Perhaps I am misunderstanding your point here, but liftgenerated by an airfoil is not defined by gravity, nor is it dependent upon it. For example, a helicopter rotor works by generating lift, and a helicopter in zero g would still move in the direction the rotor pulls it, due to the lift force generated by the rotor. Another example, an airplane making a level, coordinated turn with a 60 degree bank generates lift at twice the force of gravity, and here the lift vector of the wing is not directly opposite to the gravity vector. Perhaps, then, I have
misunderstood your point. [/B][/QUO

I can see that I should have qualified my definition of lift. I used it in a narrow "flight school" sense assuming that lift is related to "up" in the same way that gravity is related to "down". In 0g there is no "up" as there is in a gravity environment. Since there can be no "up" without a "down" with which to compare it, it is in this sense that I say that lift (up) is defined by gravity (down).

In the 60 degree bank example it must be noted that the lift vector is defined by the horizontal and vertical components of total lift acting on the airfoil. In 0g there is no "vertical" but just a direction as defined by the chordline of the airfoil.

We are on the same page here and I get your examples. It's just a matter of defining what we mean by lift.

"Birds in space" is an interesting situation for a pilot to ponder. (How's that for a piece of illiteration?)
BTW, I noticed your location. I assume you mean THE Hockeytown--DETROIT! Go WINGS!

 

[xouper]

Grommitt: I can see that I should have qualified my definition of lift. I used it in a narrow "flight school" sense assuming that lift is related to "up" in the same way that gravity is related to "down".

I don't remember being taught that in flight school, but I think I get what you are saying. By lift, you are referring to the component of the lift vector that is parallel to the gravity vector. I guess this is fine when discussing flight in the presence of a gravity vector, but is not a useful distinction when discussing flight in zero g.

If I am on the space station (zero g) and launch a small balsa glider that flies in a loop, does the wing not generate lift? Of course it does. That's what causes the glider to loop instead of going in a straight trajectory.

In the 60 degree bank example it must be noted that the lift vector is defined by the horizontal and vertical components of total lift acting on the airfoil.

I guess we are having difficulty with the jargon here. You have that definition backwards. The "lift vector" is the total lift generated by the wing and is usually perpendicular to the span, irrespective of the orientation of the wing. For convenience in discussing flight maneuvers, the lift vector can be broken down into horizontal and vertical components, but this is somewhat arbitrary.

In 0g there is no "vertical" but just a direction as defined by the chordline of the airfoil.

And that is the reference for the definition of the lift vector of the wing, independently of gravity or "vertical".

We are on the same page here and I get your examples. It's just a matter of defining what we mean by lift.

OK. As a pilot, I am not comfortable with your usage of the jargon, and although we seem to be on the same page, as you say, I am still not entirely certain. No big deal, though, as we seem to be converging on a common ground.

BTW, I noticed your location. I assume you mean THE Hockeytown--DETROIT!

Exactly. There are several JREFers in the Detroit area. Hal Bidlack (forum administrator) is also a Wings fan, although he is currently stationed in Colorado.

 

[Beanbag]

Missing the obvious point

You've all missed the point -- the ONLY reason you have to "fly" is to overcome gravity. In zero gravity, you don't fly, you SWIM. You use the air itself as a medium to push against, just like water.

The really neat thing is that unlike water, you or a bird can breathe the medium you're immersed in. The situation would be not unlike a fish, who can extract oxygen from the water.

And birds would probably swim in zero G better than any other animal, because they're alredy equipped to work against the air for propulsion. What would be different is that if they stop flapping, they won't fall "down". They'd just maintain whatever their state of inertia was when they stopped flapping, perhaps influenced by any air currents that might be present.

Regards;
Beanbag

 

[xouper]

Beanbag: You've all missed the point -- the ONLY reason you have to "fly" is to overcome gravity.

That's not strictly true. An airplane turns by using the lift of its wing and this has nothing to do with gravity.

A bird in zero g that is not flapping its wings (i.e. is holding its wings out without flapping) can still use lift to alter its flight path, such as doing graceful turns or loops while zooming though the air. This is indeed "flying" in zero g.

Submarines do a similar thing, using lift to alter their flight path through the water, up and down, right and left. A rudder is after all, just a vertical wing and the force a rudder creates by angling to the flow of water is called lift.

In other words, not all motions in zero g (or water) are swimming.

 

[Goshawk]

I read a while back that some bees were taken into space to see how they would adapt. They died.

Note: I read this a long time ago and I don't know if it is accurate.

The only reference I have been able to find on "birds in space" is to the chicken egg experiment, in which they sent up some fertilized chicken eggs, let them spend 5 days in orbit on the Discovery, then brought them back down, allowed them to hatch, then did some tests on their inner-ear balance mechanism, and compared them with control groups who had never left the ground.

http://www.cs.uic.edu/~kenyon/Chix/Chix.html

The Russians also sent up some quail eggs at one point.

But as far as I can tell, they've never sent up actual "birds".

 

[sorgoth]

I know I'd volunteer if I was a bird.

But hey, I just want to get to space.

SPACE PENGUINS! Brilliant!

 

[pupdog]

Maybe we could see some flying ostriches.

 

[MoeFaux]

I just have to say...I think my parrot would look SO CUTE in space gear!

I agree with all the bird reaction comments that Goshawk said.

And, someone mentioned bees in space, so here you go:
http://www.spacebees.li/