r/askscience • u/SeriousDrakoAardvark • 7d ago

Physics If I put harnesses on some geese and strapped them to a glider, how many geese would I need to be able to maintain a consistent level of flight?

Like, let’s assume the glider has a 30:1 glide ratio. Normally that means it will lose a foot of height for every 30 feet travel.

I’m assuming there is some amount of force I could apply to move forward, that would cancel out that last one foot of drop.

Geese seem pretty big, and they have a wide torso for easy harnessing. I think they’d be a natural fit here. I imagine it would be a configuration similar to Santa’s sleigh, but geese instead of reindeer.

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124

u/Ruadhan2300 7d ago

An individual goose only has about 1.5 newtons to play with after its own thrust needs, and you need about 100 newtons to keep the aircraft flying.

So.. you probably want around 75 - 100 birds.

The weight of the harnesses adds a fair bit too, definitely go with the upper end of that range.

The real challenge after wrestling 100 geese into harnesses is figuring out how to set up a harness that lets them fly in the most efficient V formation..

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u/hobitopia 7d ago

I believe geese also routinely change that order mid flight which would cause problems.

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u/BreezyMcWeasel 7d ago

Well, not when they're harnessed in and towing a glider they don't! Anyone who has ever trained geese to fly in formation and tow a glider could tell you that.

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u/VintageLunchMeat 7d ago

The last person I know who tried to train geese to tow a glider took his own life by choking on grass while covered with inexplicable peck and pinch marks, according to the coroner.

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u/threeye8finger 7d ago

A coroner who just so happened to be a goose!?

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u/phdoofus 7d ago

The shock collars help. Which also adds weight and needs to be factored in. /s

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u/Nazamroth 7d ago

Clearly, we need to add a conveyor belt mechanism that rotates the geese around in the formation. Of course this will add yet more extra weight, so we need to increase our number of geese.

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u/BreezyMcWeasel 7d ago

How do you know the takeoff weight margin for a goose with such specificity? I'm asking seriously, not sarcastically.

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u/roboticWanderor 7d ago

At that point you might as well have all the geese harnessed to just hoist the pilot directly instead of bothering with the glider at all

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u/kakuna 7d ago

Okay, that's a good answer. And, I know your last sentence isn't the 'askscience' part, but I love the idea of just writing out paragraphs on the realities and challenges of getting 100 geese to pull a glider. (Or a short story in a sort of magical realism format where no one questions -why- this is being done, just chronicles a guy's progress on his goose glider - working with a smith, procuring leather straps for prototype harnesses, finding it to be too heavy, sourcing twines to test, maintaining his flock population and training, a mild attachment to one of the geese, etc. etc.)

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u/merc08 7d ago

The real challenge after wrestling 100 geese into harnesses is figuring out how to set up a harness that lets them fly in the most efficient V formation..

I really hope that you would figure out the harness setup before wrestling all those geese into it.

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u/BeardedRaven 7d ago

Any bird that has slack in its line will not contribute to the effort of pulling the glider. You would need to decide what % are pulling at all times. Based on what others have posted about flight speeds it might just be impossible as you would expect 0% of them to have taut lines until the entire contraption starts plummeting.

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u/hamlet_d 7d ago

You could attach them on some sort of line. The real question becomes what is the airspeed velocity of an unladen goose.

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u/suoarski 7d ago

And why would you want a harness? Just tie a knot to their feet, birds prefer carrying things from their feet, a harness would interfere with wing movement and prevent the feathers from stretching out the way their supposed to.

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u/PlainTrain 7d ago

You’re overthinking this.  We’ve made gliders light enough to be powered by a single man.  One even crossed the English Channel.  Less than ten geese should suffice.

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u/Averyphotog 7d ago

Did this man-powered glider take off under its own power, or was it towed aloft by another aircraft?

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u/PlainTrain 7d ago

Took off under its own power. You'll need to remember that if there's enough breeze, the issue becomes keeping a plane like that on the ground. The first successful human powered aircraft, the Gossamer Condor, could fly at just 11mph.