# Lifted by flies **URL:** \ **Category:** Cecil's Columns/Staff Reports\ **Created:** [June 16, 2013, 11:13pm UTC](https://boards.straightdope.com/t/lifted-by-flies/661147 "2013-06-16T23:13:01Z")\ **Posts on this page:** 14\ **Page:** 1
**Author:** ![j\_sum1](https://avatars.discourse-cdn.com/v4/letter/j/8baadc/32.png) [@j\_sum1](https://boards.straightdope.com/u/j_sum1)\ **Post date:** [June 16, 2013, 11:13pm UTC](https://boards.straightdope.com/t/lifted-by-flies/661147/1 "2013-06-16T23:13:01Z")
> **[How many houseflies would it take to lift me?](https://www.straightdope.com/21344201/how-many-houseflies-would-it-take-to-lift-me)** Sorry Cecil. You are wrong. This is what happens when you delegate the calculations to someone else. Last time I checked, flies seem unable to fly in a straight line. Una and Fierra did not factor this essential fact into their calculations. Two points. 1. The vector sum of the force of five million flies is going to be significantly less than the sum of their individual lifting strength. 2. With the circuitous flight of the flies, those filaments holding a person will become extremely entangled which is going to have an effect on the ability of the flies to fly. The same is going to be true of hummingbirds, bats eagles or monarch butterflies although probably to a lesser extent. The big trick is going to be getting all your critters coordinated – ducks in a row so to speak. It should also be noted that the aerodynamic efficiency of a bunch of flying critters in close proximity is going to be compromised. A lot of flies are going to be caught in the downdraft of others an will therefore provide no lifting potential. I gotta say that this scheme is never going to get off the ground. ---
**Author:** ![eastcheap](https://avatars.discourse-cdn.com/v4/letter/e/8491ac/32.png) [@eastcheap](https://boards.straightdope.com/u/eastcheap)\ **Post date:** [June 17, 2013, 6:35am UTC](https://boards.straightdope.com/t/lifted-by-flies/661147/2 "2013-06-17T06:35:59Z")
What I’d like to know is, what if there was a treadmill that… Eh, never mind. ---
**Author:** ![Ranger\_Jeff](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/ranger_jeff/32/2065_2.png) [@Ranger\_Jeff](https://boards.straightdope.com/u/Ranger_Jeff)\ **Post date:** [June 17, 2013, 4:57pm UTC](https://boards.straightdope.com/t/lifted-by-flies/661147/3 "2013-06-17T16:57:39Z")
The question to Cecil was _I weigh 110 pounds. How many **trained** houseflies it would take to lift me?_ Bolding mine. I submit **trained** houseflies means they’d fly in the same direction at the same time. ---
**Author:** ![Irishman](https://avatars.discourse-cdn.com/v4/letter/i/b487fb/32.png) [@Irishman](https://boards.straightdope.com/u/Irishman)\ **Post date:** [June 17, 2013, 9:24pm UTC](https://boards.straightdope.com/t/lifted-by-flies/661147/4 "2013-06-17T21:24:46Z")
> [@j\_sum1](#): > > Last time I checked, flies seem unable to fly in a straight line. Una and Fierra did not factor this essential fact into their calculations. Two points. > > 1. The vector sum of the force of five million flies is going to be significantly less than the sum of their individual lifting strength. > 2. With the circuitous flight of the flies, those filaments holding a person will become extremely entangled which is going to have an effect on the ability of the flies to fly. > > … > It should also be noted that the aerodynamic efficiency of a bunch of flying critters in close proximity is going to be compromised. A lot of flies are going to be caught in the downdraft of others an will therefore provide no lifting potential. That’s all just logistics, man. Train the flies, spread them out sufficiently with different lengths of thread, whatever. ---
**Author:** ![Folacin](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/folacin/32/3195_2.png) [@Folacin](https://boards.straightdope.com/u/Folacin)\ **Post date:** [June 17, 2013, 11:55pm UTC](https://boards.straightdope.com/t/lifted-by-flies/661147/5 "2013-06-17T23:55:03Z")
I saw a documentary where sea gulls were trained to fly a peach across the ocean (they even used spider silk!), so I think that gives us a potential proof of concept for flies and a person. ---
**Author:** ![j\_sum1](https://avatars.discourse-cdn.com/v4/letter/j/8baadc/32.png) [@j\_sum1](https://boards.straightdope.com/u/j_sum1)\ **Post date:** [June 18, 2013, 2:28am UTC](https://boards.straightdope.com/t/lifted-by-flies/661147/6 "2013-06-18T02:28:14Z")
> [@Irishman](#): > > That’s all just logistics, man. Train the flies, spread them out sufficiently with different lengths of thread, whatever. Logistics and treadmills. Meh! Fat chance working with either in a swarm of blowflies. And no, I did not overlook the conveniently placed adjective _trained_ houseflies. My point is that what looked like an innocent physics question actually turns out to be a matter of statistics and behavioural entomology.\* Neither of these critical matters were addressed in Cecil’s column. \*(Now there’s a sentence that has probably never been written before.) ---
**Author:** ![AncientHumanoid](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/ancienthumanoid/32/278_2.png) [@AncientHumanoid](https://boards.straightdope.com/u/AncientHumanoid)\ **Post date:** [June 18, 2013, 3:27am UTC](https://boards.straightdope.com/t/lifted-by-flies/661147/7 "2013-06-18T03:27:25Z")
[squeeky voice] Help me! Please! [/sv] ---
**Author:** ![moriah](https://avatars.discourse-cdn.com/v4/letter/m/b2d939/32.png) [@moriah](https://boards.straightdope.com/u/moriah)\ **Post date:** [June 18, 2013, 3:53am UTC](https://boards.straightdope.com/t/lifted-by-flies/661147/8 "2013-06-18T03:53:25Z")
> [@Irishman](#): > > That’s all just logistics, man. Train the flies, spread them out sufficiently with different lengths of thread, whatever. Actually, this is what got me wondering. Cecil took into account the weight of the ‘wire’, i.e., the silk strand. But… really? If you have tens of thousands to millions of these flying insects working truly in tandem (they’re trained!), the still need to spread out. A million flies need their space. But then that covers a freaking huge area. This means _a lot_ of silk. Did their calculations include silk strands a mile long? And if the strand is that long, doesn’t it exceed the capacity of the fly to lift it? ---
**Author:** ![Powers](https://avatars.discourse-cdn.com/v4/letter/p/edb3f5/32.png) [@Powers](https://boards.straightdope.com/u/Powers)\ **Post date:** [June 18, 2013, 3:41pm UTC](https://boards.straightdope.com/t/lifted-by-flies/661147/9 "2013-06-18T15:41:01Z")
So the complaint is that even though Cecil demonstrated that it was impossible, he didn’t take into account factors that make it even _more impossible_ than stated? Powers &8^] ---
**Author:** ![Ranger\_Jeff](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/ranger_jeff/32/2065_2.png) [@Ranger\_Jeff](https://boards.straightdope.com/u/Ranger_Jeff)\ **Post date:** [June 18, 2013, 6:35pm UTC](https://boards.straightdope.com/t/lifted-by-flies/661147/10 "2013-06-18T18:35:42Z")
> [@Powers](#): > > So the complaint is that even though Cecil demonstrated that it was impossible, he didn’t take into account factors that make it even _more impossible_ than stated? You’re trying to make a point here, aren’t you? 😉 ---
**Author:** ![Irishman](https://avatars.discourse-cdn.com/v4/letter/i/b487fb/32.png) [@Irishman](https://boards.straightdope.com/u/Irishman)\ **Post date:** [June 18, 2013, 7:08pm UTC](https://boards.straightdope.com/t/lifted-by-flies/661147/11 "2013-06-18T19:08:44Z")
> [@Powers](#): > > So the complaint is that even though Cecil demonstrated that it was impossible, Technically, he didn’t state it is impossible, merely highly improbable. > [@moriah](#): > > If you have tens of thousands to millions of these flying insects working truly in tandem (they’re trained!), the still need to spread out. A million flies need their space. But then that covers a freaking huge area. This means _a lot_ of silk. Did their calculations include silk strands a mile long? And if the strand is that long, doesn’t it exceed the capacity of the fly to lift it? Hmm. Technically, they didn’t state how much spider silk they assumed, just a ratio of weight to length. (500 grams for 24,075 miles). Can we blanket assume they used those figures for the quantity of spider silk? I suppose it is fair to distribute the weight of the spider silk with the weight of the person, so you don’t need to know how much spider silk each fly is carrying, only a bulk total weight to be carried (110 lbs + 500 grams) and a bulk lifting capacity per fly (10 mg). We don’t know how much air space a fly needs to effectively lift before the interference reduces lift capacity, but I don’t think it’s going to be feet. I would WAG a sphere 4 inches across per fly would be sufficient. With that kind of estimate, would could work out the geometrical distribution of the flies and thus the required average lengths of spider silk or something. But 24,075 miles is probably sufficient to cover that need. 110 \* 2.205 +.5 =243.05 kgs weight 10 mg/fly = 0.00001 kg/fly # flies = 243.05 / 0.00001 = 24,305,000 flies Substantially higher than the ~5 Mill flies Una calculated. Still, it’s only totally unreasonable and impractical - not technically impossible. 😉 ---
**Author:** ![tonyfop](https://avatars.discourse-cdn.com/v4/letter/t/85f322/32.png) [@tonyfop](https://boards.straightdope.com/u/tonyfop)\ **Post date:** [June 18, 2013, 7:13pm UTC](https://boards.straightdope.com/t/lifted-by-flies/661147/12 "2013-06-18T19:13:25Z")
> [@Folacin](#): > > I saw a documentary where sea gulls were trained to fly a peach across the ocean (they even used spider silk!), so I think that gives us a potential proof of concept for flies and a person. I saw a documentary where they trained swallows to carry coconuts from Africa to England. They even contrasted the abilities of various species of swallows to carry the coconuts. Oh wait, that was a Monty Python movie. Nevermind… ---
**Author:** ![eastcheap](https://avatars.discourse-cdn.com/v4/letter/e/8491ac/32.png) [@eastcheap](https://boards.straightdope.com/u/eastcheap)\ **Post date:** [June 20, 2013, 1:07am UTC](https://boards.straightdope.com/t/lifted-by-flies/661147/13 "2013-06-20T01:07:48Z")
> [@Irishman](#): > > Technically, he didn’t state it is impossible, merely highly improbable. Perhaps if you had great big fat [flies] with steel and sapphire on their wings… ---
**Author:** ![chorpler](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chorpler/32/2888_2.png) [@chorpler](https://boards.straightdope.com/u/chorpler)\ **Post date:** [June 20, 2013, 5:09pm UTC](https://boards.straightdope.com/t/lifted-by-flies/661147/14 "2013-06-20T17:09:49Z")
> [@Folacin](#): > > I saw a documentary where sea gulls were trained to fly a peach across the ocean (they even used spider silk!), so I think that gives us a potential proof of concept for flies and a person. And boy, was that a giant peach.