Back and Forth Massive Motion makes fly more stable

[jamesadrian]

i was once told that a mechanism on the back of a house fly makes its flight more stable than it might otherwise be by driving a mass or a pair of masses back and forth along a line.

My theory is that changing the direction of the line along which these masses are traveling requires work.

I also wonder if a fly can stop rotating by starting up this back and forth motion. The two masses might alternate between moving toward each other and moving away from each other.

Whether I have the anatomy of a house fly right or not, I ask you to consider such mechanisms and whether they would work as I expect.

Thank you for your help.

Jim Adrian

 

[Simon Bridge]

My theory is that changing the direction of the line along which these masses are traveling requires work.

Is this a personal theory or have you made some inquiries, say, of the literature to find out what is actually happening?

Most flying insects have two pairs of wings - flys have one.
Where you'd normally find the second pair, the fly has a pair of stubs called "halters".
They don't work the way you seem to be expecting, but it's hard to tell. iirc they provide a kind of gyroscopic stability but also act as sensitive turn-rate sensors.

http://animals.howstuffworks.com/insects/housefly2.htm
http://jesseenterprises.net/amsci/1960/04/1960-04-fs.html

There's a robot fly that uses the same principles.
http://www.technologyreview.com/news/408265/robotic-insect-takes-off/