I have always enjoyed thinking about human powered flight!  Why not, after all it would be good, to be able to hop on a thing something like a bike and hit the skies.  Sure it would be dangerous, but if it was possible it would be a revolution!

Anyway, I discovered something new about this the other day which I’ll get to in a moment.  But how I first started thinking about this was to wonder if nature had actually succeeded with this already?  I mean is there precedence?

So I went about looking up the biggest flying bird, just how big is it?  My search ended with the Kori Bustard, here’s the wikipedia entry for it.  Up to 34kg!! That pretty big.  There’s even a link there to a video of one flying (ok.. here it is for you).  

At that stage, I decided that if the biggest flying bird was only 34kg (only!), and even then it was reluctant to get airborne.  Well maybe it was going to be much harder to get a human up in the air at 60+ kilograms.  Not forgetting the extra weight of the device.  So what took me down that path of thought?  My first step was to consider the energy required!  More or less, I wondered, if no other animal body could output enough energy to overcome gravity, one way or another for a given size… then as far as I was concerned it was over. 

If big bird weighed 34kg, then I figured human powered flight was not impossible, just very very hard.  Let me explain one step further.  Nature had apparently hit a wall, Yep, plenty of birds are bigger than 34kg.  So it was not that birds simply didn’t get any bigger than 34kg, it was more to the point that once they got bigger - they stopped flying!  That in my opinion, didn’t bode well for human flight.

Then something popped into my head, I remembered the terradactyle!  Those things were huge.  So I went looking.  Ok so, I didn’t find those exactly, but I found the Quetzalcoatlus a Pterosaur.  These things were hanging around with the dinosaus, and left when they did.  But their size! - 12m wingspan, no 18 metres maybe and their weight? 65kg!! We have a winner!  Well, that was until I just discovered the condor like Teratorns.  These were very big birds that lived 3-8 millions years ago… apparently like overgrown condors.  Weighing 80kg! with a 8m wingspan, (or maybe 7m). 

I know all these figures are best guesses, but the bones are big!  You can even find larger estimates, but the point is… it’s been done!  Nature has created creatures that can fly, that weigh as much as humans do.  That’s a much better start.

Mind you, on a side note, I noticed that apparently aroud the times of the Pterosaurs O2 levels in the atmosphere were considerably higher than they are now.  Maybe they were turbo charged!  I was also reading that birds consume far more energy or if you like far more rapidly than humans do.  Well I guess that’s not hard considering what the majority of us do most of the time.

Now, what next?  In my head, I did a couple of quick calcs on the energy that has to be expended to keep 65kg in the air.  My mechanics is rusty… I know not all that energy has to come from the flyer all the time… but on average a significant amount of energy has to come out of them sooner or later, and how much can a human produce on average? 

That’s about it for the time being… next time I touch on this subject, I want to go over the economies of flight.  Wings vs propellers vs something else??  Propellers are great for things that spin!…but humans don’t really spin all that much - ok they do pedal, but birds flap.

In the mean time, I’ll brush up on my physics a bit and address that energy issue.

This entry was posted on Thursday, July 13th, 2006 at 11:55 pm and is filed under My thoughts. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.