Swimmer Wing

This one I'm calling Swimmer Wing, meant to be one of two sets of wings that counter-rotate with respect to each other, in a dragonfly format, for inertial balance.  

In trying to figure why a bird wouldn't do it this way, there are two reasons; moving the wing forward and back is a waste of energy for the bird in the first place, and their body isn't usually long enough (or more precisely hasn't the inertia about the Z axis) to counteract this movement, so head and tail would snap left and right, and it's all very lossy.

It does happen to be convenient for my simplest single curved spar layout, where left wing is out of phase 180 degrees from the right.  Again, for balance and not losing a lot of energy, there needs to be two sets of wings, and there are several layouts that get you this inertial balance, which I'm exploring now.

Of interest later is getting a pure inertial balance so a camera payload won't shuck around all the time, but that's not my concern at the moment.  For now, it's:
Continuous spar
No guy wires
Continuous rotation of power source
Rigid wing skin
Smaller wings (dragonfly is great for that)
Viable aerodynamics no matter where the drive stops

Wavy wing, 3d morphable airfoil

This one looks cool, if I do say so.  The point of it being "corrugated" is to allow all of the motions to merely change the local waviness of a rigid skin in response to combinations of curvature.  

The main sacrifices, of course, are in the torsional and bending stiffness you'd normally get from the skin.  The need to have the airfoil flexible enough to morph flies in the face of the need to resist "flutter" while flying.  I imagine some extra lattice structure between all ribs that ONLY improve the torsional stiffness, but otherwise allow it to bend in two dimensions.

Early solidworks morphing wing

I call this an early model because I'm just learning how to make solidworks animate this type of shape change. It's a notional model still, and the only thing you should take from this animation is that it must be made of rubber to do what the central spar is asking of it.
My current thinking is to try for a single curved spar with simple bearings at the ribs. Without a sliding interface between spar and rib, the airfoil is going to swing forward and back as it flaps. Ill discuss ways to cope with that soon. I'm letting go for the moment the concept of storing energy in the spar, and assuming for now that the spar is going to be far too stiff for that, so I need to learn how to deal with fore and aft flapping that goes with the kind we want. (That is, explore it for a bit before reverting to the twin opposing spars I animated earlier.). Having a single spar and less mechanism is worth seeing if it's possible to cope with its weirdness.
All this leads to the first major riddle to this: how to make a rigid skin adapt to complex curvatures. Not njust flap and twist now, but add reaching fore and aft. One effort I found on the net talked to 2d stretchy fabrics, but really, in order to aim high, the goal needs to start with a laminar flow airfoil, and compromise as necessary, which is likely.
Laminar flow will depend on surface smoothness and a viable airfoil no matter where you take a cross section of the wing.
That last qualifier will make sense on the next post.

Air Motor Prototype Runs Great!


This is a first run of a small 8-cylinder air motor prototype using my new radial piston architecture.  Sorry I can't talk too much about how it works yet.  It is quite simple and can be variable displacement while running, and is inherently balanced.  It will be good as a pump or a motor and is highly scaleable.  It has no connecting rods or crank shafts.
This is nice confirmation of the concept, which I would scale up for use on the Manithopter.  Even though it's a good candidate for wing power when used with a scuba tank and some interesting proportional valving, I've since found some outrunner brushless motors you can hold in your hand that develop 12.5KW (16HP+).  
Electric may be my favorite method right now, but it's nice to have a workable alternative!  A 16HP version of the air motor is not very large, but is an added development I think I don't need in face of an electric off the shelf option.

Curved spar wing warping demo

So I decided to make a quick wing using a foamy glider, gear motor and a parallel gear pass. There are regularly spaced plain bearings made of PVC, and the curved spars are 3/16" aluminum running through those guides. In this case the rods have to straighten out as the wing can't bend in its plane. You can hear the gear motor labor cyclically, though it's really storing torque and getting that energy back every half rotation. My planned composite lattice wing construction is lightyears ahead of this, but I'm still making illustrative models.



Some Whys of the Manithopter

Much has been done over the centuries attempting a Manithopter, not much of it particularly practical.  Human power has worked for an ornithopter recently, and while it is a gorgeous piece of engineering, practical it is not with wings the size of a 747, in mortal danger of the slightest breeze, and maybe more scarily surrounded by grad students.  

Large powered man carrying ornithopters have worked, but not elegantly, nor lacking in wheels and weight, and tend to kill their inventors.  No success is evident in making a man carrier in ultralight form, that can be easily set up and flown, designed for legs as landing gear.  

Practical sized, or I should say, compellingly small sized wings lead to higher wing loading and stall airspeed, and yet more important to realize the need to run and land faster than human legs would allow, with 100 lbs of gear on your back.  Imagine how far you could comfortably jump down with that kind of weight on you.  Off a chair maybe?  Now imagine dropping ten feet and hitting the ground running at 25 mph.  No thanks!

This happily leads to the need for a practical exoskeleton to augment our pilot.  We will have to stiffen things up substantially in the leg department, or more precisely, from heels to shoulders.  I think the only thing I’ve thought about more than actuators and propulsion is light and practical exoskeletons.  Far more on that soon, but the thought I'll leave with you is that this part of the project alone will start us off on a wild ride!

This entire device needs to be so robust and simple that it will survive one hundred and plenty attempts at flight.  Flying must be learned by long practice and a proper takeoff run, not jumping off a giant Red Bull can once, break your legs and equipment and make the nutty inventor highlight reel.

Consider that we'll give ourselves complete control of the shape, pitch, dihedral and camber of our wings, which is not a skill set we are born with, and neither are birds born knowing how.  

I think I will make a giant model bird nest and only allow my pilot to dance around the rim for the first few weeks. 

A closer up view of the counter-rotating spars doing a flapping action

This is a little better view of the previous flapping animation.  Still just wrapping my mind around using the curved torsion spars.  Coming up are posts showing a composite lattice wing build, and some bits on the pilot's exoskeleton, which we will be molding directly on our pilot Matt's body.  Hope we can get him out of it. ha

Quicky driven morphing spar

Try to ignore the pink string.  It's there to prevent movement other than up and down.  I'm clearly driving it at lower speed than its natural frequency.  I'll be whipping up a speed change drive so I can get it resonant, but all changes when the wing has a skin.  This has a continuously rotating curved rod inside of a delrin tube.

Slowmo of simple resonant dragonfly style wing

You can see this one go quickly from a nice high amplitude fundamental mode to the quite useless second mode. That of course happens when you try to drive it faster than its resonant frequency. I need to rig a variable power supply to that electric toothbrush!

Slowmo twin torquebar

This is an example of what I mean by going for zero torque ripple or at least getting control of it and put it to work. The point here is counter rotating two curved spars with a simple gear pass between. You can see that the ends are always the same short spacing in the Z direction, while they breathe fore and aft along an imaginary airfoil chord line.

I liken the fast meshing of the two rods as a set of one tooth gears.

So this one is flapping up and down, but room needs to be made for it to breathe fore and aft, or constrain them in order to store, for instance, some of the energy of the upward part of the flap cycle.

Playing with a simple morphing wing mockup

> I've been watching seagulls a lot these days. Their normal sustaining flap is not much and particularly little at the root, as I imagine I'd like. I want to have a nice structurally sound wing spar and root connection with the fuselage. No gear teeth or other power transmission mechanism in between the two. That's what I like about the concept of pre curved spars used as torsion tubes. Rotate it so it curves down, and it remains a stout structural spar. > > This simple experiment has a cardboard web with plastic tubes fore and aft, with bent wires down both edges. Each can be torqued with a crank at the wing root. This continuous web makes for high torque ripple as the curved rods go in and out of opposing each other, or more precisely, rotating such that they must straighten out. The neat thing is that the torque required to straighten them (as the wing approaches zero dihedral) is merely stored, not lost. Torque ripple can be useful or just coped with, but lets see if striving for none makes us wonder why we were searching for pig lipstick. > It gets a nice snapping motion toward the ends of stroke, but otherwise the action is mostly wrong. Any skin needs to stretch omnidirectionally, or it will buckle trying to do combinations of curvature, namely "flapped down", whilst trying to twist, and so on. The worst comes later when we try to morph it flapped, twisted and cambered positive and negative as an airfoil is. Imagine cracking a measuring tape across your knee to get a feel for it. >

> >

Making man fly

Coming someday, the Manithopter Personal Flyer

Welcome to my blog for the Manithopter Human Flight Project. you have gotten here either through manithopter.com, humanflight.us, or from YouTube.com/humanflightproject. This blog is just my unedited musings and experiments in rough form.  In the fall, we will begin shooting a documentary about the process, experiments and our attempt at a a full scale, strap on your back set of flapping wings; hopefully culminating in successful flights of something never before seen, but dreamt about for eons.  Like the "humanbirdwings" of Jarno Smeets that you may have seen on youtube, only not a hoax; an honest effort bringing all of my and my team's talents to bear. I hope you enjoy some of the work I've been doing in the wee hours, and sometime before the end of the year will be a full site and some regular episode releases in a more polished form.  The thrust of the effort is to make something hopefully interesting of my design process, and to show that technological spinoffs happen naturally whenever we attempt an engineering goal that is widely regarded as impossible.  We may or may not fly, but it is already generating spinoffs, compelling in their own right! I truly believe that there are no longer any limits that need to be observed, and it is now down to applying designs I've done throughout my professional life and long before.   While I may be making noises about how it doesn't matter if I succeed, actually, I fully expect to succeed and nothing less will do!