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View Full Version : Would da Vinci's Helicopter have Worked?


CalMeacham
06-15-2006, 03:53 PM
Leonardo da Vinci sketched what he called a helixpteron ("screw wing"), which would ave been made of startched linen. It was intended to be a screw that would "bore up" into the air when rotated rapidly. More than once I've seen the claim made that it would have worked, if he had a motor to drive the screw (instead of the humans often shown in sketches or models). This page points out the need for something like a moder helicopter's tail rotor to resist the tendency of the machine to counter-rotate:

http://64.78.42.182/sweethaven/Aviation/Aerodynamics01/lessonMain.asp?iNum=0301



My question : I've never really bought this. Nobody else has ever designed or built a helicopter looking remotely like this (except for another early dreamer, whose ideas never got beyond the drawing board. But i forget his name). Modern heluicopters have relatively narrow blades that get tilted with variable pitch. this thing has an enormous area of non-variable pitch, and I think it would have a phenomenal amount of drag. Modern helicopters don't exactly "bore up into the air", anyway. Even with a powerful motor and a tail stabilizer, I don't see this as working.


What do you think? Has anyone heard of any critiques or Discovery-Channel or PBS-style recreations of this one?

John Mace
06-15-2006, 04:04 PM
I watched a "Da Vinci Tech" show recently on one of those channels where they showed people who had recreated some of his inventions. The helocpoter was mentioned, but no one had tried to make it work. There is a group working on his ornithopter, though, and the parachute that people thought wouldn't work actually did.

Chronos
06-15-2006, 04:13 PM
There's an old saying that a barn door will fly, given enough power. The question is just whether you could give the thing enough power. Certainly, a couple of humans turning cranks wouldn't do it: So far as I know, a working human-powered helicopter has not yet been built, though many have tried. It might be possible to get enough power at a low enough weight from some sort of engine, but I don't know. Of course, the fact that modern helis aren't actually designed that way doesn't really say anything about whether the design would work; all it really means is that there are other designs which work better.

Bryan Ekers
06-15-2006, 04:17 PM
Modern heluicopters ...
Well, in all fairness to Leonardo, modern helicopters didn't fly from the first prototype, either. Had he a motor and the means to conduct actual tests, no doubt he'd've discovered the limitations of his initial design and made many refinements, assuming he stuck with it.


I've no problem giving him credit for the theory. I did have a problem with Star Trek fans claiming the original series inspired cellphones and floppy disks.

CalMeacham
06-15-2006, 04:24 PM
John Dykstra , in a lecture where he was talking about the boxy shape of the "MiG-21" in Firefox, said that it you strap a big enought rocket to a brick it would fly. I'm, not disputing that. But I know that with some designs, more power doesn't necessarily buy you anything. My suspicion with the helixpteron is that, no matter how fast you turn that crank, with howevermuch force, it ain't going up in the air -- you just get a rapidly rotating fancy piece of machinery on the ground.

(If I put a superfast motor on my sno-cone maker, it won't fly. It'll just rotate fast. And no doubt exhibit really weird gyroscopic effects)


I'm not arguing about who gets first credit on the helicopter, either. I'm perfectly willing to give da Vinci full credit on the man-sized helicopter idea (although I note that little "hand-held" helicopter toys go back a lot earlier than da Vinci in China). My question is just "Would it Work?"

John Mace
06-15-2006, 04:33 PM
(If I put a superfast motor on my sno-cone maker, it won't fly. It'll just rotate fast. And no doubt exhibit really weird gyroscopic effects)


I'm not arguing about who gets first credit on the helicopter, either. I'm perfectly willing to give da Vinci full credit on the man-sized helicopter idea (although I note that little "hand-held" helicopter toys go back a lot earlier than da Vinci in China). My question is just "Would it Work?"
I agree with you on this, but I think there might be something missing (although I can't think of what it is). Was Da Vinci that ignorant of the the fact that if the machine starte to "bite" into the air that rather than go up, the 'bite" would make the base rotate in the opposite direction even faster?

Sevastopol
06-15-2006, 04:35 PM
John Dykstra , in a lecture where he was talking about the boxy shape of the "MiG-21" in Firefox, said that it you strap a big enought rocket to a brick it would fly. I'm, not disputing that. But I know that with some designs, more power doesn't necessarily buy you anything. My suspicion with the helixpteron is that, no matter how fast you turn that crank, with howevermuch force, it ain't going up in the air -- you just get a rapidly rotating fancy piece of machinery on the ground. ...

My question is just "Would it Work?"

Well, it supposes air to be a fluid medium. And propulsion through it to be possible by continuous/rotational motion of a screw/propellor. So in theory, it is the same thing as a helicopter, leaving aside the question of countering the torque effect.

So, sure it could work, as described given some tweaks to materials and powering.

DanBlather
06-15-2006, 09:24 PM
Hpw about if it was sitting on DaVinci's conveyer belt design?

El_Kabong
06-15-2006, 10:27 PM
Nobody else has ever designed or built a helicopter looking remotely like this (except for another early dreamer, whose ideas never got beyond the drawing board. But i forget his name).

On top of the bookshelf in my bedroom is a radio-controlled toy made by Tyco and called the XFO (http://us.st11.yimg.com/us.st.yimg.com/I/dmart_1898_196650672), which in some ways seems almost like a modern development of da Vinci's device. There are significant differences, however. In any event, if someone says I'm full of bollocks on this, I won't be hurt.

Like da Vinci's machine, the XFO has a single main rotor, without a tail rotor to compensate for the torque produced by the main rotor. As can be seen in the photo, the rotor consists of two blades mounted on hinges on the rotor shaft, and the entire rotor assembly is free to rock fore and aft at a 90 degree angle to the axis of the blades, apparently allowing the fuselage to hang like a pendulum from the rotor, without requiring active blade pitch control. The winglike appendages sticking out from the fuselage appear to slow the rate of counterrotation of the fuselage in flight, and the thing is quite stable in operation, although there is no control other than allowing the operator to make liftoffs, hovers and descents. The R/C controller has a single lever that allows one to spin up the rotor, take off and hover, with a fairly nifty feature that automatically carries out a controlled descent when the motor's electric charge runs low (after about two minutes' flight time).

Granted, the rotor resembles typical helicopter blades rather than da Vinci's airscrew, and the XFO design appears totally impractical for controlled horizontal flight, but if I squint I could see a modern Leo drawing and redrawing his design until he came up with something like the XFO. Regardless of any presumed similarity, however, my gut feeling is that even with a sufficiently lightweight and powerful motor, without a hinged rrotor mount the basic da Vinci design could not have taken off without almost immediately losing stability and toppling over.

CalMeacham
06-15-2006, 10:50 PM
I don't think you're full of bollocks, El Kabong (odd expression, that), but I do think your example looks a lot more like a modern helicopter than da Vinci's model. It's got those relatively thin helicopter blades instead of that broad helix that da Vinci's has. I have no doubt that the XFO will fly with a moderately powered motor, while I hav serious doubts that something built along da Vinci's lines would.

And that's the crux o the matter. I can build a helicopter model that will fly with an off-the-shelf motor. Heck, someone built a spring-powered helicopter that flew before the first heavier-than-air biplane mode did (see my essay First Flight in Teemings). Double heck, you can buy little toy "helicopters" made froma dowel and a fixed two-bladed wing without any motors that willfy -- you just twirl the dowel between your palms the righ way. But I seriously doubt that a daVincian helix-winged mel will fly by hand power, spring power, or off-the-shelf motor power. I even have doubts that it'll fly with souped-up atomi strength motors behind it, but that's beside the point. The point is that I suspect his helicopter design, even with minimal fixes, would be a workable, practical flying device.


I may have to go out and build my own to prove t.

cantara
06-16-2006, 11:42 AM
I was thinking of the same device as CalMeacham (example) (http://www.rosiehippo.com/productdetail.asp?groupnumber=T870). You could experiment and create a small hand driven prototype of the DaVinci machine and see whether the design will get enough lift to fly.

The propeller is essentially the same design, but with far less material. Given the speed at which the propeller must rotate, all the material that DaVinci has included is unnecessary and detrimental. I suspect that the design would give some lift, but far more inefficiently than the propeller.

Sam Stone
06-17-2006, 12:58 AM
John Dykstra , in a lecture where he was talking about the boxy shape of the "MiG-21" in Firefox, said that it you strap a big enought rocket to a brick it would fly.

And thus was born the F-104 Starfighter.

David Simmons
06-17-2006, 02:35 AM
John Dykstra , in a lecture ... , said that it you strap a big enought rocket to a brick it would fly.Well yeah, but as some point it just becomes a rocket with a brick strapped to the side of it. Is that really flying?

David Simmons
06-17-2006, 02:37 AM
Oops. Make that "Is that really a brick flying?"

matt
06-17-2006, 04:17 AM
One of the pioneers of propellers on boats was Edward Lyon Berthon, who started with an archimedes screw of several turns. Varying the length to find an optimum, he ended up with one-sixth of a turn - effectively a single-bladed prop.

Whether da Vinci's design could lift off I'm not sure, but it would generate some lift, which would be detectable if the thing was suspended from a counterbalanced boom. He could then have played with the length and pitch of his screw and ended up with something more practical.

FRDE
06-17-2006, 08:01 AM
Given that Da Vinci was pretty good with his hands
- it seems probable that he built a working prototype of some sort

Daedalus, the father of Icarus, was supposed to be toymaker for Minos
- the Greeks certainly knew about a fair few things that they never implemented
- simple turbines and mechanical toys

It seems probable that Da Vinci, like Palladio, got his hands on some Greek text books.

Not at all 'straight dope' - just a possible line of enquiry

Sevastopol
06-17-2006, 10:32 AM
...
this thing has an enormous area of non-variable pitch, and I think it would have a phenomenal amount of drag. Modern helicopters don't exactly "bore up into the air", anyway. Even with a powerful motor and a tail stabilizer, I don't see this as working. Drag: The Leonardo does not propose any horizontal direction. Even with a modern helicopter, the vertical direction or 'rate of ascent' does not reach a point where drag is a consideration: i.e rotary-wing aircraft do not go up fast enough for drag to matter.

"Bore up into the air:" In fact that is just what they do. By comparison a deep shaft coal miner which bores into the earth, closely resembles a helicopter wing or the vanes of a jet engine. Although it does not have the variable pitch.

...The point is that I suspect his helicopter design, even with minimal fixes, would be a workable, practical flying device. Read 'doubt' for 'suspect'. Well sure, practical in the sense of a modern aircraft is practical, there you are correct.

Leonardo invented modern engineering through his diagrammatic studies. As an exercise solely directed to the question of powered and heavier that air flight, his machine is correct on all the major points.

There are issues with the airflow and torque effect, but nothing that is outside the scope of minor tweaking. In fact, a modern helicopter is really a short step from the Leonardo.

Nic2004
06-17-2006, 11:28 AM
Oops. Make that "Is that really a brick flying?"
"That's not flying! That's falling...with style."
Woody to Buzz Lightyear

MonkeyMensch
06-17-2006, 12:04 PM
"Bore up into the air:" In fact that is just what they do. By comparison a deep shaft coal miner which bores into the earth, closely resembles a helicopter wing or the vanes of a jet engine.
Well, not really. Boring machines operate in a dense, incredibly viscous near-solid. Helicopters function in a light, low-viscosity fluid. That's why the blades look so different. Try boring in the earth with a helicopter rotor some time.
There are issues with the airflow and torque effect, but nothing that is outside the scope of minor tweaking. In fact, a modern helicopter is really a short step from the Leonardo.
I don't know if minor tweaking is the right term here. Overcoming the torque transmitted back to the airframe was a big problem for early rotary wing development and explains why most pioneering helos were of the counter-rotating type.
I think Leo's design shows he didn't have the slightest foresight of Newton's third law. His design, if it ever got airborne with enough power, would be a moderately rotating airfoil section and an incredibly quickly counter-rotating airframe, since the drag on the airfram would be the only offset to the torque of the lift generated.

Elendil's Heir
06-19-2006, 01:26 PM
Incidentally, da Vinci's gizmo makes a brief appearance in the movie The Da Vinci Code. When Sophie is remembering life with her grandfather, you see him holding a model of the helixpteron as she dances.

Elendil's Heir
07-24-2006, 09:34 AM
PBS will be broadcasting a two-part show called "Leonardo's Dream Machines," which "follows the world's leading experts as they attempt to build some of Leonardo da Vinci's dream machines." The shows will be broadcast on WVIZ Channel 25 from 9-11pm on Aug. 24 in Cleveland; check your local listings.

Xema
07-24-2006, 01:48 PM
In fact, a modern helicopter is really a short step from the Leonardo.
It's a matter of judgment, but I'd say that a modern helicopter's control system is not a short step.

Kevbo
07-24-2006, 03:24 PM
With enough engine lots of otherwise hidiously un-aerodynamic things will fly.

That said, the "air screw" concept is a horrible way to propel any aircraft, and worse yet to try to support it's weight.

Propellors, and helicopter rotors are just wings that chase each other. Long skinny wings always work better than short, fat wings. LdV's "air screw" is such low aspect ratio that the chord takes up more than a full revolution.

To provide thrust, you have to move a cylinder of air. A couple of blades can move that whole cylinder of air pretty well.

Once the air cylinder's motion has been started by the first part of the screw, all the last 90% does is waste power by causing drag.

Xema
07-26-2006, 11:58 PM
see my essay First Flight in Teemings
I looked and wasn't able to find this - can you tell me how to?

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