Reciprocating engine for ornithopter

[spammmer]

I was on a Russian forum and people there perceive the idea as spam.
I want to make a reciprocating engine. This engine has many advantages - a minimum of parts, cheap and because there is no gearbox has direct control of the wing.
I need to calculate the engine before producing it.

The "motor" I want to make is a speaker with an electromagnet instead of a permanent magnet. I think I need to find the speaker calculation information. But I couldn't find or searched badly.
I need a 100 W motor with a frequency of up to 8 Hz.
The moment of force (newton) is not very important, because with the help of a lever I can achieve any force.

Additional requirements: weight of 2 motors up to 500 grams.
--------------------
I made a bad model of what I want from wood in half an hour (I can't simulate on a computer)
Sorry



~ 30 turns of 0.5 mm wire are wound on an iron rod (2)
Wound one coil with 0.1mm wire, 100 turns (3)
Dual coil construction on frame (1)
The model does not work when current is applied (by design, the coils should have moved)
I hope the idea is clear. I wound it with a thin wire only because it was difficult to wind it with a thick one (0.5 mm). All this must be powered by a voltage of 3 Volts (stab.), And the engine will be made using plastic, epoxy, electrical steel and will resemble a factory

I ask you to help me create or suggest where you can buy such an existing one (or an ornithopter with it), I need a noiseless camera for photography (a quadcopter is not suitable)

 

[Ian Rogers]

You might think about using "spammer" as a name... I nearly deleted you... Lets hope you are not.

 

[Nigel Goodwin]

You might also think about doing a little simple maths - 100W at 3V will be over 35A - you also can't achieve 'any force' by using a lever, the power never changes (except from been lower due to losses).

Can ornithopter's even fly anyway?, they are basically science fiction - see Edgar Rice Burrough's Mars stories.

 

[Ian Rogers]

There is an interesting video on youtube... Looks impressive.. The workings are very precise...

https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=&cad=rja&uact=8&ved=2ahUKEwjVkdCx18HyAhXCu6QKHe-VB3UQwqsBegQICxAB&url=https%3A%2F%2Fwww.youtube.com%2Fwatch%3Fv%3D2Nd8BA3OHCc&usg=AOvVaw0_1jUFK7f58mJp4Hc--Mbs

Doesn't look like a scam..

 

[Diver300]

Can ornithopter's even fly anyway?, they are basically science fiction - see Edgar Rice Burrough's Mars stories.

I'm not sure how easy it would be to make an ornithopter hover, but I've seen rubber band powered toy ornithopters that flap their wings and fly.

Also, I've ridden three types of human-powered hydrofoils. All three were powered like an ornithopter, with the wings being moved up and down while the angle of attack of the wings changed.

On a hydrofoil, the is underwater, and the rider above water, so there is one reasonably rigid wing and no middle pivot. Lift comes from speed, and forward propulsion comes from the variable force and variable angle of attack on the wing.

 

[spammmer]

You might also think about doing a little simple maths - 100W at 3V will be over 35A - you also can't achieve 'any force' by using a lever, the power never changes (except from been lower due to losses).

The higher the current, the thicker the wire. The thicker the wire, the less insulation. The less insulation and the thicker the wire, the better the cooling.
On the other hand, if you wind with air insulation, the thinner the wire and the more turns, the larger the area, the better the cooling.
But since I do not know how to wind non-enameled wires, option 1 is suitable for me.
That is, the stator and rotor winding must be single-layer, can even with a step of 50% of the wire diameter, in good contact with air.

 

[rjenkinsgb]

The concept you are looking for is a "Voice coil linear motor".
There is no advantage I can see to using a wound field rather than permanent magnets? It's just going to take more power and produce heat; it will be very difficult to match the magnetic field strength available from neodymium magnets.

Pretty much all industrial servomotors etc. are now permanent magnet based, unless they need field weakening or are actually based on induction motors.

Note that some of the most fundamental principles are that the fixed magnetic field need polepieces both sides of the coil (inside and outside) and the air gaps between the coil and poles must be as small as possible.

Field strength is based on "ampere-turns"; eg. 100A in a ten turn coil gives the same field as 1A in a 1000 turn coil of the same size.


Hard drive head servos are good examples of linear voice coil systems, though they often use a "flattened out" version with a wide coil and two sets of magnets.

Thinking of that, a couple of hard drive head actuators could be what you need? People have done all sorts of stuff with those.
eg.

http://www.instructables.com/Hard-Drive-Speaker/

You would need a bit better drive system with some positional feedback, though..


Some other info:

http://www.acm-magnetics.com/acm/pdfs/15-BasicsOfVCMs.pdf

http://etheses.whiterose.ac.uk/1849/1/DX194430.pdf

http://ultrabird.weebly.com/uploads/9/5/2/2/9522101/vca-sies.pdf

ps. For a noiseless system, you may be better off with an airship - a dirigible, mostly helium for support plus large low speed propellers or ducted fans for directional control.

 

[alec_t]

How do you propose preventing the reciprocating engine at ~8Hz from severely vibrating the camera?

 

[Buk]

This might inspire you.

 

[audioguru]

My RC model airplanes can loop, roll and fly inverted. A model bird cant doo dat.

 

[spammmer]

What I need is called a "traction electromagnet". For example,

CN2288492Y - Double solenoid traction electromagnet - Google Patents

The utility model relates to a double solenoid type traction electromagnet which is a traction electromagnet of the low-voltage electrical apparatus. A double solenoid parallel connection structure is composed of an n-shaped armature iron (1), a magnetic yoke (5), a coil (2) and a coil (3). The...

patents.google.com

Ready-made products that can be bought on alibaba. But so far there is no one specifically for ornithopters or aircraft models.
It remains only to steal patents, try to make such an engine myself.
--------
Another name is what I need is push-pull solenoid

https://www.youtube.com/results?search_query=push-pull+solenoid

 

[Buk]

But can it swim as well

as fly?

 

[rjenkinsgb]

What I need is called a "traction electromagnet". For example,

If you look at the drawings relating to that, it's just showing variations of normal solenoid actuators, not linear motors; it's a very different system.
I think the odd name is from the Chinese translation.

The pull strength of a solenoid falls with the square of the gap, eg. they can be very powerful if the movement is small, but very weak if the armature is too far out.
It's down to "air gap" again.

 

[rjenkinsgb]

Can ornithopter's even fly anyway?, they are basically science fiction - see Edgar Rice Burrough's Mars stories.

Yes.
An example of a radio controlled model here; not a very good camera platform though..

Edit - just discovered that this is the same video Ian linked in post four.. Doh.

 

[Nigel Goodwin]

This might inspire you.

Quite nice, but it crashes every time, and is powered and controlled via a tether - a big difference from a self powered device.

 

[Buk]

and controlled via a tether - a big difference from a self powered device.

Things have moved on since 2013:

 

[Nigel Goodwin]

Things have moved on since 2013:

Cool!!

 

[spammmer]

The pull strength of a solenoid falls with the square of the gap, eg. they can be very powerful if the movement is small, but very weak if the armature is too far out.
It's down to "air gap" again.

It is possible to make a step traction electromagnet or a step push-pull solenoid. Similar to brushless motors, which have many magnets on the rotor and which have a fairly high efficiency and force.

Linear motor - Wikipedia

en.wikipedia.org

Wikipedia even has an image of such a motor

 

[spammmer]

Looks like I found what I needed

 

[Buk]

Looks like I found what I needed

Something like this would be far easier to construct and use less energy:

The coil pulls on the magnet and the spring returns the arm when the power is off.