R/C Helicopter or Airplane?

[audioguru]

If you learn about model helicopters then you will see how they control them.

 

[epilot]

How high would this go? Is it possible to add any kind of control to it?

Secondly, those motors are pretty big and heavy? In that case, can I just use any old motor I find?

It depends upon the thrust you'll get vs the model weight. the battery current is important too. I made one last year, without any battery or control
just a wire to carry the power for it, the Max high I got was 3m. I used a FF 180SH motor (much heavier than an N20 motor) and a 14cm geard prop.

The balsa woods are there to avoid spining of the motor, but I had some of rotation due to the big prop which I had, but there is a smal rotation with any motor and prop anyway I think

You can make a very light IR control (one channel) for it or you can use a control from micro R/C cars (which the reciever weighs just 2gr). I prefer IR though.

you can use a scale to measure the thrust of your motor and prop.
suppose your digital scale shows 17gr of thrust while the prop is rotating, that means if your heli weighs 17 gr AUW then you will have a a 1:1 thrust and the heli will hover and if your heli weighs less than 17gr then the heli will rise...

P.s if you want to use your motor yet, just let me know its weight and resistance

 

[Omar.M]

Sorry this might be a stupid question, but how does one find the resistance?

 

[epilot]

Oh I see. I think that last one epilot showed would be the easiest to make.
I just had a question, since the faster the motor spins the more it should fly in theory right-- so why would you want to lower the RPM's?

I have two motors from those tiny RC cars, and I can probably create a simple IR transmitter and receiver for the previous one. Just one thing, how would it go higher or lower / move left or right?

yes It is the easiest heli I ever seen. it is not able to have any horizontal control. for vertical control you can make a throttle circuitor just switch the transmitter with your finger.

almost all motors used as plane and heli engines have a very high RPM (more than 20000 revolutions per minute). you can use them direct drive but just with a small prop to avoid much air friction and the motor will rotatet at say 12000 rpm with a low thrust, but if you use the motor with a large prop then it will rotate at say 2000 rpm due to high air friction, in the last cause you will lost your motor's efficiency and the motor will draw a huge current from the battery and you will lost the speed AND the thrust and perhaps you'll lost your motor.
If you use a gear for a big prop, then your motor will rotate at its reasonable speed with a reasonable ampere draw and a good efficiency while your prop rotates at a lower speed but with a higher thrust, this mean that your heli will rise if the trust of the prop is higher than the weight of your heli but slower than when you don't use a gear but have the same thrust. ok?

 

[Omar.M]

I have about 2 of these motors:

Apparently they are above 10,000 RPM. So for these small motors, can I make the prop out of cardboard? What about gearing vs. non gearing?

If this is not efficient, I might just buy one good motor online-- shouldn't be too expensive. About the vertical control, when I press the button the motor spins, and when I let go it doesn't, so that is how it goes up and down, you mean?

 

[epilot]

Sorry this might be a stupid question, but how does one find the resistance?

Just use an ohmmeter and put its hook on the motor's pins.

you should use a high quality digital ohmmeter.

 

[epilot]

I have about 2 of these motors:

Apparently they are above 10,000 RPM. So for these small motors, can I make the prop out of cardboard? What about gearing vs. non gearing?

If this is not efficient, I might just buy one good motor online-- shouldn't be too expensive. About the vertical control, when I press the button the motor spins, and when I let go it doesn't, so that is how it goes up and down, you mean?

First see this link because I think you can properly hack your Reciver and the transmitter that you took from your zipzap car ( if it is a micro R/C car):
https://www.electro-tech-online.com/custompdfs/2007/04/Zip-Zap_article20Servo8-06.pdf
**broken link removed**

I suggest you to buy a propeller, it would not be very efficient if you DIY.

 

[Omar.M]

Thank you very much. I've checked the site out, but I think I more simply want an IR circuit. This seems more complicated, and I don't have the exact ZIP ZAP racers (just a clone).

The propeller, I am ready to buy. I'll wait it out, until I am done some more robotics projects.

 

[hack]

Well that is not so easy to be built I think. If you could make the whole propellers the same then you must consider the RPM for 4 motors (they must have the same RPM too).
If I was you and wanted to make something that just is considered to be HOVERed, I went and get some balas woods, put a low winding resistance motor (2 or 3 ohms) motor (a 4gr or 5gr, N20 or M20 is just fine), then get a GWS 2.5x1 prop( direct drive should be ok for an M20 or N20) and finally get a 3.6V lithium polymer cell (130mAh wich is less than 4gr for instance) and build this:

I like this design. I was actually working on a similar one last night and then I read this thread. Does the chassis act as a stabalizer or a "wing" inself?

My biggest question that I was pondering last night was how do I get the thing down. Up is easy, run the motor. Down though? (I am reasonably new to electronics) Naturally, you can cut the power, by use of a timer / counter or microcontroller - but that would just send it crashing down to the ground.
Would you want to reduce the voltage going to the motor to bring this device back to the ground gracefully? If yes - then how would you gradually lower the voltage? I was considering a microcontroller that (using transistors) would introduce loads in series to the motor gradually, thus lowering the voltage of the motor. Is there a better way to do this?

Thanks!

 

[Nigel Goodwin]

To bring it down simply reduce the speed of the motor (so it comes down gently), if you're using a microcontroller for the timing you can use it to PWM the motor as well.

 

[hack]

Thanks Nigel!

I found **broken link removed** who has an example picaxe script for using PWM to control a motor as you suggested. This will definitly work for me. Here's the link to the example bas file for using a picaxe to PWM the motor for speed control - **broken link removed**

 

[epilot]

I like this design. I was actually working on a similar one last night and then I read this thread. Does the chassis act as a stabalizer or a "wing" inself?

My biggest question that I was pondering last night was how do I get the thing down. Up is easy, run the motor. Down though? (I am reasonably new to electronics) Naturally, you can cut the power, by use of a timer / counter or microcontroller - but that would just send it crashing down to the ground.
Would you want to reduce the voltage going to the motor to bring this device back to the ground gracefully? If yes - then how would you gradually lower the voltage? I was considering a microcontroller that (using transistors) would introduce loads in series to the motor gradually, thus lowering the voltage of the motor. Is there a better way to do this?

Thanks!

Well, I think the below clip which is a similar project will help you to understand it.

http://www.spyplanes.com/movies/Micro_heli.mpg

I am sure that you are able to find a suitable ESC or IR control here, Just let Google to translate it.

http://www.cityfujisawa.ne.jp

**broken link removed**

 

[Omar.M]

I know I have not been replying to this thread very religiously. But I think I might have an idea that just popped into my head.
I was looking through some of my things, and I found my two mini R/C cars. Both work, but I took apart both of their receivers and the cars themselves a while ago (and never got around to finding how they worked).

I read on the internet and tested with a voltmeter and I think I may have found a solution.
I can take out the reciever from the car and the magnetic actuater that the cars have inside. I can make a simple rudder out of the steering system, and an on/off motor control with the forward/backward system.

Basically, the body of the plane will be very simple... something like this:
**broken link removed**
Constructing the basic shape out of styrofoam or balsa wood might do.

The only thing that concerns me is which motor I will use / prop and which battery. Any recommendations?

Thank you very much,
-Omar

 

[HYTECH]

here is a homemade helicopter

**broken link removed**

 

[audioguru]

Go to the meeting of your local indoor model airplane club. Some of the planes use the radio system from a mini car but it is souped up for greater range so it can still work at the length of a school gym.

The flying wing you showed doen't have a norizontal tail and doesn't have dihedral for stability. It would spin (from the torque of the motor) into the ground unless you are an expert pilot.

 

[jpanhalt]

While I agree wholeheartedly with the recommendation to go to a local club, I cannot agree with the assumption that the depicted model would be that inherently unstable. Flying wings do not have horizontal stabilizers, and they can be quite stable. Refer to Mr. Northrop, who is unfortunately dead. Our military dependence on the conventional configuration is based on political strings pulled by Boeing during the competition for the next generation bomber. The Northrop "flying wing" was a better airplane than the B36, but the proposal lost. The Zagi is a current example in the model world; the B2 bomber is one from the tax-supported world. Model Aviation published a few years ago plans for a "penny model" that was a flying wing made from an egg carton and a penny for balance that flew quite well. John

 

[Nigel Goodwin]

Model Aviation published a few years ago plans for a "penny model" that was a flying wing made from an egg carton and a penny for balance that flew quite well. John

From what I've seen, the massive power to weight ratio of the glow-plug engines mean you can fly almost anything - it's incredible what model makers have actually flown!.

 

[jpanhalt]

When one sees some of the 3D+ models, it's a question of whether they are flying or just motors on a radio-leash. Some electrics can even "fly" in reverse, and I have seen a video of power boats flying, not just skipping over the water. I prefer sailplanes. John

 

[audioguru]

I have seen a video of power boats flying

The video of the Hydrofoam is here:
**broken link removed**

I also have a video of a flying lawnmower doing loops:
**broken link removed**

 

[Sceadwian]

Google "Flying lawnmower" for a good video
Or flying pizza box, which is basically a .40 sized motor tacked onto a piece of coroboard (plastic cardboard) with a rudder and throttle for flight control.