18 replies to this topic

[ironizer]

I want to build a home made electric RC Heli, very small and light. I have one of those Mini RC racers, like these and i want to convert one into a heli. They are powered by capacitors, but I don't know If the motor and all can produce much thrust. I can make prop blades out of nylon to keep it light. Does anyone have any suggestions, ideas, or even better; has anyone actually made their own electric micro heli?
If it won't work to make it out of the car, what can I use? I want to use capacitors, because Li-Po batterie cost too much. What motor should I use, etc. Thanks for any advice.

[calbiterol]

I would be pretty surprised if anything RC is powered by a capacitor. Capacitors are meant to either smooth over the flow of electricity or to provide spikes of energy. Capacitors might be used under high-torque-requiring situations in order to give some extra juice to the motors, but powering the entire thing off of capacitors is fairly unlikely - unless you want a 2-5 second flight.

You'll need batteries (or a fuel cell haha) somewhere. Even AA or AAA or 9V might work - it all depends on the circuitry.

[Klaynos]

I've acutually just bought a micro RC helicoptor... it's not arrived yet though.

If I where you I'd build some sort of test rig using the motor just to see if it's powerfull enough with a set of rotors to lift itself.

Also most of the small cheap RC heli's I've seen have had 2 sets of rotors, I speculate that they spin in oposite directions (I dunno for sure, should be able to tell you in a couple of days) I'd guess this was to try and ballance out for consorvation of angular momentum.

[JesuBungle]

The top rotor on the cheaper micro helis is used for trim mainly. You bend it this way and that depending on how the helicopter turns.

But back to the OP, I think you could do such a thing, but a capacitor would not give a very long flight. I recall having a styrofoam plane that would charge for 5 minutes and flew for about 5 seconds lol. And that didn't even have heavy servos or anything for control. I'd say your best bet is looking for a cheap battery setup, they can't be that expensive these days(hopefully).

[Rocket Man]

a capacitor has about the best power-weight ratio untill you move into respectable energy ratings.
i've pulled one of those cars apart before, the steering mechanisim is pitifully simple. it's a magnet between two counter wound solenoids. i assure you, you cannot control enough of the aero dynamics on a chopper with just 2 channels.
if you're going to use one of these, i'd suggest making a plane.

[calbiterol]

My point is, energy density doesn't do you any good if the energy capacity is low. It'd be cheaper (in the short run) to just power the thing off of AA or AAA or C or D batteries (in the US, that is - not sure what the foreign equivalent is) and use caps for bursts of power.

In actual helicopters, two full-sized rotors will counter-rotate (opposite directions) to preserve angular momentum AND to provide even-er lift (there's a fairly complicated effect in here that I neither remember the name of nor can explain. It involves vortices, if I remember correctly).

[ironizer]

the advantage of capacitors is that they charge very fast. Those ufo things

http://www.raidentech.com/rcufo.html

have capacitors too, as well as the mini RC cars. Batteries have a limit on how fast they charge because they are chemical based. Capacitors also have a long life, something like 1/2 million cycles and you can pull them out from everywhere. I was thinking of making a semi-conductor pad so that when I want to recharge, I can just trow my heli on there and wait a few seconds.

I also have some lithium-ion cells from a laptop battery. They are a lot longer and a bit wider than AA batteries, but are surprisingly light. They also give quite a kick, so I might use those. The only thing I am afraid of is that I can't get enough lift from a motor, so I might end up making a plane.
Does an airplane require less thrust to stay in air as opposed to a helicopter?

thanks!

[Bettina]

I want to build a home made electric RC Heli, very small and light. I have one of those Mini RC racers, like these and i want to convert one into a heli. They are powered by capacitors, but I don't know If the motor and all can produce much thrust. I can make prop blades out of nylon to keep it light. Does anyone have any suggestions, ideas, or even better; has anyone actually made their own electric micro heli?
If it won't work to make it out of the car, what can I use? I want to use capacitors, because Li-Po batterie cost too much. What motor should I use, etc. Thanks for any advice.

One of my friends is into models and he always goes to this site for advice.

http://www.rcgroups....orums/index.php

Bee

[Rocket Man]

think of it in terms of kinetic energy, the more mass of air you have in your downwash, the more momentum you can have for less energy.
a plane has a longer wing span than a chopper so it moves more air more efficiently. the prop on a model plane provides relatively little force.
if the rotor on a chopper makes a downwash of the same mass per time as a plane, it's going to have the same lift for the same efficiency.

the problem with a chopper is the uneven drag on the rotor. the tips move very fast and the inside provides very little lift. you need quite a hefty motor to give enough torque. high rev motors are invariably lighter.

[Patmmr]

I have a Honybee CP2 Elec. Helicopter, Can any one tell me how to build my own main rotor blades. Thanks [[EMAIL REMOVED]]

Edited by mooeypoo, 14 September 2009 - 03:18 PM.

[Smokindodge]

Have you made any head way on this project? A smaller chainsaw engine would probably do what you want to do and have plenty of flight time. I don't know how the rpm would work out though, they run about 14,000 rpm so a gear box may be in order to preserve the integrity of the props

[calbiterol]

I'd be more worried about the weight of the engine than the prop speed, personally - if you can't get off the ground, then you're SOL, but at least something that chops props LOOKS cool while dive-bombing shrapnel...

[bmrodgers148]

buy a small but more powerful motor and use a solderind pen to solder the terminals together

[iNow]

Hopefully they've figured it out by now.

[ironizer]

Yep, by now I got LiPo and brushless motor with computer radio. I'm hauling ass. Thanks.

[Klaynos]

Yep, by now I got LiPo and brushless motor with computer radio. I'm hauling ass. Thanks.

Can we see photos?

[engr tayyab]

hi to all the members, can anybody guide me about the helicopters how to build them and where to get motor and circuitery for that, i really need some help if some can help me i will be thankful to you. I request u BETTINA plz contact me on my email, [[EMAIL REMOVED]]
I will for someone kind ?

Edited by mooeypoo, 14 September 2009 - 03:18 PM.

[forufes]

i've bought one for about 20$, made in china of course.

flies, but hard to control, the tiny thing is a spectacular knot of genius engineering, especially for being so affordable.

and you've got the right idea with capacitors, so you have to charge it every 7 minutes or so.

[mooeypoo]

I removed 2 email addresses from various posts in this thread. This is a debate forum which means the debates happen HERE, not in email. Please don't post email addresses in public. If you insist on talking to a single person in email, send them a Private Message.

Also, posting your email address in a public forum is a recipe for spam. To all those who got their emails removed: You're welcome.

~moo