RC plane, from scratch

[Cobalt60]

A buddy of mine got an RC plane for free, but it has no electronics with it. No motor, no servos, no transmitter/receiver, etc. So, its a project of ours to get this thing flying. Any tips on ways to source some cheap parts would be highly appreciated. Plan on going with an electric motor, not glow.

The plane is a Hangar 9 Twist 3D. Here is the only video on YouTube of one of these powered by an electric motor:

YouTube - Radio Control Twist 3D electric

A typical motor (equivalent to 40 - 60 size glow engine) would operate at between 14V and 28V, 40A continuous with up to 60A "burst". Just to get this thing airborne, I dont necessarily need specs that high. So any idea on where to salvage an appropriate motor would be greatly appreciated (drill? car starter? etc.).

A 60A ESC (electronic speed controller) can be had for about $20 plus shipping, not too bad, but again, if money can be saved here, why not.

Well, the other main components are servos, and the controller. Controllers tend to be very pricey, often $200 or much more. So any ideas on that would be great. Servos too, a whole set of them can cost quite a bit so if I can just use some generic parts that would be good.

Thanks!

-Chris P

 

[Cobalt60]

Just to simplify, mainly what I need is a cheap way to get:

A motor that operates at between about 12 and 24V, with a goal of about 40A sustained. Brushless seems to be whats used commonly for this purpose so Im guessing that may be the way to go. Obviously, weight matters.

A custom built controller, to control rudder (left right), throttle (0-100%), elevator (up down), and roll control (a pair where when one goes up, the other goes down). Im assuming that would be a 4 channel controller. The range should be pretty decent, maybe 1/4 mile?

Servos for controlling the rudder, elevator, and ailerons.

Thanks again

 

[audioguru]

That model plane is an extremely difficult to fly stunt plane. A beginner will just crash it.
Learn to fly with a beginner's plane.

My kids bought me one for father's day. It cost $70.00 for the plane, battery, battery charger, servos, receiver and transmitter. I had lots of fun but crashed it accidently a few times and flew it into a tree. I nearly broke the tree to retrieve it. I lost it many times then found it (the field grows wheat). I replaced its broken wings twice. Now the field I used to fly it on has houses being built so I might not fly it anymore.

 

[jpanhalt]

I agree with audioguru. I started flying RC in 1952. Please post a video of your first flight.

John

 

[Cobalt60]

Well, its OK if we crash it. A large part of the pleasure from this will be in getting it to fly. The knowledge that would be gained in getting this to fly will prove invaluable.

But it seems as though you said I can get pretty much everything minus the motor for $70? Even the remote controller?

 

[dknguyen]

**broken link removed**

Dirt cheap everything. Motors, servos, batteries, electronic speed controllers (aka ESC- the RC hobby name for a motor driver), and more. So inexpensive you'll be suspicous if it even works because of what you paid for it...seriously.

Why bother salvage anything if a motor is like $20? Drills don't use brushless motors anyways and are likely too heavy and inefficient for a plane.

You will need a transmitter and receiver though, and those are not cheap (though they do not have to beterribly expensive either.) What do you mean by controller? The functions you describe (ie. mixing) is what the receiver does (and most of the computational power is done on the transmitter prior to transmission). Instead of using two aileron servos (along with mixing and reversing on the TX/RX to control both of them), many smaller planes simply use one aileron servo with one aileron attached to each sie of the servo horn. When the servo horn turns, one goes up and the other inherently goes down pushing one aileron and pulling the other causing them to move in opposite directions.

 

[Cobalt60]

lol "Please post a video of your first flight.". I will make sure to : )

Anyway yes those motors are so cheap that they are actually probably cheap enough. But so then we come to transmitter/receiver. When I said controller I guess I meant the transmitter (that you hold in your hands and often costs hundreds of dollars). So Id like to make one, to save money, if feasible.

As for the receiver/controller end, well, havent thought about that too much yet, but any ideas appreciated. Thanks for the link.

 

[dknguyen]

It is not feasible to make your TX/RX. They are mass produced and thus are cheaper and better than anything you can make without spending significantly more money. Not only are the electronics the most complicated of any RC system but so are the mechanics (case, control sticks etc.). It is the most complicated part of an RC plane setup and about the only one that isn't DIY. You can DIY with motors, ESCs, servos (somewhat...you tend to need to steal the mechanics and gut the insides with your own electronics), even entire planes! (though helicopters are a stretch for those without machine shops).

Pretty much no electronics in RC is cheaper if you make it yourself...trust me on this one. I've looked into it a lot. Costs me at least double every time I price things out.

But the transmitter is reusable between different planes, so why not just buy one? I mean suppose you built your own system...you don't want to have to make a RX for every new plane do you when you can just buy one.

 

[Cobalt60]

Well, this is just something I think would be cool on this plane:

**broken link removed**

 

[Cobalt60]

Well, thanks for all the help guys. I guess I can take it from here. I sent the wrong link for that ducted fan, the more powerful one is $23, and produces 38oz of thrust. A hi performance electric Twist will call for about 100oz of thrust, so probably wont go with that particular motor, though for $23, I think I might just buy it anyway and give it a try!

-Chris P

 

[dknguyen]

Why don't you go with propellers rather than ducted fans? Although a properly ducted fan is more efficient than a propeller of the same size, ducted fans are difficult to design properly and propellers are able to come in much larger sizes at which they are more efficient than the ducted fans available...and without the weight of the duct. Plus ducted fans don't usually fit well onto planes that use propellers.

IMHO, ducted fans are mainly for looks or speed (though propellers can also do that just fine, especially the pylon racer propellers made for speed). For stunt planes you want thrust, not airspeed.

 

[Cobalt60]

Well, like you said, they are more efficient, and looks. As for looks, its mostly a uniqueness factor, it may be the only Twist with a ducted fan. But, will probably do both, go with the proven design of a propeller, but retrofit a ducted fan just as a proof of concept and to have something a little different.

So yes, the plane will have a regular propeller, but I still want to play around with a ducted fan just to see how they perform.

 

[audioguru]

I first won an RC airplane but it had no radio parts. So I designed a motor speed controller with timers:
1) Full power for takeoff.
2) Reduced power for cruising.
3) Low power for landing.

It crashed many times. Its motor had gears so it spinned fast and the huge propeller had lots of torque.

When the airplane comes toward you then left and right turning are backwards. You must learn this.

When the airplane is far away then you cannot see if it is coming or going.

Now I have a free (from Energizer battery company) electric IR controlled helicopter that is fun.

 

[audioguru]

Please post a video of your first flight.

On You-Tube there are funny first flights:
1) A guy bought a helicopter and tried to fly it without learning how. CRASH!
2) A guy tried to takeoff but the blades crashed into the building overhanging above. CRASH!

I like the two stories of the Canadian huge jet airplanes that ran out of fuel and glided to perfect but almost impossible landings. One flew sideways to slow down. Other pilots crashed every time they tried it in a simulator.

 

[Cobalt60]

I've spent so many ridiculous amount of hours in X-Plane Im pretty confident I won't have any problems flying. And by ridiculous I mean at least hundreds of hours.

X-Plane, by Austin Meyer

 

[Cobalt60]

Oh and I got that Micro Mosquito heli, I pretty well mastered it. I wish it didnt like, die on me, and then Id take some videos. But I could hover it in front of peoples faces, as close as possible, I liked that thing.

 

[dknguyen]

I use RealFlight. I find helis easier than planes...maybe not to fly but definately to land- and landing is the most important part of flying.

I never fly it "towards me" per se since I seem to get confused too easily. The cloest I will get to that is to fly slightly off center towards me, so it comes in towards me diagonally where I can still view the side of the heli. THen I have no problems. But when all I can see is the front, things go bad (thank goodness for the rudder!)

Flying upside down also seems to get my goat every time. The best I can do right now is to control how level it is in order to gain enough altitude to flip it right-side up again.

I've spent so many ridiculous amount of hours in X-Plane Im pretty confident I won't have any problems flying. And by ridiculous I mean at least hundreds of hours.

X-Plane, by Austin Meyer

Do they have a transmitter controls for that? Because the similarity between the practice control interface and the actual control interface is most important.

 

[audioguru]

Yesterday the battery in my heli ran out of juice when it was flying above my wife. It got tangled in her hair (she got mad at me (for a few minutes then .....)