Very early this year, I started another(!) project. This is a webbased tool for everyone RC-interested which crashed and are in need of parts. Let’s be honest, we all crash and need parts. Which makes me believe this is a good project.
RC Part Finder.com is a click’n'buy service which let’s you find accurate and cheap(est) part for your vehicle. At this moment, anyone can register and add blueprints and start helping. I don’t earn any money on this, actually I loose some due to web hotel and data transfer. My goal nevertheless to make a useful tool for everyone at the cost of nothing.
After I sold my Team Losi Mini Rock Crawler I wanted another one, but a larger one with more capabilities. XR10 was released recently and I managed to get it pretty cheap ($240+Shipping+VAT) from Ebay.
The vehicle provide motors on axial, waterproof receiver box and independent motor control. This is where the signal control comes in.
Before I could start controlling signals, I had to modify my Traxxas 2.4 TQ. By following these steps found on Traxxas forums I were able to transform my 2ch transmitter into 5 channels.
Now when I had more channels I were able to use my transmitter to select which motor to run. This was done by routing the signals through an Arduino Nano as shown in picture below.
From
Here is the code I wrote for controlling the signal routing. Thanks to Servo.h library, my code became very simple and easy to understand.
the
#include <Servo.h>
Servo FRONT;
Servo BACK;
int throttlePulse,controlPulse;
const int throttlePin = 2;
const int controlPin = 3;
const int frontPin = 4;
const int backPin = 5;
controlPulse = pulseIn(controlPin,HIGH);
if (controlPulse > 1700)
{
FRONT.writeMicroseconds(1500); //put ESC in neutral position
}
else
{
FRONT.writeMicroseconds(throttlePulse); //send signal to front ESC
}
if (controlPulse < 1300)
{
BACK.writeMicroseconds(1450); //put ESC in neutral position
}
else
{
BACK.writeMicroseconds(throttlePulse); //send signal to rear ESC
}
}
After my friend Jonny bought himself a flying wing by robbe when all my aicrafts were grounded. I speculated on how quick I could build my own. I already had a small brushed motor with speed controlled form an old MS hornet (heli) by MS Composit. Two $2 servoes, $16 DSM2 receiver and 2S 800mAh LiPo batteries I had laying.
Later that day I sat down with some 6mm depron and started cutting. I cutted one side of the wing first to make sure it was proper. Then i copied it onto another piece and glued them togheter with UHU and CA. A carbon list was installed for stiffness. To get buoyancy and more stiffness I chose to install some addional 50mm wide 6mm depron on leading edge of the wing. Known as KF-airfoil KFM-2.
Rudders were cut 30mm wide and some fin stabilators were added to the sides. The heavy yet small motor had to be installed closer to the front than first expected to make CG right.
The manual for this ESC is pretty bad, but do we really care when the product is cheap and has nice features?
This ESC has simliar features as the aquastar ESC Turnigy produces. I used aquastar`s manual and managed to produce a programming sequence chart for super brain ESC.
I`we flown RC helicopters for around three years now and only electric. We all know batteries tend to get worn out, which is what who has happened to many of my batteries. They don`t have the same punch as they had, which is essential for good 3D flying. Even tho they are bad for 3D they can still be used for low-amps applications, such as scale flying.
Therefore I`we decided to get myself an scale body for one of my Align T-rex 450 helis, the oldest in fact. At first I bought a Airwolf body, but I didn`t really want an Airwolf and it did miss the tail with retracts. Comanche on the other hand has always impressed me, being «the best» helicopter around with a very long development period.
The build process started by figuring out what scale the heli would become for a T-rex 450. If I recall correctly the 450 has a blade with of 70cm and RAH-66 has 11,9meters. This results in a scale of 1:17. From here I calculate 1:17 length of 13.20m (without gun barrel).
There are very few good pictures of this helicopter from all angles on the internet, but I were able to calculate the tail to be tilted 15 degrees. I also had to do allot of testing of bottom plate and the lower sides to make it scale looking. After the bottom was finish I used a paper-piece and draw the upper body. After I cutting the paper piece out it was easy to make a similar in 6mm depron.
Update #1
Retracts and penta head installed, but the retracts were only made for the heli and battery weight. When adding five blades to the head the retracts failed under take off. When I saw the heli was about to come to one side I accelerated it to prevent blades for hitting the ground. My attempt failed and the comanche body were damaged.
After this failure I had three things to straiten up before the fuselage was perfect.
Heli bends wrong way, should bend downwards
Tail capsule was to big for scale, this is because the heli only has a two bladed tail.
To weak gear.
I have now thrown away (in the trash) the heli and will not build another one. Not this season at least.
As little I made RC boats from scratch and since my knowledge about air vehicles is bigger I just had to build another “boat” when I came accross L‘Hydro-Foam. This “boat” has the same abilities as the ship in the Norwegian folk tale Askeladden, “Et skip som går like godt i lufta som til lands og til vanns”.
As usually I printed the PDF available on the French site and cut depron in given shapes.
After running this motor to hard outside, I managed to burn the motor. You can see pictures of the “burnt” motor in the gallery below.
First of all I opened the motor to take a look noticing protective isolation layer on the copper were melted. Not so strange, because when I approaced the motor after the plane fell from the sky, it was insane hot.
Before removing all wire I measured the wire diameter to 0,30mm. I found this king of wire inside very small tranformators in a computer power supply.
By using this picutre, found on this page. I was able to re wound the motor.
I actually did wound all the poles at the same time, well, one by one, but all three wires were in use, if you follow.
After finish wounding I had to connect wires together to make only three wires, brushless motor has three out wires.
Since it`s a pretty fast motor I made a delta hookup, but I did a mistake at first. This motor should have around 195mOhm per 14-turn, maybe I did not mention it is a 14-turn motor. Which means each pole (there are nine here) needs 14 turns of isolated copper wire and in a small motor like this one, it`s not that easy. Anyway, by hooking up wrong end`s I broke a ESC of mine ($10) so I had to buy another one.
The motor works just great now and I might add a video later.
After my first self builded depron was basically a failure, I removed all electronics and carbon from it and threw it away. Electronics on the plane were in good shape so I had to make another one. I have a Blade EPP before, but having two planes in the field is neat when one plane is down and gluing.
The plane is built as light as possible and will probably land around 150g. More information will be available when finished.
After my last to planes I still had some depron left. I decided to build myself another plane instead of throwing it away or keeping it for repair scrap.
I had already came across a free pdf version of F-117 and the choice were easy. After transforming the pdf manual into paper with a little printer help, I realised the plane were to advanced. Which is not really necessary in my opinion. This resulted in what I would call a 50/50 build. I started the nose as it should be, but shorted the back down quite allot. I ended up only using the paper as line-up before adapting the pieces were I wanted them, using eye sight.
I have finished my flybarless helicopter and had maiden flight yesterday. It flight great for maiden flight with nothing being tuned, not even vbar! the only thing I could set my finger on was the tail bogging. It kept drifting back and forth, as you can see in video below.
If you want to view build pictures of this heli you can get them here.
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