Posts Tagged ‘ parts ’

Multiplex EasyStar Airplane

Setup:

In anticipation of developing a quadcopter, I bought a Spektrum Dx5e/AR500 transmitter/receiver pair.  Knowing that the quadcopter would probably take many months to design and build, my wife lovingly thought to buy me an RC Airplane to hold me over until I finished my quadcopter.  She snooped on my computer and found that I had been looking at the Multiplex EasyStar.

The version I got (linked below) didn’t come with an Tx/Rx, servos, ESC, or battery.  I jumped on HobbyKing.com and bought two servos, a 2-cell lipo battery, and a cheap brushed ESC.  It turned out that the servos I bought were a low-voltage version and very weak.  Because I didn’t want to wait for another shipment from China, I ordered some better servos from HorizonHobby.com.

My final parts list became:

Total: $216

First Flight:

My first flight went horribly!  I was too anxious to fly and didn’t wait for a good day.  Let’s just say I flew around for a few minutes with completely no control and then ended my performance with a full throttle nose dive into the ground.  The cockpit area of the fuselage broke in half.  To those of you reading this deciding whether to get into RC planes or not, don’t let this discourage you.  I did EVERYTHING wrong.  Not only was I too anxious, but I was also nervous.  I left the throttle at full.  This was a bad combination.

I fixed the fuselage using the same glue I put it together with and some clear box tape.  It actually seemed to get even stronger!  I waited for a calm day then attempted flight number two.  I remembered to stay clam, set the throttle to full, hand launched, got control, then set the throttle to about half.  I couldn’t believe how easy it was to fly!  I was flying around with perfect control in no time.  I even got brave and applied full throttle and pulled off a loop.  It was ridiculously fun!  Then I realized I needed to land sometime soon or it would land by itself (another nose dive into the ground?).  Once I got close to the ground, I cut the throttle to about 1/4 power then slowly descended in a straight line.  It smoothly slid across the grass until it stopped!

Aggressive Flight Modification:

After a few flights, I determined that the aircraft was a bit sluggish when looping and turning.  I decided to do a few things to fix this:

  • Servo Cable Adjustment:
    Each servo cable attaches to the corresponding flap using a threaded clamp that sits in one of three slots.  When I first put the airplane together, I put the clamp in the least aggressive slot (furthest from the flap).  I just moved all the clamps to the most aggressive location (closest to the flaps).  This increased the aggressiveness of the aircraft dramatically.
  • Rudder Enhancement:
    Unlike a typical RC airplane, the rudder on the EasyStar controls the tail and the roll of the aircraft.  Its design is far too small for its purpose.  I used some thin, stiff cardboard and super glue to extend the length of the rudder.  The stock length is about 1″.  I modified it to be about 6″.  This turned out to be too much rudder when the aircraft was moving quickly.  I cut the extended flap down to about 3.5″.  It now works great.  The plane now responds very fast but I also don’t get out of control when I am moving quickly through a turn.

Durability:

This airplane is super durable.  I have crashed in one way or another numerous times!  Most of the time nothing happens.  I’m pretty sure my fuselage is now 40% glue, 45% tape, and 5% foam.  It still flys like a champ!  The location of the propeller is perfect for beginners.  It has never been harmed in all my crashes.

Too Aggressive?:

Apparently my modification makes the aircraft more aggressive than the foam wings can handle.  To get enough speed for the many tricks I’ve learned, I take the EasyStar up as high as I can while still feeling comfortable, then dive nose down.  Sometimes I just do this to see how fast I can get going and how close I can get to the ground until I pull up.  Each time I do this I can see the wings flexing back.  One day my dives were getting really fast and one of the wings finally gave out.  The wing snapped in half and the rest of the plane went spinning into the ground.  I could probably beef up the wing strength with some carbon fiber rods, however, $25 for new wings isn’t too much to ask for 6 months of abuse.

Advertisements

Quadcopter Frame Design

My first quadrotor frame design is simple, sturdy, reliable, and a bit ugly.  I have made no attempt to make it cute, flashy, or visually desirable in any way.  If and when I determine that the structural design performs well, I’ll use some better tools to make a more flashy design.  Until then, I’ll be flying on my raw cut aluminum frame.

My basic design is two 24 inch(610 mm) X 1/2 inch(13 mm) X 1/2 inch(13 mm) square aluminum arms.  I knotched both in the center so that they can cross each other.  There are two 5 1/4 inch(133 mm) alumimum plates holding everything strong and square.  The frame is very strong, rigid, and relatively low weight.

Quadrotor Parts List

Here is the initial parts list for my quadcopter design:

Product Description Quantity Price


Turnigy Brushless Outrunner

2217 20turn 860kv 22A
4 $53.12
($13.28ea)


Turnigy ESC

Plush 30amp
4 $48.76
($12.19ea)


Turnigy LiPo

5000mAh 3S 25C Lipo
1 $27.43


XT60 Connectors

Male/Female (5 pairs)
1 $3.19


Turnigy Balancer/Charger

Accucel-6 50W 6A w/ accessories
1 $22.99


Pyramid Power Supply

PS12KX 10-amp 13.8-volt
1 $46.99


APCProp

12 x 3.8″ Slow Flyer
2 $7.90
($3.95ea)


APCProp

12 x 3.8″ Slow Flyer Pusher
2 $11.84
($5.92ea)


Spektrum DX5e

5 Channel 2.4 GHz DSM2 Transmitter
1 $59.99


Spektrum AR500

5 Channel 2.4 GHz DSM2 Receiver
1 $39.99


LPCXpresso LPC1768

ARM Cortex-M3 Development Board
1 $28.50


9 DOF Sensor Stick

3-Axis Gyro, Accelerometer, Magnetometer
1 $99.99


OR Gate

CMOS Quad 2-Input
1 $1.00


Buffer

CMOS Quad 2-Input
1 $1.00


Aluminum Tubing

6061 1/2″ x 1/2″ x 72″, 0.063″ Wall
1 $21.14


Aluminum Sheet

6061 12″ x 12″, 0.063″ Thick
1 $10.06


Coleman Wire

16 Gauge 100 Feet
1 $11.24


Bullet Connectors

3.5mm 3 Pairs
4 $19.80
($4.95ea)

The aim of this design is for an extremely aggressive quadcopter. My design goals are for the stabilization system to handle VERY abrupt changes in attitude and able to recover from any acrobatic mishap. I’ll be adding a mode for acrobatics where absolute angles are not used for stabilization. Instead, the stabilzer will hold to a rotational rate. If an acrobatic maneuver goes south, one switch flip will be able to bring the helicopter back to a stabile hover. The only remaining control not adjusted by the stabilizer is the throttle.

I’m sure that there will be additional items I will need but haven’t thought of. I will try to keep this list up to date for those of you using it for your own copter build.

EDIT: added 16-gauge wire and 3.5mm connectors