The EasySky Yak 12 950mm EPO RC Plane

After giving up fixing my Axion RC Airhopper, I got the EasySky Yak 12 from HobbyKing. It was delivered on my doorstep in a matter of days from Hong Kong, Very impressive!

A bit of introduction

I’ve seen multiple reviews stating that this is a poor beginner plane because of its flight characteristics. Regarding cheap beginner planes at HobbyKing, the Bixler is often mentioned. I can see why; It’s cheap, simple to repair, steady and parts are available for a small price. For FPV etc, I agree that it is a great deal. Its huge wings can handle a big payload etc.

But let’s break it down a bit – Why does someone look into RC model planes? They want fly a plane – The bixler is a glider, it doesn’t look like a typical plane, it doesn’t even have a landing gear! Hand launching a plane is not for beginners, you need a good technique for that. And for me, after flying for a bit, I look forward to the challenge of landing it! The challenge of keeping the plane leveled, touching down with the landing gears, and taxi over to my launch point without crashing. The landing is the most critical part of flying, and that’s why I think f.ex. the Yak 12 can be a bit more interesting as a beginner plane. And believe me – it does handle a crash! And with only 950mm it is more manageable, but still not too small, compared to the Bixler’s 1400mm, which for most people means disassembling the wings every time, which again means that the wing joints get worn out and needs fixing. I’d rather have a “grab-and-go” plane like the Yak as a beginner.

Another thing is that the Yak has flaps! This means take of and landing at slower speed than usual, also this is a STOL plane (Short Takeoff and Landing), meaning you should be able to takeoff and land at a small area.

Let’s check it out!

It was in its original packing, but the cardboard was inside out, I guess to protect from theft. I also got the HK6S Transmitter from HobbyKing, which arrived in a different package.

DSCN1057

Assembly is required, but it’s a fairly simple job, all is documented in the manual. Although, I recommend you doing a couple of extra modifications…

DSCN1058

The first thing I noticed, was that the hinges were VERY poorly made. These had to be fixed.

DSCN1059

DSCN1060

The wing seen from below. These servos will be inside the fuselage when assembled. Upper servo for ailerons, lower for flaps. The flaps servo needed some alignment, but it was very simple.

DSCN1061

Aileron control horn. Notise the slot to the left, this is where the wing support is mounted. I glued it with a 4-minute epoxy. First the support, then some decorative caps which goes over. A simple 5-10 minute job for all four supports.

DSCN1062

They were nice enough to include an extra propeller. The included is a foam clue. I would recommend using two component glue for control horns etc.

DSCN1063

The plane was neatly packed without any damage.

DSCN1064

You will have to attach the rudder yourself. There are plastic hinges which you glue on the fuselage. It’s fairly simple, as there are guides in the fuselage. Just be careful with the glue, it doesn’t require much.

DSCN1066

Servos for elevator and rudder/tail wheel, everything factory installed.

DSCN1067

ESC is mounted below the nose. ย Notice the huge offset on the motor. It points down to the right (seen from the cockpit). This is most likely to counter balance the propeller rotation. After testing it later, it seemed to be a correct angle, the plane goes straight forward!

DSCN1069

The motor mount uses springs to absorb a crash. These work very well!

DSCN1070

I taped all the hinges using the glass fiber armed scotch tape. I love this tape… EPO’s best friend! ๐Ÿ˜›

3m-scotch-8959-extreme-application-packaging-tape-clear-pic1

I pushed the tape all the way down, so that it could move freely. I taped both the upper and bottom part. It will never come loose now. I think it’s better to fix these things before using the plane, it’s much worse trying to realign it later when it has fallen off.

DSCN1074

DSCN1075

DSCN1076

DSCN1078

Notice the rod, this is the flaps control rod. The flaps were hanging in total 2cm EPO… They should’ve had some plastic hinges instead, as they were very poorly cut. The flaps on my plane are a bit offset, one is 2mm higher than the other, which can’t be easily fixed, however, I didn’t notice anything when flying.

DSCN1079

I also taped the inside of the cowl, this way if you crash, it won’t shatter, only get scratched.

DSCN1080

Wing supports are screwed to the fuselage and landing gear support is glued in place.

2013-08-02 01.39.43

Letting everything dry. The wings are attached with a screw like the fuselage, so the wings are actually removable, although it’s not a simple procedure, as the servos has to be disconnected (through a small door). Actually I glued the screws with CA to be sure they don’t come of. As it’s 950mm, it’s easy to store in one piece, just throw it in the car and drive to the field.

2013-08-02 01.39.01

I’m using a 2S 1500mah battery from Turnigy, which is a bit longer than the typical recommended 1000mah battery. So does go a bit further back than I want, which messes up the center gravity point a bit. But I think it will work.

2013-07-31 13.39.39

After assembly and a quick central gravity test, I found it to be a tad tail heavy. I glued two nuts to the nose under the cowl, adding 20g to the nose. This was enough to make it a bit nose heavy, perfect for a stable flight. The total weight of the plane is at 430g without the battery, and 515g total weight. This makes for a fairly stable flight, and it does handle some wind.

2013-07-31 13.19.37

I also mounted a HD808 #16 (D-lens) cam on the wing (20g) and a couple of nuts on the other wing to stabilize it. This way I can see if something flexes more than it should etc. I secured it with a zip-tie as well, in case the velcro under the camera comes loose during flight.

2013-08-02 01.39.57

I had to calibrate the throttle on the HK6S, as it was a bit jumpy, and it didn’t react well to the throttle stick movement. This was easy, as the throttle calibration is pretty standard across all ESCs. I don’t know if the ESC has any other programming alternatives, but with throttle, it was the following:

1. Turn on transmitter, set throttle to 100% (PS, your throttle could be reversed…)
2. Connect the battery to the ESC
3. Wait for a beep
4. Set throttle to 0%
5. Wait for a initiation musical tone (startup tone).

After this the throttle was nice and smooth!

I recorded multiple videos of my first flights. Here’s one with the camera pointed towards the fuselage. Bear in mind – This is actually my first RC plane flight other than the Axion RC, which broke after the first flight.ย I had the flaps on a potentiometer on my controller, which made it possible to adjust it slowly. Although it might not seem like it – the plane was VERY stable, I just over controlled it. As you can see on the aileron control horns, it’s set to have the smallest throw possible, but still this made the plane very responsive, almost a bit jumpy, so careful on the sticks! It does have enough power to do some acrobatics as well, I just haven’t had the guts to try it yet…

After this clip, I’ve flown a handful of times, a couple of small crashes, and a bigger one (took off with a lot of side wind, and not enough throttle). The first ones knocked off the landing gear, which meant re-gluing the white bracket back on again. A 5 minute fix, no EPO was ripped apart etc. No problem! I used a lot of foam glue for the fix, which isn’t as stiff as composite glue, so it can handle a small beating.

The big crash ripped out the mount for the wing support from the fuselage, and knocked the propeller off. The propeller has an original prop saver, and the motor mount is spring loaded, which seemed to save it. No bent shaft, and the propeller had a couple of small scratches, no biggie. The wing support mount was easily glued back in place (a slot in the fuselage), and the plane was ready to fly again. The cowl was a bit damaged, some scratches, and the tape I had on the inside had ripped some paint off. Anyways, this is beneath the propeller, and not visible.

All in all I’m very satisfied with this plane. We’re talking approximately ย $120 for the plane, battery and a simple TX/RX system including shipping. It’s cheap for a nice and stable trainer. It’s not a very fast plane, but this makes it even more suitable for beginners.

Keep checking in on my blog for updates on the plane, there will definitely be some. I have plans for mounting skis, FPV system, lights etc.

Advertisements

6 thoughts on “The EasySky Yak 12 950mm EPO RC Plane

  1. Pingback: The HobbyKing HK6S – Very cheap 2.4 GHz Transmitter | A SysAdmins Perspective - Living-On-Line

  2. Pingback: The Turnigy FBL 100 3D Micro Helicopter | A SysAdmins Perspective - Living-On-Line

  3. Pingback: The Axion RC Airhopper. A mini RC plane for beginners. | A SysAdmins Perspective - Living-On-Line

  4. I wish I’d read this before launching MY yak 12……..resulting in a broken prop and busted flap hinge, probably a case of too much stick input by me 8-( ……but it’s all fixable! Now where’s the glue and tape……..

    • Well, it is a part of the hobby ๐Ÿ™‚
      Fortunately it’s simple enough to fix this plane, and parts are available! Google EasySky 9906 if you need spares.
      When I crashed mine, I only needed to glue the wing support back in, and I was good to go. I have a newer computer radio now, so I’m using dual rates where I have 70/30 throw/expo, this makes it less sensitive to control. I could probably go even lower on throw on this model.
      I hope you’ll be able to get it back in one piece soon!

  5. Yeh Dave it pays to really think things through before you challenge gravity to a showdown. I’ve seen some fantastic crashes with these Yaks ๐Ÿ™‚ I really felt for the guys but everyone loves a good crash right ๐Ÿ™‚ especially if you get it on film.
    Have you seen the one where the guy is on his maiden flight and takes off and it just hangs by the prop like a Heli for five seconds (I’ve seen a few of them do this; NOT ON PURPOSE)then heads for an engine first perfectly perpendicular 90 degree impact? Poor guy, but he took it like a champ (like we all have to do) but the model was just electronic components and little white poly styrene balls blowing away in the wind. No longer a pilot but a packing beads manufacturing company.
    I started with control line models in the 60’s. God the learners used to do some funny ones with those. A 5cc glow plug engine wired to you and to the wire operated elevators with a permanently set rudder to make them strain against the control lines in a perfect circle. A guy not watching where he was going flew one’s wires right into a the top of some rugby posts. Its ever diminishing circles got to light speed as wrapped itself around the upright like 500 dollar Bolas choking an Ostrich, with a sound that screamed higher and higher in pitch as it Dopplers itself to doomsville and BAAAAANGGGG and these were 4 month Balsa builds!!! Then this guy learning that got so dizzy that he almost fainted so had to stop spinning with the lines and the wires go zipping around him like a garrotted mummy with everyone screaming. Then the guy trying to learn to do wing overs but not keeping enough tension on the lines to keep the control surfaces responsive so it hits the zenith then comes over flat out in a perfectly vertical arc into the deck KABOOOOFA, a kid that just let go of the of the line handle when his father let him have her and off it went to the Brymay match factory dragging 60 feet of steel wire through the spectators, oh they were funny days.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s