Arttech Mig 15

[19000rpm]

I had my eye on the Arttech Mig 15 a few years ago, but was turned off by reports that it was a bit underpowered. I decided to pass on it.

As fate would have it, one came into my possesion a few days ago. Reportedly it had either a bad ESC or bad motor. Well, shucks, I just had to see what was what.

This is an ARF, so it came with everything including a 2.4 radio and a decent charger.

My first quest was to locate the ESC and see if it was bad. I opened canopy hatch. No ESC. I checked each half of the 2 part fuse. No ESC. ;D I was looking down the tail pipe and, lo and behold, there's the ESC mounted in shrink wrap behind the motor. Duh! what a great place for cooling the ESC if you don't give a hoot about destroying the thrust. No wonder this model can't get out of its own way. ;D

I fished out the EDF, a six blader powered by a 15L inrunner, and it had a sheet foam thrust tube attached that fit tightly into the fuse. Great idea for compressing the air coming out of the fan...But then they blew it by sticking the fricking ESC right in the middle of the airflow. ;D

What to do, what to do.

For sure the ESC, if it works, needs to be relocated, but the equipment area below the canopy area was very small and the big honking factory Rx is about the size and weight of 10 Spketrum AR6100's. Well, that had to go and a AR6100 put into service.

The ESC was bad, so I had a 30A lying around and manage to fit it and all of the wiring and battery by opening up the the cockpit.
I also added some rare earth magnets to keep the canopy more securely in place and foam around the vertically installed 1600 20C to keep it from ejecting when the plane goes inverted.

Here are some pics.

The Mig is quite a bit smaller than the X-35, 30" long as compared to 41", although the foreshortening by the camera makes it look almost as large.



That's one cramped equipment bay. That's the ESC, near the top of the photo, where I carved out a bit of foam and velcroed it in.

Some slight modification to the cockpit.

The photos below show some nice scale detail on the landing gears. Who ever did this should have also been working on the ESC placement.



I read the mig 15 thread on RCGroups and did the following:

I added hinge tape to the elevator and packing tape to the horizontal stab and wing/fuse joint and some black duct tape to the top of the wing to simulate a non skid strip. There were reports of having the wings come off and rather than glue it on, making it very difficult to get to the fan, I decided tape was a better solution...We'll see.

Right now the weather has 2 EDF maidens on hold, this and the X-35. It looks like it might clear up in a week. ;D

When I maiden it; I expect it will fly a bit faster than the stock just because the ESC isn't in the way of the airflow. At any rate it should be a lot of fun even if it's not a barn burner. It's hard to beat a scale like fly-by of an authentic looking Korean era warbird like the Mig 15.

BTW, if you're interested; there are some of these on Ebay that are going for about 90 bucks.

[Gabe]

Wow 19K, you did a great job cleaning up that plane. I've read reviews about Art-Tech which are all terrible. My own personal experience with my Art-Tech Falcon 3D was awful as well. They're really a crap company with no forethought on design.

Like I said, great job turning a nightmare into a good looking and well-equipped plane!

[19000rpm]

Thanks, Gabe. It was like the old saying, "...taking a sows ear and turning into a silk purse." kind of project.

I remember your frustration with the falcon. That one was also a piece of work.

It's almost like two different planes in one. One designed by a good designer and then they brought in an idiot to do the other half. And no one on the testing end to find the faults and correct them before they went into mass production. They've sold a lot of planes and helis inspite of this. Go figure. ;D

[Gabe]

That is the Art-Tech way. I'm surprised they're still in business.

Either way I'm glad you got the sow's ear flying!

[19000rpm]

Well the dang thing actually flies. Color me surprised.

Color me astounded...It actually rises off of grass. I did it 3 times on the same battery and the last takeoff it was struggling a bit, to be expected, because the 1600 20C was going down fast.

Not a lot of flight time, about 3-4 min.'s, and I don't think there's much to do about that since the battery placement rules out anything bigger due to the lack of room and the additional weight bias forward would also be too much.

Once in the air it flies very nicely. The aileron throws from the factory are a little on the radical side; unbalanced with the mild elevator throws. A balanced plane will take dialing down the ailerons a smidge and upping the elevator throws quite a lot. That should make the aerobatics a bit it more crisp and balanced.

I did some mild aerobatics and she hung right in there. Nothing fancy and keeping within my comfort level with the unbalanced ailerons/elevator. Rolls and loops were all executed at about 3/4 throttle. Full throttle produced a good 60mph straight and level. No bad habits except the glide angle is fairly steep. Kind of like the full sized one that has been compared to a rock.

Landings on the grass were also better than expected. I bent the nose gear twice when I hit ground in a little too tall a patch. I was able to bend the gear back straight and the shock didn't seem to upset the gear mount or the servo. The third landing was pefect. I managed to get it down on some shorter stuff.

Shucks, I think I like this little guy. And I was prepared to hate it after all the bad I'd heard. Surprise, surprise.

[Gabe]

Ha! That's great to hear!

[19000rpm]

I had the Mig hanging from the ceiling all winter and took it down yesterday. It had been flying in formation with the F35 since November of last year.

This time out I had the paved school lot to fly off of. The last time I flew it it was off grass.

The ROG was very quick. Great climb rate, especailly considering I was flying it into a 15-20mph, gusting to, 25 wind. The overall flight was great. I was particularly impressed with how stable it was in the wind.

The landing was another story. Bringing it on final I found it perilously close to one of the light posts. This was an error in judgement and this was also when I really wished it had a rudder.

I cranked it a bit hard in the bank to make sure I didn't hit the post and as a result didn't bleed off as much airspeed as I wished and it landed fairly hard. A gear came loose and the wing on that side got a nice sanding on the pavement.

A little light weight spackle and paint and it's as good as new. I plan on spending more time with it this season. It looks great in the air and I think I've just begun to appreciate all of its qualities.

[19000rpm]

I tried it yesterday with the battery that came with the plane. In the past I'd flown it with a 1600 20C.

I'm not sure what the C rating is on the stock battery. There's no print on the battery that states the C rating.

Well, it is a real dog with the stock battery. Maybe that's part of the reason so many owners had problems with this plane...That and the ESC behind the fan blocking the airflow.

Back to the 20c.

[akent]

That's nice you have it flying well!

[19000rpm]

I love these old jets just like I do the warbirds and when they don't live up to their reps as a model I get kinda PO'd. I gotta' make it right if I can.

I put a 1550 Genace 25C in it this AM. It's even better than the 20C.

I wish there was additional room for more battery and ESC. I don't think it's in the cards though. Every thing is cram packed as it is.

[Gabe]

19k, I love my Turnigy Nanos. They're slightly smaller than the standard Turnigy's and they pack a punch with a 40+ C rating. My Strykers have never been happier! Might be a good experiment for your mig.

[19000rpm]

That's a good idea Gabe. And well timed too. I was going to order some batteries today.

I think I'll try them in the SU-34 too. It's a little heavy for its size.

[19000rpm]

Well HK was out of the Nano's in that size so I ordered some more 1550 25C Genace's.

I took the Mig into the air and she moved a bit more briskly than the with the old 15C & 20C 1600's I think.

I'd had it in the air about 3 min.'s and was doing a low fly-by when the motor quit. It happened to be over a nice stretch of grass and as it slowed I tried to control the landing. I'm not sure I had any control but it settled in to as good a landing as if I had controlled it. I believe I deserved that bit of luck.

Anyway, when I touched the ESC it was very hot. It was never hot when I checked it in the past after a flight.

I tested it on the bench and I noticed 2 leads had melted off the ESC. One from the motor side and one from the battery side. When I tested the motor it was shot too. A major melt down.

Could the motor and the ESC have been so marginal current wise that just having a few extra C's on the supply side caused this or maybe it was something else? Maybe just not enough cooling for the ESC, but that wouldn't destroy the motor would it?

I found another EDF unit laying around, only a millimeter larger, with a bigger motor and larger fan blades. More power.

With some modifications I installed the new EDF and a 40A ESC. I put the ESC right behind the inlet splitter so it should stay relatively cool without impairing the air flow.

This set up puts out quite a bit more thrust than the stock unit. I can't wait to see how she flies. The weather is ideal today so I'm not going to have to wait long.

[Gabe]

Ah yes, Art Tech electronics are never reliable. The extra "C"s in the batteries are only "available" and they aren't pushed to the motor. The motor and battery voltage will determine the max amps that can be pushed through the electronics. The failure would be simply due to poor electronics quality.

I hope the new set up offers some new found fun!

[19000rpm]

Yep, Gabe that's exactly what I thought too. The only thing that makes sense.

Well, that baby rips now, or should I say, ripped.

I took her out to the school today. The winds were supposed to be 5-10. Instead they were varying in both direction and speed to 15 plus with nice gusts in between. And of course not prevailing in the best direction visa via the preferred takeoff and landing directions. Mostly 45 degrees or so across the optimal landing area.

Being the masterful pilot I am I through caution to the "wind" and nailed the throttle into the direction that was current at the moment. She accelerated about twice as quickly as the old set up and was in the air in 50ft. or so. Got rocked by a huge gust, suddenly coming at 90 degrees off the starboard wing, I corrected and turned into the new wind direction where huge trees grow. somehow I cleared them. Whew, that was close.

In the air it was a transformed bird. What a ball. Really quick and also stable inspite of the wind playing havoc with it.

Landing was a challenge, but I knew it would be, the conditions being so changeable, moment by moment.

Having no rudder for yaw control I waited for a steady wind direction that didn't put me in the immediate vicinity of too many light posts and trees, so if there was another abrupt change, I'd at least have a chance. Got a decent approach lined up and it weather vaned in to a good landing. Lucky me.

I should have left well enough alone.

The second takeoff was almost a duplicate of the first; including the freakish blast from the starboard. I corrected, but this time another blast hit it and flipped it completely over. A better pilot might have caught it and flown it out, inverted, possibly. It was only about 15 ft over the asphalt when the unintended inverted flight happened and I wasn't quick enough to salvage it. Cheap foam everywhere.

I'm going to try to find another of these airframes somewhere. Don't ask me why. It's a cheap piece of carp, but I'm drawn to it.

Now that it would have plenty of power with my EDF and ESC upgrades, I'd stick a seperate servo in the vertical stab for a rudder. That would make it a lot more safe to land and takeoff and more fun to fly. Then, if I use better judgement about the conditions I fly it in; it might survive a lot longer then the one that's in the big black trash bag in the car.