Written by Don Slusarczyk Jets Column As seen in the Spring 2017 issue of Park Pilot.
Pusher park-flyer jets have been around for many years. Until EDF (electric ducted-fan) units became more powerful, pusher jets were the only way to fly a decent-performing RC electric jet at your local park. When looking at HobbyKing’s (hobbyking.com) recent arrivals webpage, I noticed the MiG-29 that the company was offering as part of its Glue-N-Go series of airplanes. The kit has laser-cut, preprinted foam board, carbon-fiber spars, pushrods, the motor mount, and the control horns. The kit’s price, depending on which HobbyKing warehouse you buy it from, is approximately $20, so I ordered one.
The laser-cut foam pieces come preprinted.
Power System and Components
For the power system, the manufacturer recommends a motor in the 2,000 to 2,800 Kv range. For park flying, you will want something at approximately 2,200 Kv to keep the speed and amps down. Fortunately, with the recent popularity of quadcopters, motors in the Kv range for park jets have become plentiful and inexpensive. Suitable motors can now be purchased for approximately $10. I chose a HobbyKing 35-amp ESC, which is overkill, but it was available at the time of purchase. However, after flying the airplane, I think a 25-amp ESC would be plenty if you set it up the same way as I did mine.
The power system uses a low-cost motor and ESC.
I chose an APC (apcprop.com) 5.5 x 4.5 propeller as a good compromise of thrust, speed, and amps with the 2,200 Kv motor. I am a fan of APC propellers because I find them efficient, but with the large number of quadcopter propellers now available, I am sure there are other acceptable alternatives. You will need two 8- to 9-gram servos to complete the build.
Building
The actual assembly process is fairly easy. I am not going to go over all of the step-by-step instructions because I had no real assembly issues, and the included manual is quite complete.
Foam-Tac or UHU por glue can be used to assemble the foam parts.
The wing’s main carbon-fiber spars will probably need to be trimmed in length to fit properly, so check their length before you start to glue them in. I decided to try UHU por (uhu.com/en/home.html) foam glue, which is similar to Beacon Foam-Tac glue (foam-tac.com). UHU por is used mainly in Europe, and until now has been difficult to find in the US, but it is available on eBay (ebay.com). Either brand will work. I made a couple of small changes to the airplane that I want to mention. First is the propeller slot. The slot is narrow and can generate a lot of noise because of the proximity of the propeller to the edges of the slot. The closer the leading edge of the propeller is to the front of the slot, the louder it is, so I widened the slot to reduce noise.
Widening the propeller slot will help reduce propeller noise.
The next item was to improve the battery access hatch on the underside of the fuselage by adding a swinging latch made from some scrap foam and a spare screw. The result is an accessible battery hatch that locks into place.
Flying
The recommended CG (center of gravity) location is 75mm from the back of the motor mount. I balanced my model to this location using a 3S 1,300 mAh LiPo and went for a test flight. Launching the model is achieved by an underhand toss with partial throttle. Just make sure your hand is out of the propeller’s way when launching.
Pushpins were used to hold the foam in place while it was drying. Here you can see the added latch on the battery door.
The model started to climb out nicely, but suddenly pitched straight up on its tail! It was very tail-heavy. Luckily, I was able to power through it and land without damage, but the CG had to be moved forward before another flight was attempted. I added some ballast to the nose to move the CG 10mm forward, and it was a different airplane. It flew great. I flew around for approximately 5 minutes before landing. I then adjusted the control throws to close to a 25mm deflection in each direction and added a little more exponential. The second flight was slightly more aggressive on the throttle, and after 5 minutes I decided to land. Recharging the LiPo batteries, I found that the first flight used approximately 650 mAh and the second flight approximately 750 mAh, so I could fly longer. The airframe’s ready-to-fly weight (with ballast) is 11 ounces and 14.7 ounces with the LiPo. If you are looking for a low-cost, easy-to-build park-flyer jet, the HobbyKing MiG-29 might just be the airplane you are looking for. -Don Slusarczyk [email protected]
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