|Wing Area:||152 sq. in.|
|Wing Loading:||21 oz/sq. ft.|
|LiPoly Battery:||Tanic Packs by R/C Toys, Inc|
|Motor:||Falcon 400 geared 1.9 to 1|
|ESC:||Great Planes ElectriFly C-30|
|Manufacturer:||UltraFly Model Corporation|
|Available From:||Tower Hobbies|
I attended the 2004 Weak Signals R/C Exposition in Toledo, Ohio the weekend of April 3rd. There were certainly many new aircraft being introduced there, but the ones that caught my eye first were the UltraFly Model Corporation models on display in the Hobbico booth. I happened to be in the right place at the right time, because as I started asking questions about the models I was introduced to Charlie Hua, the General Manager of UltraFly. That discussion then lead to an exclusive interview with Charlie, which was posted on E Zone earlier this year (https://www.rcgroups.com/links/index.php?id=4426). In that interview I covered the model lineup that Hobbico would be importing and making available to the public. This review covers the UltraFly Model Corp’s “BAE Hawk”, a beautiful rendition of the Navy T-45 Goshawk, and is the first of two reviews of UltraFly’s products.
The kit included injection-molded polystyrene foam major components, all required hardware, foam glue, decals, and a specifically engineered motor/gearbox combination. It also included two sheets of full color decals and an instruction manual.
All parts were molded very precisely, with just a small amount of mold flash on the wing. I trimmed the wing and lightly sanded the leading edge of it and the stabilizer. I also lightly sanded the mold-vent bumps flat to make sure the decals seated smoothly.
The instructions called for using the provided foam glue to secure the elevator servo, after being wrapped with tape. I just pressed the servo in place and secured it at the top with hot-melt glue in case I needed to remove the servo later.
I installed the push rod housings in each fuselage half, and then glued the fuselage halves together. I found the foam glue worked very well, and reasonably fast.
The split-elevator push rod assembly was soldered together from the two rods and the connecting sleeve. I had a difficult time getting the solder to adhere to the push rods, so I crimped the connecting sleeve on and secured with CA.
The instructions called for removal of the molded-in ailerons and replacing them with the stiffer sheet-foam components provided in the kit. I carefully cut the ailerons free, beveled the replacement ailerons, and cut hinge slots.
I applied foam glue to the stabilizer assembly and attached it to the fuselage. The self-aligning features were very beneficial.
I secured the motor in place and installed the pinion making sure there was proper gear mesh. I slipped the motor mounting stick into the gearbox housing, drilled a hole for the securing screw, and epoxied the stick into position in the aft fuselage. After the epoxy was cured I removed the motor for ease of further work.
I trimmed the inner and outer canopy pieces from the vacuum-formed sheet. I used epoxy to install the magnets on the underside of the inner canopy, and painted the underside with plastic model paint. After the paint dried I glued the inner and outer canopy pieces together and epoxied the iron disks into the fuselage where the canopy latched.
The kit included two sheets of color decals. I liked the color scheme when I first saw the Hawk at Toledo, and was more than happy to decorate mine the same way. Some of the decals were used for decoration, other decal strips were used to cover the grooves in the underside of the wing and function as hinges.
Many of the decals went on well, but I encountered some difficulty in areas where there was a lot of curvature in the parts. Even with relief notches cut into the decals, there were wrinkles that I could not work out. I also had several decals where the color layer pulled off the primary layer and could not be reapplied or repositioned. I spoke with UltraFly about this, and they are working to resolve the problem, as it was not something they had seen prior to this review.
I used the Great Planes ElectriFly C-30 controller, which had 30-amp capacity and the ability to handle 10 cells or the 3 cell LiPoly. I soldered long lead wires on the motor due to its position in the plane, and the fact I wanted the speed controller and receiver in the wing bay.
Antenna routing was not discussed in the manual so I temporarily routed the antenna out through the air inlet on the lower forward portion of the fuselage, which kept it out of the propeller and gears.
With the 6x5.5 APC prop and a 10-cell battery pack, the motor drew approximately 11 amps on the 1.9:1 ratio gearbox. My typical 8-cell 600AE or 950KAN batteries fit, however they did not have enough weight to balance the airplane properly. A 10-cell pack of 600AE's needed some extra weight added. I did not have a 10-cell pack of 950KAN's to try, but they are a heavier battery and would not require the nose weight. I added velcro fastening material to the batteries and the bottom of the battery compartment to make sure the battery stayed in place during flight.
The 3-cell Tanic pack also needed extra nose weight installed to compensate for their light weight.
I verified proper control throws and amounts, and checked the balance again. I performed a range check, which was especially important given the length of the motor wires and potential interference. Everything checked out fine, so I was ready to go.
I opted to use the 10-cell pack for the first flight, just to make sure I had all the power I needed. Since this was such a new model, I didn’t have any references to how it would hand-launch. I opted to make a simple catapult launcher to ensure there was sufficient airspeed. Plus, this left me with my hands on both sticks while the plane was launched.
The first launch went well, the Hawk took to the catapult easily. I gained altitude so I could make some trim adjustments. The Hawk climbed quickly and I was soon making passes down the runway. The Hawk was decently fast and moved along at a clip much faster than my average 400 powered plane. I made sure I left plenty of battery capacity in case I needed to make several practice landing setups, and the first landing was uneventful.
The second launch was made from the catapult as well. Once in the air the Hawk performed rolls effortlessly. Loops were decent, but I didn’t push it too hard being a new plane. Turns were clean and sharp, just bank over and pull elevator. I flew pretty much the same on the second flight as the first, again, not wanting to push things too far. On this flight I noticed a mild tendency for the Hawk to always be climbing or diving, so I figured I better add some nose weight once I landed. Again, I was careful to leave plenty of power left in the battery for landing. Landing speed is a little fast, but still within what I would call acceptable limits.
The third launch was made by hand, and I heeded the warnings in the instructions regarding hand launching a plane with a rear-mounted prop. I tried to use the molded-in finger holes, but I really couldn't get a good enough grip there to adequately throw it. So I grabbed the fuselage behind the wing, powered up to half-throttle, and tossed it as hard as I could. As soon as I had my hand back on the transmitter I went to full throttle and pulled some up elevator. The Hawk dropped a little altitude before gaining enough speed to fly, but once up to speed everything was fine. I wasn’t confident enough to have the motor going full throttle when I launched it, so there does exist a slight delay in throttle application with this technique. The added nose weight (about ¾ oz) helped the oscillation I noticed in the second flight. This time I tried other flight characteristics with the Hawk. I slowed it down and started pulling up-elevator to try to stall. There was a mild stall, but nothing like I predicted. It was actually a series of very small nose-drops and recovery, with just a bit of wing-wagging during the process. At no time to did it drop a wing and snap over towards the ground. I tried this several times and got the same result.
The fourth launch was also made by hand, again grasping the fuselage behind the wing rather than using the molded-in finger holes. I set the motor at about 1/3 throttle while I threw it, and powered it to full throttle as soon as it left my hand. Having some power on during the launch process made for a much cleaner launch, and also minimized the chance of getting caught by the propeller. This flight allowed me to try slow rolls, hesitation rolls, and was capped off by some hard loops. Yanking in full-up elevator at top speed didn't seem to strain the airframe at all. Flight and tracking were very predictable throughout the flight, and there wasn’t so much as even a hiccup in RC reception with the long motor leads. Landing was fast, but again no problems.
Many more flights were conducted over several days, with a combination of catapult and hand-launch methods. I became more adept at launching the Hawk by hand and got to a point where there was no altitude loss. All the landings ended well, with the exception of one landing with the wing popping out of the front alignment socket. The Hawk needs a smooth runway to land on due to the "braking action" of the low wing, a landing in some taller grass caused a very sudden deceleration which caused some minor damage to the wing.
The Tanic Packs provided by R/C Toys Inc. had 12C capability and a unique feature allowing individual cell charging to ensure voltage matching, or series charging of the entire pack. I hooked up the 3-cell pack and it was nearly identical in consumption and voltage to the 10-cell Nicad pack (initially). It was several ounces lighter, unfortunately this lightness couldn't be used to advantage in the Hawk since it required the battery weight to balance properly. I added several ounces of lead into the battery compartment to retain the CG point, and performed a hand-launch. The flight went well, but I was not able to time it accurately. At an 11 amp consumption, I projected the 1550mah battery would have lasted nearly 8 minutes at full throttle. Although the initial current draw and voltage matched the 10-cell pack, the Tanic Pack maintained this level of output far longer than the Nicad pack.
UltraFly had also included two of their brushless motors for use, the A/30/24 and A/30/29 (2400 and 2900 KV, repsectively). These motors are "outrunner" type brushless motors, but have an outer case that allows them to be mounted like conventional motors. Detailed specs of these motors are available on the UltraFly Model Corporation website.
The use of these motors required a brushless speed controller, so I used one of my existing ones. It is not advisable to have long lead wires between the motor and the controller, so I needed to place the controller close to the motor (there was room in the aft fuselage for this) and use long battery leads instead.
The brushless motor was approximately 1 ounce lighter than the Falcon 400, but was offset slightly by the aft location of the controller. I checked the current consumption, and with the same gear ratio and prop the A/30/24 pulled 8.5 amps on a 10-cell battery and the 3-cell Tanic Pack. The power output to the propeller was almost identical to the Falcon, but with 30% less current draw. I realized the A/30/29 was the motor intended to be used with the Hawk, but the A/30/24 was already installed and I went ahead with flights.
The first brushless flight was with the 3-cell Tanic Pack. The launch was very smooth and powerful, and the Hawk quickly climbed towards the sky. I proceeded with the flight, and couldn't believe there was only an 8 amp current draw. The flight speed was very impressive, as was the ability to perform large loops with true "jet like" performance. The Hawk was simply beautiful as it climbed skyward with such authority. This time I timed the flight. I intentionally left the throttle at full for the entire flight, and after 10 minutes the Hawk was still flying strong. I noticed the rpm start to drop, but continued the flight for a few more minutes, with enough power to still perform high speed fly-by's and large loops. I landed shortly after that, with 12.5 minutes of total flight time, all of that at full throttle.
I then installed the A/30/29 brushless motor. It was an easy change-out due to the removable pinion gear, a feature that was very handy. With the 3-cell Tanic, and retaining the same prop, the current draw was 14 amps. I launched the Hawk at about half-throttle and went to full throttle as soon as it was airborne. Plain and simple, it took off like a rocket. I was climbing at a 45 degree angle with no sign of slowing down. I went several hundred feet in the air and came across the runway in a high speed run. The Hawk tracked like an arrow, and was likely traveling 3 times as fast. It was faster than with the A/30/24, and where I really noticed a difference was in the climb. From straight and level flight, I pulled up vertically and climbed several hundred feet before losing momentum. The Hawk does a neat little "torque roll" when held vertically until it stops climbing. Then from that altitude, I pushed the nose down and came across the field again. At that speed the Hawk has a neat little whistle to it that only adds to the sensation of speed. I then pulled into a huge half-loop and finalized it with several sequential rolls. I flew at this pace for over 5 minutes until my transmitter started beeping at me due to low battery. I could have made many more flights before completing this review, but I was anxious to get the word out to people!
Assembly was easy, with only 2 detractions: 1) difficulty in reading the instructions due to translation errors (although it was simple to figure out what needed to happen), and 2) the problems identified with the decals. UltraFly is looking into both these issues for future production runs. Otherwise, the kit assembled very easily and results in a very nice looking aircraft. Self-aligning features in the fuselage, wing, tail, and motor mount all contribute to a goof-proof model.
The Hawk flies fast, responsive, and looked great in the air as well as on the ground. It was a little challenging to launch at first, but that was resolved through practice and comfortability. As stated in the instructions, the Hawk is an advanced airplane to fly and is definitely not for the beginner or intermediate pilot. I preferred to fly the Hawk with a slightly more forward CG location, approximately 3/8" forward of the recommended position.
The Futaba micro servos were top notch, and a great selection for this plane. The Futaba receiver and Electri-Fly speed controller worked flawlessly. The Tanic Packs provided for far greater duration in flight than my standard Nicad/NiMh packs and worked wonderfully in this application. With the Hawk designed around a 10-cell system, the 3-cell Tanic was a perfect match.
The brushless motor upgrades were phenomenal! With the UltraFly A/30/24, the Hawk flew like a true jet for over 12 minutes with the Tanic 1550's. When upgraded with the A/30/29, it was even more of a speed demon. Flying the Hawk with the Tanic Pack and the UltraFly brushless motors was truly an exhilarating experience. Even if I had retained the use of the stock motor and Nicads, the Hawk still performed strongly and remains a real bargain for the money.
.i put a 3200 kv motor in it with a 3:1 gear box and a 6x5.5 prop
running 3cell lipo 1500mph pack . got a 20min flight with plenty of power left
love the plane
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