RCU Review: Tower Hobbies & Kontronik Uproar 40 E-Conversion

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    Contributed by: Michael Parsons | Published: February 2005 | Views: 88466 | email icon Email this Article | PDFpdf icon

    Review by: Michael "Atlantaeflyer" Parsons- email me

    Tower Hobbies
    PO Box 9078
    Champaign, IL, 61826

    Watch the video of the Uproar


    • Excellent price
    • Easy to assemble
    • Parts fit was exact

    • Landing gear could be an inch taller to allow for larger props.
    • Wing is not removable

    The Tower Hobbies' Uproar is an Almost Ready to Fly, Sport Aerobatic airplane. The Uproar follows in the footsteps of their ever popular Uproar kit. It is designed for a 40 size IC motor, but converts to electric power with very little effort.

    Model: Uproar 40 ARF
    Manufacturer: Tower Hobbies
    Price: $89.99
    Wing Span: 48 in / 1219mm
    Wing Area: 618 sq in / 39.9 sq dm
    Flying Weight: 3.25 lbs as tested
    Fuselage Length: 44 in / 1120 mm
    Radio Required: 4 channel radio w/ 4 mini servos
    Power System: 300W electric motor system

    Power System Used:

    Kontronik 480-33 geared 4.2:1
    Kontronik Jazz 40-6-18 ESC
    45vlt UBEC from Koolflightsystems

    Battery: (3) 8C 1.5ah Kokam 3S packs

    Radio equipment:
    JR 8103
    Hitec Electron
    (4)- Futaba 3002

    Kit Contents:

    The contents were very well packaged, wrapped in plastic and bagged parts as well as the control rods were tapped to the box. The one piece wing was a big plus, it meant I could get this plane in to the air sooner.

    Wing Assembly:

    Lets get started. The Wing hole is cut out on both sides of the fuse so the wing is easily slid into the fuse. Tie a a piece of string to a modeler's pin and center it in on the rear of the fuselage. Next, draw a line or arrow onto a piece of tape and fold it in half over the string. Use the string to line up the wing. Make as many adjustments as you need until you are satisfied. This step is crucial in getting your wing straight.

    Once satisfied, use either an indelible marker or pencil/pen to outline the fuse onto the wing. Remove the wing and use your soldering iron to follow the outline. Keep the iron 1/8" on the inside of the mark. This will keep bare wood from showing outside the fuse. If you don't have a soldering available, a #11 hobby knife can be substituted. Be careful not to cut into the sheeting as this will weaken the wing strength.

    Remove the covering to expose the servo tray and reinstall the wing. Using 15-30 minute epoxy, glue the wing in place. After the epoxy dries you will next install the ailerons using the supplied hinges.

    Tail Assembly:

    I was pleasantly surprised to find that the holes and recessed groove for the elevator joiner wire were already precut. I merely had to remove the covering from the two elevator halves and epoxy the wire in place. This was a time saver, and as always greatly appreciated.

    The horizontal stab covering is removed following the same procedures as was performed for the wing. It is then slid into the fuse and secured using 15 minute epoxy. Once that has set, the vertical stab can be epoxied in ensuring that a 90 degree line is maintained.

    The steer able tail wheel

    Before the Elevator and Rudder can be installed, the tail wheel must be in place. I was again impressed to find that the hole for the tail wheel wire and groove in the rudder were already in place from the manufacturer. The tail wheel hinge is placed into the slot on the fuse and then the pre-hinged rudder and elevator are installed. Thin CA is wicked onto the hinges to secure them. The tail surface is now complete.

    Gear Mains:

    A template is used to install the main gear. Using a pen drill the holes were started to assist the self tapping wood screws provided. Nylon gear straps are then saddled over the gear wire to hold it in place.

    Power system :

    Kontronik 480-33, Jazz 40 and UBEC
    3S 1.5ah Kokam packs
    Futaba S3002 MG Servos

    The Kontronik motor comes with 3.5 mm bullet connectors that need to be soldered on. The Jazz 40 comes equipped with the matching ends of those connectors.

    I used a UBEC to eliminate the need for a separate RX pack to supply power to the servos. The UBEC draws its power from the main battery pack and steps the voltage down. One lead goes to any free RX channel (a Y cable can be used here if no channels are available) and the bare leads are soldered onto the power leads of the ESC. The leads can be soldered onto the Deans connector itself, or directly to the wires, as is my choice of installation.

    Mounting the Kontronik:

    The stock IC motor mount was used along with a pair of 28 mm motor clamps.

    There are plenty of after market motor mounts that were designed with the Kontronik in mind. However, I am a big fan of simplicity and will choose that option if it is available. Two clamshell mounts fit perfectly around the kontronik to hold it snug, and the built in ears allow easy mounting to the provided IC motor mount. This also allows the use of the pre installed blind nuts for the IC mount, therefore no alteration of the firewall is needed.

    The UBEC and ESC are neatly tucked away in what would normally be the fuel tank compartment. The compartment door was hinged with clear packing tape and held closed with a standard rubber band. This allowed quick access to disconnect the battery.

    Running up the Kontronik 480-33 and 3S3P on a 12X8 APC "E" showed 279 watts on 29 amps. I decided that it wouldn't be enough, so I swapped it out to a 13X8. This drove the amps up to 35 at full throttle and 333 watts. The motor is spec 'd out at 30 amp constant and 40 amp bursts, so 35 amps I could live with.

    Mounting servos:

    Fillers must be added to accommodate the smaller servos

    The servo bays are setup for full size servos. I commonly use smaller servos in conversions, so plywood fillers are needed to give the servo a place to mount. The filler piece is CA 'd into place.

    Battery Hatch:

    I had intended for the batteries to reside in the fuel tank compartment, but it turned out that the model would be too nose heavy if they were placed there. So the batteries would be placed under the wing. I first removed the servo tray intended for the throttle servo using a dremel. Be sure to take your time so you do not damage the rib it is attached too.

    I had to remove part of the fuse and create a cavity in the front of the wing to house the battery pack. Outline the area to be cut with masking tape and use a #11 blade to cut out the hatch. Remove the hatch and reinforce it with some basswood stringer. Line this hatch up with the main hatch cover to form one hatch and glue them together using 5 minute epoxy.

    I laminated 1/8" balsa tray with 1/64th ply to form the battery tray. It was then epoxied into the hatch area and Velcro applied to secure the packs. Velcro "seatbelts" were also used to hold the packs in place.
    The RX was placed in the hatch and the control surfaces were plugged in.

    The Completed and secured hatch.

    The bottom hatch was hinged using clear packing tape. Four of the provided screws were utilized to provide a mounting point for the rubber bands.

    Finishing it up:

    The Canopy was trimmed along the mold line and secured to the fuse using Formula 560 Canopy Glue and masking tape to hold it in place until the glue sets.

    Cooling is always an issue when you are flying electrics. For this reason a hole is cut into the bottom of the fuse to allow warm air to escape. Since the weather is cool at this time of the year, I did not bother opening up cooling holes for air to pass over the battery and controller. Lithium's operate best at a warmer temperature, so allowing cool air to get in would hinder performance. It will however be necessary to provide cooling for those summer months. A winter trick is to heat the lipoly's on the dashboard of your car before a flight.

    The finished weight of the Uproar came in lower than the advertised weight, which was 3.5-4lbs. The 3.25 lbs and a power system that would give me 100 watts per lb (or 1:1), had me convinced that it would perform well.

    I met up with some club mates at the field on a Saturday afternoon to maiden the Uproar. Having charged the 3S3P pack of Kokam 1500's the night before, I installed them in the belly and checked the balance.

    Taxing out on the runway to check ground handling showed that the short moment causes the tail to "run away" unless it is traveling very slow.

    Positioned and ready to go, I applied throttle and the tail rose up after about 15 feet. With very little elevator input, the plane was airborne and tracking straight ahead. I went straight into a stall turn and the nose came around nicely.

    Roll rates are crisp and quick, and inverted requires absolutely no down elevator to maintain altitude. Next I tried a Knife Edge, but the plane would not sustain it as it dropped out. There is not enough side area on the plane in my opinion. I could get some lengthy runs at full speed, but the sink rate would eventually force me to level off.

    Bringing the plane in for a landing required little effort. Simply set it up on final and bring the throttle stick to idle. The thick airfoil allows this plane to float.


    Posing Time


    Uproar Video
    Low | High

    The Tower Hobbies Uproar is a fantastic sport flyer and is an excellent value. The scheme allows for good visual orientation in the air and the thick airfoil gives this plane a very light feel. The construction is easily completed in a few hours and the fact that the plane finished out at 3.5 lbs is quite refreshing.

    The Uproar is an easy conversion and the Kontronik 480-33 and Kokam 3S3P 4500 pack pull it around well. Vertical is not unlimited, but it makes good up line runs, and the fast roll rates and very light feel in the air more than make up for it.

    Tower Hobbies

    PO Box 9078
    Champaign, IL, 61826

    Great Planes Model Distributors
    P.O. Box 9021
    Champaign, IL 61826-9021

    FMA Direct
    Kokam 1.5AH Packs
    5716A Industry Lane
    Frederick, MD 21704
    (800) 343-2934
    Tech/Service: (301) 668-4280

    Kool Flight Systems
    355 Sunderland Circle
    Fayetteville, GA 30215
    (770) 716-7578

    Comments on RCU Review: Tower Hobbies & Kontronik Uproar 40 E-Conversion

    Posted by: truesteel on 01/04/2009
    do some of the same principles also apply to the kit?
    Posted by: Mike Parsons on 01/05/2009
    truesteel, I assume so, but I have no first hand knowledge of the kit.
    Posted by: Eyeguy on 09/22/2013
    The Uproar makes an awesome floatplane seehttp://www.youtube.com/watch?v=nWZJaFwwab8
    Page: 1
    The comments, observations and conclusions made in this review are solely with respect to the particular item the editor reviewed and may not apply generally to similar products by the manufacturer. We cannot be responsible for any manufacturer defects in workmanship or other deficiencies in products like the one featured in the review.

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