Tower Hobbies Razor 3D
|Wing Area:||579 sq. in.|
|Wing Loading:||22.4 oz/sq. ft.|
|Wing Cubic Loading:||11.2|
|Servos:||(4) Tower Hobbies TS-160 Std. Digital Servos|
|Transmitter:||Futaba 7C 2.4GHz|
|Battery:||(2) FlightPower EONX 3s 3350mah (30C) packs|
|Motor:||Great Planes Rimfire .55|
|ESC:||Great Planes Silver Series 60A HV|
|BEC:||Dimension Engineering SportBEC|
|Available From:||Tower Hobbies|
Like most r/c pilots I am always on the lookout for something new and different to fly and something that will also fit in my budget. I really enjoy flying airplanes that are capable of offering a good balance of precision, sport, and a little 3D aerobatics through in for good measure. I have to say it is not always easy finding an airplane that meets my requirements as many airplanes tend to specialize in one, maybe two of the categories that I am seeking.
So I was very impressed when I saw Tower Hobbies had come out with an airplane that looked like it could possibly fit my flying requirements without blowing my r/c budget. The Tower Hobbies Razor 3D is a fully aerobatic sport airplane that is also capable of flying mild 3D aerobatics and track like a well-seasoned pattern ship. The airplane can be flown with either electric or glow power as the well-illustrated manual completely covers setting up both options. The Tower Hobbies Razor 3D comes with a vibrant 4-color MonoKote®, pre-painted composite landing gear, and pre-painted fiberglass cowl and wheel pants. The one-piece wing design allows the airplane to be easily transported to the flying field while minimizing setup time at the field.
My Tower Hobbies Razor 3D arrived in excellent condition and free from any shipping damage. The Tower Hobbies Razor 3D parts were all nicely packaged and individually wrapped in their own protective plastic wrapping. After carefully removing all the protective plastic wrapping I found all the parts and components were in perfect condition.
Upon removing the items from the box I was immediately impressed with the quality and vivid colors of the nearly wrinkle free Monokote® covering on the Tower Hobbies Razor 3D. As I do with all my new airplanes I let it set on my workbench for a couple of days to get adjusted to the Ohio weather conditions and then I went over the entire airplane with a heat gun.
The Tower Hobbies Razor 3D ARF contains:
The Tower Hobbies Razor 3D ARF requires:
Items used to complete the Tower Hobbies Razor 3D ARF:
The Tower Hobbies Razor 3D Manual
The Tower Hobbies Razor 3D manual is well laid out and does a great job of providing the builder with all the information needed to successfully build, setup, and fly the airplane. The manual provides clear photo-illustrations for each step of the assembly. The manual clearly lays out the starting CG location and gives the builder safe forward and aft CG locations depending on how one would like to fly the plane.
The manual goes into full details on how to set up the Tower Hobbies Razor 3D as electric or glow, and the required hardware is included in the kit for either configuration. Before I got started with the build I read through the manual several times to ensure I understood what was required in each step and to ensure I had the necessary building supplies. Each step of the build smoothly transitioned into the next and at no time did I feel I needed to jump through the manual in order to complete the build in a more logical order.
The Tower Hobbies Razor 3D manual can be easily downloaded and viewed directly from the Tower Hobbies website. I think this is a great idea as it allows a prospective buyer to view the manual before purchasing the airplane. The buyer can see what equipment is needed and the online manual also allows individuals who may have purchased the airplane second hand a chance to get the proper CG and control throw setups without the need for the printed manual.
The Tower Hobbies Razor 3D comes with an addendum which states that on some kits it may be necessary to add foam tape to the wing saddle to provide a more secure and flush fit of the wing.
After mounting my wing to the wing saddle on my Tower Hobbies Razor 3D I did notice there was a small amount of gap from the bottom of the saddle to the top of the wing. The gap was removed once the foam tape was installed and the wing now fits quite securely to the bottom of the wing saddle.
The Tower Hobbies Razor 3D is setup with a one piece wing design. While a lot of planes today are being designed with a more common two-piece wing design, the relatively short wing span of the Tower Hobbies Razor 3D allows the wing to be easily transported in most any size vehicle. The wing is pre-covered with a colorful MonoKote® covering scheme which provides a nice contrasting setup to allowing for fairly easy orientation of the airplane in the air.
The ailerons are not pre-hinged but the installation process is a very simple one using the included CA style hinges and applying a few drops of CA glue to each hinge. I chose to use (2) Tower Hobbies TS-160 std. digital servos to power my ailerons on the Tower Hobbies Razor 3D. The Tower Hobbies TS-160 servos were a perfect drop in fit into the servo bay! Prior to installing the aileron servos a 12" servo extension was attached to each servo.
The ailerons bays were both supposed to have strings taped inside of them for the purpose of helping to run the servo extensions through the wing and out the exit hole in the center of the top of the wing. Unfortunately, in this particular kit only one aileron servo bay had a string inside of it. After some head scratching and a few failed attempts I was able to successful run the other aileron extension through the exit hole in the top of the wing. With the servos installed the rest of the aileron setup was very straight forward using the provided aileron hardware. The Tower Hobbies TS-160 digital servos provide LOTS of aileron deflection at full throw (more on this later)!!
The Tower Hobbies Razor 3D wing mounts onto the bottom side of the fuselage through the use of a couple of nylon wing dowels and a nylon wing bolt. A belly pan is then glued to the bottom of the wing to conceal the nylon wing bolt and to provide a clean look to the bottom of the airplane. The manual does a great job of explaining how a soldering iron can be used to safely remove the covering from the wing so the belly pan can be epoxied to the wing.
|Type:||Standard digital high torque|
|Bearings:||dual ball bearings|
|Speed:||0.17 sec. (4.8V), 0.14 sec. (6.0V)|
|Torque:||110 oz.-in. (4.8V), 131 oz.-in. (6.0V)|
|Length:||1.6 in. (41mm)|
|Width:||0.8 in. (20mm)|
|Height:||1.5 in. (38mm)|
With the wing now resting securely in the wing saddle the horizontal stabilizer and elevator can be installed. I epoxied my horizontal stabilizer in place after carefully make sure it was square and perfectly centered in the tail of the fuselage. The horizontal stabilizer fit perfectly in the pre-cut slot in the fuselage! The elevators connect to the stabilizer using CA hinges and a pre-formed metal joiner wire. As I did with my ailerons I chose once again use a Tower Hobbies TS-160 std. digital servo to power my elevator. I had no worries the Tower Hobbies TS-160 would be up for the task as it offers 110 oz.-in. of torque on 4.8V and 131 oz.-in. of torque on 6v which is more than enough holding power for an airplane this size.
Just like the elevator, installing the rudder was a very straightforward and stress free process. The Tower Hobbies Razor 3D has a very short vertical stabilizer but comes with a HUGE rudder which I knew would command plenty of authority in the air. Before installing the rudder to the fuselage the tailwheel bracket gets installed in the leading edge of the rudder. The rudder then gets attached to the fuselage using CA hinges and a few drops of CA glue. A single Tower Hobbies TS-160 std. digital servo was used to power the rudder. The rudder control horn needed to be trimmed slightly to allow the control horn to clear the side of the fuselage on full throw deflections. The Tower Hobbies Razor 3D also comes with a very nice carbon fiber tube which is installed on the rudder pushrod to prevent the rudder pushrod from flexing during those extreme in-flight maneuvers.
The Tower Hobbies Razor 3D comes with a nice set of pre-painted composite two-piece landing gear. The 2.5 in. foam wheels are easily installed on the landing gear using the provided aluminum axles and nylon locking nuts. The wheel pants are installed using a couple of machine screws, flat and locking washers, and a little bit of thread locking compound. The final landing gear setup then gets bolted to the bottom of the fuselage using some 4-40 socket head screws, washers, and once again thread locking compound. The landing gear just like the wing is swept back and gives the finished airplane a very clean and sleek appearance.
|Motor Diameter:||1.7 in. (42mm)|
|Shaft Diameter:||2.4 in. (60mm)|
|Shaft Length:||.67 in. (17mm)|
|Max. Constant Current:||45A|
|Max. Constant Watts:||830W|
|No Load Current:||1.5A|
|Input Voltage:||18.5-22.2V (5-6S LiPo)|
|RPM/V (kV Rating):||480|
|Weight:||9.5 oz. (268g)|
|Prop Range:||13x10E - 15x8E|
I chose to use a Great Planes Rimfire .55 brushless outrunner to power my Tower Hobbies Razor 3D. I have always had great success with the Rimfire line of motors so I knew this motor would provide all the power and reliability I would need to confidently fly this airplane. The Great Planes Rimfire .55 motor comes with a very nice bolt-on prop adapter which I mounted on the motor using the provided hardware. The motor gets attached to the front of an aluminum motor mount and then bolted to the airplanes firewall. The firewall has pre-installed blind nuts which make bolting the motor/motor mount assembly to the airplane a snap!
The motor mount is fully adjustable to allow the motor to be positioned correctly for mounting the cowl to the spinner backplate. I adjusted the motor mount side bolts to achieve the 4 7/8 in. spacing called out for in the manual. The completed motor mount assembly provides a very solid, robust and torque free platform for the Great Planes Rimfire .55 brushless motor.
|Type:||brushless speed controller|
|Output Current:||60A Conti. Max., 72A Surge Max.|
|Max. Output Power:||3000W|
|Dimensions:||2.3 in. x 1.9 in. x 0.7 in.|
|Input Voltage:||4-12 LiPo cells (12.4-50V)|
To complement the Great Planes Rimfire .55 brushless motor I decided to us a Great Planes Silver Series 60A HV (Opto) brushless speed controller along with a Dimension Engineering SportBEC. I have used this combination in several other airplanes with great success and new that it would work just as well in my Tower Hobbies Razor 3D. The Dimension Engineering SportBEC is nearly a plug-and-play unit which requires only a small amount of soldering to the GP Silver Series 60A HV power leads before it is ready to use. The SportBEC's output is selectable between 5V/6V using a small slide switch and can provide up to 3.5A of current all the way up to an 8s setup airplane.
The Great Planes Silver Series 60A HV speed controller is mounted to an ESC tray. The ESC tray is made of several lightweight plywood parts. After all the ESC tray parts are glued together the ESC gets mounted to it using three self-tapping screws. The ESC tray is then simply bolted on to the side of the aluminum motor mount. I velcroed the SportBEC unit inside the cooling hole cutout located at the bottom of the firewall. This location allows for plenty of air to come through the cowl and over the ESC and SportBEC units for proper cooling.
|Max. Charge Current:||(5C): 16.8A|
|Max. Conti. Discharge:||(30C) 100.5A|
|Length:||5.31 in. (135mm)|
|Width:||1.73 in. (44mm)|
|Height:||0.94 in. (24mm)|
|Weight:||9.8 oz. (279g)|
The Tower Hobbies Razor 3D comes with a fairly generous battery tray compartment considering the airplane has a relatively narrow fuselage profile. I glued down a strip of "non-fuzzy" velcro to the bottom of the battery tray and then installed a couple of hook and loop straps to restrain the batteries. The FlightPower EONX 3s 3350mah (30C) packs fit very nicely into the battery tray compartment. However, I did run into a small issue as I was not able to move the battery packs far enough back on the battery try to obtain the recommended CG (5 1/8 in.). With the FlightPower EONX batteries stacked the back of the top pack was hitting a fuselage cross brace. To help resolve this issue I simply cut out the fuselage cross brace which was preventing the battery packs from shifting further aft. With the fuselage cross brace removed I was easily able to adjust the FlightPower EONX battery packs to obtain the recommended starting CG.
The Tower Hobbies Razor 3D utilizes a very unique hatch locking setup. The canopy system uses a set of powerful magnets and hook slats that lock the canopy in place. This system works great, and I have really pushed the plane to see if I could get the canopy to eject in flight but the setup has held up perfectly. It allows quick access to the radio compartment, and there are absolutely no worries of the canopy coming off when it is properly locked in place. The canopy hatch did have to be modified slightly in order to allow the FlightPower EONX packs to fit on the battery try. One of the canopy plywood cross braces had to be removed as it was hitting the top of the FlightPower EONX battery packs. Once the plywood cross brace was removed the packs were easily able to be moved forward and aft on the battery tray without contacting the canopy hatch. After nearly 50 flights the canopy hatch has held up great with the cross brace removed!
Installing the cowl on the Tower Hobbies Razor 3D is a very straightforward and a no surprise event. The cowl gets attached to the forward fuselage using (4) 3/8 in. self-tapping screws. I added a couple of drops of CA to each screw hole to help harden the area so the cowl screws would be less likely to come loose. The included blue spinner looked great and required only a small amount of reaming in order to get it to fit nicely on the prop adapter. The spinner also required some trimming on the prop openings in order to allow the APC 14 x 7E prop to properly fit the spinner. Once completed the finished fit was perfect and really completed the looks of the Tower Hobbies Razor 3D.
Per the manual I installed the Futaba R617FS receiver just in front of the battery tray compartment. The receiver is simply held in place by a couple of pieces of velcro. The Futaba R617FS fit perfectly in the fuselage and offers full range capability without any need for remote antennas.
I was very pleased with the finished looks of my Tower Hobbies Razor 3D and was really excited about seeing how it would perform in the air! My Tower Hobbies Razor 3D weighed in at 5 lbs. 10 oz. RTF which placed my airplane slightly heavier than suggested manufactures weight of 5-5.5 lbs. The weight of my Tower Hobbies Razor 3D placed the wing loading at 22.4 oz/sq. ft. and the wing cubic loading at 11.2. The wing cubic loading is slightly high for a full on 3D/aerobatic airplane but well within the range of a very good sport aerobatic performer. With the slightly higher wing loading and excellent lines on the airplane I knew the Tower Hobbies Razor 3D would be able to cut through a moderate breeze while still being able to land at a very comfortable speed.
As indicated earlier the Tower Hobbies Razor 3D calls for a starting CG of 5 1/8 in. measured from the leading edge of the wing. Once the canopy and fuselage modifications were made (see earlier text above) I was easily able to get to the recommended starting CG. There is also plenty of room to move the battery packs further aft depending on each pilots flying preference. I keep my CG at the recommended setting as it allows me to fly the airplane through precision and aerobatic maneuvers with a very comfortable feel on the sticks. Using the FlightPower EONX 3s 3350mah (30C) packs I am able to comfortable fly for 7-8 mins. of mixed precision and sport aerobatics with plenty of power for several touch-n-goes if needed.
I set up the control surfaces per the manufacturer’s recommendations. The only setting which has been altered (lowered) slightly has been the 3D rate aileron setting. I found the recommended 3D aileron rate to be quite high and a bit challenging for my fingers to keep up with. With the Tower Hobbies Razor 3D having full-span ailerons I found a 3D aileron setting of 28 degrees was perfect for my flying preference.
|Recommended Control Throw Settings|
|Low Rate||High Rate||3D Rate|
|Ailerons||3/8 in. (10mm)||5/8 in. (16mm)||1 3/4 in. (44mm)|
|Elevator||1/2 in. (13mm)||3/4 in. (19mm)||2 1/2 in. (64mm)|
|Rudder||1 3/16 in. (30mm)||2 in. (51mm)||3 1/2 in. (64mm)|
As denoted earlier the one-piece wing design allows the Tower Hobbies Razor 3D to be transported fairly easily and assembling the airplane at the field is just a matter of plugging in the aileron servo extensions into the receiver and bolting the wing to the bottom of the fuselage. Be sure not to over tighten the nylon bolts as you could possibly strip the threads. I would recommend taking a Robart Stand (or similar) with you to the field as the Tower Hobbies Razor 3D fuselage needs to be turned upside down in order for the wing to be mounted.
The (2) FlightPower EONX 3s 3350mah (30C) batteries packs get connected to a series harness in the airplane which makes the battery configuration a 6s 3350mah setup. After installing the canopy I always like to ensure my control surfaces are moving in the correct direction (a good habit to have). The Great Planes Silver Series 60A HV speed controller has a very nice built-in safety feature which does not allow power to the prop until a set of beeps are heard when cycling the throttle stick from full open to close. With everything checked out and moving in the correct direction it is time to get the Tower Hobbies Razor 3D in the air.
|Prop:||APC 14 x 7E|
Taxing the Tower Hobbies Razor 3D is very easy thanks to the steerable tailwheel and large rudder. The airplane has absolutely no issues taxing on paved surfaces and is more than comfortable taxing on grass as well. The balance of the airplane and the fairly long tail moment help the airplane taxi without any worries of nosing over. Once lined up on the runway a smooth application of throttle and a few small taps of right rudder to maintain center line is all that is needed to get the Tower Hobbies Razor 3D in the air. Climb outs can be as gentle or aggressive as you would like as there is plenty of power on board to send the airplane into blistering ascents.
On low rates the Tower Hobbies Razor 3D is very stable and the Tower Hobbies TS-160 servos do a great job of centering on all control surfaces. The airplane tracks well and thanks to the excellent centering with the servos there is never a need to "chase" the airplane around. The airplane has a very nice pattern airplane feel to it on low rates which makes flying such maneuvers as loops, cuban eights, split s's, and point rolls fun and easy to perform. Knife edge flight can be easily accomplished, even on low rate rudder as long as some speed is maintained throughout the maneuver. The Tower Hobbies Razor 3D has very minimal knife edge coupling and I have yet to add any mixing as I'm easily able to fly it out using minimal stick input.
Stalls with the Tower Hobbies Razor 3D are very gentle with no bad characteristics. Once a stall is achieved the nose simple falls forward in an attempt to regain airspeed. Recovering from a stall is simply a matter of reducing some elevator input and smoothly reapplying power. With such benign stall characteristics landing the Tower Hobbies Razor 3D is really very straightforward event. The airplane has a very clean profile to it so a little preparation is needed to help slow it down. I like flying a full-scale landing pattern with my Tower Hobbies Razor 3D which is great for bleeding off some of the excess airspeed. I like to plan my final approaches to be slightly longer and a little shallower than normal which really helps to bring this fine little airplane in on those perfect three point landings.
The Tower Hobbies Razor 3D really comes to life at the flip of a switch(s) which is when the fun really begins!! I have to say I was really able to see what the airplane was capable of when I went from low rates to high rates and then to 3D rates. The Tower Hobbies Razor 3D went from a tamed precision pattern ship to snap happy full on aerobatic tumbling machine!! With the rates up high you really start to notice the effects of the full-span ailerons and I would highly recommend a generous application of expo. be used to help soften the feel around center. The Tower Hobbies Razor 3D really loves to snap, and I mean snap!! The digital Tower Hobbies TS-160 servo torque is really noticed when you go to perform a high rate or 3D snap. If quick is your game (and it is for me) then you will absolutely love testing out your snap reflexes with the Tower Hobbies Razor 3D. The airplane snaps very precisely and the only limiting factor is the pilot’s ability to master the fast snap rate.
I put together a list of some of the many other aerobatic and 3D style maneuvers that I've flown with my Tower Hobbies Razor 3D and my thoughts on how I thought the airplane performed flying each of them. Many of these maneuvers are featured in the video listed below.
No. While the Tower Hobbies Razor 3D can be set up on low rates to fly in a pretty docile way it does not possess the self-leveling characteristics found in most of today's modern trainers. The Tower Hobbies Razor 3D is much better suited for the intermediate sport pilot who has already perfected the basics of flight and is looking to step up to a more capable low wing aerobatic sport airplane.
The Tower Hobbies Razor 3D offers up a great value for anyone looking for a fully aerobatic precision sport airplane which is also capable of some mild 3D aerobatics thrown in for good measure. The airplane manual is well written and provides all the information needed to get the airplane from box to flight line ready in very short order. The recommended power package delivers all the power needed for some very spirited flights and will definitely please nearly any sport pilot enthusiast.
The 4-color MonoKote® covering scheme presents very well in the air and allows for easy orientation of the airplane in nearly any sky condition. Even with the one piece wing design the airplane can be easily transported and setup time at the field is only a matter for a few minutes. The Tower Hobbies Razor 3D's excellent ground handling and mild in-flight manners make it a favorite of mine any time I am headed to the field.
Yes, I would tend to agree the motor/prop setup is louder than other electrics I've flown before. Not quite sure why as the prop was balanced and the motor is bolted firmly to the motor box.
USA, VA, Newport News
Joined Jan 2010
Why in the world would you load up this plane with equipment that is way too heavy for this size plane? This plane would fly much better with a lighter motor like a Hacker A30-12XL (3.2 oz lighter), smaller servos like Hitec 85MG (22G vs 60g), and a better motor mount. Ive seen that mount, its horse heavy. Put this plane on a serious diet and run 4S 2600's-3300's instead of 6S 3350.
Did Tower just send you what they thought would work? Did you have any input at all? You only listed one minus...really? As you were putting this puppy together, you never once thought the equipment was overkill and heavy?
Isnt not having airfoiled tail surfaces a minus? On a 52" 3D plane, wouldnt you expect to have airfoiled tail surfaces...but then again, it is a cheap kit...and it is from Tower.
A nice detailed write up, thanks.
I've flown I/C powered models for 25 years, and after a couple of years away, I'm looking to get into electric. I'm looking through your write up and one of the pictures has no other reference.... The cooling cutout.
I assume this is behind the wing on the underside.
Is it always necessary on an electric model?
Is it specified in the instructions?
Sorry to ask silly questions!
Bill, Nottingham, UK.
My answers to your questions are highlighted in red above.
I just finished building one of these and have the same concern about all the heavy power equipment required. I installed the recommended 55 motor along with 6s lipo. I haven't flown it yet but it does seem a little heavy. Especially sitting beside my Precision Aerobatics Addiction 3D with a 40 size motor and 3s 2200mAh lipo. Both planes appear to be near the same size (except for weight). The Addiction flies great but I'm nervous about flying the Razor. I'm afraid when it's time to land, it will come in like a rocket! Any comments?
So not quite an apple to apple comparison there.
As far as landings go the Razor actually will slow down quite nicely. The key to the landings are to establish a nice shallow decent rate while maintaining a small amount of power right up to the flare.
Hope that helps some.
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