[Headline: JR Forza 700]
[Subhead: A capable and agile 3-D machine]
[Author: Charles Anderson]
[Photos by the author]
[Sidebars in text file]
[No additional callouts]
Model type: 3-D 700-size flybarless helicopter
Skill level: Beginner to advanced
Main rotor diameter: 61.4 inches
Tail rotor diameter: 11.3 inches
Weight: 11.0 pounds ready to fly
Length: 52.4 inches
Width: 8.3 inches
Height: 14.0 inches
Gear ratio: T11 10.2:1:4.72/T12 9.3:1:4.72
Tail drive: Shaft
Control system: Flybarless 120° CCPM
Power system: Kontronik PYRO 750-50L; Kontronik JIVE Pro 120 ESC
Main blades: 716mm Rail Blades
Tail blades: JR Carbon Tail Blades (included)
Radio system: JR XG14 DMSS with XBus
Flybarless control unit: JR TAGS Mini with RAO1L Satellite
Servos: Three JR SLS01 QRS on cyclic; one JR SPG01 QRS on tail rotor
Battery: Two Pulse 6S 5,000 mAh 45C (12S 5,000 mAh 45C stick pack)
Flight time: 4-12 minutes depending upon flying style and head speed
• Excellent power-to-weight ratio.
• Large flight envelope, which suits beginners to hardcore 3-D pilots.
• Designed for simplicity of build and repair.
• CNC helical gear results in a smooth, quiet drive system.
• Torque-tube driven tail system with 6mm output shaft is smooth and durable.
• Exceptional instruction manual and diagrams that simplify the build.
• The canopy is narrow, which means you must be diligent concerning your battery/ESC wiring up front.
• Slight hole misalignment on the rear portion FRP body-boom clamp access.
• Battery tray clip held on a little too well; needed a slight edge beveling.
It is hard to believe that an entire year has passed since I had the opportunity to build the JR Forza 450. With a lot of love, crashes, and tender care, my little Forza has been a true joy to fly.
As I have been thrilled with the performance of this new generation of JR helicopters, I was excited like many of you when I saw the first release photos of the JR Forza 700. After seeing the final product, I knew this would be on my build list for the summer, and as luck would have it, I am writing this article during the last days of summer.
Like all JR helicopters, the Forza 700 is designed and manufactured according to the highest-quality standards. What makes the Forza 700 different from most other large JR helicopters is their new design methodology. Following in the footsteps of the Forza 450, the Forza 700 brings an entirely new design concept to the table for JR. It is designed to be light, fast, modular, and cost competitive. This has all been done without any compromise to the high JR standards. As I begin, let’s look at some of the features of the Forza 700.
Key Features of the FORZA 700
• Low profile frame design. The increased cyclic response as the CG is closer to the rotor head, which creates a dynamic flight envelope.
• The modular frame design is easier to access, assemble, and repair.
• Swash servo positioning creates direct linkage to swashplate with precise control.
• Shaft-driven tail system; efficient and durable.
• Clamping-style servo arms allow for a true 90° setup.
• Helical pinion with a CNC main gear is quiet, smooth, and increases reliability.
• New body fairing provides increased visibility along with the flexibility to still fly in a standard pod-and-boom configuration.
• 6mm tail output shaft along with a solid JR pitch control creates a smooth and durable tail control system.
• Sliding-locking battery tray system provides safe and easy positioning of batteries.
• A price that is out of this world for a high-quality, 700-size helicopter!
Since I will be beginning the build immediately with the carbon components, it is important to note that you should take the time to sand all the edges. This should be done to all carbon components before you begin each and every build. I recommend wet sanding, as this will minimize any carbon dust.
ESC Tray, Battery Tray, Middle Cross Member, Battery Tray Rails
The first item called for is the ESC tray. Take special care to sand the inside edges of the Velcro slots, as rough carbon can cut through the Velcro. Also, take notice of the direction of the mounting screws. One of the cross members is for the front of the helicopter, so it has a different shape than the one for the back part of the tray. The ESC tray is quite large and easily holds my new Kontronik JIVE Pro 120. It is large enough to easily hold the Kontronik KOSMIK as shown in the assembly photos.
The Middle Cross Member is a simple subassembly; just make sure to slide the Middle Cross Member A under the edge of the Middle Cross Member B before you begin inserting your screws. Take the time to place all screws in the proper place and then tighten them in an alternating pattern. This helps to make sure the two members self-align as you secure them to the carbon plate.
The Battery Tray Rails are self-aligning and have JR engraved on the upper position. This lets you know if you have them on their respective sides of the helicopter, as there is a stop lip at the rear of the rails.
Motor Mount Assembly
A unique feature of the motor assembly is the size of the pinion—it is the longest pinion I have seen in a kit. The assembly manual photos do not do it justice. I am running a Kontronik PYRO 750 motor with a long shaft and I did not have to make any cuts to the shaft, as the JR pinion covers the entire shaft. JR has done this to ensure the pinion completely engages the lower bearing support and is then captured with the pinion nut. This is a mechanically solid drive train, which should help to increase the life span of your motor bearings.
Tail Pinion Unit Assembly
In this subassembly, one of the items of interest is the insertion of the tail bevel gear into the bearing. You will push this easily into the bearing, but the last bit takes a firm push and you will hear a slight pop as it seats itself into the bearing carrier.
Carbon Upper Frame Assembly
This step will include the attachment of the bearing blocks, left/right servo mounts, and tail pinion unit assembly. I began this step by attaching the items to one frame half first; from there you can lay it on its side and attach the other half. I did not Loctite any bolts in this step, as I like to build the frames and then make sure they are uniformly straight before final tightening.
When attaching the servo mounts, you will notice that they have the ability to move fore/aft, which will accommodate servos of different case depths. This allows you to make small corrections in the geometry that may come from different servos.
Motor Mount Installation
Once you have completed the upper frame assembly, it is now time to attach your motor-pinion assembly along with the radius arm. Examine the motor wiring to make sure that you have it exiting the side you wish it to be on prior to inserting the subassembly into the frame. Once inserted, you may choose to set your mesh accordingly. Don’t forget the two bolts that go in the back of the motor assembly, as these help to lock in your mesh once everything is set.
Carbon Tray and Middle Cross Member Installation
As you attach your ESC plate, note that you should not tighten the front screws at this point. This will be done later during final adjustments. At this point I am still keeping everything loose, as adjustments are easier if needed.
Lower Frame Assembly, Upper and Lower Frame Joining
The lower frames have some simple items to attach, including the landing gear stand-offs along with the canopy posts. From there you will begin the joining of the upper and lower sections. Prior to inserting the small carbon tray you must sand the edges slightly, as it is a tight fit. I pre-fit mine and it is best to follow the directions concerning sanding.
I really like the width of the landing gear. Even though JR has made the frames of the Forza very narrow and sleek, they still provide you with wide landing gear. Another nice feature is the skid inserts, as they are a softer rubber. Instead of the normal hard-to-fit plastic, the inserts are simple to install with just a small amount of CA.
Main Gear Assembly
The main gear is a beefy work of art. There should be no stripping of this gear; it is built like a tank. You will notice that it is straight and true, with no high or low points. Insertion of the auto hub should occur without any problems. So there is no confusion during insertion, one side of the auto hub is darker metal than the other as pictured in the manual. Take care to tighten the bolts in a crossing pattern, and do not over-tighten. This can place opposing stress on the gear-auto hub assembly.
Main Gear, Tail Drive Gear, and Main Shaft Collar Installation
After inserting the main gear and main shaft you will now work to set the proper gear mesh. The manual recommends two layers of plastic bag. To do this, I just used one of the parts bags, which worked just fine. When you insert the lower sock head bolt that retains the main shaft it should be snug, but do not over-tighten. This could put additional stress on the gear. The final part of this installation is to install the main shaft collar. You should pull upward on the main shaft while tightening the set screws. If there is any additional play, JR has included shims.
Swash Servo Installation
As mentioned earlier, the Forza 700 servo mounts are adjustable fore/aft to accommodate different servos. Once your servos are installed, you will then want to take the time to center your servo horns. If you have not purchased them, I highly recommend the JR clamping style servo horns for the Forza 700 kit. They make servo setup and 0° install a breeze. To make this even easier, JR even includes a swash alignment tool that slides directly under the swashplate.
Swashplate and Center Hub Installation
The JR swashplate is a red anodized beauty. Using high-quality bearings, it is as smooth as you might imagine. Balls and link rods are attached as instructed. The ball links are very smooth and do not need any sizing. They are tight to pop on the balls, but once on they are smooth as butter.
The center hub lines up as pictured and bolts on with a large shouldered bolt. Make sure this is snug, but do not over tighten, as this places un-due stress on the materials.
FBL Washout and Main Blade Holder Installation
The washout arm assembly is simple. The main blade holders have the thrust bearings preinstalled, and were correct with grease. One nice little feature during this assembly was completely smooth main grips at the end of the install. Both grips moved freely after installation, which is a sign of proper craftsmanship.
Rotor Head Linkages
Normally this is not something I would take the time to cover, but my thumbs mentioned this would be a good idea. The linkages from the main grips to the follower arms are tight—and I mean tight—to screw on to the linkage rods. Standard linkage rod tools do not work because the JR plastic is too thick (which is not really a bad thing). I worked until my thumbs said no more and went to using two ball-link pliers and screwed the linkage rods together. The plastic is very firm and if careful you can use this method without scarring it.
Tail Rod Installation
Instructed measurements for ball ends and placement of rod guides are true to the manual. I used J-B Weld for my install. This is always the best method for your tail rod. The torque is already assembled and inserted, so this step is quite short.
Tail Boom, Rudder Servo, and FRP Body Installation
Prior to the boom insertion, install your rudder servo; you have more direct access prior to inserting the boom. Insertion of the tail boom into the main frames is of ease, but follow the order, as you can only attach the tail box after the boom is inserted into the Fiber-Reinforced Polymer (FRP) rear body. The FRP rear body makes the boom assembly very rigid, and with the increased visibility I think this is a very good addition to the Forza 700. Do not over tighten the screws attaching the FRP body; you could potentially crack the paint. It is durable, but compressive force could crack the nice finish.
All of the steps comprise the assembly and attachment of the tail. This step can only be completed after inserting the boom into the FRP ready body. The JR tail assembly is a work of art and is about as smooth as you can expect.
Battery Plate, Electronics, Canopy
The battery tray is a great design with a positive lock at the front to ensure your batteries stay in place. I encountered a slight problem here. The clipping mechanism wanted to catch on the carbon when I was pressing downward. I fixed this by slightly beveling the top of the carbon with some sand paper, which allowed the clip to more easily disengage.
Did I mention earlier that the Forza 700 is sleek? Part of the sleekness comes from a sleek canopy fitting precisely over the sleek frames. If you tend to have a lot of wires hanging off the front of your batteries, you may have some issues when placing the canopy of the helicopter.
Please take the time to look over all bolts and attachment points to ensure the safest possible test flight. A 700-size helicopter demands your attention and respect; keep this in mind during operation.
As you decide upon your desired flight time and head speeds, the Forza 700 manual includes a helpful section on gear ration and rotor rpm setup. I usually perform my first test flights at lower head speeds and I found the approximations in the manual to be pretty close to actual flight times.
Final Setup, Flybarless Unit Programming, and Transmitter Setup
In my Forza 700, I will be using the JR Triple-Axis Gyro System (TAGS) Mini flybarless control unit and the JR XG14 14-channel DMSS radio system. Since I used both of these items with my Forza 450, I can say that you cannot go wrong with this combination.
The JR TAGS Mini is JR’s newest three-axis gyro system. It is an all-in-one unit and comes with a remote receiver. The TAGS Mini provides telemetry, and will allow seamless integration with any of the new JR DMSS transmitters. The XG14 is JR’s newest DMSS transmitter and also offers the XBus communication protocol. This is a truly top-notch radio at a very competitive price.
To begin, you must first program your transmitter. After setting up the JR XG14, I will then run a calibration with the TAGS unit that lets the TAGS learn the transmitter settings. This feature provides a comfortable transition from a standard flybarred system to a flybarless one.
Prior to performing your first test flight, it is important to verify all control settings of your helicopter. If the FBL unit is sensing in the wrong direction, you may encounter an immediate crash. The gyros should always correct against the movement. In other words, if you tilt the helicopter right, the swashplate should tilt left. Once you have verified all settings and fully charged your batteries, you will be prepared for your first flights.
I am happy to say my first flights on my Forza 700 were successful with no surprises. My flights were performed at a lower head speed of approximately 1,600 rpm. I like to start off at a lower head speed, just in case my gains are too high or I experience any type of failure on a newly built machine. The Forza is quite capable at lower head speeds, but is still smooth when moved closer to the 2,000 rpm range. It has a wide performance envelope and will be suitable for pilots of various skill levels.
In conclusion, I would like to once again congratulate JR on a wonderful helicopter design. It was an easy, pleasurable build. The only issues I encountered were very minor and easily overcome. JR delivers on what they have promised; a high-quality helicopter at a competitive price. If you are looking for your next helicopter, then look no further.
The JR Forza 700 has the lines of a Japanese bullet train, and the looks of a super model. It is sure to thrill.