[Headline: Three-blade Thunder Tiger Raptor E550]
[Subhead: A 6S fun machine with added stability]
[Author: Chris Mulcahy]
[Photos by the author]
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[Additional callout - tablet and online]
Model type: Three-blade flybarless 3-D helicopter
Skill level: Intermediate to advanced
Main rotor diameter: 45 inches
Tail rotor diameter: 9.33 inches
Length: 45.27 inches
Radio: Futaba 14SG; Futaba R6203SB receiver
Control system: Ace RC GT5.2 three-axis flybarless gyro
Drive system: Belt drive
Components needed to complete: Transmitter; receiver; flight battery
Power system: Ace RC Ripper OBL44/11-30H brushless; Castle Creations Talon 90 ESC; Flight Power 6S 5,000 mAh battery
Servos: Ace RC metal gear digital servos
Flight duration: 4-5 minutes (flying 3-D)
• Prebuilt, minor assembly required.
• Castle Creations ESC included.
• Carbon main blades included.
• Printed canopy; no decals.
• GT5.2 gyro has a steep learning curve.
• The blue canopy can be difficult to see in low light.
The International Radio Controlled Helicopter Association (IRCHA) Jamboree is a great place to show off new products, and this year something special flew during the noon demos. Nick Maxwell surprised people when he pulled out a new Thunder Tiger Raptor E550, sporting a different canopy, and more noticeably—an all-new, three-blade rotor head.
Nick proceeded to put on a great demonstration with the helicopter, as only he can do. In a day when three-blade helis are becoming popular for 3-D pilots, Thunder Tiger has jumped on the bandwagon with a twist. Its first offering in this arena is inexpensive, preassembled, and can be ready to fly in a single evening, opening the three-blade experience to more pilots who may want to try it out, but are unable or unwilling to bite the bullet and purchase a larger heli that offers a three-blade head.
This new Raptor arrived in a large box containing the helicopter’s two major subassemblies: the main frames and the boom/tail. The heli comes with everything you need to fly, except a receiver and flight battery.
Included are three Ace DS1510MG digital cyclic servos, one Ace DS0606n digital tail servo, a Castle Creations Talon 90 ESC, an Ace OBL44/11-30H brushless motor, and an Ace GT5.2 three-axis flybarless gyro.
The canopy is made from the same material as the previous version, but there are no decals on this one. The artwork is printed directly on the plastic. This is great because decals can fade and peel, whereas this printed canopy will keep its good looks for a long time. Wrapped in foam are the three main carbon-fiber 550mm rotor blades, and the included plastic tail blades.
The head is preassembled, and each blade grip contains regular and thrust bearings. It is seated on a rubber damper. There is a central triangular piece of metal that each of the blade grips bolts to, and the single-arm, clamp-on-style swashplate follower is mounted slightly beneath the head to help drive the swashplate and keep it aligned. The grips appear to be the same as the ones used on the X50, so they should be compatible. The model also comes with an extra set of dampers.
Assembly is straightforward. The boom, tail section, and boom supports are preassembled. All I had to do was slide the boom in place, taking care to make sure the belt was rotated in the correct direction so that the tail blades moved the right way. All of this is illustrated in the easy-to-follow instruction manual.
The servos are all preinstalled, and the pushrods are already made, but final assembly of the servo horns is still required. I mounted the GT5.2 gyro on the battery tray at the front of the helicopter using the included 3M tape. My receiver was mounted to the top of the servo box, where it had plenty of clearance beneath the canopy because of the receiver’s small size.
The Talon 90 has an excellent BEC, so I opted to not install an extra battery for the receiver. I mounted the Talon 90 on the tray at the back of the helicopter under the tailboom. This made it easy to install by simply removing the tray, and easy to unplug the motor wires when I am working on the setup. Safety first!
I spent time trying to figure out the best way to route all of the wiring, and settled on the final configuration as the most efficient way. I used plastic mesh to protect the wiring, as well as the motor wiring to the ESC. Using the S.Bus feature of my Futaba receiver eliminated many extra wires, making for a neater installation.
I followed the instruction manual, which includes basic setup instructions for the GT5.2 and programmed the Talon 90 using my Castle Link adapter and software. I initially set up my governor head speed to 1,700, 1,800, and 2,000 rpm. Mechanically setting up the blades was the same as setting up a two-blade helicopter, but with one extra blade. No special or unique techniques were required.
I attached a strip of Velcro to the front of the battery tray for my flight battery, and checked the heli’s balance to make sure that the CG was in the right place. The build went quickly, and one could get the heli ready to fly over the course of an evening—or two, if you agonized over wiring as I do..
The programming on my 14SG was basic. The GT5.2 takes care of nearly everything. I set up a little exponential on the cyclic, selected single-servo swash, and left everything else stock except the throttle curves that were set to activate the various head speeds through the Talon 90.
The E550 includes an enlarged blade holder, with a third slot cut for that extra blade. All three blades can be folded backward with a little care, so this heli is as easy to transport as any other. You don’t have to remove a single main blade. With the setup completed, I charged up my battery packs and prepared to head out to my flying club.
The first thing I noticed on spool up, was that this helicopter definitely had a different sound than the original 550—it seemed to have a little more bass to it. It popped right off the ground, and although the GT5.2 was set up well enough to fly, it required further tuning to get it where I like it.
I enlisted the help of Team Thunder Tiger pilot, Gary Wright (see his interview about flybarless gyros in the November 2014 issue of MA). Being the guru that he is, in 4 minutes, we had the heli dialed in!
Although the GT5.2 can be programmed through its unique touch pad interface, the optional USB dongle that allows you to plug into a PC makes programming easier. I made use of this and set the GT5.2 up through a laptop at the field.
My GT5.2 settings file is available for download on www.ModelAviation.com to help give you a starting point when trying to set it up. It’s worth noting that, as new firmware becomes available, you can update the gyro yourself using the USB dongle and software.
So, how does it fly? It flies like any other 3-D helicopter. The cyclic and collective both felt as responsive as a two-blade heli, but I initially kept bogging down the motor with hard collective inputs. I realized that when I ran my head speed at 1,800 instead of 2,000, I was no longer bogging the motor, but was still getting the same collective “pop” that a 3-D heli needs.
It felt as though fewer inputs were required during Tic-Tocks. In other words, I didn’t have to move the sticks quite as far to get the same effect. At first it seemed as though I was overcontrolling the maneuver, but after I reduced the amount of stick input I usually use, it locked back in. I thought that I might get better battery times with the lower head speed, but I didn’t notice a significant difference. The drag of the third blade might make up for any battery efficiency gained from running a lower head speed, but I’m merely speculating.
I ran a few short autorotations, and the model had slightly more hang time than normal. During autorotations, the collective felt touchier as the head speed wound down, but I think this was me overcontrolling the model.
The model felt good in the air and I think more flights will help me understand the differences between flying 3-D with a three-blade head versus a two-blade head. Not that I need an excuse to fly it more, the heli looks cool, sounds good, and with a few minor tweaks flies great!
To find out more about the characteristics between the two, I enlisted the help of Nick Maxwell who commented that the three-blade model provides extra stability and more control authority. The head speed can be run slower at around 1,950 versus the 2,300 that Nick uses with the two-blade head.
Nick also mentioned that the three-blade heli is slightly more efficient for sport flying and ought to provide slightly longer flight times, and pilots should see a benefit when flying in windier conditions.