Comparing the Raven 50, the Kinetic 50 & the Hawk Pro
Phil Noel (copyright)
The Kinetic 50 has the same rotor head as the Hawk Pro, but uses a 6mm feathering spindle system instead of the 5mm spindle system of the Hawk Pro. The Kinetic 50 also features thrust bearings in the blade grips to absorb the higher thrust loading of the heavier 600mm blades.
Both come with wood mainblades, the Kinetic 50 uses 600mm blades and the Hawk Pro uses 550mm units.
The Kinetic 50 uses a 4mm flybar instead of the 3mm unit from the Hawk Pro, but it uses the same type of separate flybar control arms and the same type of flybar paddles as the Hawk Pro.
The Raven 50 has rotor head that is a smaller version of the larger 90 sized Predator Max from Century, but with a 6mm spindle and thrust bearings instead of a 7mm system.. It features a CNC machined head block with a clamping system at the base of the hub, and the same 4mm flybar control yoke system and paddles as the Predator – this represents a significant performance and value difference over the rotor head of the Hawk Pro or Kinetic 50 rotor head,
The Raven 50 comes with 600mm F/G & C/F composite mainblades. These represent another significant performance and value difference.
The washout guide system on the Raven 50 is also different. It is a separate CNC machined unit, that is seperated from the hub. This allows it to be rotated in order to fine tune the phasing of the rotor head, in order to optimize the flight characteristics of the rotor blades one may choose to use.
Washout and Seesaw System
All three use a similar seesaw system that has ball bearings supporting both the seesaw and the flybar.
All three use the same washout system that features oilite sliders between the hub and the mainshaft, and each washout arm is supported by two radial bearings.
The Hawk Pro and the Kinetic 50 both use the same swashplate that features a machined aluminum inner star, and a molded GRP (Glass fiber Reinforced Plastic) outer star.
The Raven 50, on the other hand, uses the same superb, all aluminum, dual bearing CNC machined swashplate found on the larger 90 sized Predator MAX. This expensive type of swashplate is generally only found in the elite class of 90 size nitro and gas powered helicopters, not on sport priced 50 sized helicopters!
The Hawk Pro and Kinetic 50 both have the same mechanical collective/cyclic pitch mixing control system (mCCPM). For maximimum precision and to insure long term smooth operation, it uses dual ball bearing supported control arms and bellcranks.
The Raven 50 uses a direct-to-swashplate electronic mixing eCCPM system that offers the same long term precision and smooth operation, but is much simpler (as it incorporates mauch fewer parts), is much lighter, and has less collective-to-cyclic interactions at extreme collective/cyclic 3D settings.
Tail Drive System
The Kinetic 50 and Hawk Pro both use the same efficient aluminum torque tube tail rotor drive system that has the advantage of a dog-bone type of universal joint coupler system at the front. This reatains all the advantages of a torque tube drive system over a belt drive system, or the wire-in-tube shaft drive system, but further minimizes possible damage in a mishap.
Of course, to accomodate the extra length of the 600mm blades needed to properly harness the power of the 50 size engines, the tail boom and the drive shaft of the Kinetic 50 is longer then that of the Hawk Pro.
The Raven 50 uses the same stainless steel torque tube drive system as the larger Predator Max, only the tube itself is shorter then the one from the Predator. Of course, the tail boom is also longer then that of the Hawk Pro. This system has the added rigidity of the stainless steel tube, with even more crash resistance, as it has a two dog-bone type of universal joint coupler system...one at the front and one at the back. These are both significant improvements on that of the Hawk Pro and Kinetic 50.
Tail Rotor System
The Hawk Pro and Kinetic 50 use the same tail rotor system. It uses 3mm hex bolts that not only attach the blade grips to each end of the machined aluminum hub, but also become their feathering shafts. This is a rather common system found on many 30 & 50 sized helis.
The Raven 50 on the other hand, uses the same heavy duty, precision tail rotor found on the Predator Max. This tail rotor uses a CNC machined steel hub that incorporates the spindles into the machining of the hub itself, with threads machined onto the ends.
Just like mainblade grips, each tail blade grip in the Raven 50 is supported by two radial bearings to keep the precision of all tail rotor blade pitch changes and also a thrust bearing to take any of the centrifugal loads. The grip assembly is secured to the rotor hub by locknuts screwed to the threads machined into the ends of the hub spindles.
This relatively expensive type of tail rotor is generally only found on very high end 90 size helicopters, not on 50 size birds. Again, this is a very significant difference to the one in the Kinetic 50 or most any other 50 or 90.
Mainframe & Canopy
The Hawk Pro, Kinetic 50 and Raven 50 all use the same tough, crash resistant GRP upper mainframe and the same aluminum lower mainframes.
TheHawk Pro and Kinetic 50 also both use the same front servo/radio frame set, but the Raven has a different servo frame system and radio tray, due to the different control system that it uses.
The Kinetic 50 and Raven 50 both use the same wide stance, heavy duty landing gear system. The Hawk Pro uses a taller, lighter and more narrow landing gear.
All three use the same canopy that is made of the common, relatively crash resistant "milk jug" plastic found in most R/C helicopters today. This canopy also features a separate, see-through windshield, which allows one to easily check the radio gear, without having to remove the canopy.
All three use the same efficient two-stage power system that is super simple to assemble. This type of system does not require any critical alignment of gears or other components (e.g. clutch to clutch bell) or dial indicating of shafts etc. in order to eliminate any run-out.
All major drive components (clutch, clutch bell, clutch bell support bearings & cooling fan) fit directly onto the same shaft – the crankshaft of the engine. Consequently, they all align perfectly with each other and do not require dial indicating to remain true to each other. As these heavy components are all also situated directly in front of front bearing of the engine, any possible minute misalignment will have a very short moment arm to work through. This means that any vibration modes that may be in existence, would be many times less powerful then they would be in a single stage system, where they are located far forward of the front engine bearing.
Another advantage of this type of system is that the clutch bell support bearings only turn when the engine is at idle. As soon as the clutch engages the bell, these bearings no longer have to turn. Consequently, they seem to last forever. This is another big advantage over single stage drive systems.
The Hawk Pro and Kinetic 50 use a molded GRP clutch bell, the Raven 50 on the other hand, uses one that is CNC machined from aluminum. This bell also features a pinion gear that can be changed for different ratios if one wants to experiment with another that is avaliable.
The Hawk Pro uses a 13T primary pinion that results in a 9.76 ratio that is best for the 32 to 40 size engines it is designed to work with. The Kinetic 50 uses a 14T primary pinion for a 9.0 gear ratio that is better suited for the 46/50 size engines.
Both the Hawk Pro and the Kinetic 50 use a standard auto-rotation system that does not drive the tail rotor during an autorotation. This conserves energy in the head, but does not allow backwards, inverted or 3D aerobatic autos to be performed.
The Raven 50 uses a driven tail auto-rotation system, so it can fly backwards, inverted and do 3D maneuvers on its’ way down during an auto-rotation.
The Raven 50 also uses a different primary drive gear (grey) that results in a lower gear ratio of 8.76. This means it will get a higher head speed for the same engine speed.
All three use the same spring loaded, hex start system that disengages the internal start shaft and hex coupler completely, after the engine starts. The big advantage here, is that the internal start shaft stops turning after the engine starts, so the bearings that support it also seem to last forever.
As you can see, there are some differences between the Hawk Pro and the Kinetic 50 that render one a 30 size machine and the other a 50 size version of the other. Of note, is that one can purchase the different parts from one to convert to the other, for a relatively small sum.
But there are many more significant differences between the Kinetic 50 and Raven 50, even though they are both 50 size machines. That is why many people consider the Raven 50 more like a smaller version of the Predator Max, rather then a bigger version of the Hawk Pro.
Here also, one can purchase seperately, the many different parts or systems used in the Raven 50 to convert the Kinetic 50. But here unfortunately, the cost would be substantally more then that of the difference between the initial cost difference of the two. So if one wants to go into a top class of 50 heli from the beginning, he would be much better served by going into the Raven 50 right from the start, rather then getting the Kinetic 50 and upgrading it later.