dkshema
rrMaster
Location: Cedar Rapids, IA
My Posts This: Topic Forum | Added more pictures to the gallery. Some side-by-side comparisons with a T-Rex 450X-V2.
As for the kit, it is nearly an RTF heli, not an ARF. About all that is left for the buyer to do is install the electronics, paint and assemble the canopy, and bolt on the rotor blades.
I've read a lot about slop in the head stuff. I'll find out more about this in the next few days, but right now, with no electronics in it, the head controls seem to be quite slop-free. Some have reported that the balls on the swash don't quite fit the plastic links -- the plastic links are "too big". They do move a tiny bit if you tug on them, but the are firmly held on the ball, and at least at this point, don't appear to contribute any real slop to the control system.
I've also read about slop in the washout and pitch slider mechanism. Again, at this point, everything is ship-shape and I don't notice any play in the mechanism.
Slop, if any, will show up as I get the servos installed, and afterwards, as I get some air-time on the mechanics.
I am, at this point of the build, impressed at how free the entire MR control system is when compared to the two T-Rex helis I own. I am also impressed with the obvious quality of parts in this kit as compared to that of the Align kits. The plastic is much better grade, parts fit is standard Kyosho quality
The main rotor gear train is unique. The motor pinion drives a molded gear that contains a 20-tooth pinion, and a larger 67 tooth spur gear. The motor's pinion gear meshes with the 67-tooth spur. When the 67-tooth spur turns, the 20-tooth pinion molded below meshes with a 105-tooth spur that contains the one-way clutch, and that drives the MR shaft.
The 20-tooth to 105-tooth gear set provides a fixed reduction ratio of 5.25:1. The number of teeth on the motor pinion (which can vary from 16 to 50 teeth -based upon a search for 64 pitch pinions with an 1/8 inch bore), coupled with the 67-tooth spur gives the builder an easy method to vary the overall gear reduction.
With a 20-tooth pinion driving the 67-tooth spur, there is an intermediate reduction ratio of 3.35:1. The 3.35:1 ratio coupled with the fixed 5.25:1 reduction yields an out-of-the-box overall reduction ratio of 17.58:1.
Poking around on the Tower Hobbies website, looking for 64 pitch pinions with an 1/8th inch bore shows that you can pick up pinions in one-tooth increments from 16 to 50 teeth. This means the EP 400 can be run with an overall reduction ratio in the range of 7.035: 1 up to 22:1. Seems that with this kind of versatility, we ought to be able to find a motor/pinion combo that works well in the EP.
The main rotor hub looks to be a miniaturized copy of the Caliber 30 head. The kit ships with some alternate parts to allow the damping in the head to be altered easily. The dampers are O-rings ala the T-Rex, but the O-rings are much larger and more robust than those in the T-Rex.
The MR grips look like modified TR grips from a Caliber 30. The TR pitch slider looks to be much more precise and slop free than the original T-Rex sliders. The entire TR assembly and control system seems to be executed much better than the plastic T-Rex equivalents.
The drive system for the TR belt is very robust compared to the T-Rex.
The kit main frames are milled from 1mm thick Carbon Fiber. I haven't installed any of the electronics (UPS says they arrive tomorrow) but there appears to be plenty of room for the various goodies. I'll post pics on the radio installation when that part of the build is finished.
The canopy is a two-piece affair, consisting of clear top and bottom halves. These can be masked and painted from the inside, harking back to the old Schluter Heliboy / Superior / HeliStar/ Miniboy /Champion...days. The halves are held together by stickers (tape) instead of glue. Wonder how that will hold up? I haven't looked closely at the plastic to see what it might be made from, or how paintable it is.
The main rotor blades look functional. As can be seen in some of the photos I posted in my gallery, the blades are wood, covered with a clear heat shrink material. The blades lack a plastic root reinforcement. The T-Rex started out this way, but Align has gravitated to making wood blades with a plastic root reinforcement. A small brass bushing fits into the hole in the blade root, and it is through this bushing that the MR blade bolts go. The MR blade bolts thread into the lower part of the MR grip. I guess this is functional. Time will tell.
With regard to the MR blades, I'd prefer a good, solid MR blade root reinforcement over the simple brass bushing with these wood blades. I'd also prefer that the MR blade bolt thread into a small hex lock nut as the T-Rex and most other helis these days do. Kyosho should add the reinforcement plates as this would not only improve the strength of the root, but would also improve the fit of the blades in the MR grips. I believe there are some CF blades in the works. It may be possible to put some Mavrikk 305 mm CF blades on the EP, but at this point I don't know if the added length (about 20 mm per blade) would cause problems with smacking the TR blades.
Main rotor collective pitch is accomplished by using a sliding rod that moves in a milled out slot in the main rotor shaft. This reminds me of the way the older Schluter helis achieved collective control. It worked quite well for them, I expect it to be trouble free here, as well.
Someone complained about the plastic swash and the plastic uniball that the swash swivels on. The swash doesn't look all that bad, and the ball appears to be either a nylon or a delrin type material. I would expect this to actually be a trouble-free system and fairly rugged. Time again, will tell.
A close look at pics of the head and TR reveals that Kyosho has had the Z-bend machine working overtime. Since the kit is new and has NO time on it, I am somewhat impressed at how tight the control system is -- I would have expected a lot of slop from the Z-bends. Perhaps time will tell how well this works out. Kyosho should rethink the Z-bend thing and find a way to get some decent ball links into the head and the TR system. This would make for much more satisfied customers in the long-run.
The motor mouting method and accessibility of the mount screws is by far much better than the T-Rex. The screws for the motor are readily available without having to fish around through the pitch mechanism as in the T-Rex. This should make motor experimentation a breeze, as it is easy to swap out motors. The motor mount itself has slotted holes to allow for a wide range of pinion diameters. And the slots for the motor mount screws actually line up with the mounting holes on the motors, they don't have to be hogged out as in the T-Rex motor mount.
Size-wise, if you look at the pics in my gallery, the EP400 is nearly identical to the T-Rex. Side-by-side comparison shows that the overall length, width and height are comparable. I haven't measured the rotor diameter, the TR diameter, or the flybar diameter, they look to be very close. Weight comparisons can't be made until I get the electronics installed.
Well, time to wind this down for now. More to come as I install some Hitec HS 56 servos, an Electron 6 RX, a GY401 gyro, and a Castle Creations Phoenix 35 ESC.
I think I'll toss a coin to see which motor to try first. The Align 430L/3550 or the JGF 450TH.
Flight tests may be delayed a bit due to the crappy Iowa winter weather. Nothing like wet heavy snow in the morning followed by drizzle in the mid-afternoon. I guess it beats the six or so inches of light, fluffy snow of last week, simply because it's not below zero in the morning!
Dave |
