Bonkers
Senior Heliman
Location: New York
My Posts This: Topic Forum | I own a couple of 3D-NTs. I have yet to fly them. (Just haven't gotten around to getting them up in the air).
The build is definitely different. Jan Henseleit clearly designed the heli from scratch rather than copying what others had done.
While the design is a simple, I will say that it is a royal pain in the ass to build and (presumably) maintain. Clearly, Jan Henseleit did not have ease of maintenance in mind when he designed the heli. Practically nothing on the heli is "modular" (i.e. where you can remove it without having to disassemble a lot of things around it). Everything is intimately assembled ontop of the things assembled before it. This makes for a very pretty, light, and efficient machine, but also produces a product that is difficult to maintain. Allow me to explain. Take a look at this photo for reference:
http://www.runryder.com/helicopter/.../3/DSC00223.jpg
Let us say you need to replace the flybar. You cannot simply unscrew the collars that hold the flybar in place and slide the flybar out the way you can in virtually every other heli. You have to remove the entire damn rotor head from the main shaft!! Why? Because the pitch inputs to the flybar (from the swash plate) are delivered to the flybar at its centerpoint inside the rotor head via a ring that has two pillow balls attached to it at 3 o'clock and 9 o'clock. The grub screw holding this ring tight against the flybar is tightnened against the underside of the flybar. There is no way to access this grub screw without removing the whole rotor head. On every other heli produced by Japanese and American companies, flybar pitch inputs are delivered by L-shaped arms that are fastened to the flybar outside of the collars that hold the flybar in place, and thus, are easily accessed.
Or, let us say that you need to replace a fuel line from the carburetor to the fuel tank. Sounds like an easy task, right? Not on the 3D-NT. The nipples for the fuel line on the fuel tank are inaccessible to your fingers. They are sunken deep into the chassis where you cannot reach them readily with your fingers. You can pull the fuel line out easily, but there's no way to push it all the way onto the ribbed nipples. To replace the fuel line, you have to remove the fuel tank. But, the fuel tank is boxed-in by the engine in front of it, the landing gear mounts below it, the main gear and servos above it, and the main shaft behind it. There is no way to remove the tank without removing one of those obstructions. Which is the easiest to remove? I went with the engine. Although I was tempted to use a hemostat to put the new fuel line onto the nipple, I didn't want to worry about having a damaged fuel line on the heli.
Anyway, the heli is a really nice one. But if you fly it and crash it, I'd imagine you are going to spend a hell of a lot of time just on the disassembly and re-assembly process to get it back up in the air.
Still though, I do intend on flying them....eventually. |
thanks Geoff
