JR Venture CP ARF

Model Airplane News, Nov 2002 by Boyd, Matt, Bell, Rick

A high-tech, low-cost heli trainer

OK, I'll admit it: when this project started, I knew precious little about RC helicopters. Sure, I knew about the basic layout and the parts required, and I understood the basic physics involved. I'd seen helis flown by others, and I'd even spent several hours on the new Ikarus Aerofly RC flight simulator trying to get an idea of heli flight characteristics. But to say that I know how they fly based on that is like saying I know what a hamburger tastes like because I've seen a McDonald's commercial.

The JR Venture CP was the ideal choice for my first taste of RC helicoptering. It is almost ready to fly (ARF), so the major assembly has already been completed for you. Model Airplane News associate editor, resident heli guru and my flight instructor for this enterprise, Rick Bell, assures me that it is among the easiest to assemble glow-powered helis on the market. It is .30-size, so it is big enough to be stable but not so big that it is difficult to build or transport. It is also remarkably affordable, considering its level of quality and completeness. So, with the proper equipment, it was time to see whether I could master the art of helicopter flight.

WHAT YOU GET

Pop open the box, and the Venture already looks like a helicopter! This is both gratifying and a little misleading. It is an ARF, so the major components come bolted together; but there are still a few hours' worth of minor assembly and adjustments to complete. The main rotor head has been assembled and installed in the chassis, as has the drive train. The landing gear is already mounted, as are the flybar and the fuel tank. The tail rotor assembly is also built, and though you must connect the tail boom to the chassis (it wouldn't have fit in the box otherwise), this is quite easy to do. The manual contains detailed instructions, diagrams and photos that will walk you through the assembly.

The rotor head is especially impressive because it features 120-degree cyclic/collective/pitch mixing (CCPM). In a nutshell, this allows each of the rotor head's three directional movements to be actuated by multiple servos instead of by just one. There are two advantages to this; first is a much simplified linkage system. Second, because there are fewer joints and bends in the linkage, and because each motion is driven by the strength of more than one servo, CCPM produces more precise control movements. This is a really nice feature for a relatively inexpensive heli, and it gives the Venture a lot of performance hop-up potential down the line (see Rick Bell's sidebar "Upgrading the Venture").

The manual also lists the items you'll need to complete the Venture; these include a .32 to .38ci heli engine with muffler, a 6-channel radio with 120-- degree CCPM function, five servos and a gyro. Also required is a host of basic assembly and field equipment that most modelers already have, along with a few heli-specific items (e.g., a blade balancer, a pitch gauge, etc.) that you probably don't have unless you're already a heli owner.

ASSEMBLY

Assembling the Venture is fairly easy, though it is time-consuming-especially if, like me, this is your first heli. Quite a bit of fine-tuning is necessary; proper centering, alignment and travel of all of a helicopter's moving parts are essential-- much more so than in any other sort of RC vehicle. With an airplane (especially a trainer type) you can get away with "close enough" on some things; but with a heli, everything has to be dead-on, or the aircraft can become extremely difficult to control.

Start with the tail boom; attach it with four bolts and two setscrews after you've made sure that you have the proper belt tension. Too loose, and it may pop off the drive gear; too tight, and it may cause binding and wear. Next, bolt on your tail fins and tail control-rod guides. The guides are clamped onto the tail boom and the round bushings on the rod itself. You'll need to move the guides back and forth and around the boom to get the rod to slide smoothly. At Rick's suggestion, I put a shallow Z-bend in the rod between the third guide and the chassis; this greatly reduced tension on the rod.

Next is the engine. I opted for the recommended Webra Speed .35 Heli engine. It was broken in on the bench and then installed with the included engine mount. The engine is oriented so the head points aft, and this makes the glow plug fairly easy to access through the rear of the chassis. Attaching the cooling fan and clutch assemblies is pretty straightforward and well documented, but the orientation of the engine mount can be tough to determine from the diagram; be sure to note the addendum to the manual inside the front cover. Now it's time to bolt on the muffler; I used the stock JR .32 to .36 muffler. The chassis's bottom rail partially obscures the lower mounting-bolt location, so it takes a bit of wrestling to get it on. Then, connect your fuel and pressure lines, and you're ready for the radio gear.

Radio gear. You'll need five servos, all of which are installed using the supplied self-- tapping 12mm screws and washers. The screws are threaded into soft-plastic mounting tabs on the chassis. Rick used longer screws to attach his servos, and I plan to do so as well, as an added safety measure.