Graupner Augusta A-119 Koala

RC Heli Pilot Staff January 10, 2011 Flight Reports

As the Police Chief and Mayor of the City of Lone Tree, CO, eyed my helicopter in the parking lot of the city hall, my mind whirled with possibilities: I imagined showing off the impressive turbine model at civic events, police press events and the D.A.R.E. visits that the police officers make to schools. The chief asked if I would send him a photograph of the helicopter in flight. I proudly emailed one that day, but the mayor informed me that the city could not risk being associated with the model in case of the unlikely event that somebody got hurt, a fire started, or something else untoward happened during a flight or demonstration. Oh, well; at least the chief had a picture.

That was three weeks ago. This morning, I got pulled over for speeding in a school zone. I had just dropped my daughter off as I do every day, but I didn’t head straight to the office as usual. Instead, I went to the dry cleaners, and on the way back, I just spaced out and got nailed by the radar officer I usually wave to when I pull into the school parking lot. After walking my license back to his squad car, the officer returned to my window. That’s when I proudly mentioned to the officer that I owned a jet-powered Lone Tree Police model helicopter. Oh, the one in the picture in the chief’s office, he responded. I couldn’t believe he knew about it! Yeah, that’s a cool looking bird, he offered earnestly. I was stunned that he not only knew about my helicopter but he liked it, too. Hope for leniency swelled in my heart. He went on; So, you can reduce your fine by paying it within 20 days, or you can contest it in court. He handed me a crisp blue citation for $200 and four points on my license and told me to have a nice day. Ker-plunk. Oh well, I guess that trick only works in Muncie, IN. What’s great about the story is that the chief of police has a picture of my model posted

in his office. That’s just plain cool. It is not only cool for me, but more important, it is cool for the hobby. We are so used to having so much great technology in our aircraft that we often forget how impressive it is to people outside our hobby. My Graupner Agusta A-119 is one of those impressive models, and others think it is too. In case you think I am too impressed with my own models, I should tell you that I did not build it. I didn’t paint it either. Sure, I finished the cockpit (after taking these photos), re-plumbed the tanks and fiddled with the wiring, but I paid an expert to build it for me (more on him later). I’m writing about it because it’s an entertaining model, and more important, because I believe that some in our hobby would rather do without a scale model than have someone else build it for them. Whether they’d be embarrassed or would feel guilty about not building their own model, these people are missing out. I have had some of my most enjoyable flights in 35 years with this helicopter. Before I share those thoughts, however, I will give you the lowdown on the Agusta. The A-119 Koala is made by Graupner, and mine has a smattering of Various parts.

1. Receiver Satellite Antenna
2. Propane Fuel Line
3. Onboard Propane
4. Light Board
5. Propane Fill Valve
6. Temp & RPM Sensor
7. UAT Header Tank
8. Reduction gears
9. JetCat Turbine
10. Left main tank
11. Glow Plug
12. 3-Axis Gyro

I purchased the model from V-Eastonline.com. I hired Joe Howard of East Coast Scale Helicopters to build and finish it. The model is powered by a JetCat HP5 propane-start turbine, which ships with a single-stage engine and integrated helicopter mechanics. I use JR digital servos, a JR receiver and a 2.4GHz JR 9303 transmitter. For stabilization, I use the HeliCommand RIGID for pitch and roll axes and a Futaba 401GY gyro for tail control. Even though the HeliCommand has an integrated tail gyro, a strong argument can be made for having a separate tail gyro in case the HeliCommand ever fails. It isn’t impossible to fly a scalehead ship without two-axis control, but it’s nearly impossible to fly without tail control. The model comes with a 10mm main shaft, but we opted for a more reliable 12mm shaft and the Vario head, which uses dual bolts on each blade of the 4-blade head. The main rotor blades are 825mm long, and the tail rotor has 140mm blades. From the factory, the model comes with a wire tail drive. I opted for a more robust torque tube. The wire drive is not necessarily unfit for a turbine model simply because it is less hearty than a torque tube.

Wire drives are stressed when rapid changes in head speed cause it to twist with rapid changes in throttle. With a turbine, you should fly at a constant head speed so that this type of torque stress should not occur. Nonetheless, both Joe and I felt that a torque tube would eliminate any question about the reliability of the tail drive. Installing a torque tube and transmission required more work, but I’m glad we did it. The model comes with two 1.25-liter saddle tanks, and that’s how Joe built it. After speaking with a few pilots, however, I quickly learned about the division between those who believe a header tank is absolutely necessary and those who believe you can do without it in a scale aircraft that will be flown in a scale manner.

My friend Eric Balay, an autonomous helicopter designer, engineer and test pilot, was adamant that I install some type of header tank or the BVM Ultimate Air Trap (UAT). Eric told of numerous bench tests in which a single micro-bubble caused his turbine to flame out. On the other hand, there were those who insisted that unless I did violent maneuvers, I did not need the tank. I weighed the options and determined that $65 for the UAT was a very small price to pay to ensure that a $10,000 model did not suffer a midflight engine flame-out. I created a small wooden ramp and installed the UAT just aft of the cockpit firewall. The ramp allows the tank to rest at the optimal angle to ensure a minimum of trapped air.

I removed all of the tubing and replumbed the system to ensure that equal lengths of tubing ran from each main tank to a T-connector, which itself ran directly to the UAT. Having to re-plumb the fuel system gave me a hands-on lesson in turbine fuel flow. Having the UAT provides a cushion of safety in case I run the main tanks dry (which I try not to do as a practice). When it was time to finish the model, I was prepared to have Joe apply an NYPD helicopter paint scheme. But the Graupner A-119 model has the turbine exhaust protruding from the right side of the fuselage. This would have cut a nearly 3-inch hole in the NYPD insignia, so Joe asked me to come up with another scheme. After looking online at literally thousands of helicopter paint schemes, I decided to borrow the basic color lines of the NRMA Graupner used on its promotional model and to replace the colors and markings with those of our local police department. As you can tell from the pictures, the black paint on the rear is very effective in camouflaging the exhaust. From a performance perspective, the exhaust minimizes the ductwork needed in the ship. This makes the turbine more efficient, so from that perspective, its location is good. It also provides lateral thrust that allows the helicopter to hover nearly level. The exhaust is also conveniently placed for cooking hot dogs and roasting marshmallows.
BUILD OR BUY?
My foray into RC hobbies began in 1973the year that Clint Eastwood starred in the movie Magnum Force. Fittingly, Harry Callahan, Eastwood’s character, cautioned that A man’s got to know his limitations. I can now say that I have come to grips with my limitations in the rarified world of scale helicopters. I know that I cannot and will never attempt to paint a helicopter. My advances in the art of painting shook to a grinding halt at age 16 with a Testors rattle can. Yes, it is still painful to contemplate, but with therapy, I’ve worked through it. I also hate sanding fiberglass. Why admit all this? Well, I think lots of scale helicopter enthusiasts would like a new helicopter but are afraid to spend thousands of dollars only to end up with a mediocrelooking model that garners hushed comments at the flying field. You know what I’m talking about. Can you believe he turned seven grand into that piece of ? I did not want to be one of those guys! I have been flying helicopters since 2003 and have built a dozen pod-and-booms, a scale Century helicopter and two Hirobo scale shipsthe Super Cobra and the CH-46 tandem. I have also purchased and flown completed scale models from Graupner and Vario. But up until my police helicopter, I had never owned a turbine-powered aircraft or ever designed my own finishing scheme. So when I wanted to juice up my hangar, it was easy for me to accept my shortcomings and call in the expert Joe Howard. The project began in February 2009, and I took delivery of the ship on the last day of July 2009. I corresponded with Joe throughout the project and learned a great deal in the process. When the heli was complete, I traveled to Joe’s shop in Franklin, MA, and spent the day learning and videotaping everything I would need to know to properly operate the turbine system. He took me out to his flying field, and I ran through the safety and startup procedures. I couldn’t be more pleased with the outcome. My helicopter looks great, sounds awesome and flies beautifully. But am I missing the pride that comes with building? Sure, I wish I could say I built it, but on balance, I would definitely do this again. Since I got theI finished the cockpit, which I had Joe leave in its basic form. Besides, if I own it long enough and make enough modifications, I am positive that I will completely forget that Joe built it in the first place!
NO SUBSTITUTE FOR KNOWLEDGE
Purists may disagree, but I think that people can participate thoroughly in and enjoy scale RC helicopters without being accomplished builders or finishers. This is especially true of those who lack the skills needed to create a work of art. If someone does build your scale ship, you must still understand exactly how it functions. Once it’s out of the builder’s hands, the responsibility for maintenance and safe operation lies with the owner. I always fully study and understand how my helicopters work. I have also completely rebuilt the mechanics on scale ships I have bought. There is no substitute for this, and learning how your helicopter and its powerplant and electronics function provides much of the fun and learning that comes with our hobby. I have read the JetCat manual cover to cover at least five times and have referred to parts of it many more times. I have pored over the HeliCommand documentation and spent hours on line reading about its functions and subtleties. I have also consulted many friends who are experts in the hobby; without guys like Joe Howard, Tom Toledo and Eric Balay, my learning would have taken far longer.

ARMED READY TO FLY
Armed with more information than I could handle, I took to the sky with my A-119. Without a doubt, the Lone Tree Police chopper casts an impressive shadow at my field. Scale helicopters are rare there, and turbinepowered helicopters appear with the same regularity as unicorns. My friend Tom Toledo accompanied me on my first flight. He chuckled as I reviewed the preflight checklist I had taped inside the removable left door. Boy, was I nervous!so much so that I decided to have Tom take it up first and trim it for me. That’s how much I trust this guy. Having trimmed it, he handed me the radio, and I lifted the ship into a hover. Powerful and responsive, the helicopter moved in a line that was perpendicular to my line of sight. After 6 minutes, I landed to wipe the sweat off my forehead and hands! Even though I’ve owned several scale ships of this size, the sound and power of the turbine produces an involuntary clenching of the buttock-al region. On my second flight a few days later, my friend Eric Balay assisted me. Both he and Tom encouraged me to fly as conservatively as I wanted to for as long as I needed to get comfortable. Within a few more flights, I was moving the ship around with much greater comfort and ease. The last flight I took, however, was not comfortable. During six flights on four days, I had adjusted the trims significantly enough to cause the HeliCommand some confusion on takeoff. After eating some grass with the tail rotor, I landed the turbine and shut it down for the day. I took it home and quickly learned that by pressing the set button on the HeliCommand, I could cause it to relearn the trim settings and regain the stability I had in all the previous flights. Since making that adjustment, I haven’t had any problems with the HeliCommand. The model flies very smoothly, there’s no shortage of power. With the added sound, smell and smoothness of turbine power, the A-119 has quickly become my all-time favorite helicopter. As I do with any new helicopter, I plan to push the edges of the envelope slowly. I am in no rush to whip this machine around the sky, so I gradually add maneuvers to each flight. Frankly, I would enjoy just hovering the A-119.

LESSONS LEARNED
I truly enjoy my Agusta A-119. I will wax poetic about it when any person makes mere mention of a helicopter. Words uttered out of context such as skid, tail, or rotate will cause me to launch into riveting prose that may continue long after people have walked away shaking their heads. I jest of course, but I am enjoying to the fullest a model that someone else created for me. I hope other modelers who are so inclined will take the leap and tap into the vast building and finishing talent that permeates our hobby. If you do take the plunge, stay involved in the process, and contribute your ideas and visions to the builder. When you take delivery, make sure that you understand every inch of the ship. Read and go slowly. When you do, you’ll find great enjoyment in the process and take great pride in your model, even though it probably won’t get you out of a speeding ticket. Michael Kravitz is CEO of RCUniverse.com.

Links
Bob Violett Models
www.bvmjets.com
(407) 327-6333

East Coast Scale Helicopters (Helicommand RIGID)
www.eastcoastvario.com
(508) 520-1140

JetCat USA
www.jetcatusa.com
(805) 226-8700

JR, distributed exclusively by Horizon Hobby Distributors
www.jrradios.com
(877) 504-0233

Graupner Helicopters USA
www.v-eastonline.com
(941) 925-9653