Why do you compete?
by Mike Riggs [email protected]
Good luck and fair winds to all of this year’s Nats contestants. For those stuck at home like me, Jim Quinn will again be providing daily NatsNews updates this year. Someday I hope to make the trek to Muncie, Indiana.
Competition
Those who compete in RC Aerobatics (Pattern) are a rare breed. National Society of Radio Controlled Aerobatics (NSRCA) members number only a few hundred. Many understand our rarity. Some members, including me, ask why they compete at all. It certainly isn't for the prize money. Why then?
RC Aerobatics readers have corresponded that they are Pattern enthusiasts, but choose not to compete. Some fly Pattern airplanes; others do not. If you are a Pattern enthusiast, perhaps you can help me understand why I compete by telling me why you do not compete. Is it because of cost, commitment, travel, or is it that you simply don't want to? I would like to hear from you.
Help us all understand the other side of Pattern flying—the enthusiast who flies just for fun. I look forward to hearing from you, and feel free to share a picture or two of your favorite airplane.
Energy
Last year I sold my Honda EU2000i generator in favor of a deep-cycle battery. After selling our travel trailer, I couldn't justify the size and weight of the generator. Hondas have great resale value and I got almost what I paid for it through a Craigslist posting.
Deep-cycle batteries are great for everyday flying. They are small and compact, but lack capacity for dry camping during a contest weekend. After investigating many alternatives, I concluded contests are for flying, not setting up solar arrays, wind generators, or carrying more deep-cycle batteries.
A clever idea is to charge every LiPo at home, take them all to the contest, and use a battery charger with regenerative discharge to keep a deep-cycle battery topped off. Pretty 21st century if you ask me; watts are watts.
For convenience and independence, it's hard to beat a small generator and power supply. I purchased an 800-watt Honeywell generator for less than half the price of a Honda EU1000i, and my calculations show it should be more than enough to run an IOTA 55 power supply all weekend.
Different Kinds of Boxes
Switching from glow- to electric-powered airplanes has made me rethink field boxes several times. I'll never forget the looks on the faces of my children the night I threw my old fuel-soaked field box into a campfire. The kids roared as the flames grew tall, displaying magical colors.
Being a frugal person, my first charge box was a converted $15 plastic toolbox. Its biggest shortcoming was the externally mounted power socket and fan. When set up on the ground—as it often was at contests—the fan sucked in dirt and I never felt comfortable powering it up on dew-laden grass.
The next and current box was built from a CD case, with the fans and power socket mounted on top. When the top is latched shut, there are no external openings and dirt cannot get inside. The shortcoming of this box is insects. The box has two lighted fans (intake and exhaust) used to cool an internally mounted IOTA 55 power supply. With the aid of an IQ4 Smart Controller, the IOTA is often left in our dark garage charging a deep-cycle (field) battery. Guess what— insects are attracted to the light of the fans and get sucked into the box to their deaths. A charge box full of dead insects is not a pretty sight. The upside is an insect-free garage!
With the old field box up in smoke, I purchased another $15 toolbox to replace it. I like having a field box with a lid. It keeps dirt out and sun off the tools. The downside of this box is its size. Being big enough to carry 20-inch propellers or larger made it a lug to carry to and from the car. I later purchased a small toolbox for everyday tools. Now, the big toolbox stays in the car with "just-in-case" parts and equipment.
At this point I thought I had perfected my field box setup, until I attended a contest where quite a few yards separated the pits from the parking lot. Counting boxes—transmitter box, battery box (small), tool box, and charge box—represented two trips from the car to the pits. This didn't count a sun shade, lawn chair, ice chest, generator/deep-cycle battery, and most importantly, an airplane. Valet anybody?
One day it dawned on me that one of the best attributes of the old (glow) field box was that it contained my everyday tools and transmitter. A (on-sale) $25 Harbor Freight briefcase now carries my everyday tools and transmitter dirt free, thereby reducing the box count by one.
For a quick after-work practice session, I only need to take charged batteries, transmitter briefcase, and an airplane to the field. Only two trips to and from the car.
O.S. 1.60 Powerplant
More than a decade ago, Pattern enthusiasts began using the O.S. 1.60 as a Pattern engine. Their efforts were collectively quantified in 2006 by Jon Lowe in the O.S. 160 Cookbook. The cookbook, now dated, was the O.S. 1.60 de facto standard of its day.
During the same time the "Cookbook" approach was being developed, another distinctly different approach was being established called "Caveman." The goal of Caveman was to limit the number of components, thereby reducing the risk of failure. With help and encouragement from others, Art Wagner has, for the past 12 years, continued developing the Caveman approach. Art was kind enough to spend an afternoon talking with me about the Caveman setup that is in his beautifully executed, Mark Hunt–designed Pentathlon Evo.
Components of the Caveman include:
- O.S. 1.60 engine
- Merle Hyde soft engine mount
- Hatori header
- ES carbon pipe
- Tettra bubbleless tank
That's it—no pump, regulator, or other maintenance items. Cool Power Pro-Pattern 20% is the fuel of choice. Economical and simple! Working our way from the fuel source and out through the exhaust, let's take a closer look.
A 14-ounce Tettra bubbleless tank is mounted behind the firewall, with the neck of the fuel tank protruding through the firewall into the open center of a Merle Hyde soft engine mount. This arrangement minimizes the length of the fuel tubing. Art calculates that 14 ounces of fuel by volume weighs 13 ounces. During FAI competition, the Caveman consumes roughly 7 to 8 ounces of fuel, thereby minimizing the CG shift.
Art reports the CG shift of a firewall-mounted fuel tank is not the "big mountain" that people think it is. His Evo doesn't require any inflight trim adjustments, even during practice flights when the tank has been run nearly dry. A simple header-mounted pressure nipple provides tank pressure. Mounting the engine at a slight cant centers a wraparound Hatori header in the pipe tunnel. To compensate for engine right thrust, the tail of the header is cut at an angle parallel to the face of the center-mounted ES pipe.
The pipe length is not critical on the Caveman setup. The header-to-pipe gap is anywhere from 1/16 inch to 1/8 inch. Although expensive, Vitube has been the longest-lasting coupler material found to date. The edges of the NMP pipe clamps are smoothed to prevent abrasion and ensure the assembly's long life.
After breaking many headers, Art discovered exhaust waves cause longitudinal pipe movement leading to the headers breaking. He developed a mounting method to lock the pipe longitudinally. To accommodate future removal, a piece of carbon cloth is added to the pipe where the mount will contact it.
J-B Weld is then used to epoxy a Dave Brown pipe mount to the ES pipe. The resulting epoxy fillet locks the pipe to the mount longitudinally. The entire assembly is then attached to the airframe using a Lord mount.
Art was specific that if a power loss develops, it means there is a leak in the system. When properly set up, pilots can expect the Caveman to go many flights without maintenance. Art plans to build another Evo weighing less than 10 pounds and powered by an O.S. Caveman 1.40.
I wish Art the best of luck in his endeavor, and look forward to pictures of his Caveman 1.40.
Transcribed from original scans by AI. Minor OCR errors may remain.
