CL Navy Carrier
Dick Perry, 427 Live Oak Ln. NE, Albuquerque NM 87122; E-mail: [email protected]
IT'S THAT TIME of the year again.
Although you will be reading this in the heart of the summer flying season, I'm writing it at the end of the winter building opportunity and before the contest season really gets started. I haven't heard from any of you about your winter projects yet, and my own projects are flying only in my dreams, so I'm a little short of new items to report in this column.
I'm still debating on whether or not to stick to my "no-MO" pledge. I have plans for Vought XFSU-1 and Short Seamew models, but neither is beyond the paper stage at this point. I have to decide whether to accept the fact that the only models I am likely to finish are the partially completed MO-1s on the shelf or go for the new designs and fall back on my antiques in the likely event that I don't get the building time I need.
Those of you who attend the Nationals will know which course of action I finally decided on. I'm looking forward to seeing what new models the rest of you bring.
One thing is for certain: I expect to be flying a Nelson .36 in Profile this year, whatever the model. I've been enjoying flying one of Bill Melton's Nelsons this winter. The engine's high-speed capability is excellent, but the low-speed reliability has been disappointing.
I'm in the middle of a carburetor rework and will take a close look at the sealing of the carburetor body in the intake when it goes back together. This is the only engine I saw in Bill's stable that did not have the carburetor installed with epoxy, so there is at least the small possibility that an air leak has been affecting reliability.
Another possibility I'm looking into involves the Nelson glow plugs. The sudden engine stoppage with throttle movement is similar to symptoms of a plug with a melted element. In every case when I've checked the plug after a flameout, I've discovered a variety of element conditions, but the elements have usually been essentially complete, even if broken or deformed. However, there was a consistent trend of oil accumulation in the element hole.
I've compared the diameter of the element hole in the Nelson plugs to those of other plugs in my stock, and I've seen a pronounced difference. The Nelson hole is the smallest of the lot. The other plugs are at least 60% and as much as 125% larger than Nelson in cross-sectional area of the element hole.
I plan on a set of test-stand trials to see if the Nelson plug may be trapping oil around the element. If that is the case, the oil is, at best, shielding the element from the combustion mixture and, at worst, quenching the element and preventing ignition.
I have noted similar, but less severe or consistent, reliability problems with other Nelsons, but I had not paid enough attention to see it as a trend until I had one of my own. In no case was the issue as pronounced as the problems I have been having.
If any of you are having similar experiences, I'd like to hear from you. If you use a Nelson and have not encountered any difficulties, I'd like to know what you are using for fuel, plug, carburetor, etc.
I enjoyed a nice spin up to the Southwest Regionals in January. This was the 50th year of the event in Arizona, making it possibly the longest continuous fly-running contest in the country aside from the Nationals.
When I lived in the Phoenix area in the early 1970s, the contest was held on an old military airfield in Buckeye, Arizona. All the events were held at the same location on the same weekend. It was a grand time, and modelers came from quite a distance to compete. Carrier was well contested, and all three classes were offered. At least one Carrier model that were later published were flown at Buckeye just in the three years I attended.
Since then, the contest has separated into different venues and weekends for the various Radio Control, Free Flight, and Control Line (CL) disciplines.
The CL meet was run by Robin Sizemore, and the Cholla Choppers Model Airplane Club was the host. The facility is the city park, which includes facilities for three circles; two paved and one grass. The park also has a boat pond. It is a great place to fly, and it rivals Dayton, Ohio for a city-owned modeling facility. The Vintage Stunt Championships and the TopGunCombat meet are also held there each year.
The Carrier part of the contest has been reduced to only the Profile event. Only one New Mexico Carrier flier—Ted Knauer—attended, which was a disappointment. There are quite a few people still flying models in Arizona who were consecutive in Carrier. One of them, Nick Lemak, came out with a new Grumman Guardian. The other contesters were from California (Eric Conley) and New Mexico (me).
Nick's Guardian used a Thunder Tiger .35 engine, which is now officially legal since the displacement limits were increased to 0.3661 cubic inch (6.0 cubic centimeters). Nick used a two-braced throttle arrangement of his own design.
Eric Conley (Clovis CA) brought his new Supermarine Spitfire design. It is similar in features to the Messerschmitt Bf109 I described in a previous column, but it's even better looking with its distinctive elliptical wing. He uses a Nelson based on the Quickie .50 Pylon Racing case. With a round intake, it is easier to accommodate a throttle in the intake than in the .36 Combustion with its square intake.
Eric uses left-hand rotation and an APC 9 x 6 propeller. The engine is equipped with a large SuperTigre carburetor. His top speed was 93.1 mph, and he achieved a low speed of more than 27 seconds—even with some confusion on timing and signals, which resulted in a couple of fast-than-usual heats.
That's it for now. Good luck on the contest circuit this year. RAN
Transcribed from original scans by AI. Minor OCR errors may remain.
