Control Line Navy Carrier
Dick Perry [[email protected]]
Line options for Profile Carrier
One of the rules-change proposals this year was to allow the use of two-line control systems in Profile Carrier. As it turns out, the proposal was redundant.
Although the current Competition Regulations rule book, and the previous Navy Carrier rules, specify three-line control systems for Profile Navy Carrier, the 1999–2001 rules correctly included specifications for all three control-system configurations in all three events. Nobody knows what happened during the printing of the rule book in 2002, but it has been wrong for two cycles.
During the rules-change cycle that became effective in 1999, Fred Cronenwett of Washington proposed allowing monoline and two-line control systems in Profile Navy Carrier. His proposal passed. In subsequent rules-change cycles, there were no proposals to return to the three-line-only rules that existed before 1999.
Check the AMA web site at www.modelaircraft.org/comp/competition.htm for the official notification. As this is being written the correction has not yet been published, but it should be available before this column appears.
The current policy of having the official version of the Competition Regulations published on the AMA web site allows for updates to the rules much more efficiently than in the past, when emergency actions or error corrections required printed changes. Fred’s reason for submitting the proposal was to accommodate the electronic control systems that have become extremely reliable. The electronic control systems used for throttle and other auxiliary functions on CL models have been described in earlier Navy Carrier columns.
The specifications for two-line control systems for Profile are identical to those for Class I; i.e., .020‑inch‑diameter lines. As speed modelers learned decades ago, smaller lines produce higher speeds with all other factors being equal. The difference can be significant because line drag is a major contributor to total drag. The effect in Speed is more pronounced than in our event because of the lower drag of the model alone.
To ensure that the control signal isn’t short-circuited by the control lines touching one another, the lines must be insulated. The additional diameter required for the insulation negates the advantage of the two-line system for Carrier compared to the three-line system. Modelers who want to use a two-line system with mechanical elevator control and electronic throttle control generally do so for the ease of adjustment and installation rather than for performance potential.
The lightest systems are single-channel types used for electronic throttle control. Since the actuating force needed for a throttle is low, the newer ultraminiature servos can be used to save weight for a throttle-only system. Systems with more channels are popular in CL Scale and can be used in Carrier for independent control of flaps, tailhook, or any other function a contestant can dream up. The weight of the electronic decoder itself is only slightly more for multichannel systems. Battery weight changes little for multichannel applications in Carrier; the weight of an additional servo or two is the predominant factor. Considering the weight of pushrods, bellcranks, and other mechanical actuating systems for auxiliary functions, the overall weight gain for multichannel applications might not be significant.
Batteries could substitute for wingtip weight with single-channel or multichannel systems, making the weights even more comparable.
The control systems are available from Clancy Arnold:
- Clancy Arnold
- 4006 Eagle Cove Ct., Indianapolis, IN 46254
- E-mail: [email protected]
Clancy constructed a Vought Kingfisher based on my design published in MA in the April 1984 issue. Clancy uses two channels: one for throttle and one for flaps, aileron, and line slider.
Nostalgia Carrier
It looks as though the Nostalgia Navy Carrier events are gaining in popularity. More contests are offering these classes, and more modelers are building for the events.
Joe Cservenko is assembling a Smurthwaite (Brodak) Skyraider for this season, and others have asked for rules and advice. I’m looking forward to seeing some new Nostalgia models at the Nats this summer.
The Nostalgia event is flown with the scoring system used through 1976 that places a significant advantage on high-speed performance. Historic models and non‑Schnuerle engines receive bonus points. I’ll gladly provide rules for anyone who requests them.
I hope to see many of you at the Nats this summer flying Carrier.
MA
Transcribed from original scans by AI. Minor OCR errors may remain.
