Citabria 7KCAB Inverted Oil System

Question: What are the merits of an inverted oil system for a Citabria 7KCAB? I've heard about a Christen Inverted Oil System. The Pilots' Operating Handbook describes a system that uses the vent baffle as a sump in inverted flight with a check valve making the switch.

Answer: There isn't any reason that the 7KCAB can't use the inverted oil systems that the 150 hp Decathlons used, since the Decathlon and the 7KCAB were essentially the same firewall forward. The most common inverted oil systems found on the Decathlon are 1) a factory-designed system and 2) a retrofit of the Christen system via an STC. Either way, it would be smart to contact the American Champion Aircraft Company (800-223-9381) to see what inverted system they recommend and what paperwork exists for such an installation on the Citabria. The Christen system is probably the most popular one used in aerobatics and is of very high quality. Most of the hands-on experience with this brand is recorded in Technical Safety Tips published in Sport Aerobatics magazine which is the official publication of the International Aerobatic Club (IAC) division of EAA. Most of these have been condensed into Technical Tip Manuals in four volumes (Vol 1,2 & 3 are $10 each, Volume 4 is $15) containing many articles on the Christen system and other technical matters on Citabrias and Decathlons. To order, call EAA at 800-843-3612; you can become a member at the same time.

The Bellanca-Champion Club has also published some writings on inverted oil systems about cold weather operations. There is some danger of condensation freezing in the oil breather tube that is controlled by a ball valve for inverted flight; your oil could be dumped overboard when inverted.