It has been a long and winding road trying to figure out what we were going to use for an oil system on the RV-3 project, but it looks like we have reached the straightaway, and have figured out how to have both a somewhat inverted capability and still leave room on the firewall for a cabin heater! Our early plans had been to go with the Half-Raven system documented here:
Smoky Schreck and others have been flying this for awhile, and that?s what planted the idea in my mind. Then along came a deal too good to pass up on a complete Christen system, so we picked that up and put it on the shelf. Alas, once we began fitting all of the necessary items in to the cramped cowling of the RV-3, it became apparent that while it is POSSIBLE to put the full system there, it really wasn?t going to be PRACTICAL if we wanted a useful airplane that was also maintainable. Rob Holmes managed to squeeze the oil valve on the firewall, but had to put his heat box in the cheek cowl ? and we already other plans for that space ? so the Half-Raven (tank only) once again looked like the best option for keeping the belly clean. I was holding the Accumulator idea in reserve in case I really felt it was necessary after flight testing.
The only issue I had with the ?tank only? option was if the Raven tank would fit. Rob had gone with the Raven Air/Oil Separator, because it was smaller, but I knew that would provide less volume as an oil reservoir. In talking with Raven, they really thought I should go with the actual oil tank to make the system do what I wanted ? and they said that their tank was smaller than the Christen. After trying the Christen tank in the space available, and finding that it would JUST fit if it had to, I went ahead and ordered the Raven oil tank and sump fitting, electing to keep the new-in-the-box Christen system intact for another project (or resale). The new tank was waiting for me when we got back from a week of flying around out west, and I couldn?t be happier with the choice ? beautiful work, nice fit, and quick turn-around from Raven.
Here you can see the comparison of the two tanks (Raven on the left) ? the Raven is definitely smaller, leaving a bit more room for maintenance:
I attached the Raven tank mounting plate to the engine mount with three Adel clamps, and will see how well that works out ? I can always stiffen the mount later if required.
And here is the tank in place ? it might move up or down a little, and the fittings might or might not bey the final versions ? still have some hoses to fabricate:
Many thanks to Raven for their help in deciding on a configuration and plan, and to Smoky who first brought the idea to my attention!