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RV-3: Going Half-Raven!

Ironflight

VAF Moderator / Line Boy
Mentor
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:

http://www.vansairforce.com/community/showthread.php?t=51286&highlight=half+Raven

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:
IMG_5985.JPG


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.
IMG_5990.JPG


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:
IMG_5991.JPG


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!

Paul
 
Finished!

So now that I finished plumbing the half-Raven system, I thought I?d post a couple of additional pictures. Tom Swearingen at TS Flightlines was able to supply us with some of that metal-jacketed, Teflon-lined, corrugated hose that bends so nice ? ?? to fit on the hose fittings for the breather. It is much lighter than the pressure-type steel-jacketed hose, thanks goodness! The routing to avoid the oil cooler made for a lot of hose, but a couple of hose clamps secured it nicely. That 45 degree ?? hose barb was not easy to find ? Summit Racing had one though:

IMG_6010.JPG


IMG_6011.JPG


The return line to the sump was easy to fabricate ? it turned out to be pretty short, as Mahlon Russel at Mattituck said that I could use the right-side sump fitting for this system without difficulty, That allowed me room to put the quick-drain for the oil on the left where I Had more clearance from the exhaust ? it all worked out great:

IMG_6001.JPG

I used the same ?? hose for the overboard drain line ? you just can?t really see it do to the snake?s nest of hoses in this tight cowling.

Note - not all of the hoses and wiring you see in these pictures are properly secured for flight....yet! there will be additional routign and retention added.

Paul
 
It looks like it fits better than I thought it would. If I switch my air oil separator out if it burps too much oil, do you think it would be possible to snake a 2" scat tube past the tank and into the cowl cheek?
 
It looks like it fits better than I thought it would. If I switch my air oil separator out if it burps too much oil, do you think it would be possible to snake a 2" scat tube past the tank and into the cowl cheek?

Yes, I think it would fit Rob - the "can" is mostly in the fuselage moldline - should be room to go in the cheek.
 
? I was holding the Accumulator idea in reserve in case I really felt it was necessary after flight testing.?

Did you end up adding an accumulator? Great post and thanks for all the detail.
 
? I was holding the Accumulator idea in reserve in case I really felt it was necessary after flight testing.?

Did you end up adding an accumulator? Great post and thanks for all the detail.

Nope - never felt it was needed. 750 hours on the airplane now.
 
Raven

I put the full Raven inverted on ours. It doesn't take up that much more space and gives unlimited inverted capability. Glad we made the extra hoses. We use motorcycle electric heated jacket and gloves for instant heat. Works well.
 
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