RV-9A, SoCal

[rightrudder]

Thanks, Bruce. A quarter-inch clearance it is, then. Thank you for the offer for Ramona, but I can't make it this Saturday. However, next year I'll be there with my own plane!!

[rightrudder]

I'm almost to the "paperclip" stage and final trimming of the baffling...after a solid seven hours of snipping, filing, measuring, taking everything apart and reassembling everything a dozen times. It feels great, though, when you can finally fit the upper cowling without interference. A test of patience to be sure.

I was going to leave the baffling in bare aluminum, but it got pretty scratched up during all the riveting and fitting, so I might go the powder coating route. Then again, the Airseal rubber will cover a lot of the scratches. I might just paint/powder coat the portions of the inlet ramps that are visible through the inlets.

I cut maybe 40 percent off the air dams in front of the cylinders, as I won't be flying in cold conditions much. If I have to remove more, I'll slide some scrap aluminum sheet between the dams and the cylinders and remove material with a cutoff wheel. Next, I need to fab a block off plate for the feed to the heat muff behind the No. 3 cylinder. The crossover muff I've got takes its air from in front of No.2.

[rightrudder]

Finally ready to start cutting patterns for the Airseal material. Baffling is final-mounted, blast tube holes drilled, everything is nicely deburred. I decided to leave the baffling as bare aluminum, as you really can't see much of it with the cowling mounted. With the inlet ramp angles, you almost have to crouch to see any of it past the rubber seals.

I probably have 50 hours into the baffling so far. Altogether a very tedious process, but rewarding when you get a nice fit. The threaded stainless rods that secure the baffles beneath the cylinders took about a half a day by themselves. I bought a trick little wire bender (made by K&S, about $25) that certainly made that part of the job easier.

I added a brace to the No. 4/oil cooler baffle, as many others have done. My approach is short and sweet...on the engine side, I mounted it directly to the cylinder fins. In the pic, you can see there's just enough space to slide a -3 metal locknut in between the fins. Getting the nut started on the bolt is yet another test of patience, but doable.

[Waterobert]

Wow, I just spend few hours reading your build story.
Doug,your work is so fast and detail oriented at the same time! If you don't mind I would love to visit your garage and see your progress or lend you helping hand. I am interested in building RV-3B in not so distant future, so seeing your build would help me greatly.
Thanks Doug.

[rightrudder]

Sure, Waterobert! I sent you a PM with my phone number. Happy to impart any insight, much as others have done for me (thanks Pete, John & Bruce )

[Vlad]

Extra cylinder cooling rib! Genius!

[rightrudder]

Originally Posted by Vlad

Extra cylinder cooling rib! Genius!

Yeah, a bit of a heat sink. Now, No. 4 will run too cool.

[Rand]

I have just read through your build thread.Everything looks great.

[rightrudder]

Baffle seals, done! Someone ought to sell a transparent upper cowling to make this process easier. I spent a ton of time fitting the "elephant ears" on the housing around the crank flange, and I'm still not 100 percent happy with the fit. I guess when I start flying, I'll see what a little heat and pressure do to make the fabric conform.

Old file folders make great stock for templates. The sides came out nice (I used 3/4" rivet spacing for the front pieces, and 1" spacing thereafter) but the rear seals had a noticeable pucker at the outboard corners. Here, I slit the fabric in a couple of places and it lays down real nice. With a flashlight poked into the left air inlet, I can just see the interface. On the right side, the No. 1 cylinder is too far forward to allow a view. Anyway, the slit "tabs" overlap a little, and the leakage is bound to be less than leaving the pucker.

After riveting the material, I squeezed some high-temp RTV between the sheet metal and fabric from the top, fitted the top cowling, and let it set up overnight. This fillet seals the air leaks, but also helps the fabric curl inward.

A couple of other pics.... I fitted my Classic Aero dash pad just for a look-see. And for anyone who's really frustrated trying to fit the rear -4 bolts and their associated clamps to the roll hoop, here's my solution to deal with that tiny space under the canopy rail. Drill a hole in the outboard portion of the clamp, and super-glue a section of piano wire in there to use as a handle. It will save you HOURS! I also tried gluing the washer and nut to the clamp---less successful, as I kept knocking it off, but once the clamp was in place I was able to get the washer on and nut started. I'm sure if you have less than XL-size hands this step will be much easier.

[rightrudder]

I'm getting close to completing the engine wiring, and no Adel clamp is safe in the workshop...it seems I've used hundreds of them, and you just never seem to have the right size. Oh well, another order to ACS for theses and a few dozen more 3A-4 bolts, which are the perfect length.

It's really a puzzle behind the engine to get everything routed cleanly, with just enough slack to account for engine waggle and enough separation to avoid chafing. I think I'm pretty much there....the only contact that I couldn't avoid is between the heater scat tube and the throttle cable. I'll do the time-honored fix of silicone and tie-wraps here so they move as a unit instead of sawing each other in half.

It took me a while to grapple with the EGT/CHT wiring and their bulky connectors. At first, I tried coiling everything up and tie-wrapping the bundle together, but it looked like a nasty bird's nest, so I cut and butt-spliced several of the wires so they would fit inside some conduit secured to the mount with...you guessed it. It's a few more minutes of work to change out a sensor, but the cleaner appearance is worth it to me.